Characteristics of enterotoxin-producing methicillin-resistant Staphylococcus aureus strains isolated from meat in Tehran, Iran

Abstract

In this study, we investigated the clonality, antibiotic susceptibility and presence of different enterotoxin genes among 49 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from 131 fresh raw meat samples in Tehran, Iran during 2016. 47% of beef, 30% of chicken and 27% of turkey samples were MRSA positive. PhenePlate (PhP typing) revealed the presence of 12 PhP types consisting of five common types and seven single types, and 86% of the strains harbored staphylococcal cassette chromosome mec (SCCmec) type III and type 3 cassette chromosome recombinases (ccr). Moreover, SCCmec type IVa was positive in all isolates with SGA prophage types. High level resistance to ciprofloxacin, erythromycin, tobramycin and kanamycin was also observed. The rate of resistance to most of the antibiotics tested was higher in chicken samples compared to other meat samples. Out of eleven different enterotoxin genes found, sea, sek and seq were the dominant genes in all strains. Our results illustrate the presence and persistence of highly resistant clonal groups of enterotoxin-producing MRSA in meat samples. These isolates had PhP and SCCmec types and prophage patterns which were similar to the clinical isolates previously reported in Iran, supporting the notion of dissemination of the MRSA in the hospital, community, as well food products in Iran.