Investigation of Molecular Mechanisms of Carbapenemase Producing Acinetobacter baumannii complex Isolates Isolated from Blood Cultures

INTRODUCTION: It was aimed to determine the presence of metallo-beta-lactamases (MBL) and oxacillinases (OXA) enzymes in Acinetobacter baumannii complex (ABC) isolates, which show decreased sensitivity to carbapenems isolated from blood cultures and to investigate the relationships of isolates among each other and with European clones (EU) I, II, III. METHODS: The study included ABC isolate which has reduced sensitivity to at least one of either imipenem or meropenem which was isolated from blood samples obtained from 74 patients who were admitted to the hospital between 2008 and 2009. Identification of isolates and their antimicrobial susceptibilities were performed using BD Phoenix Automated System (Becton-Dickinson, USA). OXA and MBL genes were investigated by polymerase chain reaction (PCR). The clonal relationship of the isolates was determined by pulsed-field gel electrophoresis (PFGE) method. RESULTS: MBL genes and blaOXA-24-like gene were not determined in any of the isolates. blaOXA-51-like was detected in all isolates, blaOXA-58-like gene in 32 isolates and blaOXA-23-like gene in 26 isolates. Using PFGE method, it was detected that fifty-five blood isolates carrying the blaOXA23-like and/or blaOXA-58-like gene were clustered under six clusters. The similarity of EU clones with clinical ABC isolates in the clusters was found to be over 90%. DISCUSSION AND CONCLUSION: ABC isolates producing oxacillinase in our hospital; The presence of association with EU clone III, which is reported very rarely in our country, and the detection of possible related isolates with EU clones I and II show the potential for the spread of these clones in our hospital and in our country.