Detection of OXA Beta Lactamases Among Clinical Isolates of Acinetobacter baumannii Isolated from Tehran Hospitals, Iran

Background and Objective: Acinetobacter baumannii is a non-motile Gram-negative bacterial pathogen with the history of vast resistant to antibiotics. The aim of this study was to determine the possibility of existence of OXAs genes among clinical isolates of A. baumannii obtained from Tehran hospitals. Materials and Methods: A total of 101 isolates were identified as A. baumannii by common biochemical and molecular tests. The susceptibility to different antibiotics was assessed with Kirby-Bauer disk diffusion method. Phenotypic Detection of MBLs was performed with CDT test and PCR assay was also performed for detection of bla OXA-23-like , bla OXA-24-like , bla OXA-40-like, bla OXA-51-like, bla OXA-58-like and bla OXA-143-like genes Results: All isolates of A. baumannii showed high-level of resistance to all antibiotics except for Polymyxin B. The bla OXA-51 like genes was found in all of the isolates and the prevalence of bla OXA-143like , bla OXA-23like, bla OXA-40like and bla OXA-24like were 56%, 45.45%, 33% and 11.8%, respectively. Conclusion: The bla OXA-51-like was the predominant mechanism of resistance to imipenem in A. baumannii and therefore, early recognition of carbapenem-resistant A. baumannii isolates is a useful tools to prevent their spreading within the hospital environment.