Salmonellain the pork production chain and its impact on human health in the European Union

Abstract

Salmonella spp. comprise the second most common food-borne pathogens in the European Union (EU). The role of pigs as carriers of Salmonella has been intensively studied both on farm and at slaughter. Salmonella infection in pigs may cause fever, diarrhoea, prostration and mortality. However, most infected pigs remain healthy carriers, and those infected at the end of the fattening period could pose a threat to human health. Contamination of pig carcasses can occur on the slaughter line, and it is linked to cross-contamination from other carcasses and the presence of Salmonella in the environment. Therefore, Salmonella serovars present on pig carcasses can be different from those detected in the same bathes on the farm. In recent years, S. Typhimurium, S. Derby and S. serotype 4,[5],12:i:- (a monophasic variant of S. Typhimurium) have been the most common serovars to be detected in pigs in EU countries, but S. Rissen, S. Infantis, S. Enteritidis and S. Brandenburg have also been reported. In humans, several cases of salmonellosis have been linked to the consumption of raw or undercooked pork and pork products. Among the main serovars of porcine origin detected in confirmed human cases, S. Typhimurium, the monophasic variant S. 4,[5],12:i:- and S. Derby are certainly the most important.

Isolation and characterization of Salmonella in pork samples collected from retail and wholesale markets in each season from 2016 to 2018 in Wuhan, China

“…It was also observed that pork samples from retail markets possessed a significantly higher prevalence of Salmonella than those from wholesale markets, indicating that the environment may also be an important factor leading to Salmonella contamination. This is supported by the previous study that Salmonella in the environment can cause the contamination of pork (Bonardi, ). It is also possible that the difference in the prevalence of Salmonella between pork samples from retail and wholesale markets was attributed to the different origin of pig farms or slaughterhouses.…”

SGI-4 in monophasic Salmonella Typhimurium ST34 is a novel ICE that enhances resistance to copper

“…However, even under anaerobic conditions, the effect of the silCBA deletion on the MIC for copper was not comparable to the absence of SGI-4 in U288, DT104 and DT204 isolates which had a MIC that was below 5 mg/ml copper sulphate. Copper resistance at a similar level to these strains 9 was only observed in monophasic S. Typhimurium ST34 strain SO4698-09 when both silCBA and pcoABDE were deleted.…”

“…Typhimurium DT104 emerged around 1990, becoming a globally pandemic clone that affects numerous domesticated and wild animal species (5). In 2007 a monophasic S. Typhimurium (S. 4, [5],12:i-) variant emerged in European pig populations and spread globally; monophasic S. Typhimurium is multi-locus sequence type 34 (ST34) (hereafter referred to as monophasic S. Typhimurium ST34), and predominantly phage type DT193 or DT120 (6)(7)(8)(9)(10)(11)(12). The mechanisms for succession in S. Typhimurium variants in Europe are not known, but selection by commonly-used antibiotics is unlikely since variants share similar AMR profiles (3): ACSSuT (ampicillin, chloramphenicol, streptomycin, sulphonamide, tetracycline) for S. Typhimurium DT104 and ASSuT for monophasic S. Typhimurium ST34.…”

Worldwide Epidemiology ofSalmonellaSerovars in Animal-Based Foods: a Meta-analysis

“…Salmonella serovars in pork. Pigs are one of the most common sources of Salmonella infections in humans (38)(39)(40), and in some countries it is indicated as the most important source of salmonellosis, as in a great part of Europe and the United States (19,40). This is because these animals are frequently asymptomatic carriers and disseminators of this pathogen throughout the production chain.…”