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In vitro activity of tigecycline and comparators against Gram-negative pathogens isolated from blood in Europe (2004–2009)
International Journal of Antimicrobial Agents 39 (2012) 115–123
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In vitro activity of tigecycline and comparators against Gram-negative pathogens isolated from blood in Europe (2004–2009) Arjana Tambic Andrasevic a,∗ , Michael J. Dowzicky b a b
Department of Clinical Microbiology, University Hospital for Infectious Diseases, Mirogojska 8, 10000 Zagreb, Croatia Pfizer Inc., Collegeville, PA 19426, USA
a r t i c l e
i n f o
Article history: Received 7 September 2011 Accepted 20 October 2011 Keywords: Tigecycline T.E.S.T. Escherichia coli Klebsiella pneumoniae Gram-negative organisms Europe
a b s t r a c t Here we report on the antimicrobial resistance amongst Gram-negative isolates (excluding Acinetobacter spp.) collected from blood culture sources at European study sites as part of the global Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) from the study start in 2004 until August 2009. All isolates were collected and tested for minimum inhibitory concentrations using Clinical and Laboratory Standards Institute methodology. Over the collection period, extended-spectrum -lactamase (ESBL) production was recorded in 21.1% of Klebsiella pneumoniae, 2.6% of Klebsiella oxytoca and 11.3% of Escherichia coli, primarily in Croatia, Greece, Hungary, Italy, Poland, Romania and the Slovak Republic. ESBL rates stabilised amongst K. pneumoniae over 2006–2009, but doubled amongst E. coli in 2008–2009. The patterns of antimicrobial resistance changed accordingly for both organisms. Generally, Greece had the highest antimicrobial resistance for K. pneumoniae, Italy for E. coli, Serratia marcescens and Enterobacter spp., and Croatia for Pseudomonas aeruginosa. High resistance rates amongst K. pneumoniae were also seen in Croatia and Italy. Imipenem resistance amongst K. pneumoniae was reported exclusively in Greece (13.8%); amongst other Enterobacteriaceae, imipenem resistance was absent or low. Similarly, meropenem resistance was low amongst the Enterobacteriaceae except K. pneumoniae from Greece (42.6%). Across Europe, the most active antimicrobial agents against the Enterobacteriaceae were tigecycline, amikacin and the carbapenems, each with <10% resistance each year. Against the other antimicrobials, significant increases in non-susceptibility were reported for K. pneumoniae and E. coli, both important causative pathogens of bacteraemia. © 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
1. Introduction The re-emergence of Gram-negative bloodstream infections in the last decade [1–4] can be largely attributed to the escalating antimicrobial resistance amongst these pathogens (most commonly Escherichia coli, followed by Klebsiella spp., Enterobacter spp. and Pseudomonas aeruginosa) [5]. Of global importance are the extended-spectrum -lactamases (ESBLs), which hydrolyse thirdgeneration cephalosporins used widely for empirical therapy of infections caused by Enterobacteriaceae. In Europe, following a decade of outbreaks of infection with ESBL-producing Klebsiella pneumoniae, ESBL-producers are now more prevalent amongst E. coli, particularly the CTX-M family of ESBLs [6]. Carbapenems have been stable against the hydrolysing activity of ESBLs and widely used as the drug of choice for the treatment of infections caused by multiresistant Enterobacteriaceae. Consequently, carbapenem-resistant isolates of Enterobacteriaceae
∗ Corresponding author. Tel.: +385 1 28 26 642; fax: +385 1 28 26 280. E-mail address: [email protected] (A.T. Andrasevic).
and P. aeruginosa have emerged globally [7]. These isolates are usually resistant to all -lactam agents as well as most other classes of antimicrobial agents. In a recent survey of 104 isolates of carbapenemase-producing Enterobacteriaceae collected globally, the MIC90 value (minimum inhibitory concentration for 90% of the organisms) for tigecycline was 1 mg/L and no resistance was seen [7]. Tigecycline is a novel glycylcycline antimicrobial with an expanded spectrum of activity, licenced for the treatment of complicated skin and skin-structure infections, complicated intraabdominal infections and (in the USA) community-acquired bacterial pneumonia. Amongst the Gram-negative pathogens, it has activity against ESBL-producing Enterobacteriaceae but not against Pseudomonas spp. In the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.), which is a global multicentre surveillance study, the in vitro activity of tigecycline and comparators are determined against a range of clinically important bacterial pathogens. This paper will report on Gram-negative isolates (excluding Acinetobacter spp.) collected from blood culture sources at European study sites from the start of the study in 2004 until August 2009. Data relating to blood isolates of
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A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Acinetobacter spp. are excluded as they have largely been previously published [8].
Table 1 Resistance phenotypes of Gram-negative blood isolates collected across Europe between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) by year and by country (pooled 2004–2009).
2. Methods
ESBL-producing Klebsiella pneumoniae
2.1. Isolate collection Collection of isolates for T.E.S.T. began at study centres globally in 2004 and is ongoing. Centres participating in T.E.S.T. were instructed to submit in each year consecutive and clinically significant (as determined by local criteria) isolates of Streptococcus pneumoniae (15 isolates), Enterococcus spp. (15), Staphylococcus aureus (25), Streptococcus agalactiae (10), Haemophilus influenzae (15), Acinetobacter spp. (15), E. coli (25), Enterobacter spp. (25), P. aeruginosa (20), Serratia spp. (10) and Klebsiella spp. (25). A single isolate per patient was accepted and its inclusion in the study was independent of the patient’s medical history, previous antimicrobial use, sex and age. 2.2. Antimicrobial susceptibility testing Testing procedures relating to Gram-negative organisms are described briefly here. Minimum inhibitory concentrations (MICs) of a defined panel of antimicrobial agents were determined at study centres using broth microdilution methodology [Sensititre® plates (TREK Diagnostic Systems, East Grinstead, UK) or MicroScan® panels (Siemens, Sacramento, CA)] according to guidelines published by the Clinical and Laboratory Standards Institute (CLSI) [9]. Gram-negative isolates were tested against amikacin, amoxicillin/clavulanic acid (AMC), ampicillin, cefepime, ceftazidime, ceftriaxone, imipenem, levofloxacin, meropenem, minocycline, piperacillin/tazobactam (TZP) and tigecycline. In 2006, unreliability of the imipenem testing led to a switch from MicroScan panels with imipenem to Sensititre plates with meropenem. Quality control strains used in the testing were E. coli ATCC 25922 and P. aeruginosa ATCC 27853. CLSI interpretive criteria to determine antimicrobial susceptibility were recently revised for the Enterobacteriaceae against select cephalosporins and carbapenems based upon pharmacokinetic/pharmacodynamic analyses [10,11] and these revised criteria were applied in this report; for tigecycline, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) approved breakpoints were used [12]. Isolates of E. coli and Klebsiella spp. were tested for ESBL production according to CLSI guidelines [9] using Mueller–Hinton agar (Remel Inc., Lenexa, KS) and disks with cefotaxime (30 mg/L), cefotaxime/clavulanic acid (30/10 mg/L), ceftazidime (30 mg/L) and ceftazidime/clavulanic acid (30/10 mg/L) (Oxoid Inc., Ogdensburg, NY). Standard strains of ESBL-positive K. pneumoniae ATCC 700603 and ESBL-negative E. coli ATCC 25922 and P. aeruginosa ATCC 27853 were used for quality control of the ceftazidime and cefotaxime disks. Confirmation of isolate identification and management of a centralised database were performed by a central laboratory [Laboratories International for Microbiology Studies, a division of International Health Management Associates, Inc. (IHMA), Schaumburg, IL]. This report includes all Gram-negative pathogens (except Acinetobacter spp.) with a culture source of blood submitted between the start of T.E.S.T. in 2004 and August 2009 in Europe. 3. Results A total of 8509 Gram-negative isolates (excluding Acinetobacter spp.) were cultured from blood at 181 European centres participating in T.E.S.T. between 2004 and 2009. Approximately one-half
Year 2004 2005 2006 2007 2008 2009 All years Country Austria Belgium Bulgaria Croatia Czech Republic Denmark Finland France Germany Greece Hungary Ireland Italy Latvia Lithuania Poland Portugal Romania Slovak Republic Slovenia Spain Sweden Switzerland The Netherlands UK Europe
ESBL-producing Escherichia coli
N
%a
N
%a
25/163 7/107 25/127 72/322 132/495 97/480 358/1694
15.3 6.5 19.7 22.4 26.7 20.2 21.1
17/221 14/194 13/298 39/518 125/842 115/791 323/2864
7.7 7.2 4.4 7.5 14.8 14.5 11.3
1/8 11/73 2/5 52/112 9/32 10/88 0/9 27/246 8/88 25/76 10/22 7/59 91/268 2/4 3/3 14/28 7/30 15/35 8/17 4/22 42/324 1/48 0/26 1/9 8/62 358/1694
– 15.1 – 46.4 28.1 11.4 – 11.0 9.1 32.9 45.5 11.9 34.0 – – 50.0 23.3 42.9 47.1 18.2 13.0 2.1 0.0 – 12.9 21.1
1/14 8/191 1/8 3/112 0/40 5/155 0/9 35/493 19/184 10/93 6/24 8/101 131/500 3/10 1/28 4/40 3/40 13/46 4/17 2/43 49/440 4/78 2/70 0/16 11/112 323/2864
7.1 4.2 – 2.7 0.0 3.2 – 7.1 10.3 10.8 25.0 7.9 26.2 – 3.6 10.0 7.5 28.3 23.5 4.7 11.1 5.1 2.9 0.0 9.8 11.3
ESBL, extended-spectrum -lactamase. a Percentage not calculated when denominator is ≤10 isolates.
of the isolates were collected from France, Italy and Spain. For each of the eight species included in this report, countries with ≤50 isolates were not considered individually, although their data were included in the pooled analysis for Europe. Amongst the 25 participating countries, 12 (Belgium, Croatia, Denmark, France, Germany, Greece, Ireland, Italy, Spain, Sweden, Switzerland and the UK) contributed >50 isolates of at least one species; their data were also analysed accordingly by country. In all data tables in this report, percentage values are not shown where the data relate to the pooled analysis and the denominator is ≤20 isolates, or where the data relate to individual countries and the denominator is ≤10 isolates. Data are also not tabulated for antimicrobials against which an organism is considered to be intrinsically resistant, nor are they discussed.
3.1. Klebsiella pneumoniae Over the collection period (2004–2009), 21.1% of K. pneumoniae isolates in Europe were ESBL-producers (Table 1), with rates at least double this overall value in Croatia, Hungary, Poland, Romania and the Slovak Republic (Table 1). No ESBL-producing K. pneumoniae were collected in Switzerland or Finland; the lowest rate was otherwise reported for Sweden (2.1%). Following a dip at 6.5% in 2005, the rates for Europe remained within a 7% range over the last 4 years (19.7–26.7%) (Table 1).
