Antimicrobial susceptibility of bacterial isolates from burn units in Gaza

JBUR-4026; No. of Pages 7 burns xxx (2013) xxx–xxx

Available online at www.sciencedirect.com

journal homepage: www.elsevier.com/locate/burns

Antimicrobial susceptibility of bacterial isolates from burn units in Gaza Abdelraouf A. Elmanama a,*, Nahed A. Al Laham b, Ghassan A. Tayh a a b

Medical Laboratory Science Department, Islamic University-Gaza, P.O. Box 108, Gaza Strip, PNA Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Al Azhar University-Gaza, PNA

article info

abstract

Article history:

Background: Bacterial infections continue to be a leading cause of morbidity and mortality

Accepted 14 April 2013

among burn patients despite intensive prophylaxis and treatment. Often treatment is

Keywords:

or published data on the susceptibility profiles of bacteria isolated from burn patients in the

complicated by the emergence of antimicrobial resistance pathogens. There are no reports Antimicrobial resistance

Gaza strip.

Burn units

Patients and methods: A cross sectional study was performed in the two burn units of Al-Shifa

Nosocomial infection

and Naser hospitals for 6 months from October 2010 to March 2011. A total of 118 wound

Gaza strip

samples from burn patients, 97 environmental samples and 28 samples from health care workers (HCWs) were collected and cultured according to the standard microbiological procedures. The bacterial isolates were identified by conventional methods and the antibiotic susceptibility profiles were determined by the standard disc diffusion method according to CLSI guidelines. Results: The overall percentage of positive cultures from both hospitals was 45.8%, where Nasser burn unit revealed higher positive cultures than Al-Shifa burn unit. Pseudomonas aeruginosa was the most common pathogen isolated (50%) followed by Enterobacter cloacae (28.3%). Meanwhile, fingers and nasal samples that collected from HCWs showed 78.6% and 32.3% positive cultures respectively, where P. aeruginosa was the highest pathogen isolated (32.3%), followed by Coagulase Negative Staphylococci (CoNS) (29%). Environmental samples also showed higher isolation rate of Pseudomonas and CoNS. Pseudomonas isolates from patients samples were found to be resistant to most of antimicrobials used except for piperacillin–tazobactam. The family Enterobacteriaceae isolated from patients and environmental samples were resistant to most of the tested antimicrobials. However, the Enterobacteriaceae isolates from HCWs samples were sensitive to the most of the tested antimicrobials. The incidence of methicillin-resistant Staphylococci according to oxacillin sensitivity test was 60% in patient’s samples, 77.8% in HCWs samples and 90% in environmental samples. Conclusion: High percentage of resistance was found among clinical isolates in general to the commonly used antibiotics with a notable increase in MRSA incidence among both patients and environmental samples as well as HCWs. # 2013 Elsevier Ltd and ISBI. All rights reserved.

* Corresponding author. E-mail address: [email protected] (A.A. Elmanama). 0305-4179/$36.00 # 2013 Elsevier Ltd and ISBI. All rights reserved. http://dx.doi.org/10.1016/j.burns.2013.04.011 Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

JBUR-4026; No. of Pages 7

2

burns xxx (2013) xxx–xxx

1.

