Outbreak of Escherichia coli O157 Phage Type 32 linked to the consumption of venison products

Prevalence of Shiga Toxin-Producing Escherichia coli O157 in Wild Scottish Deer with High Human Pathogenic Potential

Shiga toxin-producing E. coli (STEC) infections associated with wildlife are increasing globally, highlighting many 'spillover' species as important reservoirs for these zoonotic pathogens. A human outbreak of STEC serogroup O157 in 2015 in Scotland, associated with the consumption of venison meat products, highlighted several knowledge gaps, including the prevalence of STEC O157 in Scottish wild deer and the potential risk to humans from wild deer isolates. In this study, we undertook a nationwide survey of wild deer in Scotland and determined that the prevalence of STEC O157 in wild deer is low 0.28% (95% confidence interval = 0.06-0.80). Despite the low prevalence of STEC O157 in Scottish wild deer, identified isolates were present in deer faeces at high levels (>104 colony forming units/g faeces) and had high human pathogenic potential based on whole genome sequencing and virulence gene profiling. A retrospective epidemiological investigation also identified one wild deer isolate from this study as a possible source of a Scottish human outbreak in 2017. These results emphasise the importance of food hygiene practices during the processing of wild deer carcasses for human consumption.

Food safety incidents in the red meat industry: A review of foodborne disease outbreaks linked to the consumption of red meat and its products, 1991 to 2021

Red meat is a significant source of human nutrition, and the red meat industry contributes to the economy of nations. Nonetheless, there is a widespread global concern about public health issues posed by severe food safety incidents within the red meat industry. Most of these incidents are associated with foodborne disease outbreaks that impact individual consumers, food businesses and society. This study adopts a systematic search and review approach to identify three decades of published investigation reports of global foodborne disease outbreaks linked with the consumption of red meat and products made from them. The review aims to evaluate the critical features of these outbreak incidents to get insight into their contributing factors and root causes. In particular, this review discusses the transmission setting (origin of pathogenic agents), the food vehicles mostly incriminated, the causative pathogens (bacteria, viruses, and parasites) causing the most illnesses, and the most commonly reported contributing factors to the outbreaks. This information can help researchers and food business operators (FBOs) inform future risk assessment studies and support risk management activities in developing risk-mitigating strategies for the industry. Findings from this study suggest that implementing food safety management strategies which include adequate control measures at all stages of the food chain, from farm to fork, is imperative in preventing outbreak incidents. Of equal importance is the need for enhanced and sustained public education about the risk of foodborne illnesses associated with meat and its products whilst discouraging the consumption of raw meat products, especially by high-risk groups.

A survey of enteric disease agents in UK deer populations

Wild deer products have been linked to outbreaks of Escherichia coli 0157 in humans and bovine tuberculosis (bTB) in domestic cats, raising concerns around foodborne diseases from venison. This study investigated the prevalence of several enteric disease agents in UK deer populations, including foodborne pathogens and other diseases of import to livestock health. Intestinal samples were collected from slaughtered farmed deer (N = 211, eight farms), shot wild deer (N = 136) and ground faecal samples were collected from two farms (N = 90), six parks (N = 228) and five zoos (N = 67). DNA was extracted and multiplex qPCR assays were run to amplify targets of, C. perfringens toxins, Campylobacter spp., E. coli toxins, Mycobacterium avium subsp. Paratuberculosis (MAP), Salmonella spp. and Yersinia spp. The most commonly amplified targets were E. coli astA (61.2%) and Campylobacter spp. (43.3%), but the prevalence of C. coli and C. jejuni were ≤ 3.0% and Salmonella spp., MAP and Yersinia pseudotuberculosis also had low overall prevalences of 1.6%, 3.3% and 2.6%, respectively. However, notable targets included C. perfringens toxins α (20.4%) and β2 (16.9%); E. coli stx1 (14.6% overall, 28.0% in abattoir samples) and stx2 (17.8% overall, 31.6% in wild samples); and Yersinia enterocolitica (10.8% overall, 25% in wild samples). The low prevalence of some foodborne pathogens is reassuring for food safety; further investigations into the commonly found targets are needed to quantify the risk to public health and the possibility of wild deer acting as reservoirs of disease.

Antimicrobial resistant Escherichia coli in Scottish wild deer: Prevalence and risk factors

Antimicrobial resistance (AMR) is a recognised threat to global health. Obtaining data on the prevalence of AMR in environmental bacteria is key to understanding drivers and routes of transmission. Here, 325 Shiga toxin negative deer faecal samples-gathered from across the Scottish mainland-were screened for the presence of AMR Escherichia coli and investigated for potential risk factors associated with AMR occurrence. E. coli with resistance to antimicrobials of clinical health concern, including carbapenems and 3rd generation cephalosporins, were targeted. Ninety-nine percent of samples yielded E. coli, and the prevalence of resistant E. coli at the level of faecal samples was 21.8% (n = 71) for tetracycline, 6.5% (n = 21) for cefpodoxime, 0.3% for ciprofloxacin (n = 1), with no recorded resistance to meropenem. Potential risk factors for tetracycline and cefpodoxime resistance were investigated. The presence of broadleaved woodlands was significantly associated with both AMR phenotypes, which may relate to land use within or around such woodlands. Associated risk factors varied across resistance phenotype and deer species, with proximity or density of horses an indicator of significantly decreased and increased risk, respectively, or tetracycline and cefpodoxime resistance in E. coli from roe deer, but not from red deer. