Prevalence and Distribution of Resistance and Enterotoxins/Enterotoxin-likes Genes in Different Clinical Isolates of Coagulase-negative Staphylococcus

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Background:</jats:bold> Coagulase-negative <jats:italic>staphylococcus</jats:italic> (CoNS) are considered to be the major reservoirs for genes facilitating the evolution of <jats:italic>S. aureus</jats:italic> as a successful pathogen. The present study aimed to determine the occurrence of genes conferring resistance to fluoroquinolone, determining of the prevalence of insertion sequence elements IS256, IS257 and different superantigenes (SAgs) among CoNS isolates obtained from various clinical sources.<jats:bold>Materials and Methods:</jats:bold> The current study conducted on a total of the 91 CoNS species recovered from clinical specimens in Hamadan hospitals in western Iran in 2017-19. The antimicrobial susceptibility testing was performed using disk diffusion method and the presence of the IS256 and IS257, genes conferring resistance to fluoroquinolone and enterotoxins/enterotoxin-like encoding genes were investigated by Polymerase Chain Reaction (PCR) method. <jats:bold>Results:</jats:bold> Among genes encoding classic enterotoxins, <jats:italic>sec </jats:italic>was the most frequent which was carried by 48.4% of the 91 isolates, followed by <jats:italic>seb</jats:italic> in 27.5% of the isolates. None of the <jats:italic>CoNS </jats:italic>isolates was found to be positive to enterotoxin-like encoding genes. In 11(12%) of all isolates that were phenotypically resistant to levofloxacin, 9 isolates (81.8%) were positive for <jats:italic>gyrB</jats:italic>, 8 isolates (72.7%) were positive for <jats:italic>gyrA,</jats:italic> 8 isolates (72.7%) harbored <jats:italic>grlB </jats:italic>and<jats:italic> </jats:italic>7 isolates (63.6%)<jats:italic> </jats:italic>were found to carry <jats:italic>grlA</jats:italic>. The IS256 and IS257 were identified in 31.8 % and 74.7% of the isolates, respectively. The results of statistical analysis showed a significant association between the occurrence of <jats:italic>staphylococcal</jats:italic> enterotoxins (SEs) encoding genes and antimicrobial resistance.<jats:bold>Conclusion:</jats:bold> Antimicrobial resistant determinants and SEs are co-present in clinical CoNS isolates that confer selective advantage for colonization and survival in hospital settings. The coexistence of insertion elements and antibiotic resistance indicate their role in pathogenesis and infectious diseases.</jats:p>