Molecular Characterization of Carbapenem-Resistant Acinetobacter Baumannii Blood Culture Isolates from Three Hospitals in Turkey

We aimed to investigate the clonal relationships, common sequence types, and carbapenemase genes in 177 non-repetitive blood culture isolates of Acinetobacter baumannii collected from patients at three university hospitals in Turkey in 2016. Molecular epidemiological characteristics of the isolates were examined using pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) (Pasteur scheme-cpn60, fusA, gltA, pyrG, recA, rplB, and rpoB). Multiplex PCR was used to investigate the carbapenemase genes, including blaoxA23-liker blaoxA-24-likes blaoxA-48-likes blaoxA-S8-liker blaTMP blavIM, and blaNDM: PFGE genotyping yielded 92 pulsotypes with a clustering ratio of 69.7%. As per a 285% similarity coefficient, 159 (90.9%) isolates were found to be clonally related. The blaoxA-23-take and blaoxA-58-ike genes were identified in 100% and 28.2% of the isolates, respectively. The blaNDM gene was identified in two isolates. The MLST analysis included 54 isolates with different pulsotypes, and 29 sequence types (STs). Most of the isolates (n = 36) belonged to the clonal complex (CC)2, one isolate belonged to CC1, and one isolate belonged to CC164. Sixteen new STs (ST1235- ST1250) were identified. Identifying both global ST2 and a large number of new STs, revealed high genetic diversity in A. baumannii isolates in the study population.