Detection of carbapenem-resistance and biofilm formation genes, and genetic relatedness of Acinetobacter baumannii isolates

Abstract

Acinetobacter baumannii is one of the most important nosocomial pathogen worldwide. This study aimed to investigate the virulence potential and genomic relatedness of A. baumannii strains isolated from patients hospitalized in the Military Medical Academy (MMA) by detecting OXA-type carbapenemases genes, biofilm-associated genes, and by RAPD analysis. PCR was used to detect the blaoxa genes, ISAba-1 genetic element, and biofilm-associated genes. The genomic relatedness was determined by RAPD analysis using four different primers (AP2, DAF4. M13, and DECA). blaoxa-51-like, blaoxa-23-like, blaoxa-24-like, and blaoxa-58-like were present in 100%, 34.0%, 62.4%, and 3.1% of isolates, respectively. All isolates had the ISAba1 sequence in their genome, in 35.1% of isolates it was associated with the blaoxa-51-like, and in 97.0% with the blaoxa-23-like gene. Biofilm-associated genes bap, ompA, epsA, csuA/BABCDE, and pgaABCD were detected in 93.8%, 95.8%, 88.1%, 98.4%, and 98.9% isolates, respectively. RAPD analysis showed a high degree of genome similarity and clonal dispersion of the isolates. Detection of blaoxa genes, especially biofilm-associated genes, in a high percentage of A. baumannii isolates indicated their great pathogenic potential. RAPD analysis revealed a high level of genomic similarity and clonal dispersion of the majority of isolates through MMA. Further, a continuous introduction of individual strains with different profiles contributes to the genetic diversity of A. baumannii isolates. These results can be useful for further management and tracking nosocomial outbreaks.