Epidemiology and antibiotic resistance of bacterial isolates from patients with bacteraemia in an intensive care unit

Abstract number: 1734_156

Ikonomopoulou E., Georgakoloulos P., Michail P., Paratiras S., Stavropoulou G., Verra C., Dondou V., Regli A.

Objectives: The aim of this study was to carry out the prevalence and the antibiotic resistance of bacterial isolates from patients with bacteraemia in the intensive care unit (ICU) of our hospital.

Methods: Blood cultures from ICU patients were performed using the Bactec 9120 (Becton Dickinson) and the Bact – alert (bioMérieux) during 2003 and 2004–2005 respectively. The identification and the antimicrobial resistance of bacterial isolates were carried out by the VITEK system (bioMérieux). MBL production was performed by E-test (Imipenem, Imipenem and EDTA). Colistin sensitivity was performed by E-test (AB–Biodisc).

Results: During a three year period (2003 –2005) 155 patients (99 males/56 females) hospitalised in our ICU and 30 (19.4%) had one or more episodes of bacteraemia. A total of 53 bacterial strains were isolated. The most prevalent pathogen was P. aeruginosa 14 (26.4%) followed by K. pneumoniae 8 (15%), Coag- staphylococci 8 (15%), Acinetobacter baumannii 7 (13.2%), Candida spp. 6 (11.3%), E. faecalis 3 (5.7%), Stenotrophomonas maltophilia 3 (5.7%), S. aureus 2 (3.8%) and E. coli 2 (3.8%). 5 P. aeruginosa strains produced MBLs and 4 K. pneumoniae strains produced ESBL. Resistance rates of P. aeruginosa and K. pneumoniae for commonly used drugs respectively were: amikacin 21.5%/0%, aztreonam 36%/12.5%, cefepime 29%/50%, ceftazidime 21.5%/50%, ciprofloxacin 21.5%/75%, imipenem and meropenem 36%/0%, piperacillin/tazobactam 36%/12.5%. All Acinetobacter baumannii strains were multiresistant (resistance rate: 83% to amikacin, cefepime, imipenem and 100% to aztreonam, piperacillin/tazobactam, gentamycin, netimicin, tobramycin and ceftazidime). All Acinetobacter baumannii strains were sensitive to Colistin. Among staphylococci all isolates were resistant to oxacillin but they were susceptible to glycopeptides. Candida spp. (C. albicans 4 strains, 1 strain C. sake and 1 strain C. glabrata) were sensitive to Amphotericin B, Fluconazole and Flucytocine.

Conclusions: Bacteraemia happens in 19.4% of ICU patients and multiresistant strains are mainly responsible so we must be careful in antibiotic usage in order not to increase the antibiotic resistance of bacterial isolates.