Table 2 In vitro resistance of Gram-negative blood isolates collected across Europe between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial. (T.E.S.T.) Species/antimicrobiala
2004 MIC90 b
d
2006 %R
N = 107 (96/11) 4 0.0 16 9.3 1 4.7 16 10.3 16 12.1 0.5 1.0 4 8.4 – – 16 14.0 32 7.5 1 1.9 N = 25 (24/1) 4 0.0 32 12.0 1 0.0 ≤8 4.0 4 12.0 0.5 0.0 0.25 0.0 – – 2 0.0 ≥256 20.0 0.5 0.0 N = 194 (188/6) 4 1.0 16 9.8 ≥64 55.7 ≤0.5 4.6 ≤8 6.2 0.5 8.8 0.5 0.0 ≥16 16.0 – – 8 5.7 16 4.1 0.25 0.0 N = 87 (85/2) 2 1.1 8 2.3 ≥64 49.4 ≥128 52.9 1 1.2 ≥16 12.6 – – 8 9.2 128 14.9 2 5.7 N = 17 (16/1) 8 0.0 4 0.0 ≥64 47.1 32 47.1 – –
MIC90
2007 %R
N = 127 (103/24) 8 3.9 ≥64 24.4 32 11.8 ≥64 26.8 ≥128 26.8 0.5 2.9 ≥16 18.1 1 8.3 16 11.8 ≥256 22.0 2 3.9 N = 48 (41/7) 2 0.0 16 6.3 1 2.1 ≤8 2.1 8 12.5 0.25 0.0 0.5 6.3 – – 4 2.1 32 8.3 1 4.2 N = 298 (258/40) 4 0.7 32 10.1 ≥64 60.1 1 2.7 ≤8 2.7 0.5 6.7 0.25 0.0 ≥16 23.8 ≤0.06 0.0 16 11.7 8 2.7 0.25 0.0 N = 140 (113/27) 4 0.7 16 7.9 ≥64 35.7 ≥128 41.4 1 1.8 8 11.4 0.12 7.4 8 7.1 ≥256 22.1 2 7.1 N = 34 (31/3) 4 0.0 1 0.0 ≥64 29.4 16 29.4 0.5 0.0
MIC90
2008 %R
N = 322 (17/305) 8 1.2 32 17.7 ≥64 18.3 ≥64 25.2 ≥128 28.3 – – ≥16 17.7 0.25 2.0 16 17.4 128 13.0 2 4.7 N = 101 (8/93) 4 0.0 32 13.9 2 1.0 ≤8 6.9 8 16.8 – – 2 6.9 0.12 0.0 8 2.0 ≥256 13.9 1 2.0 N = 518 (35/483) 8 0.4 32 10.8 ≥64 59.1 4 7.3 ≤8 6.4 32 11.0 ≤0.06 0.0 ≥16 22.6 ≤0.06 0.0 16 12.0 8 2.7 0.5 0.0 N = 238 (11/227) 4 0.0 8 3.8 ≥64 31.9 ≥128 37.4 – – 8 10.9 0.25 0.4 8 8.4 128 18.9 2 2.5 N = 55 (3/52) 8 1.8 2 1.8 16 10.9 4 20.0 – –
MIC90
2009 %R
N = 495 (0/495) 16 5.5 32 26.5 ≥64 21.4 ≥64 29.1 ≥128 34.5 – – ≥16 23.0 0.25 2.4 ≥32 30.5 ≥256 21.8 2 4.6 N = 112 (0/112) 4 0.0 32 14.3 4 2.7 ≤8 8.9 16 21.4 – – 4 8.0 0.12 0.9 16 11.6 ≥256 24.1 1 3.6 N = 842 (0/842) 8 1.8 32 15.2 ≥64 65.6 16 9.3 16 12.9 ≥128 21.4 – – ≥16 32.3 ≤0.06 0.8 16 16.3 32 6.8 0.5 0.0 N = 388 (0/388) 8 4.4 8 5.7 ≥64 37.9 ≥128 41.5 – – ≥16 16.5 0.25 3.9 16 14.2 ≥256 19.6 2 4.1 N = 97 (0/97) 8 2.1 32 10.3 ≥64 36.1 64 47.4 – –
MIC90
2004–2009 %R
N = 480 (0/480) 8 2.5 32 22.9 ≥64 17.9 ≥64 24.8 ≥128 30.4 – – ≥16 19.6 0.12 2.5 ≥32 22.1 ≥256 17.9 2 3.8 N = 102 (0/102) 4 1.0 16 9.8 4 2.9 ≤8 4.9 32 20.6 – – 4 8.8 ≤0.06 1.0 8 8.8 ≥256 17.6 1 2.9 N = 791 (0/791) 8 0.4 32 14.9 ≥64 67.1 32 11.1 16 11.1 ≥128 21.5 – – ≥16 32.2 ≤0.06 0.4 16 20.5 32 5.4 0.5 0.0 N = 351 (0/351) 4 3.7 16 9.1 ≥64 35.3 ≥128 46.2 – – ≥16 14.8 0.25 1.4 16 19.7 ≥256 21.7 2 4.6 N = 91 (0/91) 4 0.0 1 0.0 32 25.3 16 29.7 – –
MIC90
%R
N = 1694 (369/1325) 8 2.9 32 20.9 ≥64 16.7 ≥64 24.6 ≥128 28.7 0.5 1.1 ≥16 18.1 0.25 2.4 ≥32 21.7 ≥256 16.8 2 4.4 N = 454 (131/323) 4 0.2 32 11.7 2 2.4 ≤8 6.4 16 17.4 0.5 0.0 2 7.0 0.12 0.6 8 5.5 ≥256 16.5 1 2.6 N = 2864 (700/2164) 8 0.8 32 13.1 ≥64 63.1 8 7.9 ≤8 9.1 64 16.3 0.5 0.0 ≥16 27.5 ≤0.06 0.5 16 14.7 16 4.6 0.5 0.0 N = 1333 (331/1002) 4 2.4 8 6.0 ≥64 36.5 ≥128 41.9 1 1.2 8 13.1 0.25 2.3 16 12.6 ≥256 19.5 2 4.3 N = 326 (81/245) 8 1.2 4 4.3 ≥64 29.1 32 35.0 1 0.0
117
N = 163 (153/10) 8 0.6 16 9.2 8 7.4 ≥64 16.6 32 19.0 0.5 0.0 4 6.1 – – 16 14.7 16 7.4 2 6.7 N = 66 (58/8) 4 0.0 32 10.6 2 4.5 ≤8 7.6 8 12.1 0.5 0.0 1 6.1 – – 0.0 4 10.6 ≥256 1.5 1 N = 221 (219/2) 4 0.0 32 10.4 ≥64 58.8 1 2.7 ≤8 5.0 4 10.4 0.5 0.0 ≥16 19.5 – – 8 6.3 4 1.4 0.25 0.0 N = 129 (122/7) 4 0.0 4 3.1 ≥64 36.4 64 33.3 1 0.8 2 4.7 – – 8 4.7 128 14.7 1 3.1 N = 32 (31/1) 16 3.1 16 9.4 ≥64 40.6 64 37.5 1 0.0
MIC90
A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Klebsiella pneumoniae Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Klebsiella oxytoca Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Escherichia coli Amikacin AMC Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter cloacae Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter aerogenes Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem
2005 %Rc
118
Table 2 (Continued) Species/antimicrobiala
2004 MIC90
c
%R
≥16 34.4 – – 16 12.5 128 12.5 1 0.0 N = 70 (68/2) 4 1.4 1 1.4 ≤8 5.7 16 17.1 1 1.5 1 2.9 – – 8 2.9 8 2.9 1 4.3 N = 116 (116/0) 8 3.4 16 6.0 16 6.9 8 6.9 ≥16 23.3 – – 64 7.8 N = 11 (11/0) 16 – 0.5 – ≤0.5 – ≤0.5 – ≤0.06 – 1 – – 0.015 – – 1 – ≤0.06 – – 0.12
MIC90 ≥16 – 8 64 1 N = 33 (31/2) 4 1 ≤8 16 2 1 – 4 32 1 N = 71 (69/2) 16 32 32 16 ≥16 – 128 N=5 – – – – – – – – – – –
2006 %R 47.1 – 5.9 5.9 5.9 0.0 3.0 3.0 24.2 0.0 0.0 – 3.0 9.1 6.1 4.2 11.3 15.5 10.1 36.6 – 12.7 – – – – – – – – – – –
MIC90
2007 %R
8 11.8 – – 4 5.9 64 5.9 1 2.9 N = 52 (40/12) 8 1.9 1 1.9 ≤8 9.6 16 25.0 1 2.5 2 3.8 – – 8 3.8 64 3.8 2 5.8 N = 96 (76/20) 16 6.3 32 14.6 ≥64 16.7 8 5.3 ≥16 22.9 – – 128 11.5 N = 10 (5/5) 8 – 0.5 – 32 – ≤0.5 – 0.25 – – – – 0.03 – – 2 – 0.25 – – 0.25
MIC90
2008 %R
8 10.9 1.9 0.25 8 3.6 16 1.8 1 1.8 N = 89 (4/85) 4 1.1 ≤0.5 2.2 ≤8 4.5 2 9.0 – – 1 4.5 2.4 0.12 8 4.5 4 2.2 2 1.1 N = 205 (23/182) 16 4.9 32 12.7 32 13.2 8 8.7 ≥16 28.3 16 10.4 128 10.2 N = 12 (0/12) 16 – 1 – 16 – ≤0.5 – ≤0.06 – – – 0.03 – 0.12 – ≤0.5 – ≤0.06 – – 0.12
MIC90
2009 %R
≥16 22.7 0.5 4.1 16 12.4 128 15.5 2 1.0 N = 171 (0/171) 8 2.3 1 4.7 ≤8 4.1 16 15.8 – – 1 1.8 1.8 0.25 8 8.8 16 2.9 2 2.3 N = 338 (0/338) 64 11.5 32 14.8 ≥64 25.4 – – ≥16 40.2 ≥32 20.7 ≥256 22.5 N = 42 (0/42) 8 – 1 0.0 ≥64 23.8 ≤0.5 – ≤0.06 – – – 0.03 – 0.12 – 2 2.4 ≤0.06 0.0 0.25 –
MIC90 , minimum inhibitory concentration for 90% of the organisms; %R, percent resistant; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam. a Antimicrobials with no intrinsic activity against the organism are excluded. b MIC90 values in mg/L; MIC90 values not given when N < 10. c Percent resistance is not shown when N ≤ 20. d Values in brackets refer to the number of isolates tested against imipenem and meropenem, respectively (not given where N < 10).
MIC90
2004–2009 %R
1 6.6 0.12 1.1 8 6.6 64 4.4 1 2.2 N = 171 (0/171) 4 1.2 1 2.3 ≤8 7.0 8 14.0 – – 2 1.2 0.12 0.0 16 15.2 16 4.1 2 3.5 N = 322 (0/322) 32 9.9 32 14.3 ≥64 23.6 – – ≥16 28.6 16 15.2 ≥256 16.5 N = 24 (0/24) 8 – 2 0.0 4 12.5 ≤0.5 – ≤0.06 – – – 0.015 – ≤0.06 – 2 0.0 ≤0.06 0.0 0.25 –
MIC90
%R
≥16 17.5 0.25 2.9 8 8.3 64 8.3 1 1.8 N = 586 (143/443) 8 1.5 1 2.9 ≤8 5.6 16 15.7 1 1.4 1 2.2 0.12 1.1 8 8.5 16 3.6 2 3.2 N = 1148 (284/864) 32 8.2 32 13.2 ≥64 19.5 8 7.4 ≥16 31.4 16 17.0 128 15.6 N = 104 (20/84) 8 – 1 0.0 32 17.3 ≤0.5 – ≤0.06 – 1 – 0.03 – 0.12 – 2 1.9 ≤0.06 0.0 0.25 –
A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Levofloxacin Meropenem Minocycline TZP Tigecycline Serratia marcescens Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Pseudomonas aeruginosa Amikacin Cefepime Ceftazidime Imipenem Levofloxacin Meropenem TZP Haemophilus influenzae Amikacin AMC Ampicillin Cefepime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline
2005 b
Table 3a In vitro resistance of Gram-negative blood isolates collected between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) (data pooled for all years) by country. Species/antimicrobiala,b
Croatia
Denmark
MIC90 c,d
0.9 43.8 38.4 47.3 52.7 – 41.1 1.8 51.8 33.9 3.6 – – – – – – – – – – – 0.0 20.5 62.5 3.6 10.7 11.6 – 25.0 0.9 26.8 6.3 0.0 – – – – – – – – – – – – – – –
France %R
N = 88 (22/66) 2 0.0 16 5.7 4 5.7 ≤8 6.8 64 11.4 0.25 0.0 2 3.4 ≤0.06 0.0 8 5.7 8 1.1 2 9.1 N = 42 – – – – – – – – – – – – – – – – – – – – – – N = 155 (60/95) 4 0.0 16 4.5 ≥64 51.6 ≤0.5 2.6 ≤8 1.3 ≤0.06 3.9 0.25 0.0 4 7.1 ≤0.06 0.0 8 5.8 2 0.6 0.5 0.0 N = 97 (38/59) 2 0.0 1 0.0 32 16.5 16 20.6 0.25 0.0 0.25 0.0 0.12 0.0 4 2.1 64 6.2 1 1.0 N = 14 – – – – – – – – – –
MIC90
Germany %R
N = 246 (63/183) 4 0.8 32 11.0 8 8.5 16 13.0 ≥128 13.0 0.5 0.0 4 9.8 ≤0.06 0.0 ≥32 16.3 32 7.3 1 2.8 N = 106 (24/82) 4 0.0 16 7.5 1 0.9 ≤8 2.8 2 9.4 0.5 0.0 0.25 5.7 0.12 0.0 4 1.9 ≥256 12.3 1 0.0 N = 493 (128/365) 4 0.4 32 11.2 ≥64 56.6 1 4.1 ≤8 4.5 0.5 9.3 0.25 0.0 8 13.8 ≤0.06 0.0 8 9.5 8 2.4 0.5 0.0 N = 249 (63/186) 4 0.8 8 5.2 ≥64 34.5 ≥128 41.8 1 1.6 ≥16 15.3 0.25 0.5 16 11.2 ≥256 16.1 2 2.4 N = 66 (17/49) 8 0.0 1 3.0 ≥64 34.8 16 36.4 1 0.0
MIC90
Italy %R
N = 88 (14/74) 2 0.0 32 12.5 8 6.8 ≤8 9.1 ≥128 11.4 0.5 0.0 8 11.4 ≤0.06 1.4 16 20.5 32 6.8 2 5.7 N = 30 – – – – – – – – – – – – – – – – – – – – – – N = 184 (38/146) 8 0.5 32 10.9 ≥64 63.6 16 9.2 ≤8 9.8 ≥128 17.9 0.25 0.0 ≥16 33.2 ≤0.06 1.4 16 16.8 16 3.8 0.5 0.0 N = 93 (16/77) 2 1.1 4 0.0 ≥64 32.3 ≥128 39.8 1 0.0 1 7.5 0.25 1.3 8 8.6 128 14.0 1 4.3 N = 16 – – – – – – – – – –
MIC90
Spain %R
N = 268 (63/205) 64 11.2 32 23.9 ≥64 25.7 ≥64 38.1 ≥128 39.9 1 0.0 ≥16 29.5 1 0.5 ≥32 28.4 ≥256 23.9 2 6.0 N = 61 (19/42) 4 0.0 32 11.5 2 0.0 32 13.1 8 27.9 0.5 0.0 1 4.9 0.25 0.0 8 4.9 ≥256 23.0 1 4.9 N = 500 (134/366) 8 2.8 32 19.2 ≥64 72.8 ≥64 19.0 32 21.6 ≥128 33.4 0.5 0.0 ≥16 49.4 ≤0.06 1.1 ≥32 19.8 64 8.4 0.5 0.0 N = 249 (62/187) 8 3.6 32 10.0 ≥64 53.8 ≥128 57.8 1 0.0 ≥16 24.1 1 3.7 16 14.5 ≥256 35.3 2 8.4 N = 64 (19/45) 16 4.7 32 17.2 ≥64 54.7 ≥128 64.1 1 0.0
MIC90
UK %R
N = 324 (55/269) 4 0.3 32 16.0 8 6.8 16 10.2 32 17.3 1 0.0 8 10.8 0.12 1.9 ≥32 17.0 128 11.1 1 1.9 N = 73 (19/54) 4 0.0 32 16.4 4 6.8 16 11.0 32 19.2 0.5 0.0 8 12.3 0.25 1.9 16 13.7 ≥256 19.2 1 5.5 N = 440 (73/367) 4 0.5 32 14.3 ≥64 71.8 4 4.3 ≤8 8.2 32 15.2 0.5 0.0 ≥16 29.3 ≤0.06 0.0 16 14.1 16 4.1 0.5 0.0 N = 257 (57/200) 4 0.8 4 5.1 ≥64 29.6 64 33.1 2 3.5 8 10.5 0.25 2.5 16 10.9 128 12.1 1 2.7 N = 76 (9/67) 4 0.0 1 0.0 32 18.4 16 25.0 – –
MIC90
%R
N = 62 (23/39) 2 0.0 16 6.5 16 9.7 16 11.3 ≥128 24.2 0.5 0.0 4 4.8 ≤0.06 0.0 8 8.1 128 11.3 1 1.6 N = 30 – – – – – – – – – – – – – – – – – – – – – – N = 112 (54/58) 8 0.0 16 9.8 ≥64 67.0 8 8.9 ≤8 9.8 ≥128 18.8 0.5 0.0 ≥16 33.0 ≤0.06 0.0 16 15.2 32 1.8 0.25 0.0 N = 52 (20/32) 2 0.0 4 1.9 32 19.2 32 32.7 0.5 0.0 1 1.9 ≤0.06 0.0 8 5.8 64 5.8 1 1.9 N=9 – – – – – – – – – –
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N = 112 (0/112) 8 32 ≥64 ≥64 ≥128 – ≥16 0.12 ≥32 ≥256 2 N=6 – – – – – – – – – – – N = 112 (0/112) 8 32 ≥64 1 16 8 – ≥16 ≤0.06 ≥32 32 0.5 N = 44 – – – – – – – – – – N=7 – – – – –
e
MIC90
A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Klebsiella pneumoniae Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Klebsiella oxytoca Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Escherichia coli Amikacin AMC Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter cloacae Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter aerogenes Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem
%Rd
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Table 3a (Continued)
MIC90 Levofloxacin Meropenem Minocycline TZP Tigecycline Serratia marcescens Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Pseudomonas aeruginosa Amikacin Cefepime Ceftazidime Imipenem Levofloxacin Meropenem TZP
Denmark
Croatia c,d
– – – – – N = 13 – – – – – – – – – – N = 86 (0/86) ≥128 32 ≥64 – ≥16 ≥32 ≥256
d
%R – – – – – – – – – – – – – – –
27.9 29.1 39.5 – 44.2 32.6 32.6
France
Germany %R
MIC90
%R
MIC90
– – – – – N = 19 – – – – – – – – – – N = 58 (25/33) 4 8 ≤8 4 4 2 16
– – – – –