Introduction

Burns infection remains the leading cause of morbidity and death among burn patients [1,2]. As a result of significant improvements of surgical treatments and intensive care in burn wards, it seems that infection is the direct cause of nearly 75% of deaths following burn [3–5]. Most of the infections are thought to be of nosocomial origin [6]. Infection in the wound prolongs the healing process; treatment includes rational antibiotic administration, removal of necrotic tissues, sufficient blood and oxygen supply to the wound and good nutritional support. All these measures are very important in the care of burn victims [7]. The spectrum of pathogenic bacteria on burn wounds varies in the course of burn treatment [8]. Health care workers (HCWs) move from patient to patient thus providing a means for pathogens to spread perhaps related to sanitation protocols regarding uniforms, equipment sterilization, washing and other preventive measures. Lastly, the routine use of antimicrobial agents in hospitals creates selection pressure for the emergence of the resistant strains of microorganisms [9]. The increase of multi-drug resistant (MDR) strains among the clinical isolates has further limited the therapeutic options [10]. It is therefore necessary to carry out periodic monitoring of patterns of isolation and susceptibility profiles of microorganisms in burn wounds in order to modify the preventive and therapeutic strategies. This especially is of utmost importance because regional variation in the type and susceptibility profiles exists. Colonization rates in burn patients from Gaza strip have been rarely reported and according to our best knowledge there is no documented reports or published scientific work. Furthermore, there is no data concerning the antimicrobial drug resistance of burn infections pathogens. Therefore, the aim of this study was to determine the antimicrobial resistance among pathogens isolated from burn patients and burn unit environment from the two burn units in Gaza strip, Palestine. It is worth mentioning that burn wound colonization does not necessarily mean disease, however, burn wound colonization is a risk factor for clinical disease. Positive cultures in this study indicate colonization.

were collected over the same period; Al-Shifa 72 and Nasser 25 and a similar sampling strategy was performed for 28 health care workers (HCWs).

2.2.1.

2.2.2.

Materials and methods

2.1.

Setting and patients

This prospective cross-sectional study involved 118 patients who were admitted to the burn units of Al-Shifa (94) and Nasser (24) hospital during the period from October 2010 to March 2011. Any repeat sample or isolate obtained on more than one occasion from the same patient was excluded. The study design was approved by Helsinki committee and an informed consent was obtained from participating patients and HCWs.

2.2.

Sample collection

The total number of burn wound swabs was 118 (Al-Shifa 94 and Nasser 24). The environmental and indoor air samples

Health care workers specimens

The fingers of 28 HCWs who agreed to participate in this study (25 from Al-Shifa and 3 from Nasser hospital) were rubbed for 1 min in a Petri plate containing 10 ml of Tryptic Soy Broth (TSB). After 24 h incubation at 35 8C, the turbid plates were subcultured on blood agar and MacConkey agar [12].

2.2.3.

Environmental and indoor air samples

A sterile cotton swab moistened in sterile normal saline were used to collect environmental samples from the floors, doors, sinks, incubators, and other instruments in the unit. The area of the swab was approximately 10 cm2 [13]. Ninety seven samples were taken (72 from Al-Shifa and 25 from Nasser) from patient’s rooms, dressing rooms, halls, toilets, ICU, operation room, and physiotherapy room, where different objects such as walls, beds, wheelchairs, trolley, halls, floors, doors, and patients instruments were included. Environmental sampling was based on the expectation of the researchers of what could be called hot spots (possible sources of contamination). Indoor air samples from various places in the two burn units such as patient’s rooms, dressing rooms, burn care units, operation rooms, and halls were collected using Air sampler (AES CHEMUNEX, France) by suction of 50 l of air from these places. Blood agar plates were used as isolation media. The plates were transported to the laboratory and incubated for 48 h at 37 8C.

2.3.

2.

Clinical specimens

A sterile swab was used for sampling from all burn in-patients after 3 days of admittance. The swabs were collected by the attending physicians and obtained from deep areas of the burns before any cleaning. Multiple samples from several areas of the burn were collected in order to obtain the most accurate assessment. Surface swabs were collected from burn wound after the removal of dressings and topical antibacterial agents and cleansing of the wound surface with 70% alcohol [11].

Microbiological investigation

The swabs were dipped in Stuart’s transport medium, and then plated on blood agar and MacConkey. The isolates were identified using conventional identification techniques after incubation for 18–48 h at 37 8C [14]. Positive cultures were subcultured on blood agar and MacConkey agar, as per routine bacteriologic guidelines. An oxidase test was used to differentiate P. aeruginosa from Enterobacteriaceae. API 20E system was used to identify the isolated gram negative bacteria to the species level. While gram stain, catalase, hemolysis on blood agar, coagulase and other tests were used to identify gram positive bacteria [15].

