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 bla(OXA-23-like),bla(OXA-24-like), bla(OXA-48-like), bla(OXA-58-like), bla(IMP), bla(VIM) and bla(NDm). PFGE genotyping yielded 92 pulsotypes with a clustering ratio of 69.7%. As per a >= 85% similarity coefficient, 159 (90.9%) isolates were found to be clonally related. The bla(OXA-)(23-like) and bla(OXA-)(58)-like genes were identified in 100% and 28.2% of the isolates, respectively. The bla(NDM) 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.

Automated summary

This study investigated the clonal relationships, common sequence types, and carbapenemase genes in 177 Acinetobacter baumannii blood culture isolates from three university hospitals in Turkey in 2016. The findings revealed high genetic diversity and clonal relationships among the isolates.