Quinolone-Resistant Isolates of Acinetobacter baumannii in a Teaching Hospital in Iran

Background: Acinetobacter baumannii could develop resistance through different mechanisms, leading to the emergence of strains resistant to all commercially accessible antibiotics. This research aimed to evaluate the antimicrobial resistance pattern and the prevalence of genes encoding quinolone resistance in quinolone-resistant isolates. Materials Methods: In this study, 114 A. baumannii strains were isolated from patients admitted to a teaching hospital in Kashan, during 2013-2014. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk-diffusion breakpoint assay. Polymerase chain reaction (PCR) was employed to identify quinolone resistance encoding genes (gyrA and parC). Findings: All A. baumannii strains showed resistance to piperacillin, ceftriaxone, ceftazidime, and cefotaxime, and all of them were susceptible to colistin and polymyxin B. In addition, 100% of A. baumannii strains were MDR (Multi-drug resistance), and 68.4% (78 isolates) of them were XDR (Extensively-drug resistant), while none of them were PDR (Pan-drug resistant). All A. baumannii strains isolated in this study were positive for the presence of parC and gyrA genes. Conclusion: MDR A. baumannii strains were highly prevalent among hospitalized patients in this study. Based on these comes about, novel prevention and treatment procedures against A. baumannii infections are justified. Moreover, these information may help in reexamining treatment rules and territorial arrangements in care units to moderate the rise of antimicrobial resistance.