2.4. Antimicrobial susceptibility test (The Kirby-Bauer method) The antimicrobial susceptibility of all isolates was done according to CLSI (2011). All the isolated bacteria were tested

Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

JBUR-4026; No. of Pages 7

3

burns xxx (2013) xxx–xxx

Table 1 – Distribution of bacterial pathogens by isolation source. Isolate

Total no.

Pseudomonas spp. Enterobacter spp. Staphylococcus spp. Escherichia spp. Citrobacter spp. Acinetobacter spp. Klebsiella spp. Proteus spp. Streptococcus spp Serratia spp. Pasteurella spp.

Patients no. (%)

58 19 42 6 1 2 5 1 1 2 2

27 15 5 3 1 1 1 0 0 0 0

138

Total

HCWs no. (%)

(51) (28) (9) (6) (2) (2) (2) (0) (0) (0) (0)

10 2 9 3 0 0 3 1 1 2 0

53 (100)

(32) (6) (29) (10) (0) (0) (10) (3) (3) (6) (0)

31 (100)

for their sensitivity to some of the following Antibiotics: Penicillin G, Ampicillin, Piperacillin, Cefazolin, Ceftriaxone, Gentamicin, Amikacin, Imipenem, Vancomycin, Ciprofloxacin, Chloramphenicol, Tetracycline, Erythromycin, Piperacillin + Tazobactam, Oxacillin, Linezolid, Cefepime, Cefuroxime, Co-Trimoxazole, Ceftazime, Aztreonam and Norfloxacin [16].

2.5.

Env. no. (%)

3.

Air no. (%)

8 (35) 1 (4) 10 (44) 0 (0) 0 (0) 1 (4) 1 (4) 0 (0) 0 (0) 0(0) 2 (9)

13 1 18 0 0 0 0 0 0 0 0

(41) (3) (56) (0) (0) (0) (0) (0) (0) (0) (0)

23 (100)

32 (100)

Results

The overall percentage of positive cultures from both hospitals was 45.8%. In Al-Shifa burn unit the negative cultures account for 60.6% in comparison to 39.4% positive cultures while, Nasser burn unit showed higher percentage of positive cultures (70.8%). From the 97 different environmental samples that have been investigated, there were 23 (23.7%) positive samples from both burn units. A total of 138 bacterial isolates were recovered from various sources in burn units including patients. The highest isolation

Data analysis

The statistical tests and analysis of the this work were performed using IBM SPSS Statistics (version 15, IBM Corporation, Somers, NY).

Table 2 – Antimicrobial susceptibility for Pseudomonas spp. isolated from all samples. Antimicrobial

HCWs samples (N = 10)

Patients samples (N = 27)

Environmental samples (N = 8)

Air samples (N = 13)

S

I

R

S

I

R

S

I

R

S

I

R

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

Gentamycin

3 11.1

1 3.7

23 85.2

7 70.0

1 10.0

2 20.0

7 87.5

–

1 12.5

11 84.6

–

2 15.4

Piperacillin

5 18.5

3 11.

