Distribution of antimicrobial resistance genes and virulence genes in different genotypes of Acinetobacter baumannii.

Abstract

In accordance with high genomic plasticity of Acinetobacter baumannii, the aim of this study was to investigate the distribution of 22 genes including 16 S rRNA, integrase genes (intI and intII), antimicrobial resistance genes (ARGs) (acquired carbapenemase genes (ACGs) and Extended-spectrum beta-lactamase (ESBL) genes) and virulence genes (VGs) (involving adeABC, ompA genes) among different genotypes of A. baumannii and providing an epidemiological pattern in association with both of ARGs and VGs in this bacterium. The present study was conducted through collection of A. baumannii isolates from clinical samples during six months between December 2021 and May 2022. In this regard, routine biochemical and microbiological tests and molecular diagnostic techniques were recruited. More than 94% of the A. baumannii strains were resistant to 15 antibiotics. In addition, 37%, 40% and 23% of the isolated strains were recognized as MDR, XDR and PDR, respectively. The genes of 16 S rRNA (100%), intI (66%), intII (9%), bla_NDM (98%), bla_SIM (98%), bla_OXA-23-like (100%), bla_OXA-24-like (99%), bla_OXA-51-like (97%), adeA (100%), adeB (95%), adeC (85%), ompA (82%), bla_CTX-M (15%), and bla_TEM (50%) were present in isolated strains while, the genes of bla_AIM, bla_DIM, bla_GIM, bla_IMP, bla_SPM, bla_VIM, bla_SHV and bla_VEB were absent in A. baumannii isolates. In accordance with the results obtained from ERIC-PCR, the isolated strains of A. baumannii were classified into 12 clades and four genotypes. In conclusion, our findings confirm the previous reported records in association with molecular characteristics and the related patterns in Iran and worldwide. Moreover, the obtained results in the present study show an obvious antimicrobial resistance rise in the epidemiological pattern.