Antibiotic Resistance Patterns and Distribution of Ampc β-Lactamases Genes Among Acinetobacter Baumannii Clinical Isolates from Hospitals of Tehran, Iran

Abstract

Background Acinetobacter is a Gram-negative coccobacilli bacterium that can produce severe and different infections. Among the species of these bacteria, Acinetobacter baumannii is the most common cause of nosocomial infections. Due to the high prevalence of antibiotic resistance in this bacterium and the significant increase in antibiotic resistance, this study was conducted to investigate the antibiotic susceptibility of A. baumannii isolates from Iran. A total of 60 A. baumannii bacteria were isolated from the different clinical samples in hospitals of Tehran, Iran. The isolates susceptibility to 13 commonly used antibiotics was examined according to the Clinical & Laboratory Standards Institute (CLSI) guidelines. Using PCR, three important AmpC β-lactamases relayed genes (DHA, CIT and MOX) were detected. Results The highest and lowest resistance rate was related to ampicillin (98.3%) colistin (35%), respectively. Of 60 isolates, 59 isolates (98.34%) were resistant to more than 8 antibiotics. The frequencies of DHA, CIT and MOX genes were 1 (2%), 7 (12%), 27 (46%), respectively. Based on definition, 59 (88.33%), 44 (73.33%) and 13 (21.66%) isolates were MDR, XDR and PDR, respectively. Twenty-four isolates (40%) were negative for all three genes. There was a significant relationship between the presence of MOX gene and antibiotic resistance. Conclusions The high resistance rates of the A. baumannii isolates reported in the present study is alarming and need the management of treatment such as performing of antibiogram test before antibiotic therapy for select the appropriate antibiotic and also completes the course of treatment period.