19 70.4

7 70.0

–

3 30

7 87.5

–

1 12.5

6 46.2

–

7 53.8

Ciprofloxacin

4 14.8

–

23 85.2

8 80.0

2 20.0

7 87.5

–

1 12.5

7 53.8

–

6 46.2

Cefepime

3 11.1

1 3.7

23 85.2

8 80.0

1 10.0

1 10.0

7 87.5

–

1 12.5

8 61.5

–

5 38.5

Imipenem

6 22.2

1 3.7

20 74.1

8 80.0

–

2 20.0

7 87.5

–

1 12.5

9 69.2

2 15.4

2 15.4

Amikacin

4 14.8

1 3.7

22 81.5

8 80.0

–

2 20.0

7 87.5

–

1 12.5

9 69.2

2 15.4

2 15.4

Ceftazidime

4 14.8

–

23 85.2

7 70.0

2 20.0

1 10.0

7 87.5

–

1 12.5

3 23.1

2 15.4

8 61.5

Norfloxacin

4 14.8

2 7.4

21 77.8

7 70.0

1 10.0

2 20.0

7 87.5

–

1 12.5

6 46.2

–

7 53.8

Aztreonam

–

–

–

–

–

8 100

–

–

9 90.0

–

8 100

–

–

9 69.2

–

Piperacillin/tazobactam

24 88.9

–

2 7.4

27 100 1 3.7

10 100 1 10.0

13 100 4 30.8

S, susceptible; I, intermediate; R, resistance

Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

JBUR-4026; No. of Pages 7

4

burns xxx (2013) xxx–xxx

rate was for Pseudomonas spp. followed by Staphylococcus spp. (Table 1). To determine the antimicrobial resistance for the isolated bacteria from all samples, the isolates were divided into three groups: (1) Enterobacteriaceae (Enterobacter spp., Escherichia spp., Citrobacter spp., Proteus spp., Serratia spp. and Klebsiella spp.), (2) Pseudomonas spp. and (3) Staphylococcus spp. (two isolates from the genus Pasteurella, Acinetobacter, and one isolate of Streptococcus were not included in the antimicrobial sensitivity testing). Table 2 shows that antimicrobial resistance profile of Pseudomonas spp. isolates recovered from patient’s samples was higher than those from other sources. Pseudomonas isolates of patients samples were found to be resistant to most of antimicrobials used except for piperacillin–tazobactam, so they are considered as multidrug resistant (MDR). However, it is interesting to find that all isolates of Pseudomonas irrespective of their isolation source were resistant to the azetreonam and most of them were sensitive to piperacillin– tazobactam. The second effective antimicrobials against these isolates was imipenem.

Table 3 shows that the family Enterobacteriaceae isolated from patients and environmental samples were resistant to most of the tested antimicrobials. However, the Enterobacteriaceae isolates from air and HCWs samples were sensitive to the most of the tested antimicrobials. However, it is interesting to find that all isolates of the family Enterobacteriaceae that were tested, irrespective of their isolation source were resistant to ampicillin and cefazoline, whereas most of them were sensitive to imipenem. Table 4 shows that, penicillin and cefuroxime were the least effective drugs against most of Staphylococcus spp. isolated from all samples but linezolid and imipenem were the best effective drugs against most of Staphylococcus spp. from all samples. Totally, 74.62% of all Staphylococcus spp. from all samples were resistant to oxacillin. This is a high percentage of presumptive identification of methicillin resistant staphylococci. The incidence of methicillin-resistant Staphylococci according to oxacillin sensitivity test was 60% in patients samples, 70.6% in air samples, 77.8% in HCWs samples and 90% in environmental samples.

Table 3 – Antimicrobial susceptibility for Enterobacteriaceae isolated from different samples. Patients samples (N = 20)

Antimicrobial

HCWs samples (N = 11)

Environmental samples (N = 2)

Air samples (N = 1)