≥16 19.7 2.0 0.12 8 7.6 64 7.6 1 1.5 N = 108 (20/88) 4 0.0 0.0 ≤0.5 ≤8 4.6 16 13.0 0.5 0.0 2 0.9 0.12 0.0 7.4 8 8 0.9 2 1.9 N = 165 (39/126) 16 4.2 16 9.1 32 13.9 2 5.1 ≥16 30.3 8 4.8 128 12.7
– – – – – – – – – – 0.0 1.7 1.7 0.0 8.6 3.0 0.0
MIC90
Italy %R
– – – – – – – – – – N = 40 – – – – – – – – – – – – – – – – – – – – N = 58 (10/48) 8 0.0 16 3.4 16 6.9 16 20.0 ≥16 27.6 4 6.3 128 10.3
MIC90
Spain %R
≥16 31.3 2 8.9 8 9.4 ≥256 25.0 1 0.0 N = 102 (29/73) 8 0.0 2 2.9 16 10.8 32 15.7 2 3.4 1 1.0 0.12 1.4 8 5.9 16 4.9 2 3.9 N = 250 (44/206) 32 5.6 32 16.0 ≥64 26.4 8 9.1 ≥16 38.8 ≥32 22.3 ≥256 18.8
MIC90 , minimum inhibitory concentration for 90% of the organisms; %R, percent resistant; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam. a For each species, data shown only where the country has contributed a total of >50 isolates over the 6 years of collection. b Antimicrobials with no intrinsic activity against the organism are excluded. c MIC90 in mg/L. d – Data not available because of low numbers of isolates. e Values in brackets refer to the number of isolates tested against imipenem and meropenem, respectively (not given where N < 50).
MIC90
UK %R
0.25 3.9 0.12 0.0 4 3.9 0.0 64 1 1.3 N = 121 (23/98) 4 0.0 ≤0.5 0.8 ≤8 3.3 1 5.0 1 0.0 0.5 0.0 0.25 0.0 8 6.6 8 0.8 2 0.8 N = 213 (62/151) 16 8.0 16 8.9 ≥64 19.7 8 4.8 ≥16 34.7 16 18.5 128 14.1
MIC90
%R
– – – – – N = 29 – – – – – – – – – – N = 53 (26/27) 4 8 16 2 4 8 32
– – – – – – – – – – – – – – – 0.0 1.9 5.7 3.8 7.5 3.7 5.7
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Species/antimicrobiala,b
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A significant increase in non-susceptibility rates was seen over the collection period for all antimicrobials tested (Cochran–Armitage trend test, P < 0.01; data not shown), except for tigecycline and the carbapenems for which the overall resistance rates across Europe remained <10% (Table 2). Resistance rates were also <10% for amikacin, although non-susceptibility increased significantly (P < 0.01) over the collection period. For AMC, ceftazidime, ceftriaxone and TZP, an increase of ca. 15% in resistance was noted between 2005 and 2006. Over the collection period, Greece had the highest rates of resistance for eight of the antimicrobial agents (AMC, ceftazidime, ceftriaxone, imipenem, levofloxacin, meropenem, TZP and tigecycline) (Tables 3a and 3b). Imipenem resistance was reported exclusively in Greece [13.8% (4/29) over the collection period], with a MIC90 of 4 mg/L. Meropenem-resistant isolates were collected from Greece in each study year between 2006 and 2009 [20 isolates (42.6% of total)]; meropenem-resistant isolates were also collected from Croatia [2 (1.8% of total)], Germany (1; 1.4%), Italy (1; 0.5%) and Spain (5; 1.9%), all in 2008. The meropenem MIC90 value for the collection period was high for Greece (≥32 mg/L) but remained at or below the susceptibility breakpoint (1 mg/L) for the other four countries. Three further resistant isolates (making a total of 32) were collected from Slovenia (one isolate collected in 2008) and Portugal (two isolates collected in 2009); both are countries that contributed ≤50 K. pneumoniae isolates. Notably, high resistance rates were also seen for Croatia and Italy for most of the antimicrobials, particularly the -lactams. Low levels (<10%) of tigecycline resistance were reported from each of the 12 countries. 3.2. Klebsiella oxytoca Low numbers of K. oxytoca were collected; of a total of 454 isolates, 12 (2.6%) were ESBL-producers from five countries (Denmark, France, Germany, Italy and Spain; data not shown). By year, the highest rate of ESBL production (4.5%) across Europe was recorded in both 2004 and 2008. A significant increase in the rates of non-susceptibility over the collection period was detected for AMC, minocycline and TZP (P < 0.05; data not shown) and an increasing trend was detected in resistance rates to ceftriaxone and levofloxacin (Table 2). Resistance to AMC, ceftazidime, ceftriaxone, minocycline and TZP peaked in 2008. Resistance rates remained low (<5%) each year for amikacin, cefepime, tigecycline and the carbapenems; MIC90 values of ≤1 mg/L were recorded for tigecycline and the carbapenems. Two isolates (one from Spain in 2008 and the other from Greece in 2009) were resistant to meropenem; no imipenem resistance was seen. Only three countries (France, Italy and Spain) contributed sufficient isolates for their data to be analysed separately for K. oxytoca (Table 3a). For most antimicrobials, the highest rate of resistance amongst these three countries occurred in Spain. 3.3. Escherichia coli An apparent doubling in the rates of ESBL-producing E. coli collected across Europe was observed in 2008 and 2009 compared with earlier years (Table 1). By country, the highest rates (23.5–28.3%) were recorded for Hungary, Italy, Romania and the Slovak Republic. No ESBL-producing E. coli were collected from the Czech Republic, Finland or The Netherlands. With the exception of amikacin, tigecycline and the carbapenems, a significant increase in the rates of non-susceptibility over the collection period was detected for all antimicrobials tested (P < 0.001; data not shown) (ceftazidime was not included in this analysis). Resistance rates were highest amongst E. coli isolates collected in 2008 or 2009; these were markedly increased
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from previous years for ceftriaxone and levofloxacin (Table 2). Escherichia coli remained largely susceptible (<10% resistance in each year) to amikacin, meropenem and TZP and totally susceptible to tigecycline and imipenem (data for imipenem available from 2004–2007 only). A single isolate with intermediate resistance to imipenem was collected in France in 2005. A total of 10 isolates were meropenem-resistant (in 2008: Croatia, 1; Ireland, 1; Italy, 4; Slovenia, 1; and in 2009: Belgium, 1; Germany, 2). MIC90 values remained at ≤1 mg/L in all cases for tigecycline and the carbapenems. Italy had the highest resistance rates for 2004–2009 for amikacin, ampicillin, cefepime, ceftazidime, ceftriaxone and levofloxacin (Tables 3a and 3b). The lowest resistance rates amongst most antimicrobials were found in Sweden, Denmark and Switzerland. 3.4. Enterobacter cloacae A total of 1333 isolates of E. cloacae were collected during 2004–2009, largely from six countries (Table 3a). The rates of non-susceptibility increased significantly over the collection period for amikacin, cefepime, levofloxacin and minocycline (P < 0.01; data not shown). Four imipenem-resistant isolates were collected: France, one in 2006; Spain, one in 2004 and one in 2005; and Ireland, one in 2006. The MIC90 values remained at ≤1 mg/L except for Spain (2 mg/L). MIC90 values also remained at ≤1 mg/L for meropenem, although there was a total of 23 meropenem-resistant isolates: Croatia, 2 in 2008; France, 1 in 2008; Germany, 1 in 2008; Greece, 1 in 2006 and 3 in 2008; Ireland, 1 in 2008; Italy, 1 in each in 2006 and 2007, 2 in 2008 and 3 in 2009; Poland, 2 in 2009; and Spain, 5 in 2008. Low (<10%) resistance rates were recorded for amikacin, cefepime, tigecycline, meropenem and imipenem (data for 2004–2007 only) in each year (Table 2). The lowest rates were recorded for Denmark, followed by the UK, Germany and Spain (Table 3a). With few exceptions, Italy had the highest resistance rate for each antimicrobial agent, both over the collection period and for individual years. 3.5. Enterobacter aerogenes Almost two-thirds of the 326 isolates of E. aerogenes were collected from France, Italy and Spain. Italy had markedly higher resistance rates than France and Spain for all antimicrobials except tigecycline (Table 3a). Low resistance rates (<10%) were recorded for amikacin, tigecycline and the carbapenems in each year (Table 2). No imipenem resistance was seen. Seven isolates were meropenem-resistant: France, one in 2009; Greece, one in 2008; Italy, one in each in 2004 and 2007 and two in 2008; and Slovenia, one in 2008. Meropenem MIC90 values over 2004–2009 were ≤1 mg/L in all countries except for Italy (2 mg/L). Enterobacter aerogenes showed a significant decrease in non-susceptibility to levofloxacin (P < 0.001; data not shown); no trends in antimicrobial resistance rates were otherwise detected as the data for this species were largely variable. 3.6. Serratia marcescens Of a total of 586 isolates of S. marcescens, over one-half were collected from France, Italy and Spain. This organism remained largely susceptible to the antimicrobial panel, with ceftriaxone as the least effective antimicrobial in vitro in terms of both susceptibility and MIC90 values (Tables 2 and 3a). Two isolates were imipenemresistant: one from Italy in 2006 and the other from Germany in 2004. Five meropenem-resistant isolates were collected: Germany and Greece, one each in 2007; and Hungary, Italy and Portugal, one each in 2008. Non-susceptibility increased significantly for
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Table 3b In vitro resistance of Gram-negative blood isolates collected between 2004 and 2009 (data pooled for all years) by country. Species/antimicrobiala,b
Belgium MIC90 c,d
Klebsiella pneumoniae Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Escherichia coli Amikacin AMC Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline
Greece %Rd
N = 73 (19/54)e 4 0.0 32 11.0 32 11.0 16 11.0 32 17.8 1 0.0 1 4.1 ≤0.06 0.0 16 13.7 32 8.2 2 2.7 N = 191 (41/150) 8 0.0 15.2 32 ≥64 64.9 3.1 ≤0.5 ≤8 3.7 5.2 0.5 0.5 0.0 ≥16 20.4 ≤0.06 0.7 16 13.6 32 8.9 1 0.0
MIC90 N = 76 (29/47) 32 ≥64 ≥64 ≥64 ≥128 4 ≥16 ≥32 ≥32 ≥256 2 N = 93 (31/62) 4 16 ≥64 4 ≤8 8 0.25 ≥16 ≤0.06 16 8 0.25
Ireland %R 9.2 55.3 34.2 69.7 75.0 13.8 44.7 42.6 21.1 53.9 9.2 0.0 7.5 51.6 5.4 9.7 10.8 0.0 16.1 0.0 16.1 1.1 0.0
MIC90
Sweden %R
N = 59 (29/30) 8 1.7 32 10.2 4 5.1 32 13.6 8 20.3 0.5 0.0 4 8.5 1 0.0 ≥32 28.8 128 10.2 2 8.5 N = 101 (33/68) 4 0.0 32 12.9 ≥64 69.3 4 3.0 ≤8 3.0 32 16.8 0.25 0.0 ≥16 29.7 0.12 1.5 16 10.9 16 5.9 1 0.0
MIC90
Switzerland %R
N = 48 – – – – – – – – – – – – – – – – – – – – – – N = 78 (30/48) 4 0.0 16 2.6 ≥64 38.5 ≤0.5 1.3 ≤8 1.3 0.12 5.1 0.25 0.0 8 12.8 ≤0.06 0.0 8 3.8 2 1.3 0.25 0.0
MIC90
%R
N = 26 – – – – – – – – – – – – – – – – – – – – – – N = 70 (36/34) 4 0.0 16 8.6 ≥64 45.7 ≤0.5 2.9 ≤8 1.4 0.12 2.9 0.25 0.0 ≥16 20.0 ≤0.06 0.0 8 8.6 8 1.4 0.25 0.0
MIC90 , minimum inhibitory concentration for 90% of the organisms; %R, percent resistant; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam. a For each species, data shown only where the country has contributed a total of >50 isolates over the 6 years of collection. b Antimicrobials with no intrinsic activity against the organism are excluded. c MIC90 in mg/L. d – Data not available because of low numbers of isolates. e Values in brackets refer to the number of isolates tested against imipenem and meropenem, respectively (not given where N < 50).
