Comprehensive analysis of antibiotic resistance and gene expression patterns in <i>Enterococcus</i> spp. isolated from clinical samples in Al Muthanna, Iraq

AbstractThe current study was conducted to determine the prevalence of antibiotic resistance genes and their gene expression levels, with a highlight on vancomycin-resistant <i>enterococci</i> (VRE) genes. Phenotypically, this study identified 63 (77.7 %) <i>Enterococcus faecalis</i> (<i>E.faecalis</i>) isolates and 18 (22.2 %) <i>Enterococcus faecium</i> (<i>E.faecium</i>) isolates, and antibiotic sensitivity tests revealed 16 (19.7 %) isolates resistant to vancomycin. Subsequently, the molecular diagnosis was done to confirm VRE strains, nine VRE isolates were confirmed to be <i>E.faecalis</i>, and only four were <i>E.faecium</i> using Taqman real-time PCR. Among these 13 VRE isolates, <i>van</i>A, <i>van</i>B, and <i>bla</i>_TEM genes were detected. VanB and <i>bla</i>_TEM genes being are the most prevalent genes among them, with nine isolates for each gene and only one isolate harbouring the <i>van</i>A gene. Moreover, the <i>van</i>A gene-carrying isolates showed increased gene expression after induced with vancomycin, with a folding value of 1.62, while <i>van</i>B and <i>bla</i>_TEM genes expression folding values were 3.47 and 2.12 respectively. The sequence result for selected genes (16S rRNA, <i>van</i>A, and <i>bla</i>_TEM genes) showed genetic relationship with the isolates registered in NCBI.