S

I

R

S

I

R

S

I

R

S

I

R

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

Gentamycin

8 40.0

1 5.0

11 55.0

7 63.6

–

4 36.4

–

–

2 100

1 100

–

–

Piperacillin

2 10.0

1 50.0

17 85.0

6 54.5

1 9.1

4 36.4

–

–

2 100

1 100

–

–

Ciprofloxacin

8 40.0

3 15.0

9 45.0

8 72.7

–

3 27.3

1 50

–

1 50

–

1 100

–

Ceftriaxone

5 25.0

1 5.0

14 70.0

8 72.7

–

3 27.3

–

–

2 100

1 100

–

–

Cefuroxime

2 10.0

4 20.0

14 70.0

2 18.2

3 27.3

6 54.5

–

–

2 100

–

–

1 100

Cefazoline

–

–

–

–

–

–

2 100

–

–

1 100

Cefepime

5 25.0

3 15.0

8 72.7

–

1 50

–

1 50

1 100

–

–

Ampicillin

–

–

–

–

–

–

2 100

–

–

1 100

Tetracycline

–

2 10

18 90.0

6 54.5

3 27.3

2 18.2

–

–

2 100

1 100

–

–

Chloramphenicol

–

4 20.0

16 80.0

7 63.6

–

4 36.4

–

–

2 100

1 100

–

–

14 70.0

2 10.0

4 20.0

–

–

–

–

2 100

1 100

–

–

1 5.0

–

19 90.0

–

4 36.4

–

–

2 100

1 100

–

–

Imipenem

Co-Trimoxazol

20 100 12 60.0 20 100

11 100 7 63.6

11 100 3 27.3 11 100

S, susceptible; I, intermediate; R, resistance

Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

JBUR-4026; No. of Pages 7

5

burns xxx (2013) xxx–xxx

Table 4 – Antimicrobial susceptibility pattern of Staphylococci isolated from different samples. Antimicrobial

Patients samples (N = 5)

HCWs samples (N = 9)

Environmental samples (N = 10)

Air samples (N = 17)

S

I

R

S

I

R

S

I

R

S

I

R

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

Gentamycin

2 40.0

–

3 60.0

6 66.7

1 11.1

2 22.2

8 80

1 10

1 10

15 88.2

1 5.9

1 5.9

Tetracycline

3 60.0

–

2 40.0

2 22.2

3 33.3

4 44.4

8 80

–

2 20

14 82.4

1 5.9

2 11.8

Ciprofloxacin

2 40.0

1 20.0

2 40.0

7 77.8

–

2 22.2

5 50

2 20

3 30

9 52.9

5 29.4

3 17.6

Chloramphenicol

1 20.0

–

4 80.0

5 55.5

1 11.1

3 33.3

6 60

1 10

3 30

11 64.7

2 11.8

4 23.5

Ceftriaxone

1 20.0

1 20.0

3 60.0

1 11.1

–

8 88.9

1 10

1 10

8 80

13 76.5

1 5.9

3 17.6

Cefuroxime

1 20.0

1 20.0

3 60.0

3 33.3

–

6 66.7

–

–

10 100

6 35.3

3 17.6

8 47.1

Linezolid

4 80.0

–

1 20.0

9 100.0

–

–

9 90

–

1 10

16 94.1

–

1 5.9

Erythromycin

1 20.0

–

4 80.0

4 44.4

1 11.1

4 44.4

2 20

1 10

7 70

12 70.6

2 11.8

3 17.6

Pencillin

–

–

5 100.0

–

–

–

–

10 100

–

2 11.8

15 88.2

Oxacillin

1 20.0

1 20.0

3 60.0

–

2 22.2

1 10

–

9 90

4 23.5

1 5.9

12 70.6

Imipenem

3 60.0

–

2 40.0

–

–

9 90

–

1 10

Trimthoprim

2 40.0

–

3 60.0

3 33.3

–

4 40

1 10

5 50

9 100 7 77.8 9 100 6 66.7

17 100 13 76.5

–

–

–

4 23.5

S, susceptible; I, intermediate; R, resistance

Comparison of antimicrobial resistance patterns of isolated bacteria from patients with burns and from other sources was tabulated in Table 5. We found no significant difference in antimicrobial resistance patterns of E. cloacae that were isolated from the burn patients samples in comparison to those isolated from other samples (P > 0.05). Also, same nonsignificant difference was found between antimicrobial resistance patterns of staphylococci spp. isolated from burn patients in comparison to isolates from other sources. However, the difference between the two groups of P. aeruginosa was statistically significant (P < 0.05).

4.

Discussion

The present study is the first that attempts to isolate and characterize the possible etiological bacterial pathogens from burn patients and their environment in the two main burn units in Gaza strip. In this study we aimed not only to present the type and frequencies of the bacterial genera present in burn patients and that present in their environment, but also we tested its antimicrobial resistance profile against most used antibiotics at our burn units in order to modify the preventive and therapeutic strategies.

