Research Article Safety Evaluation of the Coagulase-Negative Staphylococci Microbiota of Salami: Superantigenic Toxin Production and Antimicrobial Resistance

Abstract

Copyright © 2015 Raquel Soares Casaes Nunes et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The risks of contracting staphylococci food poisoning by the consumption of improperly manufactured salami and the possibility of this food being reservoirs for antibiotic resistance were evaluated. Nineteen coagulase-negative staphylococci (CNS) strains were found in commercial and artisanal salami. The species in commercial salami were S. saprophyticus, S. sciuri, S. xylosus, and S. carnosus. Artisanal salami showed S. succinus, S. epidermidis, and S. hominis but no S. carnosus. Phylogenetic analyses grouped the strains into three major staphylococcal species groups, comprised of 4 refined clusters with similarities superior to 90%. Fifteen strains harbored multiple enterotoxin genes, with high incidence of seb/sec and sea, 57 % and 50%, respectively, intermediate incidence of sed/seh/selm and sei/seln/tst-H, 33 % and 27%, correspondingly, and low incidence of see/selj/selo and seg, of respectively 13 % and 1%. Real time RT-PCR and enzyme-linked-immunosorbent assays confirmed the enterotoxigenicity of the strains, which expressed and produced enterotoxins in vitro. The CNS strains showed multiresistance to several antimicrobials of therapeutic importance in both human and veterinarian medicine, such a