minocycline and tigecycline (P < 0.001), although the increase in resistance was consistent for minocycline only.
3.7. Pseudomonas aeruginosa Over the collection period, a significant increase in nonsusceptibility rates was recorded across Europe for amikacin, cefepime, ceftazidime and TZP (P < 0.05; data not shown). Resistance rates were highest in 2008 (Table 2). The lowest resistance rates recorded for 2004–2009 across Europe were those to amikacin (8.2%) and imipenem (7.4%). Croatia had the highest resistance rates to all antimicrobials tested for 2004–2009 and for 2008 (Table 3a). High resistance rates were also documented for Italy and Spain, with Italy having the highest rates for all antimicrobials in 2006. Isolates from Germany had a high rate of resistance to imipenem (20%); however, the number of P. aeruginosa isolates (n = 10) tested against imipenem was lower than for other countries. Tigecycline showed reduced activity against P. aeruginosa, with a MIC90 of 16 mg/L across Europe during this study.
3.8. Haemophilus influenzae The rate of -lactamase-producing H. influenzae was 17.3% for the collection period, peaking in 2008 at 23.8% (data not shown). Pooled analysis of antimicrobial susceptibility was limited as there were fewer than 20 isolates each year except for 2008 and 2009 (Table 2). Over 2004–2009, H. influenzae remained susceptible to all antimicrobials, with MIC90 values of ≤2 mg/L, except for amikacin (8 mg/L) and ampicillin (32 mg/L). No individual country data are available as insufficient isolates were collected.
4. Discussion The consensus from national surveillance networks, as indicated by the European Antimicrobial Resistance Surveillance Network (EARS-Net), is that the prevalence of multiresistant Gram-negative pathogens is escalating in Europe [13]. Given the diversity of resistance rates at national levels, reliable information on the local distribution of pathogens and their susceptibility patterns (as provided by T.E.S.T., amongst others) is essential in the fight to treat many serious infections. Although Europe is well represented by the number of countries included in T.E.S.T., it is worth noting that some 80% of the isolates have been contributed by fewer than onehalf of the participating countries. Published literature indicates an upsurge of ESBL resistance in E. coli in recent years, surpassing any increase in ESBL-producing K. pneumoniae [6,14]. The T.E.S.T. data appear to support these reports as the prevalence of ESBL-producers in Europe doubled amongst E. coli in the last 2 years whilst stabilising amongst K. pneumoniae over the last 4 years. The patterns of antimicrobial resistance changed accordingly for both organisms, and significant (P < 0.05) increases in non-susceptibility were reported for both organisms against tigecycline and the carbapenems as well as for E. coli against amikacin. The rates of ESBL-producing isolates both of K. pneumoniae and E. coli were typically three to five times higher for countries in the east of the region, e.g. Hungary, Romania and the Slovak Republic, compared with those in the west. However, no correlation between resistant phenotypes and antimicrobial resistance could be inferred for individual countries because of insufficient numbers of isolates. Greece is recognised as the country in Europe with the highest antimicrobial resistance in K. pneumoniae [13]. This was the case in T.E.S.T., although Greece was not associated with the highest rates of ESBL production. Greece is also notable for its high carbapenem resistance in K. pneumoniae (a phenomenon first reported
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in 2001 [15]), and in T.E.S.T. it was the only European country with imipenem resistance in this species. Its meropenem resistance rate of 43% is similar to those reported in the EARS-Net 2007 and 2009 reports [4,13]. ESBL production in Croatia was markedly more prevalent amongst K. pneumoniae than E. coli (46% vs. 3%); Tonkic et al. [16] report similar proportions amongst blood isolates (35% vs. 5%). Resistance amongst K. pneumoniae isolates from Croatia was correspondingly high for most antimicrobials. Italy also harbours a high level of antimicrobial resistance and had the highest rates amongst all the countries for E. coli, Enterobacter spp. and S. marcescens. For E. coli, the greatest increases in resistance across Europe from 2004 to 2009 were to ceftriaxone, levofloxacin and minocycline. To date, few reports of carbapenem resistance in E. coli in Europe have been published [17,18]. In T.E.S.T., low levels of meropenem resistance were detected amongst blood isolates in 2008 and 2009 from Belgium, Croatia, Germany, Ireland and Italy. The change of breakpoints for carbapenems in 2010 had an impact on susceptibility reporting, as 5/10 (50%) of meropenem-resistant isolates had MICs of 4.0 mg/L, which was considered susceptible according to the old CLSI guidelines. No resistance to imipenem or tigecycline was seen in E. coli; however, imipenem was not tested in 2008 and 2009. Resistance in P. aeruginosa remained lowest to amikacin and imipenem, although the T.E.S.T. data show a progressive loss of susceptibility to all the antimicrobials with available breakpoints. Ceftazidime resistance increased most of all, by 17% over the 6 years. Peak resistance to most antimicrobials in 2008 was largely due to high values in Croatia for that year. The antimicrobial resistance profile was most stable for S. marcescens, with little change over the years except for a large increase in minocycline resistance. The largest increases in resistance from 2004 to 2009 were frequently associated with levofloxacin and minocycline. Curiously, in E. aerogenes, resistance to all antimicrobials decreased over the years, except for tigecycline (no resistance in 2004 to 2.2% in 2009). Overall, the T.E.S.T. data show mounting resistance over the period of 2004–2009 to the antimicrobial agents tested amongst the Enterobacteriaceae, with the exception of amikacin, carbapenems and tigecycline. These findings would appear to follow on from those of an earlier study of Enterobacteriaceae isolated from blood between 2000 and 2004 (although it should be noted that collection was not limited to Europe) [19]. In vitro activity was similar in both studies for amikacin, imipenem and tigecycline, with MIC90 values of ≤8, ≤1 and ≤2 mg/L, respectively. Cephalosporin and TZP activity against K. pneumoniae, E. cloacae and E. coli in T.E.S.T., however, showed a marked decline from the earlier study. In summary, this data set from T.E.S.T. concurs with published reports on the increasing antimicrobial resistance amongst Gramnegative pathogens in Europe. Of special concern is the escalating resistance amongst E. coli and K. pneumoniae, both of which predominate as causative organisms of bacteraemia, as well as the emergence of carbapenem resistance amongst E. coli. Tigecycline has retained excellent in vitro activity against the Enterobacteriaceae and H. influenzae, including -lactamase-producing strains, over the course of this longitudinal study. Acknowledgments Thanks to all the investigators and laboratories for submitting isolates to the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) as well as to the staff at International Health Management
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Associates, Inc. (IHMA) (Schaumburg, IL) for their co-ordination of T.E.S.T. Micron Research Ltd. (Chatteris, UK) provided editorial assistance (from Mrs Wendy Wilkinson), statistical analyses (from Mr Vaughan Reed) and data management services, all of which were funded by Pfizer Inc. Funding: Pfizer Inc. (Collegeville, PA). Competing interests: ATA has received financial support for conference attendance and honoraria for lectures from Antiseptica, MSD, Novartis, Pfizer and Pliva; MJD is an employee of Pfizer Inc. Ethical approval: Not required. References [1] Albrecht SJ, Fishman NO, Kitchen J, Nachamkin I, Bilker WB, Hoegg C, et al. Reemergence of Gram-negative health care-associated bloodstream infections. Arch Intern Med 2006;166:1289–94. [2] Mikulska M, Del Bono V, Raiola AM, Bruno B, Gualandi F, Occhini D, et al. Blood stream infections in allogeneic hematopoietic stem cell transplant recipients: reemergence of Gram-negative rods and increasing antibiotic resistance. Biol Blood Marrow Transplant 2009;15:47–53. [3] Wu CJ, Lee HC, Lee NY, Shih HI, Ko NY, Wang LR, et al. Predominance of Gram-negative bacilli and increasing antimicrobial resistance in nosocomial bloodstream infections at a university hospital in southern Taiwan, 1996–2003. J Microbiol Immunol Infect 2006;39:135–43. [4] European Centre for Disease Prevention and Control. Antimicrobial resistance surveillance in Europe 2009. Annual report of the European Antimicrobial Resistance Surveillance Network (EARS-Net). Stockholm, Sweden: ECDC; 2010. http://www.ecdc.europa.eu/en/publications/Publications/1011 SUR annual EARS Net 2009.pdf [accessed 3 February 2011]. [5] Peleg AY, Hooper DC. Hospital-acquired infections due to Gram-negative bacteria. N Engl J Med 2010;362:1804–13. [6] Cantón R, Novais A, Valverde A, Machado E, Peixe L, Baquero F, et al. Prevalence and spread of extended-spectrum -lactamase-producing Enterobacteriaceae in Europe. Clin Microbiol Infect 2008;14:144–53. [7] Castanheira M, Sader HS, Deshpande LM, Fritsche TR, Jones RN. Antimicrobial activities of tigecycline and other broad-spectrum antimicrobials tested against serine carbapenemase- and metallo--lactamase-producing Enterobacteriaceae: report from the SENTRY Antimicrobial Surveillance Program. Antimicrob Agents Chemother 2008;52:570–3. [8] Wang YF, Dowzicky MJ. In vitro activity of tigecycline and comparators on Acinetobacter spp. isolates collected from patients with bacteremia and MIC change during the Tigecycline Evaluation and Surveillance Trial, 2004 to 2008. Diagn Microbiol Infect Dis 2010;68:73–9. [9] National Committee for Clinical Laboratory Standards. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard. 6th ed. Document M7-A6. Wayne, PA: NCCLS; 2003. [10] Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing; twentieth informational supplement. Document M100-S20. Wayne, PA: CLSI; 2010. [11] Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing, twentieth informational supplement (June 2010 update). Document M100-S20U. Wayne, PA: CLSI; 2010. [12] Kahlmeter G, Brown DFJ, Canton R, MacGowan AP, Mouton JW, Rodloff A, et al. EUCAST technical note on tigecycline. Clin Microbiol Infect 2006;12:1147–9. [13] Souli M, Galani I, Giamarellou H. Emergence of extensively drug-resistant and pandrug-resistant Gram-negative bacilli in Europe. Euro Surveill 2008;13, pii: 19045. [14] Hawkey PM. The growing burden of antimicrobial resistance. J Antimicrob Chemother 2008;62(Suppl. 1):i1–9. [15] Vatopoulos A. High rates of metallo--lactamase-producing Klebsiella pneumoniae in Greece—a review of the current evidence. Euro Surveill 2008;13, pii: 8023. [16] Tonkic M, Barisic IG, Punda-Polic V. Prevalence and antimicrobial resistance of extended-spectrum -lactamases-producing Escherichia coli and Klebsiella pneumoniae strains isolated in a university hospital in Split, Croatia. Int Microbiol 2005;8:119–24. [17] Pfeifer Y, Witte W, Holfelder M, Busch J, Nordmann P, Poirel L. NDM1-producing Escherichia coli in Germany. Antimicrob Agents Chemother 2011;55:1318–9. [18] Mantengoli E, Luzzaro F, Pecile P, Cecconi D, Cavallo A, Attala L, et al. Escherichia coli ST131 producing extended-spectrum -lactamases plus VIM1 carbapenemase: further narrowing of treatment options. Clin Infect Dis 2011;52:690–1. [19] Sader HS, Jones RN, Stilwell MG, Dowzicky MJ, Fritsche TR. Tigecycline activity tested against 26,474 bloodstream isolates: a collection from 6 continents. Diagn Microbiol Infect Dis 2005;52:181–6.
