R2136 Antibiotic resistance of Stenotrophomonas maltophilia in children with cysticfibrosis to the currently used antibiotics

S618 Methods: There were isolated 288 Klebsiella spp. strains and 285 P. aeruginosa strains from patients with severe sepsis admitted on medical and surgical wards between 1999–2002 and 2003–2006 in ClujNapoca. Identification was performed with API 20E and API 20NE. Antibiotic susceptibility testing was performed by disk diffusion method and API ATB. Expression according to CLSI Guidelines. Strains with resistance at more than 3 antibiotic groups were considered multidrug resistant strains (MDR). Results: On that two periods, resistance of Klebsiella spp. strains to ceftazidim and ciprofloxacin increased from 33% to 54% (p = 0.007) respectively from 26% to 30.3%. Amikacin, carbapenems and colistin resistance was constantly low. The frequency of ESBL strains significantly increased from 21% to 34.8% (p = 0.017). MDR strains were detected in 21.8% respectively in 23% of cases. 50.6% of these strains were isolated in nosocomial infections. There was significantly increasing resistance to ceftazidim and amikacin from 63% to 73% and from 25% to 37.5% (p = 0.03) in P. aeruginosa strains. Colistin and carbapenems resistance remain low. Comparing the two periods we detected significant increasing of MDR strains from 23.7% to 43.75% (p = 0.0003). 77.3% of these strains were isolated in nosocomial infections. Conclusions: Klebsiella spp. and P. aeruginosa strains isolated from patients with severe sepsis demonstrate increasing trends of resistance to ceftazidim, ciprofloxacin and amikacin correlated with nosocomial infections. Carbapenems and colistin remains the only reliable antibiotics against MDR strains. R2135 Investigation of the gentamicin MIC values by e test method in the Gram-negative bacteria isolated from different clinic samples F. Yildirim, G. Sengoz, K. Kart Yasar, O. Nazlican (Istanbul, TR) Objectives: Pseudomonas and Acinetobacter species and enteric Gramnegative bacilli isolated from various materials sent from intensive care unit (ICU) and other clinics of our hospital were examined for their gentamicin resistance. Methods: The 100 bacteria examined within this study were identified using conventional methods and API-ID 32E. Gentamicin resistance was studied with E test according to the recommendations of CLSI. Results: 48 of them were enteric Gram-negative bacilli (6 Klebsiella spp., 7 Enterobacter spp. and 35 E. coli), and 40 of them were Acinetobacter, and 12 of them were Pseudomonas. 51 of the strains were isolated from the materials sent from ICU and 49 from other clinics. 85% of the Acinetobacter strains were isolated from ICU. But the ratio of ICU strains was 20% in enteric Gram-negative bacilli. Pseudomonas strains isolated from the ICU and other clinics were approximately the same rate. 29% of the E. coli strains were found from urine and 20% of the Acinetobacter strains were isolated from sputum and abscess. The resistance in Pseudomonas and Acinetobacter strains was over 40%. In the Enterobacteriaceae family, the resistance was 14.5%. Among Pseudomonas strains, resistance ratio was higher in materials sent from ICU (57%) than materials obtained from other clinics (20%). However in Acinetobacter strains there was an opposite situation: the resistance in ICU samples was 38% and in other clinical materials was 80%. These resistant strains from other clinics were taken from diabetic foot wounds. Among the enteric Gram-negative bacilli, the resistance rates were similarly low in strains isolated from ICU and other clinics. (10% and 15.7% respectively) Conclusion: In our hospital Since 1994 gentamicin has been administered freely whereas usage of other agents have always been under control of microbiologists. However almost for the last 10 years aminoglycoside resistance declined considerably due to wide usage of quinolones.

17th ECCMID / 25th ICC, Abstracts accepted for publication only R2136 Antibiotic resistance of Stenotrophomonas maltophilia in children with cystic fibrosis to the currently used antibiotics H. Alexandrou-Athanasoulis, S. Doudounakis, K. Samantas, J. Papavasiliou, C. Baclakou, A. Pangalis (Athens, GR) Stenotrophomonas maltophilia (SM) is an important emerging pathogen which has been cultured with increasing prevalence from the sputum of patients with cystic fibrosis (CF). The aim of our study is to determine the resistance to currently used antibiotics for the treatment of these patients. Material and Method: Eighty seven Stenotrophomonas maltophilia isolates from sputum and deep throat cultures, which were obtained from 87 patients with cystic fibrosis, during 2000–2006, were examined. The isolates were stored at −70ºC, thawed and subcultured twice on blood agar. The identification of the isolates was made by the API 20NE identification system (bioM´erieux, France) and the antibiotic resistance was determined with the E test strips (AB Biodisk, Sweden) on Muller Hinton agar according to CLSI recommendations. Results: (1) The resistance (%) to ticarcillin/clavulanic acid, cotrimoxazole, minocycline, ciprofloxacin, levofloxacin and colistin were 25.3, 36.0, 1.6, 22.5, 7.8, and 48.3 respectively. (2) The MIC50 and MIC90 of ticarcillin/clavulanic, co-trimoxazole, minocycline, and levofloxacin are seen in Table 1. Table 1 Antibiotic

Ticarcillin/clavulanic acid Co-trimoxazole Minocycline Levofloxacin

MIC (mg/L) Range

MIC50

MIC90

0.5–256 0.125−32 0.125−16 0.125−32

8 0.75 0.75 1

128 24 2 6

Conclusions: (1) The most effective antibiotic for our isolates of Sm is minocycline, followed by levofloxacin, co-trimoxazole and ticarcillin/clavulanic acid. (2) The multidrug resistant isolates were 3.4%. R2137 First report of methicillin-resistant Staphylococcus aureus strain of animal provenience in the Czech Republic J. Bardon, M. Kolar, P. Sauer, D. Koukalova, J. Petrzelova, L. Cekanova (Olomouc, CZ) Objectives: Bacterial resistance to antimicrobial agents has become a serious problem both in human and veterinary medicine. It is not unrealistic to presume that multiresistant bacteria may spread from animal to human populations by foods of animal origin as well by persons working e.g. in livestock breeding. Therefore, the study aimed at determining the susceptibility of Staphylococcus sp., Enterococcus sp. and Escherichia coli strains to antimicrobial agents in pigs bred in one of the regions of the Czech Republic. Methods: The tested strains were isolated from bred pigs (piglets aged 7 to 30 days). Bacterial species were identified by standard microbiological techniques and susceptibility to antibiotics was determined quantitatively by the standard microdilution method. Resistance of the Staphylococcus aureus strain to oxacillin was confirmed by detection of the mecA gene and PBP2a. Susceptibility of staphylococci to penicillin was determined by production of B-lactamase, using the chromogenic cephalosporin method. Susceptibility to clindamycin, if simultaneous with resistance to erythromycin, was verified by modified disk diffusion test. Results: From the piglet rectal swabs, a total of 115 strains of Staphylococcus sp., 61 strains of Enterococcus sp. and 111 strains of Escherichia coli were isolated. In the case of staphylococci, the methicillinresistant Staphylococcus aureus strain (MRSA) was identified. Moreover, higher frequency of coagulase-negative staphylococci with minimum inhibitory concentration of oxacillin ± 0.5 mg/L was noticed. Inducible