engleski

Diversity of oxacillinases in Acinetobacter baumannii from Croatia ; The results of the multicenter study

Objectives: Carbapenems have a potent activity against and are often used as last resort for the treatment of infections due to multiresistant Acinetobacter baumannii isolates. The first carbapenem-resistant isolates in Croatia were found in University Hospital Split in 2002 The carbapenem-resistance was mediated by hyperproduction of OXA-51 due the ISAba1 located upstream of the genes. Later, the studies of carbapenem-resistance in Croatia reported OXA-72 β-lactamase in University Hospital Center Zagrebit and University Hospital Split Zagreb. These observations gave rise to a multicenter study conducted in 2009. in Northern Croatia and Istria. The aim of the present study was to characterize the genetic basis of carbapenem resistance and to compare the genotypes of the isolates. Methods: In total, 185 isolates were collected from 13 centers in Northern Croatia and Istria. Antibiotic susceptibilities were determined by broth microdilution method according to CLSI. Genes encoding carbapenem hydrolyzing-oxacillinase, metallo-beta-lactamases (MBLs) of VIM, IMP and SIM series and extended-spectrum beta-lactamases (ESBLs) belonging to PER and TEM family were detected by PCR and when needed identified by sequencing. Sequence groups SG corresponing to international clonal lineages (ICL I-III) were determined by multiplex PCR and genotyping of the strains was performed by MLST (multilocus sequence typing), pulsed-field gel electrophoresis (PFGE) and random amplification of polymorphic DNA (RAPD). Results: Thirty-six strains (19.5%) were found to produce acquired oxacillinases. The most prevalent group was OXA-24 with 17 positive isolates. Sequencing of blaOXA-24 gene from the representative strain identified OXA-72 β-lactamase.

Acinetobacter baumannii; carbapenems; OXA-24; OXA-58

nije evidentirano