Molecular detection of enterotoxigenic Staphylococcus aureus isolated from mutton marketed in retail outlets of Chennai, India

Abstract

The present study was aimed at detection of enterotoxigenic S. aureus in mutton marketed in retail outlets of Chennai. A total of 120 meat samples were collected from across Chennai for isolation of S. aureus and it was observed that 66.28 per cent of the samples were contaminated with S. aureus. The S. aureus count in mutton samples ranged from 1.8 x 102 to 4.9 x 104 CFU/ g with an overall average of 1.30 x 104 CFU/ g. All the isolates presumptively identified as S. aureus biochemically, amplified 181 bp product specific for nuc gene by PCR, which is species specific marker for S. aureus. Enterotoxin gene profiles (multiplex PCR) results revealed that 70.17 percent of the isolates were enterotoxigenic carrying only six genes (seb, sed, seg, seh, sei and sej) either alone or in combination, whereas none of these isolates harbored sea, sec and see. It was clear that seb (72.5 %) was the predominant enterotoxin gene followed by seg and sei, seh, sej and sed. Six different toxin gene profiles were exhibited by different isolates and majority of the isolates (55 %) carried two or more genes as compared to only one toxin gene.