Microbiological Quality, Virulence Genes, and Antimicrobial Resistance of Escherichia coli and Staphylococcus aureus Isolated from Ready-to-Eat Meals Served in Collective Catering Facilities in Ouagadougou, Burkina Faso

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Résumé

Collective catering can expose many consumers to foodborne and antimicrobial-resistant bacteria but is poorly monitored in sub-Saharan Africa. This study assessed the microbiological quality of 159 ready-to-eat meals served in university, hospital-adjacent, and industrial canteens in Ouagadougou, Burkina Faso, and the virulence genes and antimicrobial resistance (AMR) of Escherichia coli and Staphylococcus aureus isolates. Genes were detected by PCR and susceptibility by disk diffusion. Under criteria adapted from those for cooked ready-to-eat dishes, 70.4% and 50.3% of meals were unsatisfactory for coagulase-positive staphylococci and E. coli, respectively (38.4% for staphylococci under UK Health Protection Agency guidelines). E. coli isolates carrying astA as the sole virulence gene (n = 50) were recovered from 44 meals (27.7%), and enterotoxigenic E. coli (estIa) from five meals; aggR and pic were not detected. The exfoliative toxin A gene eta was detected by PCR (not sequenced) in 73 S. aureus isolates from 51 meals; none carried mecA or sea–see. Multidrug resistance affected 76.0% of astA-positive E. coli and 73.9% of S. aureus isolates (68.0% and 65.2%, excluding presumptive phenotypes). In E. coli, bla SHV (81.8%), bla CTX-M −1 group (27.3%), and bla TEM (25.5%) predominated. These findings indicate inadequate microbiological control and warrant AMR surveillance across the food chain.

Mots-clés

collective catering; ready-to-eat food; Escherichia coli; astA; Staphylococcus aureus; exfoliative toxin; antimicrobial resistance; β -lactamase genes; Burkina Faso