Molecular characterization of virulence and antibiotics resistance genes and genetic diversity of Salmonella enteritidis from raw chicken meat in Duhok city, Iraq

Abstract

Salmonella enteritidis (S. enteritidis) is considered a major cause of human salmonellosis and the infection is acquired through the consumption of contaminated meat and meat products with this pathogen. The objective of this study was to investigate the presence of virulence and resistance-associated genes in S. enteritidis isolates from local and imported raw chicken meat and to study their genetic diversity using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) profile analysis. The results of the current study showed that the prevalence of virulence genes was high and the isolates harbored more than five class of virulence-associated genes and their frequency were different among the isolates. All the isolates showed 100% positivity for the invite and hilA genes. Genes including lpfA, avrA, sopE2, spvB, sifA and flaK were in 91%, 82%, 82%, 82%, 73% and 54.5% respectively. The sipA was only present in one isolate. The susceptibly test showed 100% sensitivity to chloramphenicol, norfloxacin, ceftriaxone, and cefotaxime and all the isolates were 100% resistant to ampicillin. However, two of the isolates showed resistance to gentamycin and trimethoprim with sulphamethoxazole. The isolates were found to harbor the dfrA1 for trimethoprim, blaTEM for ampicillin, and the resistance rate was 100%. However, none of the S. enteritidis isolates were found to contain the resistance genes specific to fluoroquinolone, erythromycin, chloramphenicol, cefotaxime, and carbapenems (NDM and OXA) resistance. ERIC-PCR allowed the grouping of the isolates into 5 different ERIC patterns including ET1-ET5. It can be concluded that the detection of the high frequency of virulence genes and MDR suggests the high virulence potential of S. enteritidis isolates which could be of major public health concern.

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