distribution of Oxa-Type Carbapenemase Genes in Carbapenem-resistant Acinetobacter Baumannii strains: an Investigation by Real-Time Polymerase Chain Reaction Method

Abstract

Objective: Carbapenems are the most important broad spectrum antimicrobials used in the treatment of Acinetobacter baumannii infections, but resistance to carbapenems is increasing worldwide. In this study, we aimed to investigate the distribution of OXA-type carbapenemase genes observed in carbapenem-resistant A. baumannii strains by real-time polymerase chain reaction (PCR) method and to provide epidemiological data. Methods: Between January 2016 and January 2018, 20 carbapenem-resistant A. baumannii strains from clinical specimens were included in the study. DNA isolations were performed, and distribution of OXA-type carbapenemase genes were examined using primers and TaqMan probes specific to genes of OXA-23, OXA-24, OXA-51 and OXA-58 carbapenemases by real-time PCR method. Results: Tigecycline was the best choice for carbapenem-resistant A. baumannii strains, of which 16 (80%) were susceptible to this antimicrobial. bla(OXA-51) was detected in all strains, while bla(OXA-24) was detected in only 1 (5%) strain. Of 20 strains, 10 showed the presence of bla(OXA-23) and bla(OXA-51) simultaneously. Conclusions: Simultaneous occurence of bla(OXA-23) and bla(OXA-51 )is remarkable in terms of distribution of OXA-type carbapenemases in carbapenem-resistant A. baumannii strains. Valuable epidemiological data can be obtained by performing routine surveillance of such strains by means of techniques that can produce fast and reliable results such as real-time PCR.