Marzieh Hashemian - Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran

Background and Aim : Background: Acinetobacter baumannii, as one of the most important pathogens in nosocomial infections, causes a wide range of respiratory, urinary tract and blood infections. The high prevalence of antibiotic resistance mechanisms in this bacterium has caused widespread health concerns in various countries around the world. One of the mechanisms of resistance in this bacterium is the production of carbapenemases and metallobetalactamases, which makes this bacterium resistant to almost all beta-lactams. In this study, the frequency of genes encoding metallobetalactamases and carbapenemases was investigated by PCR.Methods : Materials and Methods: ۷۴ isolates of Acinetobacter baumannii involved in nosocomial infections were examined for phenotypic and genotypic identification of isolates producing metallobetalactamase and carbapenemase. Isolates were selected from Ilam and Tehran teaching hospitals. After identifying the isolates by biochemical methods, screening and confirmation methods according to the ۲۰۲۰ CLSI guidelines were used to identify the phenotypic isolates of metallobetalactamase producing isolates. In the next step, DNA of isolates was extracted and PCR method was used to evaluate the frequency of genes encoding metallobetalactamase including NDM, OXA۲۳, OXA۴۸, KPC, IMP and VIM Results : Results: Out of ۷۴ isolates studied by screening method, ۶۷ isolates were identified as metallobetalactamase resistant which in the confirmation phase the number of isolates was reduced to ۶۱ isolates. Based on PCR results, ۴۰ isolates (۵۴%) encoded NDM, ۵۸ isolates (۷۸.۴%) encoded VIM and ۵۲ isolates (۷۰.۳%) encoded OXA۲۳. The frequencies of genes encoding IMP, OXA۴۸ and KPC were ۱.۳۵%, ۲.۷% and ۲.۷%, respectively.Conclusion : Conclusion: The results of this study showed that a high percentage of Acinetobacter baumannii isolates are phenotypically and genotypically producing metallobetalactamase. Among the ۶ genes encoding metallobetalactamase, the highest frequency was observed in VIM, OXA۲۳ and NDM genes.

Acinetobacter baumannii, resistance to carbapenems, metallobetalactamase