The overall percentage of positive cultures from both hospitals was 45.8% which is in agreement to a study from Brazil where the positive cultures from burn unit was 44.8% [17]. In environmental samples, 76.3% were negative cultures. This may be an indicator of the cleanliness in units and the use of suitable disinfectants. In air samples, the highest bacterial count was found in the samples collected from patients’ rooms and dressing room because these places are crowded with patients and health care workers. The present study found that P. aeruginosa (50%) is the most commonly isolated bacteria from the burn patients followed by E. cloacae (27.8%), CoNS (9.3%), and E. coli (5.6%). Our results were compatible with those found in a study in USA [18] in which P. aeruginosa was the highest isolated bacteria followed by Enterobacter species. Different results were obtained in Turkey [19]. They reported the following percents: P. aeruginosa (57%), A. baumannii (21%), and S. aureus (14%). Other studies showed that most commonly isolated organisms from burn patients were Pseudomonas species followed by S. aureus and Klebsiella species [20–23]. These variations are expected as a result of variations in disinfection protocols and antimicrobial therapy protocols which may favor the survival of some pathogens over others.

Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

JBUR-4026; No. of Pages 7

6

burns xxx (2013) xxx–xxx

Table 5 – Comparison of antimicrobial resistance of isolated bacteria from patients and other sources. Antimicrobial

P. aeruginosa Gentamycin Piperacillin Ciprofloxacin Cefepime Imipenem Amikacin Ceftazidime Norfloxacin

No. of resistant isolates (%) Patients isolates (N = 27)

Other isolates (N = 31)

24(88.9) 20(74.1) 24(88.9) 23(85.2) 20(74.1) 23(81.5) 23(85.2) 21(77.8)

5(16.1) 11(35.5) 9(29) 7(22.6) 5(16.1) 5(16.1) 11(35.5) 10(32.3)

Antimicrobial

Enterobacter cloacae Gentamycin Piperacillin Ciprofloxacin Cefepime Trimethoprim Ampicillin Cefuroxime Ceftriaxone

No. of resistant isolates (%) Other isolates (N = 4)

8(61.5) 11(84.6) 6(46.2) 8(61.5) 12(92.3) 13(100) 10(76.9) 9(69.2)

2(50) 2(50) 2(50) 2(50) 4(100) 3(75) 3(75) 2(50)

No. of resistant isolates (%)

0.682 0.143 0.849 0.607 0.567 0.063 0.498 0.539

P value

Patients isolates (N = 5)

Other isolates (N = 37)

3(60.0) 2(40) 3(60.0) 5(100) 3(60.0) 3(60.0)

19(51.4) 8(21.6) 24(64.9) 34(91.9%) 15(40.5) 27(73.0)

The antimicrobial resistance pattern of Pseudomonas spp. isolates that were recovered from patients samples was as follows: (gentamycin (85.2%), piperacillin (70.4%), ciprofloxacin (85.2%), cefepime (85.2%), ceftazidime (85.2%), norfloxacin (77.8%), imipenem (74.1%), amikacin (81.5%), and aztreonam (100%). So these isolates are considered MDR because they are resistant to three or more antipseudomonal agents [24]. These strains have almost the same antibiotic resistance profile which means that they are clonal identical or at least related to each other and may be spread from one patient or more to others in the burn unit. These results need to be confirmed in future studies using molecular epidemiological tests. This resistance could be due to overuse or misuse of these antimicrobials and acquisition of resistant genes from other MDR bacteria, however, this should be confirmed and approved by molecular techniques as pulsed field gel electrophoresis typing method and this is beyond this work. MDR P. aeruginosa isolates were also found in previous studies [19,25,26]. The higher resistance rates found among P. aeruginosa clinical isolates compared to environmental isolates may be due the fact that these isolates are selected by the use of antibiotics given to patients therefore, flourish. Continuous disinfection may limit the presence of those resistance strains in the environment. This is supported by the fact only 23.7% of the environmental samples were positive in

