Salmonella identified in pigs in Kenya and Malawi reveals the potential for zoonotic transmission in emerging pork markets

Wilson, Catherine N; Pulford, Caisey V; Akoko, James; Perez-Sepulveda, Blanca; Predeus, Alexander V.; Bevington, Jessica A.; Duncan, Patricia; Hall, Neil; Wigley, Paul; Feasey, Nicholas; Pinchbeck, Gina; Hinton, Jay C. D.; Gordon, Melita A.; Fèvre, Eric M.

doi:10.1371/journal.pntd.0008796

Cited by 20 publications

(18 citation statements)

References 52 publications

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“…Generally, animal farms are considered natural reservoirs of Salmonella, especially poultry and pigs (Li et al, 2013;Zhou et al, 2017;. Salmonella could colonize the digestive tract of animals and are excreted in feces and spread into the environment (Kagambèga et al, 2013;Bonardi, 2017;Jiang et al, 2019), then transmitted to humans via the food chain (Ed-Dra et al, 2018;Wang et al, 2019;Wilson et al, 2020;Liu et al, 2021). Therefore, several studies have reported the presence of Salmonella in foods of animal origin, especially meat products (Ed-Dra et al, 2017;Jiang et al, 2021;Liu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Genomic Investigation of Salmonella Isolates Recovered From a Pig Slaughtering Process in Hangzhou, China

Ed-Dra

Pan

et al. 2021

Front. Microbiol.

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The pig industry is the principal source of meat products in China, and the presence of pathogens in pig-borne meat is a crucial threat to public health. Salmonella is the major pathogen associated with pig-borne diseases. However, route surveillance by genomic platforms along the food chain is still limited in China. Here, we conducted a study to evaluate the dynamic prevalence of Salmonella in a pig slaughtering process in Hangzhou, Zhejiang Province, China. Fifty-five of 226 (24.37%) samples were positive for Salmonella; from them, 78 different isolates were selected and subjected to whole genome sequencing followed by bioinformatics analyses to determine serovar distribution, MLST patterns, antimicrobial resistance genes, plasmid replicons, and virulence factors. Moreover, phenotypic antimicrobial resistance was performed using the broth dilution method against 14 antimicrobial agents belonging to 10 antimicrobial classes. Our results showed that samples collected from the dehairing area (66.66%) and the splitting area (57.14%) were the most contaminated. Phenotypic antimicrobial resistance classified 67 of 78 isolates (85.90%) as having multidrug resistance (MDR), while the highest resistance was observed in tetracycline (85.90%; 67/78) followed by ampicillin (84.62%; 66/78), chloramphenicol (71.80%; 56/78), and nalidixic acid (61.54%; 48/78). Additionally, serovar prediction showed the dominance of Salmonella Typhimurium ST19 (51.28%; 40/78) among the 78 studied isolates, while plasmid prediction reported the dominance of IncHI2A_1 (20.51%; 16/78), followed by IncX1_1 (17.95%; 14/78) and IncHI2_1 (11.54%; 9/78). Virulence factor prediction showed the detection of cdtB gene encoding typhoid toxins in two Salmonella Goldcoast ST358 and one Salmonella Typhimurium ST19, while one isolate of Salmonella London ST155 was positive for genes encoding for the siderophore “yersiniabactin” and the gene senB encoding for enterotoxin production. From this study, we conclude that pig slaughterhouses are critical points for the dissemination of virulent and multidrug-resistant Salmonella isolates along the food chain which require the implementation of management systems to control the critical points. Moreover, there is an urgent need for the implementation of the whole genome sequencing platform to monitor the emergence of virulent and multidrug-resistant clones along the food chain.

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Section: Introductionmentioning

confidence: 99%

“…Pork meat is considered the most frequently contaminated food and the major source of Salmonella infections in humans (Bonardi, 2017;Wilson et al, 2020). In fact, pig farms seem to be a suitable environment for the replication and the persistence of Salmonella (Lettini et al, 2016;Bonardi, 2017;Vico et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Genomic Investigation of Salmonella Isolates Recovered From a Pig Slaughtering Process in Hangzhou, China

Ed-Dra

Pan

et al. 2021

Front. Microbiol.

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“…However, a high prevalence of porcine and human cysticercosis has been reported (44)(45)(46), as well as non-typhoidal Salmonella isolates which were recovered from pig faecal samples (47). In neighbouring countries, trichinellosis, salmonellosis, and cysticercosis have been documented in pigs (48)(49)(50)(51)(52) and in humans (53,54).With the exception of the single modern abattoir, slaughter houses had intercrossing of clean and dirty operations, from killing through to carcass preparation. This is likely to lead to cross-contamination with pathogens such as Salmonella (55), especially as no running water was available inside the visited slaughterhouses, as has been reported elsewhere (49).…”

Section: Discussionmentioning

confidence: 99%

“…In neighbouring countries, trichinellosis, salmonellosis, and cysticercosis have been documented in pigs (48)(49)(50)(51)(52) and in humans (53,54).With the exception of the single modern abattoir, slaughter houses had intercrossing of clean and dirty operations, from killing through to carcass preparation. This is likely to lead to cross-contamination with pathogens such as Salmonella (55), especially as no running water was available inside the visited slaughterhouses, as has been reported elsewhere (49). Installing cold and hot water, as per international guidelines, can help to reduce occurrence of such contamination.…”

