Characterisation of Staphylococcus aureus strains isolated from food for human consumption

Abstract

An investigation was conducted to evaluate Staphylococcus aureus contamination in various types of food of animal origin. Of the 350 samples examined, 14.0% were found to be contaminated with S. aureus. Prevalence rates varied according to type, namely: 19.3% for fresh meat products, 13.3% for fresh cheeses, 3.6% for bakery products and 7.7% for deli products. The isolated S. aureus strains then underwent 16S rDNA polymerase chain reaction (PCR) followed by reverse latex agglutination tests to identify enterotoxigenic strains. The results were compared with data obtained by subjecting the same strains to tests for the genes coding for the S. aureus enterotoxins (SEs) sea, seb, sec, sed, see, seg, seh, sei and toxic shock syndrome toxin—1 (TSST—1). Reversed passive latex agglutination (RPLA) testing revealed that 16.3% of strains (8/49) produced enterotoxins, while on PCR, 48.97% (24/49) were found to carry one or more genes for the production of SEs, and were therefore potentially enterotoxigenic.

Keywords

• Enterotoxin
• Food
• Italy
• PCR
• Polymerase chain reaction
• Reversed latex agglutination test
• Reversed passive latex agglutination
• RPLA
• Safety
• Staphylococcus aureus.