Investigation and Follow-Up of a Staphylococcal Food Poisoning Outbreak Linked to the Consumption of Traditional Hand-Crafted Alm Cheese
Virginia Filipello,
Emanuela Bonometti,
Massimo Campagnani,
Irene Bertoletti,
Angelo Romano,
Fabio Zuccon,
Chiara Campanella,
Marina Nadia Losio,
Guido Finazzi
Affiliations
Virginia Filipello
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Headquarters, 25124 Brescia, Italy
Emanuela Bonometti
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Headquarters, 25124 Brescia, Italy
Massimo Campagnani
Azienda di Tutela della Salute della Montagna, 22014 Dongo, Italy
Irene Bertoletti
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Sondrio Chapter, 23100 Sondrio, Italy
Angelo Romano
National Reference Laboratory for Coagulase Positive Staphylococci, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria, e Valle d’Aosta, 10154 Torino, Italy
Fabio Zuccon
National Reference Laboratory for Coagulase Positive Staphylococci, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria, e Valle d’Aosta, 10154 Torino, Italy
Chiara Campanella
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Headquarters, 25124 Brescia, Italy
Marina Nadia Losio
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Headquarters, 25124 Brescia, Italy
Guido Finazzi
Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Headquarters, 25124 Brescia, Italy
Staphylococcal food poisoning (SFP) is one of the most important foodborne diseases. This work describes a SFP event linked to the consumption of alm cheese and involved three people belonging to the same family. Leftovers of the consumed cheese, samples from the grocery store and the producing alm were collected and tested for Coagulase positive staphylococci (CPS) enumeration and for the presence of staphylococcal enterotoxins (SEs). Isolates were typed with MLST, spa typing, and tested for SEs and methicillin resistance genes. An in vitro test evaluated SEs production in relation to bacterial growth. The presence of CPS and SEs was detected in all cheese samples and all isolates belonged to the same methicillin sensitive ST8/t13296 strain harbouring sed, ser and sej genes. The in vitro test showed the production of enterotoxins started from 105 CFU/mL. The farmer was prescribed with corrective actions that led to eradication of the contaminating strain.
