engleski

Emergence of VIM-1-carbapenemase-producing Enterobacter cloacae in the intensive care unit (ICU), University Hospital Split, Croatia

The emergence of carbapenem-resistant Enterobacteriaceae has become a substantial global health problem. The aim of our study was to analyse the antimicrobial resistance, the clinical background and the type of B-lactamase genes among carbapenemase resistant strains of Enterobacter cloacae isolated from patients in ICU. The strains were selected in period between June to August 2012, according to their susceptibility patterns to carbapenems. The antibiotic susceptibility testing was performed by disk diffusion method according to EUCAST guidelines and/or MICs by using the E-test method (AB Biodisk, Solna, Sweden) and Vitec 2 Compact (bioMérieux). Isolates were screened for metallo-B-lactamase (MBL) production by modified Hodge-Test and positive findings were confirmed by PCR. PCRs were performed in Veriti Thermal Cycler (Life Technologies). Type of VIM B-lactamase gene was determined by sequencing of PCR products using an ABI Prism 1.1 BigDye sequencing kit and an ABI 310 DNA analyzer (Life Technologies). Extended spectrum B-lactamase (ESBL) production was detected by double-disc synergy test (DDT). The demographic and clinical data (sex, age, underlying diseases, date of admission, date of isolation, site of infection, coinfection, antimicrobial treatment, mechanical ventilation, white blood cell count and outcome) were retrospectively analyzed from medical records. Results: Five patients were infected and one was colonized with phenotypically identical multidrug-resistant (MDR) VIM-1 producing E. cloacae strain susceptibile only to colistin. The site of isolation was lower respiratory tract (3 of 6), blood (1of 6), abdominal cavity (1 of 6) and rectal swab (1 of 6). All cases were hospital acquired. All patients had serious underlying diseases, were on mechanical ventilation, received a broad spectrum antibiotic and were coinfected with carbapenem resistant Acinetobacter baumannii strain. Four patients died and two had unimprovable medical condition. VIM-1 producing E. cloacae has emerged in our hospital. Since the carbapenemase-producing strains usually show MDR phenotype, the antibiotic therapy options for infections caused by such strains are strongly limited. This highlights the need for continuous surveillance to prevent further spread.

Enterobacter cloacae; VIM-1 carbapenemase; MDR; ICU

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