0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.001

P value

Patients isolates (N = 13)

Antimicrobial

Staphylococcus spp. Ceftriaxone Ciprofloxacin Cefuroxime Penicillin Trimethoprim Oxacillin

P value

0.374 0.804 0.840 0.804 0.843 0.763

this study. Therefore, it could be hypothesized that environmental isolates are continuously changing and only those with antimicrobial resistance properties could colonize patients. In these burn units the main focus of the preventive measures practiced by the staff are mainly directed against P. aeruginosa. P. aeruginosa was found to have the highest resistance for the tested antimicrobials, followed by Enterobacter spp. This is in agreement with other findings in an American study [18]. All isolates of Pseudomonas spp. were resistant to most antimicrobials. The most effective antimicrobial agent against these isolates was piperacillin–tazobactam which also coincides with the results of an American study [18]. Isolated members of the family Enterobacteriaceae were resistant to the most antimicrobial agents tested, whereas most of them were sensitive for imipenem. A similar report of MDR gramnegative bacilli was also reported in the burn units in Delhi, India [22,23]. Staphylococcus spp. strains isolated from patients0 samples were sensitive to linezolid. This is in agreement with the a previous study in India [23]. A marked increase in the number of hospital infections due to methicillin-resistant staphylococci has been reported in many countries [27,28]. In the present study, among the staphylococci strains isolated from patients the incidence of methicillin-resistant staphylococci

Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

JBUR-4026; No. of Pages 7 burns xxx (2013) xxx–xxx

was 60% based on oxacillin resistance test. However, the methicillin-resistant in staphylococci should be confirmed by other molecular techniques as PCR for mec gene and this is beyond this study. This percentage is similar to that reported in a study [29] in Japan where MRSA isolates accounted for 60% of all S. aureus strains. A higher incidence of MRSA was reported in Italy and France although some European hospitals reported no cases caused by MRSA [30]. But it is much lower than the mean incidence in Korea (98%) [26].

5.

[11] [12]

[13] [14]

Conclusion [15]

P. aeruginosa (50%), was the most common isolated bacteria in this study and patients isolates were all considered as MDR and suspected to be clonal identical according to its antimicrobial resistant profiles. Higher rates were demonstrated in the Nasser hospital burn unit. Periodic monitoring of patterns of isolation and susceptibility profiles of pathogens in our burn units should be performed regularly in order to find out the best preventive and therapeutic strategies.

[18]

Conflict of interest

[19]

The authors declare no conflict of interest

[20]

references

[16]

[17]

[21] [22]

[1] Manson WL, Pernot PC, Fidler V, Saver EW, Klasen HJ. Colonization of burns and the duration of hospital stay of severely burned patients. J Hospital Infect 1992;22:55–63. [2] Revathi G, Puri J, Jain BK. Bacteriology of burns. Burns 1998;24(4):347–9. [3] Heggers JP, Robson MC. Infection control in burn patients. Clin Plast Surg 1986;13:39–47. [4] Ansermino M, Hemsley C. Intensive care management and control of infection. Mol Biol Rep 2004;329:220–3. [5] Agnihotri N, Gupta V, Joshi RM. Aerobic bacterial isolates from burn wound infections and their antibiograms – a five year study. Mol Biol Rep 2004;30:241–3. [6] Gupta M, Gupta OK, Yaduvansh RK, Upadhyahy J. Burn epidemiology: the pink city scene. Burns 1993;19:47–51. [7] Bowler PG, Duerden BI, Armstrong DG. Wound microbiology and associated approaches to wound management. Clin Microbiol Rev 2001;14:244–69. [8] Erol S, Altoparlak U, Akcay MN, Celebi F, Parlak M. Changes of microbial flora and wound colonization in burned patients. Burns 2004;30:357–61. [9] Samuel SO, Kayode OO, Musa OI, Nwigwe GC, Aboderin AO, Salami TAT, et al. Nosocomial infections and the challenges of control in developing countries. Afr J Clin Exper Microbiol 2010;11:102–10. 2. [10] Marais E, Aithma N, Perovic O, Oosthuysen WF, Musenge E, Duse AG. Antimicrobial susceptibility of methicillin-resistant

