Evaluation of the antibiotic resistance pattern and prevalence of oxacillinase genes in clinical isolates of Acinetobacter baumannii from hospitals in Shiraz. (۲۰۱۳-۲۰۱۴)

Background and Aim : Acinetobacter baumannii is one of the main factors of nosocomial and pneumonia infections. Most of the major difficulties related to the treatment of Acinetobacter baumannii infections is the emergence of MDR-strains (multi-drug resistant). In majority of medical centers, the best choice for the treatment of Acinetobacter baumannii infections is carbapenems. However, in the last years, resistance to these antibiotics due to the production of carbapenem-hydrolysing beta-lactamases such as OXA-carbapemase genes has been increased. Hence, the goal of this study was to investigate the presence of Oxacillinase genes in isolated acinetobacter baumannii strains from clinical samples.Methods : This study has been done in four Shiraz teaching hospitals( Namazi, Faghihi, Ali-asghar, Ghotbo-aldin).we were gathered about ۲۰۰ Acinetbacter baumannii clinical samples during the six-months. All the isolates were investigated through the disk diffusion tests in order to antibiotic resistance patterns. Also, the MIC concentration of imipenem and colistin antibiotics were evaluated by E-test methods. Additionally, the polymerase chain reaction (PCR) and multiplex PCR was used to survey the presence of blaOXA-۲۳-like, blaOXA-۲۴-like ,blaOXA-۵۱-like and blaOXA-۵۸-like genes.Results : First, all the isolates were positive for the presence of blaOXA-۵۱-like genes and ۷۱ isolates were harbored blaOXA-۲۳-like genes. Among the tested antibiotics through the disk-diffusion methods, all the isolates were susceptible to Colistin and polymixin B antibiotics, however, all isolates had shown resistance to the ampicillin,pepiracilin, pepiracili-tasobactam, ceftazidime, and cefotoxin. According to the results of E-test of ۸۶ isolates of Acinetobacter baumannii, ۸۵ isolates were susceptible to Colistin antibiotics, and only one isolate (۱/۲%) was resistant to this antibiotic.Conclusion : According to the data we were gathered through the mentioned tests, the rate of resistance to Colistin and polymixin B was significantly high. Also, resistance rate of isolates to imipenem and meropenem were remarkably high. Among the Oxacillinase genes, blaOXA-۲۳-like and bla-OXA-۲۴-like genes had the most frequency.

کلیدواژه ها:

Acinetobacter baumannii ، antibiotic resistance ، OXA-carbapenemase ، Oxacillinase.