Molecular Analysis of the Isolates of Acinetobacter baumannii isolated from Tehran Hospitals Using ERIC-PCR Method

Background and Objective: Acinetobacter is a genus of non-fermenting Gram-negative cocci or coccobacilli, which have low nutritional requirements for growth and can survive for a long time in adverse conditions, on dry surfaces, and also in aqueous environments. The importance of the members of Acinetobacter genus as pathogens involved in nosocomial infections, is increasing. Acinetobacter baumannii is the most common species involved in a broad spectrum of nosocomial infections, including pneumonia, bacteremia, surgical wound infections, urinary tract infections, and meningitis. In this study, enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) technique was used for analysis and molecular typing of Acinetobacter strains, which has high discrimination power compared to phenotypic markers.  Methods: In the present study, a total of 40 A. baumanniies strains were isolated from patients hospitalized in Tehran hospitals. After identification and confirmation of the isolates by serotyping and biochemical tests, a single colony of each isolate was cultured on liquid LB medium, and after DNA extraction, PCR was performed. After electrophoresis of PCR product, gel images were stored electronically for analysis and comparison of the isolates.  Results: In this study, 40 strains of A. baumannii were analyzed by ERIC-PCR method, of which 29 strains were typed into 10 groups and 11 other strains had no PCR bands or had a band that could not be assigned to any of the above groups. Conclusion:  In this study, it was found that A. baumanniie strains could be typed using repetitive sequences. This extent of polymorphism shows that ERIC-PCR is a useful method for analysis of genetic variation of A. baumannii strains. High genetic variation of A. baumannii strains may be due to wide geographical distribution of this species in Iran