An article published in Eurosurveillance describes a recent multiple-serotype Salmonella outbreak in France in 2020, which led to an international investigation. The outbreak affected 44 people who consumed dried pork sausages contaminated by two different serotypes of Salmonella. 33 cases were contaminated with S. Bovismorbificans ST142, and 11 cases with the monophasic variant of S. Typhimurium ST34. qPCR technology identified both serotypes in the same food sample. Suggesting that the food products could have been contaminated at different rates by both serotypes, simultaneously escaping the standard procedures of microbiology laboratories to identify multi-strain contaminations. The study showed two concurrent Salmonella enterica outbreaks linked to the consumption of dried pork sausages produced in a short time by the same manufacturer: the former caused by S. Bovismorbificans and the latter by the monophasic variant of S. Typhimurium, 4,12:i:-. However, molecular methods revealed dual contamination of a single food sample analyzed. @ https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.2.2200123
In France, a multi-serotype outbreak of Salmonella Bovismorbificans ST142 and monophasic Salmonella Typhimurium ST34 associated with dried pork sausages, September 2020- January 2021
The French National Reference Centre for Escherichia coli, Shigella and Salmonella (FNRC-ESS) detected two human clusters of 33 cases (median age: 10 years; 17 females) infected by Salmonella enterica serotype Bovismorbificans, ST142, HC5_243255 (EnteroBase HierCC‑cgMLST scheme) in September–November 2020 and of 11 cases (median age: 11 years; seven males) infected by S. enterica serotype 4,12:i:-, ST34, HC5_198125 in October–December 2020. Epidemiological investigations conducted by Santé publique France linked these outbreaks to the consumption of dried pork sausages from the same manufacturer. S. Bovismorbificans and S. 4,12:i:- were isolated by the National Reference Laboratory from different food samples, but both strains were identified in a single food sample only by qPCR. Three recalls and withdrawals of dried pork products were issued by the French general directorate of food of the French ministry for agriculture and food in November 2020, affecting eight supermarket chains. A notification on the European Rapid Alert System for Food and Feed and a European urgent enquiry on the Epidemic Intelligence Information System for Food and Waterborne Diseases and Zoonoses (EPIS-FWD) were launched. No cases were reported outside France. Outbreaks caused by multiple serotypes of Salmonella may go undetected by protocols in standard procedures in microbiology laboratories.