engleski

Nursing home as reservoir of carbapenem-resistant Acinetobacter baumannii

ABSTRACT Acinetobacter baumannii is an increasingly common pathogen in health care settings globally. It is frequently resistant to multiple antimicrobial agents and there are recent reports on strains that are pandrug resistant.The aim of the study was to characterize the mechanisms carbapenem-resistance of A. baumannii strains from a nursing home in Zagreb and to genotype the strains. Antimicrobial susceptibility testing was performed by broth microdilution method according to CLSI. PCR was used to detect genes encoding carbapenemases of group A, B and D and extended-spectrum β-lactamases (ESBL). Genotyping of the strains was performed by rep-PCR. All strains were found to be resistant to ceftazidime, cefotaxime, ceftriaxone, cefepime, piperacillin/tazobactam, imipenem, meropenem and ciprofloxacin. All but one strain were resistant to gentamicin. PCR revealed the blaOXA-23 genes in fourteen, blaOXA-24 in five, and blaVIM in eleven strains. All strains positive for blaVIM genes coharboured blaOXA-23 genes. The fourteen strains with OXA-23 belonged to ICL II whereas the five strains positive for blaOXA-24 belonged to ICL I. In contrast to hospitals where OXA-24/40-like β-lactamases and OXA-58 were the most prevalent OXA-23 like β-lactamases are the dominant group in the nursing home. OXA-58-like β-lactamase which is the most widespread group was not found. Acquistion of blaMBL genes in A. baumannii strains was observed. Rep-PCR identified two clones. Nursing homes can act as a source of dissemination of blaOXA and blaMBL genes in the environment and the possible influx to the hospital environment.

Acinetobacter baumannii ; meropenem ; OXA-23 ; OXA-24 ; resistance

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