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International Journal of Antimicrobial Agents journal homepage: http://www.elsevier.com/locate/ijantimicag
In vitro activity of tigecycline and comparators against Gram-negative pathogens isolated from blood in Europe (2004–2009) Arjana Tambic Andrasevic a,∗ , Michael J. Dowzicky b a b
Department of Clinical Microbiology, University Hospital for Infectious Diseases, Mirogojska 8, 10000 Zagreb, Croatia Pfizer Inc., Collegeville, PA 19426, USA
a r t i c l e
i n f o
Article history: Received 7 September 2011 Accepted 20 October 2011 Keywords: Tigecycline T.E.S.T. Escherichia coli Klebsiella pneumoniae Gram-negative organisms Europe
a b s t r a c t Here we report on the antimicrobial resistance amongst Gram-negative isolates (excluding Acinetobacter spp.) collected from blood culture sources at European study sites as part of the global Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) from the study start in 2004 until August 2009. All isolates were collected and tested for minimum inhibitory concentrations using Clinical and Laboratory Standards Institute methodology. Over the collection period, extended-spectrum -lactamase (ESBL) production was recorded in 21.1% of Klebsiella pneumoniae, 2.6% of Klebsiella oxytoca and 11.3% of Escherichia coli, primarily in Croatia, Greece, Hungary, Italy, Poland, Romania and the Slovak Republic. ESBL rates stabilised amongst K. pneumoniae over 2006–2009, but doubled amongst E. coli in 2008–2009. The patterns of antimicrobial resistance changed accordingly for both organisms. Generally, Greece had the highest antimicrobial resistance for K. pneumoniae, Italy for E. coli, Serratia marcescens and Enterobacter spp., and Croatia for Pseudomonas aeruginosa. High resistance rates amongst K. pneumoniae were also seen in Croatia and Italy. Imipenem resistance amongst K. pneumoniae was reported exclusively in Greece (13.8%); amongst other Enterobacteriaceae, imipenem resistance was absent or low. Similarly, meropenem resistance was low amongst the Enterobacteriaceae except K. pneumoniae from Greece (42.6%). Across Europe, the most active antimicrobial agents against the Enterobacteriaceae were tigecycline, amikacin and the carbapenems, each with <10% resistance each year. Against the other antimicrobials, significant increases in non-susceptibility were reported for K. pneumoniae and E. coli, both important causative pathogens of bacteraemia. © 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.
1. Introduction The re-emergence of Gram-negative bloodstream infections in the last decade [1–4] can be largely attributed to the escalating antimicrobial resistance amongst these pathogens (most commonly Escherichia coli, followed by Klebsiella spp., Enterobacter spp. and Pseudomonas aeruginosa) [5]. Of global importance are the extended-spectrum -lactamases (ESBLs), which hydrolyse thirdgeneration cephalosporins used widely for empirical therapy of infections caused by Enterobacteriaceae. In Europe, following a decade of outbreaks of infection with ESBL-producing Klebsiella pneumoniae, ESBL-producers are now more prevalent amongst E. coli, particularly the CTX-M family of ESBLs [6]. Carbapenems have been stable against the hydrolysing activity of ESBLs and widely used as the drug of choice for the treatment of infections caused by multiresistant Enterobacteriaceae. Consequently, carbapenem-resistant isolates of Enterobacteriaceae
∗ Corresponding author. Tel.: +385 1 28 26 642; fax: +385 1 28 26 280. E-mail address: [email protected] (A.T. Andrasevic).
and P. aeruginosa have emerged globally [7]. These isolates are usually resistant to all -lactam agents as well as most other classes of antimicrobial agents. In a recent survey of 104 isolates of carbapenemase-producing Enterobacteriaceae collected globally, the MIC90 value (minimum inhibitory concentration for 90% of the organisms) for tigecycline was 1 mg/L and no resistance was seen [7]. Tigecycline is a novel glycylcycline antimicrobial with an expanded spectrum of activity, licenced for the treatment of complicated skin and skin-structure infections, complicated intraabdominal infections and (in the USA) community-acquired bacterial pneumonia. Amongst the Gram-negative pathogens, it has activity against ESBL-producing Enterobacteriaceae but not against Pseudomonas spp. In the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.), which is a global multicentre surveillance study, the in vitro activity of tigecycline and comparators are determined against a range of clinically important bacterial pathogens. This paper will report on Gram-negative isolates (excluding Acinetobacter spp.) collected from blood culture sources at European study sites from the start of the study in 2004 until August 2009. Data relating to blood isolates of
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Acinetobacter spp. are excluded as they have largely been previously published [8].
Table 1 Resistance phenotypes of Gram-negative blood isolates collected across Europe between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) by year and by country (pooled 2004–2009).
2. Methods
ESBL-producing Klebsiella pneumoniae
2.1. Isolate collection Collection of isolates for T.E.S.T. began at study centres globally in 2004 and is ongoing. Centres participating in T.E.S.T. were instructed to submit in each year consecutive and clinically significant (as determined by local criteria) isolates of Streptococcus pneumoniae (15 isolates), Enterococcus spp. (15), Staphylococcus aureus (25), Streptococcus agalactiae (10), Haemophilus influenzae (15), Acinetobacter spp. (15), E. coli (25), Enterobacter spp. (25), P. aeruginosa (20), Serratia spp. (10) and Klebsiella spp. (25). A single isolate per patient was accepted and its inclusion in the study was independent of the patient’s medical history, previous antimicrobial use, sex and age. 2.2. Antimicrobial susceptibility testing Testing procedures relating to Gram-negative organisms are described briefly here. Minimum inhibitory concentrations (MICs) of a defined panel of antimicrobial agents were determined at study centres using broth microdilution methodology [Sensititre® plates (TREK Diagnostic Systems, East Grinstead, UK) or MicroScan® panels (Siemens, Sacramento, CA)] according to guidelines published by the Clinical and Laboratory Standards Institute (CLSI) [9]. Gram-negative isolates were tested against amikacin, amoxicillin/clavulanic acid (AMC), ampicillin, cefepime, ceftazidime, ceftriaxone, imipenem, levofloxacin, meropenem, minocycline, piperacillin/tazobactam (TZP) and tigecycline. In 2006, unreliability of the imipenem testing led to a switch from MicroScan panels with imipenem to Sensititre plates with meropenem. Quality control strains used in the testing were E. coli ATCC 25922 and P. aeruginosa ATCC 27853. CLSI interpretive criteria to determine antimicrobial susceptibility were recently revised for the Enterobacteriaceae against select cephalosporins and carbapenems based upon pharmacokinetic/pharmacodynamic analyses [10,11] and these revised criteria were applied in this report; for tigecycline, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) approved breakpoints were used [12]. Isolates of E. coli and Klebsiella spp. were tested for ESBL production according to CLSI guidelines [9] using Mueller–Hinton agar (Remel Inc., Lenexa, KS) and disks with cefotaxime (30 mg/L), cefotaxime/clavulanic acid (30/10 mg/L), ceftazidime (30 mg/L) and ceftazidime/clavulanic acid (30/10 mg/L) (Oxoid Inc., Ogdensburg, NY). Standard strains of ESBL-positive K. pneumoniae ATCC 700603 and ESBL-negative E. coli ATCC 25922 and P. aeruginosa ATCC 27853 were used for quality control of the ceftazidime and cefotaxime disks. Confirmation of isolate identification and management of a centralised database were performed by a central laboratory [Laboratories International for Microbiology Studies, a division of International Health Management Associates, Inc. (IHMA), Schaumburg, IL]. This report includes all Gram-negative pathogens (except Acinetobacter spp.) with a culture source of blood submitted between the start of T.E.S.T. in 2004 and August 2009 in Europe. 3. Results A total of 8509 Gram-negative isolates (excluding Acinetobacter spp.) were cultured from blood at 181 European centres participating in T.E.S.T. between 2004 and 2009. Approximately one-half
Year 2004 2005 2006 2007 2008 2009 All years Country Austria Belgium Bulgaria Croatia Czech Republic Denmark Finland France Germany Greece Hungary Ireland Italy Latvia Lithuania Poland Portugal Romania Slovak Republic Slovenia Spain Sweden Switzerland The Netherlands UK Europe
ESBL-producing Escherichia coli
N
%a
N
%a
25/163 7/107 25/127 72/322 132/495 97/480 358/1694
15.3 6.5 19.7 22.4 26.7 20.2 21.1
17/221 14/194 13/298 39/518 125/842 115/791 323/2864
7.7 7.2 4.4 7.5 14.8 14.5 11.3
1/8 11/73 2/5 52/112 9/32 10/88 0/9 27/246 8/88 25/76 10/22 7/59 91/268 2/4 3/3 14/28 7/30 15/35 8/17 4/22 42/324 1/48 0/26 1/9 8/62 358/1694
– 15.1 – 46.4 28.1 11.4 – 11.0 9.1 32.9 45.5 11.9 34.0 – – 50.0 23.3 42.9 47.1 18.2 13.0 2.1 0.0 – 12.9 21.1
1/14 8/191 1/8 3/112 0/40 5/155 0/9 35/493 19/184 10/93 6/24 8/101 131/500 3/10 1/28 4/40 3/40 13/46 4/17 2/43 49/440 4/78 2/70 0/16 11/112 323/2864
7.1 4.2 – 2.7 0.0 3.2 – 7.1 10.3 10.8 25.0 7.9 26.2 – 3.6 10.0 7.5 28.3 23.5 4.7 11.1 5.1 2.9 0.0 9.8 11.3
ESBL, extended-spectrum -lactamase. a Percentage not calculated when denominator is ≤10 isolates.
of the isolates were collected from France, Italy and Spain. For each of the eight species included in this report, countries with ≤50 isolates were not considered individually, although their data were included in the pooled analysis for Europe. Amongst the 25 participating countries, 12 (Belgium, Croatia, Denmark, France, Germany, Greece, Ireland, Italy, Spain, Sweden, Switzerland and the UK) contributed >50 isolates of at least one species; their data were also analysed accordingly by country. In all data tables in this report, percentage values are not shown where the data relate to the pooled analysis and the denominator is ≤20 isolates, or where the data relate to individual countries and the denominator is ≤10 isolates. Data are also not tabulated for antimicrobials against which an organism is considered to be intrinsically resistant, nor are they discussed.
3.1. Klebsiella pneumoniae Over the collection period (2004–2009), 21.1% of K. pneumoniae isolates in Europe were ESBL-producers (Table 1), with rates at least double this overall value in Croatia, Hungary, Poland, Romania and the Slovak Republic (Table 1). No ESBL-producing K. pneumoniae were collected in Switzerland or Finland; the lowest rate was otherwise reported for Sweden (2.1%). Following a dip at 6.5% in 2005, the rates for Europe remained within a 7% range over the last 4 years (19.7–26.7%) (Table 1).
