engleski

Molecular epidemiology of carbapenem resistant Acinetobacter baumannii in University Hospital Split, Croatia

Acinetobacter baumannii is an opportunistic pathogen that is frequently involved in outbreaks of infection, occurring mostly in intensive care units. Carbapenem resistance is now being reported increasingly in A. baumannii isolates in association with the production of carbapenem-hydrolysing class D beta-lactamases or oxacillinases that have now emerged worldwide. The aim of the present study was to analyse and compare genotypes of clinical isolates of carbapenem resistant Acinetobacter baumannii collected from three different Intensive Care Units in University Hospital Split, Croatia. During 2004, twenty-two non- repetitive A. baumannii isolates with an unusual resistance profile were obtained from patients hospitalised at three different Intensive Care Units (two adults ICU and one children ICU) inside University Hospital Split. All collected isolates of A. baumannii displayed intermediate (MICs>8 mg/L) or resistant (MICs>16 mg/L) profile to imipenem and/or meropenem. Minimum inhibitory concentrations were also determined for ceftazidime, cefepime, ceftriaxone, amikacin, gentamicin, ciprofloxacin and piperacillin-tazobactam by broth microdilution according to CLSI (formerly NCCLS) recommendation. All isolates were multidrug-resistant exhibiting high resistance to tested antimicrobials. The isolates of A. baumanii were genetically characterized using pulsed-field gel electrophoresis (PFGE). Strain typing was performed by macrorestriction analysis of chromosomal DNA by use of PFGE (Apa I enzyme, in a CHEF DR III drive module). Results. We report the clonal dissemination of pulsotype A between two different adult intensive care units in University Hospital Split, belonging to the same pulsed-field gel electrophoresis (PFGE) profile, probably by hospital staff during medical procedures. The strain characterised as pulsotype B was the only strain isolated from children intensive care unit without expanding inside the hospital. The infection control team of the hospital implemented restriction of carbapenem usage and strict antiseptic techniques, which included the rigorous use of alcohol-clorhexidine solutions before and between patient and equipment contact and before leaving the units. Consequently, incidence and spread of multidrug-resistant A. baumannii nosocomial infections suggest the necessity of a surveillance program and enforcing adequate control measures in different hospital settings.

acinetobacter baumaniii; oxacillinases; carbapenems

Clinical Microbiology and Infection 13 (2007) (S1) P1338