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Virulence and resistance profile of Staphylococcus aureus isolated from food

Publication . Castro, A.; Palhau, C.; Cunha, S.; Camarinha, S.; Silva, J.; Teixeira, P

Staphylococcus aureus is considered a global community and health care pathogen responsible for staphylococcal food poisoning. The aim of this study was to characterize several isolates of S. aureus recovered from different food products concerning enterotoxin genes and other virulence factors including antimicrobial resistance. In 2009, a total of 78 coagulase-positive staphylococci from 1454 food samples were identified to species level; 73 were confirmed as S. aureus. Of the S. aureus isolates 5.5% were resistant to oxacillin, 52.0% showed resistance to erythromycin, and 45.2% to tetracycline. Multidrug resistance was observed in 33.3% of the isolates (resistance to three or more antibiotics of different classes). SCCmec types IV and V were detected among methicillin-resistant S. aureus (MRSA). One MRSA isolate was pvl positive. The 52.0% of food isolates were shown to be enterotoxigenic; egc (63.0%), secbov (44.7%) were the main detected SEs. tst gene was also detected in food isolates. The present work demonstrates the presence of virulent S. aureus collected in 2009 in foods.

2017Journal article

Restricted access

Food handlers as potential sources of dissemination of virulent strains of Staphylococcus aureus in the community

Publication . Castro, A.; Santos, C.; Meireles, H.; Silva, Joana; Teixeira, Paula

Food handlers may constitute a reservoir of virulent strains of Staphy-lococcus aureus and may be vehicles of their transmission to food.One hundred and sixty-two volunteers were assessed for the presence of S. aureuson the hands and in the nose. S. aureus was isolated by routine procedures, and theisolates were tested for susceptibility against a panel of nine antimicrobial agents.The isolates were further characterized by SmaI-PFGE profiling and the presence ofvirulence factors.Results: The prevalence of S. aureus was 19.8% in the nose and 11.1% on the hands;6.2% of the individuals carried S. aureus both in their noses and hands, and threeindividuals had the same strain (PFGE type) in the nose and on the hands. Although82% of the isolates were resistant to at least one antibiotic, none demonstrated thepresence of either mecA gene or resistance to oxacillin (none identified as MRSA).Sixty-eight percent of the isolates from the nose and hands possessed enterotoxingenes.This study revealed a high prevalence of antibiotic resistance and virulence deter-minants among the isolates, including not only classical and novel enterotoxin genesbut also major virulence factors such as tst. Potential dissemination of these strainsin the community is a matter of concern.© 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by ElsevierLimited. All rights reserved

2016Journal article

Open access