Table 2 In vitro resistance of Gram-negative blood isolates collected across Europe between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial. (T.E.S.T.) Species/antimicrobiala
2004 MIC90 b
d
2006 %R
N = 107 (96/11) 4 0.0 16 9.3 1 4.7 16 10.3 16 12.1 0.5 1.0 4 8.4 – – 16 14.0 32 7.5 1 1.9 N = 25 (24/1) 4 0.0 32 12.0 1 0.0 ≤8 4.0 4 12.0 0.5 0.0 0.25 0.0 – – 2 0.0 ≥256 20.0 0.5 0.0 N = 194 (188/6) 4 1.0 16 9.8 ≥64 55.7 ≤0.5 4.6 ≤8 6.2 0.5 8.8 0.5 0.0 ≥16 16.0 – – 8 5.7 16 4.1 0.25 0.0 N = 87 (85/2) 2 1.1 8 2.3 ≥64 49.4 ≥128 52.9 1 1.2 ≥16 12.6 – – 8 9.2 128 14.9 2 5.7 N = 17 (16/1) 8 0.0 4 0.0 ≥64 47.1 32 47.1 – –
MIC90
2007 %R
N = 127 (103/24) 8 3.9 ≥64 24.4 32 11.8 ≥64 26.8 ≥128 26.8 0.5 2.9 ≥16 18.1 1 8.3 16 11.8 ≥256 22.0 2 3.9 N = 48 (41/7) 2 0.0 16 6.3 1 2.1 ≤8 2.1 8 12.5 0.25 0.0 0.5 6.3 – – 4 2.1 32 8.3 1 4.2 N = 298 (258/40) 4 0.7 32 10.1 ≥64 60.1 1 2.7 ≤8 2.7 0.5 6.7 0.25 0.0 ≥16 23.8 ≤0.06 0.0 16 11.7 8 2.7 0.25 0.0 N = 140 (113/27) 4 0.7 16 7.9 ≥64 35.7 ≥128 41.4 1 1.8 8 11.4 0.12 7.4 8 7.1 ≥256 22.1 2 7.1 N = 34 (31/3) 4 0.0 1 0.0 ≥64 29.4 16 29.4 0.5 0.0
MIC90
2008 %R
N = 322 (17/305) 8 1.2 32 17.7 ≥64 18.3 ≥64 25.2 ≥128 28.3 – – ≥16 17.7 0.25 2.0 16 17.4 128 13.0 2 4.7 N = 101 (8/93) 4 0.0 32 13.9 2 1.0 ≤8 6.9 8 16.8 – – 2 6.9 0.12 0.0 8 2.0 ≥256 13.9 1 2.0 N = 518 (35/483) 8 0.4 32 10.8 ≥64 59.1 4 7.3 ≤8 6.4 32 11.0 ≤0.06 0.0 ≥16 22.6 ≤0.06 0.0 16 12.0 8 2.7 0.5 0.0 N = 238 (11/227) 4 0.0 8 3.8 ≥64 31.9 ≥128 37.4 – – 8 10.9 0.25 0.4 8 8.4 128 18.9 2 2.5 N = 55 (3/52) 8 1.8 2 1.8 16 10.9 4 20.0 – –
MIC90
2009 %R
N = 495 (0/495) 16 5.5 32 26.5 ≥64 21.4 ≥64 29.1 ≥128 34.5 – – ≥16 23.0 0.25 2.4 ≥32 30.5 ≥256 21.8 2 4.6 N = 112 (0/112) 4 0.0 32 14.3 4 2.7 ≤8 8.9 16 21.4 – – 4 8.0 0.12 0.9 16 11.6 ≥256 24.1 1 3.6 N = 842 (0/842) 8 1.8 32 15.2 ≥64 65.6 16 9.3 16 12.9 ≥128 21.4 – – ≥16 32.3 ≤0.06 0.8 16 16.3 32 6.8 0.5 0.0 N = 388 (0/388) 8 4.4 8 5.7 ≥64 37.9 ≥128 41.5 – – ≥16 16.5 0.25 3.9 16 14.2 ≥256 19.6 2 4.1 N = 97 (0/97) 8 2.1 32 10.3 ≥64 36.1 64 47.4 – –
MIC90
2004–2009 %R
N = 480 (0/480) 8 2.5 32 22.9 ≥64 17.9 ≥64 24.8 ≥128 30.4 – – ≥16 19.6 0.12 2.5 ≥32 22.1 ≥256 17.9 2 3.8 N = 102 (0/102) 4 1.0 16 9.8 4 2.9 ≤8 4.9 32 20.6 – – 4 8.8 ≤0.06 1.0 8 8.8 ≥256 17.6 1 2.9 N = 791 (0/791) 8 0.4 32 14.9 ≥64 67.1 32 11.1 16 11.1 ≥128 21.5 – – ≥16 32.2 ≤0.06 0.4 16 20.5 32 5.4 0.5 0.0 N = 351 (0/351) 4 3.7 16 9.1 ≥64 35.3 ≥128 46.2 – – ≥16 14.8 0.25 1.4 16 19.7 ≥256 21.7 2 4.6 N = 91 (0/91) 4 0.0 1 0.0 32 25.3 16 29.7 – –
MIC90
%R
N = 1694 (369/1325) 8 2.9 32 20.9 ≥64 16.7 ≥64 24.6 ≥128 28.7 0.5 1.1 ≥16 18.1 0.25 2.4 ≥32 21.7 ≥256 16.8 2 4.4 N = 454 (131/323) 4 0.2 32 11.7 2 2.4 ≤8 6.4 16 17.4 0.5 0.0 2 7.0 0.12 0.6 8 5.5 ≥256 16.5 1 2.6 N = 2864 (700/2164) 8 0.8 32 13.1 ≥64 63.1 8 7.9 ≤8 9.1 64 16.3 0.5 0.0 ≥16 27.5 ≤0.06 0.5 16 14.7 16 4.6 0.5 0.0 N = 1333 (331/1002) 4 2.4 8 6.0 ≥64 36.5 ≥128 41.9 1 1.2 8 13.1 0.25 2.3 16 12.6 ≥256 19.5 2 4.3 N = 326 (81/245) 8 1.2 4 4.3 ≥64 29.1 32 35.0 1 0.0
117
N = 163 (153/10) 8 0.6 16 9.2 8 7.4 ≥64 16.6 32 19.0 0.5 0.0 4 6.1 – – 16 14.7 16 7.4 2 6.7 N = 66 (58/8) 4 0.0 32 10.6 2 4.5 ≤8 7.6 8 12.1 0.5 0.0 1 6.1 – – 0.0 4 10.6 ≥256 1.5 1 N = 221 (219/2) 4 0.0 32 10.4 ≥64 58.8 1 2.7 ≤8 5.0 4 10.4 0.5 0.0 ≥16 19.5 – – 8 6.3 4 1.4 0.25 0.0 N = 129 (122/7) 4 0.0 4 3.1 ≥64 36.4 64 33.3 1 0.8 2 4.7 – – 8 4.7 128 14.7 1 3.1 N = 32 (31/1) 16 3.1 16 9.4 ≥64 40.6 64 37.5 1 0.0
MIC90
A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Klebsiella pneumoniae Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Klebsiella oxytoca Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Escherichia coli Amikacin AMC Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter cloacae Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter aerogenes Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem
2005 %Rc
118
Table 2 (Continued) Species/antimicrobiala
2004 MIC90
c
%R
≥16 34.4 – – 16 12.5 128 12.5 1 0.0 N = 70 (68/2) 4 1.4 1 1.4 ≤8 5.7 16 17.1 1 1.5 1 2.9 – – 8 2.9 8 2.9 1 4.3 N = 116 (116/0) 8 3.4 16 6.0 16 6.9 8 6.9 ≥16 23.3 – – 64 7.8 N = 11 (11/0) 16 – 0.5 – ≤0.5 – ≤0.5 – ≤0.06 – 1 – – 0.015 – – 1 – ≤0.06 – – 0.12
MIC90 ≥16 – 8 64 1 N = 33 (31/2) 4 1 ≤8 16 2 1 – 4 32 1 N = 71 (69/2) 16 32 32 16 ≥16 – 128 N=5 – – – – – – – – – – –
2006 %R 47.1 – 5.9 5.9 5.9 0.0 3.0 3.0 24.2 0.0 0.0 – 3.0 9.1 6.1 4.2 11.3 15.5 10.1 36.6 – 12.7 – – – – – – – – – – –
MIC90
2007 %R
8 11.8 – – 4 5.9 64 5.9 1 2.9 N = 52 (40/12) 8 1.9 1 1.9 ≤8 9.6 16 25.0 1 2.5 2 3.8 – – 8 3.8 64 3.8 2 5.8 N = 96 (76/20) 16 6.3 32 14.6 ≥64 16.7 8 5.3 ≥16 22.9 – – 128 11.5 N = 10 (5/5) 8 – 0.5 – 32 – ≤0.5 – 0.25 – – – – 0.03 – – 2 – 0.25 – – 0.25
MIC90
2008 %R
8 10.9 1.9 0.25 8 3.6 16 1.8 1 1.8 N = 89 (4/85) 4 1.1 ≤0.5 2.2 ≤8 4.5 2 9.0 – – 1 4.5 2.4 0.12 8 4.5 4 2.2 2 1.1 N = 205 (23/182) 16 4.9 32 12.7 32 13.2 8 8.7 ≥16 28.3 16 10.4 128 10.2 N = 12 (0/12) 16 – 1 – 16 – ≤0.5 – ≤0.06 – – – 0.03 – 0.12 – ≤0.5 – ≤0.06 – – 0.12
MIC90
2009 %R
≥16 22.7 0.5 4.1 16 12.4 128 15.5 2 1.0 N = 171 (0/171) 8 2.3 1 4.7 ≤8 4.1 16 15.8 – – 1 1.8 1.8 0.25 8 8.8 16 2.9 2 2.3 N = 338 (0/338) 64 11.5 32 14.8 ≥64 25.4 – – ≥16 40.2 ≥32 20.7 ≥256 22.5 N = 42 (0/42) 8 – 1 0.0 ≥64 23.8 ≤0.5 – ≤0.06 – – – 0.03 – 0.12 – 2 2.4 ≤0.06 0.0 0.25 –
MIC90 , minimum inhibitory concentration for 90% of the organisms; %R, percent resistant; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam. a Antimicrobials with no intrinsic activity against the organism are excluded. b MIC90 values in mg/L; MIC90 values not given when N < 10. c Percent resistance is not shown when N ≤ 20. d Values in brackets refer to the number of isolates tested against imipenem and meropenem, respectively (not given where N < 10).
MIC90
2004–2009 %R
1 6.6 0.12 1.1 8 6.6 64 4.4 1 2.2 N = 171 (0/171) 4 1.2 1 2.3 ≤8 7.0 8 14.0 – – 2 1.2 0.12 0.0 16 15.2 16 4.1 2 3.5 N = 322 (0/322) 32 9.9 32 14.3 ≥64 23.6 – – ≥16 28.6 16 15.2 ≥256 16.5 N = 24 (0/24) 8 – 2 0.0 4 12.5 ≤0.5 – ≤0.06 – – – 0.015 – ≤0.06 – 2 0.0 ≤0.06 0.0 0.25 –
MIC90
%R
≥16 17.5 0.25 2.9 8 8.3 64 8.3 1 1.8 N = 586 (143/443) 8 1.5 1 2.9 ≤8 5.6 16 15.7 1 1.4 1 2.2 0.12 1.1 8 8.5 16 3.6 2 3.2 N = 1148 (284/864) 32 8.2 32 13.2 ≥64 19.5 8 7.4 ≥16 31.4 16 17.0 128 15.6 N = 104 (20/84) 8 – 1 0.0 32 17.3 ≤0.5 – ≤0.06 – 1 – 0.03 – 0.12 – 2 1.9 ≤0.06 0.0 0.25 –
A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Levofloxacin Meropenem Minocycline TZP Tigecycline Serratia marcescens Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Pseudomonas aeruginosa Amikacin Cefepime Ceftazidime Imipenem Levofloxacin Meropenem TZP Haemophilus influenzae Amikacin AMC Ampicillin Cefepime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline
2005 b
Table 3a In vitro resistance of Gram-negative blood isolates collected between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) (data pooled for all years) by country. Species/antimicrobiala,b
Croatia
Denmark
MIC90 c,d
0.9 43.8 38.4 47.3 52.7 – 41.1 1.8 51.8 33.9 3.6 – – – – – – – – – – – 0.0 20.5 62.5 3.6 10.7 11.6 – 25.0 0.9 26.8 6.3 0.0 – – – – – – – – – – – – – – –
France %R
N = 88 (22/66) 2 0.0 16 5.7 4 5.7 ≤8 6.8 64 11.4 0.25 0.0 2 3.4 ≤0.06 0.0 8 5.7 8 1.1 2 9.1 N = 42 – – – – – – – – – – – – – – – – – – – – – – N = 155 (60/95) 4 0.0 16 4.5 ≥64 51.6 ≤0.5 2.6 ≤8 1.3 ≤0.06 3.9 0.25 0.0 4 7.1 ≤0.06 0.0 8 5.8 2 0.6 0.5 0.0 N = 97 (38/59) 2 0.0 1 0.0 32 16.5 16 20.6 0.25 0.0 0.25 0.0 0.12 0.0 4 2.1 64 6.2 1 1.0 N = 14 – – – – – – – – – –
MIC90
Germany %R
N = 246 (63/183) 4 0.8 32 11.0 8 8.5 16 13.0 ≥128 13.0 0.5 0.0 4 9.8 ≤0.06 0.0 ≥32 16.3 32 7.3 1 2.8 N = 106 (24/82) 4 0.0 16 7.5 1 0.9 ≤8 2.8 2 9.4 0.5 0.0 0.25 5.7 0.12 0.0 4 1.9 ≥256 12.3 1 0.0 N = 493 (128/365) 4 0.4 32 11.2 ≥64 56.6 1 4.1 ≤8 4.5 0.5 9.3 0.25 0.0 8 13.8 ≤0.06 0.0 8 9.5 8 2.4 0.5 0.0 N = 249 (63/186) 4 0.8 8 5.2 ≥64 34.5 ≥128 41.8 1 1.6 ≥16 15.3 0.25 0.5 16 11.2 ≥256 16.1 2 2.4 N = 66 (17/49) 8 0.0 1 3.0 ≥64 34.8 16 36.4 1 0.0
MIC90
Italy %R
N = 88 (14/74) 2 0.0 32 12.5 8 6.8 ≤8 9.1 ≥128 11.4 0.5 0.0 8 11.4 ≤0.06 1.4 16 20.5 32 6.8 2 5.7 N = 30 – – – – – – – – – – – – – – – – – – – – – – N = 184 (38/146) 8 0.5 32 10.9 ≥64 63.6 16 9.2 ≤8 9.8 ≥128 17.9 0.25 0.0 ≥16 33.2 ≤0.06 1.4 16 16.8 16 3.8 0.5 0.0 N = 93 (16/77) 2 1.1 4 0.0 ≥64 32.3 ≥128 39.8 1 0.0 1 7.5 0.25 1.3 8 8.6 128 14.0 1 4.3 N = 16 – – – – – – – – – –
MIC90
Spain %R
N = 268 (63/205) 64 11.2 32 23.9 ≥64 25.7 ≥64 38.1 ≥128 39.9 1 0.0 ≥16 29.5 1 0.5 ≥32 28.4 ≥256 23.9 2 6.0 N = 61 (19/42) 4 0.0 32 11.5 2 0.0 32 13.1 8 27.9 0.5 0.0 1 4.9 0.25 0.0 8 4.9 ≥256 23.0 1 4.9 N = 500 (134/366) 8 2.8 32 19.2 ≥64 72.8 ≥64 19.0 32 21.6 ≥128 33.4 0.5 0.0 ≥16 49.4 ≤0.06 1.1 ≥32 19.8 64 8.4 0.5 0.0 N = 249 (62/187) 8 3.6 32 10.0 ≥64 53.8 ≥128 57.8 1 0.0 ≥16 24.1 1 3.7 16 14.5 ≥256 35.3 2 8.4 N = 64 (19/45) 16 4.7 32 17.2 ≥64 54.7 ≥128 64.1 1 0.0
MIC90
UK %R
N = 324 (55/269) 4 0.3 32 16.0 8 6.8 16 10.2 32 17.3 1 0.0 8 10.8 0.12 1.9 ≥32 17.0 128 11.1 1 1.9 N = 73 (19/54) 4 0.0 32 16.4 4 6.8 16 11.0 32 19.2 0.5 0.0 8 12.3 0.25 1.9 16 13.7 ≥256 19.2 1 5.5 N = 440 (73/367) 4 0.5 32 14.3 ≥64 71.8 4 4.3 ≤8 8.2 32 15.2 0.5 0.0 ≥16 29.3 ≤0.06 0.0 16 14.1 16 4.1 0.5 0.0 N = 257 (57/200) 4 0.8 4 5.1 ≥64 29.6 64 33.1 2 3.5 8 10.5 0.25 2.5 16 10.9 128 12.1 1 2.7 N = 76 (9/67) 4 0.0 1 0.0 32 18.4 16 25.0 – –
MIC90
%R
N = 62 (23/39) 2 0.0 16 6.5 16 9.7 16 11.3 ≥128 24.2 0.5 0.0 4 4.8 ≤0.06 0.0 8 8.1 128 11.3 1 1.6 N = 30 – – – – – – – – – – – – – – – – – – – – – – N = 112 (54/58) 8 0.0 16 9.8 ≥64 67.0 8 8.9 ≤8 9.8 ≥128 18.8 0.5 0.0 ≥16 33.0 ≤0.06 0.0 16 15.2 32 1.8 0.25 0.0 N = 52 (20/32) 2 0.0 4 1.9 32 19.2 32 32.7 0.5 0.0 1 1.9 ≤0.06 0.0 8 5.8 64 5.8 1 1.9 N=9 – – – – – – – – – –
119
N = 112 (0/112) 8 32 ≥64 ≥64 ≥128 – ≥16 0.12 ≥32 ≥256 2 N=6 – – – – – – – – – – – N = 112 (0/112) 8 32 ≥64 1 16 8 – ≥16 ≤0.06 ≥32 32 0.5 N = 44 – – – – – – – – – – N=7 – – – – –
e
MIC90
A.T. Andrasevic, M.J. Dowzicky / International Journal of Antimicrobial Agents 39 (2012) 115–123
Klebsiella pneumoniae Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Klebsiella oxytoca Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Escherichia coli Amikacin AMC Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter cloacae Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Enterobacter aerogenes Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem
%Rd
120
Table 3a (Continued)
MIC90 Levofloxacin Meropenem Minocycline TZP Tigecycline Serratia marcescens Amikacin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Pseudomonas aeruginosa Amikacin Cefepime Ceftazidime Imipenem Levofloxacin Meropenem TZP
Denmark
Croatia c,d
– – – – – N = 13 – – – – – – – – – – N = 86 (0/86) ≥128 32 ≥64 – ≥16 ≥32 ≥256
d
%R – – – – – – – – – – – – – – –
27.9 29.1 39.5 – 44.2 32.6 32.6
France
Germany %R
MIC90
%R
MIC90
– – – – – N = 19 – – – – – – – – – – N = 58 (25/33) 4 8 ≤8 4 4 2 16
– – – – –
≥16 19.7 2.0 0.12 8 7.6 64 7.6 1 1.5 N = 108 (20/88) 4 0.0 0.0 ≤0.5 ≤8 4.6 16 13.0 0.5 0.0 2 0.9 0.12 0.0 7.4 8 8 0.9 2 1.9 N = 165 (39/126) 16 4.2 16 9.1 32 13.9 2 5.1 ≥16 30.3 8 4.8 128 12.7
