High frequency of blaPER-1 gene in clinical strains of Acinetobacter baumannii and its association with quorum sensing and virulence factors

Abstract

Acinetobacter baumannii is known as the main pathogenic organisms, especially for the nosocomial infections. Multi-drug resistance and the presence of different virulence factors are recognized as causes of the organism's survival and the infection's risk. In this study, 70 Acinetobacter baumannii isolates were collected from three hospitals located in the Northwest of Iran. Antimicrobial susceptibility of these isolates was determined by agar dilution and disk diffusion methods. Production of gelatinase, proteolytic, and hemolytic activities of the isolates was also assessed. The frequencies of epsA, pld, ptk, luxR, luxI, and blaPER-1 genes were investigated by polymerase chain reaction (PCR). Furthermore, molecular typing of the isolates was performed using random amplified polymorphic DNA (RAPD-PCR). All the obtained isolates were multi drug resistant and 58.5% of them were extensively drug resistance. Six of the 70 study isolates were found to be resistant to all the tested antibiotics. Nine (12.8%) of the isolates were found to be resistant to colistin (MIC = 4 μg/mL). 38.5%, 45.7%, and 15.5% of the isolates were positive for gelatinase production, protease, and hemolysis, respectively. The frequency of the genes was as follows: pld 100%, epsA 91.9%, luxI 85.7%, ptk 80%, luxR 75.7% and blaPER-1 64.2%. Based on the RAPD patterns obtained, the 70 isolates in this study clustered into twelve major genotypes. In this study, the prevalence of blaPER-1 was worryingly high. On the other hand, a significant relationship was found between the presence of this gene and the production of some virulence factors in the strains.