[23]

[24]

[25] [26]

[27] [28]

[29]

[30]

Staphylococcus aureus isolates from South Africa. S Afr Med J 2009;99:170e3. Church D, Elsayed S, Reid O, Winston B, Lindsay R. Burn wound infections. Clin Microbiol Rev 2006;19:403–34. Kampf G, Ostermeyer C. Efficacy of two distinct ethanolbased hand rubs for surgical hand disinfection – a controlled trial according to prEN 12791. BMC Infect Dis 2005;5:1471–2334. Ness S. Surface and dermal monitoring for toxic exposure. New York: Wiley Blackwell; 1994. Uppal SK, Ram S, Kwatra B, Garg S, Gupta R. Comparative evaluation of surface swab and quantitative full thickness wound biopsy culture in burn patients. Burns 2007;33: 460–3. Pechorsky A, Nitzan Y, Lazarovitch T. Identification of pathogenic bacteria in blood cultures: comparison between conventional and PCR methods. J Microbiol Methods 2009;78:325–30. CLSI. Performance standards for antimicrobial susceptibility testing; seventeenth informational supplement, document M100-S17, 2007; 27 No. 1. Soares J, Macedo A, Barberino B. Nosocomial infections in a Brazilian burn unit. Burns 2006;32:477–81. Agata E. Rapidly rising prevalence of nosocomial multidrug resistant, gram negative bacilli: a 9-year surveillance study. Infect Control Hosp Epidemiol 2004;25:842–6. Oncul O, Ulkur E, Acar A, Turhan V, Yeniz E, Karacaer Z, et al. Prospective analysis of nosocomial infections in a burn care unit, Turkey. Indian J Med Res 2009;130:758–64. Lari A, Alaghehbandan R. Nosocomial infections in an Iranian burn care center. Burns 2000;26:737–40. Ozumba C, Jiburum C. Bacteriology of burn wounds in Enugu, Nigeria. Burns 2000;26:178–80. Singh NP, Goyal R, Manchanda V, Das S, Kaur I, Talwar V. Changing trends in bacteriology of burns in the burn units, Delhi, India. Burns 2003;29. 132-129. Mehta M, Dutta P, Gupta V. Bacterial isolates from burn wound infections and their antibiograms: A eight-year study. Indian J Plast Surg 2007;40:25–8. Defez C, Fabbro-Peray P, Bouziges N, Gouby A, Mahamat A, Daure`s JP, et al. Risk factors for multidrug-resistant Pseudomonas aeruginosa nosocomial infection. J Hosp Infect 2004;57:209–16. Alaghehbandan R, Rossignol A, Lari A. Pediatric burn injuries in Tehran, Iran. Burns 2001;27:115–8. Song W, Lee K, Kang H, Shin D, Kim D. Microbiologic aspects of predominant bacteria isolated from the burn patients in Korea. Burns 2001;27:136–9. Husain M, Karim Q, Tajuri S. Analysis of infection in a burn ward. Burns 1989;15:299–302. Taylor G, Kibsey P, Kirkland T, Burroughs E, Tredget E. Predominance of staphylococcal organisms in infections occurring in a burns intensive care unit. Burns 1992;18: 332–5. Kimura A, Igarashi H, Ushioda H. Epidemiological study of Staphylococcus aureus isolates from Japanese national united and medical college hospitals. Jpn J Infect Dis 1992;66: 1543–9. Vincent L, Bihari J, Suter M. The prevalence of nosocomial infection in intensive care units in Europe. J Am Med Assoc 1995;274:639–45.

Please cite this article in press as: Elmanama AA, et al. Antimicrobial susceptibility of bacterial isolates from burn units in Gaza. Burns (2013), http://dx.doi.org/10.1016/j.burns.2013.04.011

7