– – – – – – – – – – 0.0 1.7 1.7 0.0 8.6 3.0 0.0
MIC90
Italy %R
– – – – – – – – – – N = 40 – – – – – – – – – – – – – – – – – – – – N = 58 (10/48) 8 0.0 16 3.4 16 6.9 16 20.0 ≥16 27.6 4 6.3 128 10.3
MIC90
Spain %R
≥16 31.3 2 8.9 8 9.4 ≥256 25.0 1 0.0 N = 102 (29/73) 8 0.0 2 2.9 16 10.8 32 15.7 2 3.4 1 1.0 0.12 1.4 8 5.9 16 4.9 2 3.9 N = 250 (44/206) 32 5.6 32 16.0 ≥64 26.4 8 9.1 ≥16 38.8 ≥32 22.3 ≥256 18.8
MIC90 , minimum inhibitory concentration for 90% of the organisms; %R, percent resistant; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam. a For each species, data shown only where the country has contributed a total of >50 isolates over the 6 years of collection. b Antimicrobials with no intrinsic activity against the organism are excluded. c MIC90 in mg/L. d – Data not available because of low numbers of isolates. e Values in brackets refer to the number of isolates tested against imipenem and meropenem, respectively (not given where N < 50).
MIC90
UK %R
0.25 3.9 0.12 0.0 4 3.9 0.0 64 1 1.3 N = 121 (23/98) 4 0.0 ≤0.5 0.8 ≤8 3.3 1 5.0 1 0.0 0.5 0.0 0.25 0.0 8 6.6 8 0.8 2 0.8 N = 213 (62/151) 16 8.0 16 8.9 ≥64 19.7 8 4.8 ≥16 34.7 16 18.5 128 14.1
MIC90
%R
– – – – – N = 29 – – – – – – – – – – N = 53 (26/27) 4 8 16 2 4 8 32
– – – – – – – – – – – – – – – 0.0 1.9 5.7 3.8 7.5 3.7 5.7
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Species/antimicrobiala,b
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A significant increase in non-susceptibility rates was seen over the collection period for all antimicrobials tested (Cochran–Armitage trend test, P < 0.01; data not shown), except for tigecycline and the carbapenems for which the overall resistance rates across Europe remained <10% (Table 2). Resistance rates were also <10% for amikacin, although non-susceptibility increased significantly (P < 0.01) over the collection period. For AMC, ceftazidime, ceftriaxone and TZP, an increase of ca. 15% in resistance was noted between 2005 and 2006. Over the collection period, Greece had the highest rates of resistance for eight of the antimicrobial agents (AMC, ceftazidime, ceftriaxone, imipenem, levofloxacin, meropenem, TZP and tigecycline) (Tables 3a and 3b). Imipenem resistance was reported exclusively in Greece [13.8% (4/29) over the collection period], with a MIC90 of 4 mg/L. Meropenem-resistant isolates were collected from Greece in each study year between 2006 and 2009 [20 isolates (42.6% of total)]; meropenem-resistant isolates were also collected from Croatia [2 (1.8% of total)], Germany (1; 1.4%), Italy (1; 0.5%) and Spain (5; 1.9%), all in 2008. The meropenem MIC90 value for the collection period was high for Greece (≥32 mg/L) but remained at or below the susceptibility breakpoint (1 mg/L) for the other four countries. Three further resistant isolates (making a total of 32) were collected from Slovenia (one isolate collected in 2008) and Portugal (two isolates collected in 2009); both are countries that contributed ≤50 K. pneumoniae isolates. Notably, high resistance rates were also seen for Croatia and Italy for most of the antimicrobials, particularly the -lactams. Low levels (<10%) of tigecycline resistance were reported from each of the 12 countries. 3.2. Klebsiella oxytoca Low numbers of K. oxytoca were collected; of a total of 454 isolates, 12 (2.6%) were ESBL-producers from five countries (Denmark, France, Germany, Italy and Spain; data not shown). By year, the highest rate of ESBL production (4.5%) across Europe was recorded in both 2004 and 2008. A significant increase in the rates of non-susceptibility over the collection period was detected for AMC, minocycline and TZP (P < 0.05; data not shown) and an increasing trend was detected in resistance rates to ceftriaxone and levofloxacin (Table 2). Resistance to AMC, ceftazidime, ceftriaxone, minocycline and TZP peaked in 2008. Resistance rates remained low (<5%) each year for amikacin, cefepime, tigecycline and the carbapenems; MIC90 values of ≤1 mg/L were recorded for tigecycline and the carbapenems. Two isolates (one from Spain in 2008 and the other from Greece in 2009) were resistant to meropenem; no imipenem resistance was seen. Only three countries (France, Italy and Spain) contributed sufficient isolates for their data to be analysed separately for K. oxytoca (Table 3a). For most antimicrobials, the highest rate of resistance amongst these three countries occurred in Spain. 3.3. Escherichia coli An apparent doubling in the rates of ESBL-producing E. coli collected across Europe was observed in 2008 and 2009 compared with earlier years (Table 1). By country, the highest rates (23.5–28.3%) were recorded for Hungary, Italy, Romania and the Slovak Republic. No ESBL-producing E. coli were collected from the Czech Republic, Finland or The Netherlands. With the exception of amikacin, tigecycline and the carbapenems, a significant increase in the rates of non-susceptibility over the collection period was detected for all antimicrobials tested (P < 0.001; data not shown) (ceftazidime was not included in this analysis). Resistance rates were highest amongst E. coli isolates collected in 2008 or 2009; these were markedly increased
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from previous years for ceftriaxone and levofloxacin (Table 2). Escherichia coli remained largely susceptible (<10% resistance in each year) to amikacin, meropenem and TZP and totally susceptible to tigecycline and imipenem (data for imipenem available from 2004–2007 only). A single isolate with intermediate resistance to imipenem was collected in France in 2005. A total of 10 isolates were meropenem-resistant (in 2008: Croatia, 1; Ireland, 1; Italy, 4; Slovenia, 1; and in 2009: Belgium, 1; Germany, 2). MIC90 values remained at ≤1 mg/L in all cases for tigecycline and the carbapenems. Italy had the highest resistance rates for 2004–2009 for amikacin, ampicillin, cefepime, ceftazidime, ceftriaxone and levofloxacin (Tables 3a and 3b). The lowest resistance rates amongst most antimicrobials were found in Sweden, Denmark and Switzerland. 3.4. Enterobacter cloacae A total of 1333 isolates of E. cloacae were collected during 2004–2009, largely from six countries (Table 3a). The rates of non-susceptibility increased significantly over the collection period for amikacin, cefepime, levofloxacin and minocycline (P < 0.01; data not shown). Four imipenem-resistant isolates were collected: France, one in 2006; Spain, one in 2004 and one in 2005; and Ireland, one in 2006. The MIC90 values remained at ≤1 mg/L except for Spain (2 mg/L). MIC90 values also remained at ≤1 mg/L for meropenem, although there was a total of 23 meropenem-resistant isolates: Croatia, 2 in 2008; France, 1 in 2008; Germany, 1 in 2008; Greece, 1 in 2006 and 3 in 2008; Ireland, 1 in 2008; Italy, 1 in each in 2006 and 2007, 2 in 2008 and 3 in 2009; Poland, 2 in 2009; and Spain, 5 in 2008. Low (<10%) resistance rates were recorded for amikacin, cefepime, tigecycline, meropenem and imipenem (data for 2004–2007 only) in each year (Table 2). The lowest rates were recorded for Denmark, followed by the UK, Germany and Spain (Table 3a). With few exceptions, Italy had the highest resistance rate for each antimicrobial agent, both over the collection period and for individual years. 3.5. Enterobacter aerogenes Almost two-thirds of the 326 isolates of E. aerogenes were collected from France, Italy and Spain. Italy had markedly higher resistance rates than France and Spain for all antimicrobials except tigecycline (Table 3a). Low resistance rates (<10%) were recorded for amikacin, tigecycline and the carbapenems in each year (Table 2). No imipenem resistance was seen. Seven isolates were meropenem-resistant: France, one in 2009; Greece, one in 2008; Italy, one in each in 2004 and 2007 and two in 2008; and Slovenia, one in 2008. Meropenem MIC90 values over 2004–2009 were ≤1 mg/L in all countries except for Italy (2 mg/L). Enterobacter aerogenes showed a significant decrease in non-susceptibility to levofloxacin (P < 0.001; data not shown); no trends in antimicrobial resistance rates were otherwise detected as the data for this species were largely variable. 3.6. Serratia marcescens Of a total of 586 isolates of S. marcescens, over one-half were collected from France, Italy and Spain. This organism remained largely susceptible to the antimicrobial panel, with ceftriaxone as the least effective antimicrobial in vitro in terms of both susceptibility and MIC90 values (Tables 2 and 3a). Two isolates were imipenemresistant: one from Italy in 2006 and the other from Germany in 2004. Five meropenem-resistant isolates were collected: Germany and Greece, one each in 2007; and Hungary, Italy and Portugal, one each in 2008. Non-susceptibility increased significantly for
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Table 3b In vitro resistance of Gram-negative blood isolates collected between 2004 and 2009 (data pooled for all years) by country. Species/antimicrobiala,b
Belgium MIC90 c,d
Klebsiella pneumoniae Amikacin AMC Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline Escherichia coli Amikacin AMC Ampicillin Cefepime Ceftazidime Ceftriaxone Imipenem Levofloxacin Meropenem Minocycline TZP Tigecycline
Greece %Rd
N = 73 (19/54)e 4 0.0 32 11.0 32 11.0 16 11.0 32 17.8 1 0.0 1 4.1 ≤0.06 0.0 16 13.7 32 8.2 2 2.7 N = 191 (41/150) 8 0.0 15.2 32 ≥64 64.9 3.1 ≤0.5 ≤8 3.7 5.2 0.5 0.5 0.0 ≥16 20.4 ≤0.06 0.7 16 13.6 32 8.9 1 0.0
MIC90 N = 76 (29/47) 32 ≥64 ≥64 ≥64 ≥128 4 ≥16 ≥32 ≥32 ≥256 2 N = 93 (31/62) 4 16 ≥64 4 ≤8 8 0.25 ≥16 ≤0.06 16 8 0.25
Ireland %R 9.2 55.3 34.2 69.7 75.0 13.8 44.7 42.6 21.1 53.9 9.2 0.0 7.5 51.6 5.4 9.7 10.8 0.0 16.1 0.0 16.1 1.1 0.0
MIC90
Sweden %R
N = 59 (29/30) 8 1.7 32 10.2 4 5.1 32 13.6 8 20.3 0.5 0.0 4 8.5 1 0.0 ≥32 28.8 128 10.2 2 8.5 N = 101 (33/68) 4 0.0 32 12.9 ≥64 69.3 4 3.0 ≤8 3.0 32 16.8 0.25 0.0 ≥16 29.7 0.12 1.5 16 10.9 16 5.9 1 0.0
MIC90
Switzerland %R
N = 48 – – – – – – – – – – – – – – – – – – – – – – N = 78 (30/48) 4 0.0 16 2.6 ≥64 38.5 ≤0.5 1.3 ≤8 1.3 0.12 5.1 0.25 0.0 8 12.8 ≤0.06 0.0 8 3.8 2 1.3 0.25 0.0
MIC90
%R
N = 26 – – – – – – – – – – – – – – – – – – – – – – N = 70 (36/34) 4 0.0 16 8.6 ≥64 45.7 ≤0.5 2.9 ≤8 1.4 0.12 2.9 0.25 0.0 ≥16 20.0 ≤0.06 0.0 8 8.6 8 1.4 0.25 0.0
MIC90 , minimum inhibitory concentration for 90% of the organisms; %R, percent resistant; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam. a For each species, data shown only where the country has contributed a total of >50 isolates over the 6 years of collection. b Antimicrobials with no intrinsic activity against the organism are excluded. c MIC90 in mg/L. d – Data not available because of low numbers of isolates. e Values in brackets refer to the number of isolates tested against imipenem and meropenem, respectively (not given where N < 50).