Section: Discussionmentioning

confidence: 99%

Using a Value Chain Approach to Map the Pig Production System in Rwanda, Its Governance, and Sanitary Risks

et al. 2022

Self Cite

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Rwanda has a fast growing pig production sector projected to continue expansion, due to rising local and regional demand. We undertook a value chain analysis to establish the flows of pigs and pork in Rwanda and the roles of various actors involved, and to understand governance and sanitary risks in the value chain. Cross-sectional qualitative data were collected through focus group discussions and key informant interviews with farmers, brokers, butchers, abattoir managers, and veterinarians. Data were collected on pig production methods and inputs, the source and destination of live and slaughtered pigs, value-adding infrastructures (abattoirs and processing factories), the people involved and interactions between them, governance, and challenges. Pig production in Rwanda is dominated by smallholders, mainly as a source of supplementary income and secondarily for manure. Emerging medium-sized and large pig farms were also identified, located mainly around urban areas. Live pig markets are the main mechanism allowing various actors to buy/sell pigs. Brokers have an important role in pig transactions: they are key in setting prices at markets, examining pigs for disease, organising the supply of pigs for abattoirs and for export. Only a few formal pig abattoirs were identified, which mainly supply to pork processing factories based in Kigali and/or export to customers. Local consumers rely on informal slaughtering at farm or bar/restaurant backyards, with irregular veterinary inspection. Formal abattoirs were attended by a veterinary inspector, however a lack of record keeping was noted. Sanitary risks identified were a lack of biosecurity throughout the chain and poor hygiene at slaughter places. Lingual palpation was practised in pig markets to identify cysticercosis infection, however cyst-positive pigs were not destroyed, but were sold for reduced prices in the same market or later informally sold by the owner. There are few veterinarians attending farms, with most services provided by less qualified technicians or self-treatment of pigs by farmers. Overall, this production system is characterised by a high degree of informality at all nodes, combined with the rapid growth trajectory in the sector. These findings provide a basis to plan interventions tailored to vulnerabilities identified in the Rwanda pig value chain.

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“…Salmonella is a Gram-negative zoonotic bacteria that is a leading cause of food-borne diseases in developed countries and causes bloodstream infections in infants and elderly in developing countries [ 33 ]. Salmonella are frequently asymptomatic in livestock, but has been highly associated with mild and severe diarrhea in piglets [ 34 , 35 ]. In pigs, Salmonella Typhimurium is by far the most isolated serotype in the EU and US, followed by Salmonella Derby and Salmonella Arizona.…”

Section: Introductionmentioning

confidence: 99%

Salmonella Vaccine Vector System for Foot-and-Mouth Disease Virus and Evaluation of Its Efficacy with Virus-Like Particles

Zhi

Guo

et al. 2021

Vaccines

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Foot-and-mouth disease virus (FMDV) causes a highly contagious and devastating disease in livestock animals and has a great potential to cause severe economic loss worldwide. The major antigen of FMDV capsid protein, VP1, contains the major B-cell epitope responsible for effectively eliciting protective humoral immunity. In this study, irradiated Salmonella Typhimurium (KST0666) were used as transgenic vectors containing stress-inducible plasmid pRECN-VP1 to deliver the VP1 protein from FMDV-type A/WH/CHA/09. Mice were orally inoculated with ATOMASal-L3 harboring pRECN-VP1, and FMDV virus-like particles, where (VLPFMDV)-specific humoral, mucosal, and cellular immune responses were evaluated. Mice vaccinated with attenuated Salmonella (KST0666) expressing VP1 (named KST0669) showed high levels of VLP-specific IgA in feces and IgG in serum, with high FMDV neutralization titer. Moreover, KST0669-vaccinated mice showed increased population of IFN-γ (type 1 T helper cells; Th1 cells)-, IL-5 (Th2 cells)-, and IL-17A (Th17 cells)-expressing CD4+ as well as activated CD8+ T cells (IFN-γ+CD8+ cells), detected by stimulating VLPFMDV. All data indicate that our Salmonella vector system successfully delivered FMDV VP1 to immune cells and that the humoral and cellular efficacy of the vaccine can be easily evaluated using VLPFMDV in a Biosafety Level I (BSL1) laboratory.

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Salmonella identified in pigs in Kenya and Malawi reveals the potential for zoonotic transmission in emerging pork markets

Cited by 20 publications

References 52 publications

Genomic Investigation of Salmonella Isolates Recovered From a Pig Slaughtering Process in Hangzhou, China

Genomic Investigation of Salmonella Isolates Recovered From a Pig Slaughtering Process in Hangzhou, China

Using a Value Chain Approach to Map the Pig Production System in Rwanda, Its Governance, and Sanitary Risks

Salmonella Vaccine Vector System for Foot-and-Mouth Disease Virus and Evaluation of Its Efficacy with Virus-Like Particles

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