Non-typhoidal Salmonella among slaughterhouse workers and in the pork value chain in selected districts of Uganda

Overall NTS prevalence was 19.2% (365/1899). Proportions at slaughter were; 46.7% in floor swabs, 30.5% in carcass swabs, 20.5% in pig faeces,19.2% in mesenteric lymph nodes,18.4% in hand swabs, 9.5% in water and 5.2% in slaughterhouse workers. At retail, proportions were 33.8% in pork chopping surface, 33.1% in raw pork, 18.9% in hand swabs, 4.0% in cooked pork and 0.7% in vegetables. Sixty-one serovars were identified, with significant overlap between humans and the pork value chain. Overall, zoonotic <i>S</i>. Zanzibar, monophasic serovars of <i>S</i>. subspecies <i>salamae</i> (II) and subspecies <i>enterica</i> (I), <i>S</i>. Typhimurium and <i>S</i>. Newport, were the most prevalent. <i>S</i>. Typhimurium was predominant in humans and exhibited multi-drug resistance. NTS infection was significantly associated with eating, drinking, or smoking while working (OR = 1.95, 95% CI: 0.67-2.90%, <i>p</i> = 0.004). The detected NTS serovars in slaughterhouse workers could be a potential indicator of circulating serovars in the general population. The persistent presence of NTS along the pork value chain highlights occurrence of cross-contamination and the potential for transmission to consumers and slaughterhouse workers. This emphasizes the need to reduce <i>Salmonella</i> prevalence on pig farms and improve hygiene and pork handling practices at slaughter and retail points.