minocycline and tigecycline (P < 0.001), although the increase in resistance was consistent for minocycline only.
3.7. Pseudomonas aeruginosa Over the collection period, a significant increase in nonsusceptibility rates was recorded across Europe for amikacin, cefepime, ceftazidime and TZP (P < 0.05; data not shown). Resistance rates were highest in 2008 (Table 2). The lowest resistance rates recorded for 2004–2009 across Europe were those to amikacin (8.2%) and imipenem (7.4%). Croatia had the highest resistance rates to all antimicrobials tested for 2004–2009 and for 2008 (Table 3a). High resistance rates were also documented for Italy and Spain, with Italy having the highest rates for all antimicrobials in 2006. Isolates from Germany had a high rate of resistance to imipenem (20%); however, the number of P. aeruginosa isolates (n = 10) tested against imipenem was lower than for other countries. Tigecycline showed reduced activity against P. aeruginosa, with a MIC90 of 16 mg/L across Europe during this study.
3.8. Haemophilus influenzae The rate of -lactamase-producing H. influenzae was 17.3% for the collection period, peaking in 2008 at 23.8% (data not shown). Pooled analysis of antimicrobial susceptibility was limited as there were fewer than 20 isolates each year except for 2008 and 2009 (Table 2). Over 2004–2009, H. influenzae remained susceptible to all antimicrobials, with MIC90 values of ≤2 mg/L, except for amikacin (8 mg/L) and ampicillin (32 mg/L). No individual country data are available as insufficient isolates were collected.
4. Discussion The consensus from national surveillance networks, as indicated by the European Antimicrobial Resistance Surveillance Network (EARS-Net), is that the prevalence of multiresistant Gram-negative pathogens is escalating in Europe [13]. Given the diversity of resistance rates at national levels, reliable information on the local distribution of pathogens and their susceptibility patterns (as provided by T.E.S.T., amongst others) is essential in the fight to treat many serious infections. Although Europe is well represented by the number of countries included in T.E.S.T., it is worth noting that some 80% of the isolates have been contributed by fewer than onehalf of the participating countries. Published literature indicates an upsurge of ESBL resistance in E. coli in recent years, surpassing any increase in ESBL-producing K. pneumoniae [6,14]. The T.E.S.T. data appear to support these reports as the prevalence of ESBL-producers in Europe doubled amongst E. coli in the last 2 years whilst stabilising amongst K. pneumoniae over the last 4 years. The patterns of antimicrobial resistance changed accordingly for both organisms, and significant (P < 0.05) increases in non-susceptibility were reported for both organisms against tigecycline and the carbapenems as well as for E. coli against amikacin. The rates of ESBL-producing isolates both of K. pneumoniae and E. coli were typically three to five times higher for countries in the east of the region, e.g. Hungary, Romania and the Slovak Republic, compared with those in the west. However, no correlation between resistant phenotypes and antimicrobial resistance could be inferred for individual countries because of insufficient numbers of isolates. Greece is recognised as the country in Europe with the highest antimicrobial resistance in K. pneumoniae [13]. This was the case in T.E.S.T., although Greece was not associated with the highest rates of ESBL production. Greece is also notable for its high carbapenem resistance in K. pneumoniae (a phenomenon first reported
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in 2001 [15]), and in T.E.S.T. it was the only European country with imipenem resistance in this species. Its meropenem resistance rate of 43% is similar to those reported in the EARS-Net 2007 and 2009 reports [4,13]. ESBL production in Croatia was markedly more prevalent amongst K. pneumoniae than E. coli (46% vs. 3%); Tonkic et al. [16] report similar proportions amongst blood isolates (35% vs. 5%). Resistance amongst K. pneumoniae isolates from Croatia was correspondingly high for most antimicrobials. Italy also harbours a high level of antimicrobial resistance and had the highest rates amongst all the countries for E. coli, Enterobacter spp. and S. marcescens. For E. coli, the greatest increases in resistance across Europe from 2004 to 2009 were to ceftriaxone, levofloxacin and minocycline. To date, few reports of carbapenem resistance in E. coli in Europe have been published [17,18]. In T.E.S.T., low levels of meropenem resistance were detected amongst blood isolates in 2008 and 2009 from Belgium, Croatia, Germany, Ireland and Italy. The change of breakpoints for carbapenems in 2010 had an impact on susceptibility reporting, as 5/10 (50%) of meropenem-resistant isolates had MICs of 4.0 mg/L, which was considered susceptible according to the old CLSI guidelines. No resistance to imipenem or tigecycline was seen in E. coli; however, imipenem was not tested in 2008 and 2009. Resistance in P. aeruginosa remained lowest to amikacin and imipenem, although the T.E.S.T. data show a progressive loss of susceptibility to all the antimicrobials with available breakpoints. Ceftazidime resistance increased most of all, by 17% over the 6 years. Peak resistance to most antimicrobials in 2008 was largely due to high values in Croatia for that year. The antimicrobial resistance profile was most stable for S. marcescens, with little change over the years except for a large increase in minocycline resistance. The largest increases in resistance from 2004 to 2009 were frequently associated with levofloxacin and minocycline. Curiously, in E. aerogenes, resistance to all antimicrobials decreased over the years, except for tigecycline (no resistance in 2004 to 2.2% in 2009). Overall, the T.E.S.T. data show mounting resistance over the period of 2004–2009 to the antimicrobial agents tested amongst the Enterobacteriaceae, with the exception of amikacin, carbapenems and tigecycline. These findings would appear to follow on from those of an earlier study of Enterobacteriaceae isolated from blood between 2000 and 2004 (although it should be noted that collection was not limited to Europe) [19]. In vitro activity was similar in both studies for amikacin, imipenem and tigecycline, with MIC90 values of ≤8, ≤1 and ≤2 mg/L, respectively. Cephalosporin and TZP activity against K. pneumoniae, E. cloacae and E. coli in T.E.S.T., however, showed a marked decline from the earlier study. In summary, this data set from T.E.S.T. concurs with published reports on the increasing antimicrobial resistance amongst Gramnegative pathogens in Europe. Of special concern is the escalating resistance amongst E. coli and K. pneumoniae, both of which predominate as causative organisms of bacteraemia, as well as the emergence of carbapenem resistance amongst E. coli. Tigecycline has retained excellent in vitro activity against the Enterobacteriaceae and H. influenzae, including -lactamase-producing strains, over the course of this longitudinal study. Acknowledgments Thanks to all the investigators and laboratories for submitting isolates to the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) as well as to the staff at International Health Management
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Associates, Inc. (IHMA) (Schaumburg, IL) for their co-ordination of T.E.S.T. Micron Research Ltd. (Chatteris, UK) provided editorial assistance (from Mrs Wendy Wilkinson), statistical analyses (from Mr Vaughan Reed) and data management services, all of which were funded by Pfizer Inc. Funding: Pfizer Inc. (Collegeville, PA). Competing interests: ATA has received financial support for conference attendance and honoraria for lectures from Antiseptica, MSD, Novartis, Pfizer and Pliva; MJD is an employee of Pfizer Inc. Ethical approval: Not required. References [1] Albrecht SJ, Fishman NO, Kitchen J, Nachamkin I, Bilker WB, Hoegg C, et al. Reemergence of Gram-negative health care-associated bloodstream infections. Arch Intern Med 2006;166:1289–94. [2] Mikulska M, Del Bono V, Raiola AM, Bruno B, Gualandi F, Occhini D, et al. Blood stream infections in allogeneic hematopoietic stem cell transplant recipients: reemergence of Gram-negative rods and increasing antibiotic resistance. Biol Blood Marrow Transplant 2009;15:47–53. [3] Wu CJ, Lee HC, Lee NY, Shih HI, Ko NY, Wang LR, et al. Predominance of Gram-negative bacilli and increasing antimicrobial resistance in nosocomial bloodstream infections at a university hospital in southern Taiwan, 1996–2003. J Microbiol Immunol Infect 2006;39:135–43. [4] European Centre for Disease Prevention and Control. Antimicrobial resistance surveillance in Europe 2009. Annual report of the European Antimicrobial Resistance Surveillance Network (EARS-Net). Stockholm, Sweden: ECDC; 2010. http://www.ecdc.europa.eu/en/publications/Publications/1011 SUR annual EARS Net 2009.pdf [accessed 3 February 2011]. [5] Peleg AY, Hooper DC. Hospital-acquired infections due to Gram-negative bacteria. N Engl J Med 2010;362:1804–13. [6] Cantón R, Novais A, Valverde A, Machado E, Peixe L, Baquero F, et al. Prevalence and spread of extended-spectrum -lactamase-producing Enterobacteriaceae in Europe. Clin Microbiol Infect 2008;14:144–53. [7] Castanheira M, Sader HS, Deshpande LM, Fritsche TR, Jones RN. Antimicrobial activities of tigecycline and other broad-spectrum antimicrobials tested against serine carbapenemase- and metallo--lactamase-producing Enterobacteriaceae: report from the SENTRY Antimicrobial Surveillance Program. Antimicrob Agents Chemother 2008;52:570–3. [8] Wang YF, Dowzicky MJ. In vitro activity of tigecycline and comparators on Acinetobacter spp. isolates collected from patients with bacteremia and MIC change during the Tigecycline Evaluation and Surveillance Trial, 2004 to 2008. Diagn Microbiol Infect Dis 2010;68:73–9. [9] National Committee for Clinical Laboratory Standards. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard. 6th ed. Document M7-A6. Wayne, PA: NCCLS; 2003. [10] Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing; twentieth informational supplement. Document M100-S20. Wayne, PA: CLSI; 2010. [11] Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing, twentieth informational supplement (June 2010 update). Document M100-S20U. Wayne, PA: CLSI; 2010. [12] Kahlmeter G, Brown DFJ, Canton R, MacGowan AP, Mouton JW, Rodloff A, et al. EUCAST technical note on tigecycline. Clin Microbiol Infect 2006;12:1147–9. [13] Souli M, Galani I, Giamarellou H. Emergence of extensively drug-resistant and pandrug-resistant Gram-negative bacilli in Europe. Euro Surveill 2008;13, pii: 19045. [14] Hawkey PM. The growing burden of antimicrobial resistance. J Antimicrob Chemother 2008;62(Suppl. 1):i1–9. [15] Vatopoulos A. High rates of metallo--lactamase-producing Klebsiella pneumoniae in Greece—a review of the current evidence. Euro Surveill 2008;13, pii: 8023. [16] Tonkic M, Barisic IG, Punda-Polic V. Prevalence and antimicrobial resistance of extended-spectrum -lactamases-producing Escherichia coli and Klebsiella pneumoniae strains isolated in a university hospital in Split, Croatia. Int Microbiol 2005;8:119–24. [17] Pfeifer Y, Witte W, Holfelder M, Busch J, Nordmann P, Poirel L. NDM1-producing Escherichia coli in Germany. Antimicrob Agents Chemother 2011;55:1318–9. [18] Mantengoli E, Luzzaro F, Pecile P, Cecconi D, Cavallo A, Attala L, et al. Escherichia coli ST131 producing extended-spectrum -lactamases plus VIM1 carbapenemase: further narrowing of treatment options. Clin Infect Dis 2011;52:690–1. [19] Sader HS, Jones RN, Stilwell MG, Dowzicky MJ, Fritsche TR. Tigecycline activity tested against 26,474 bloodstream isolates: a collection from 6 continents. Diagn Microbiol Infect Dis 2005;52:181–6.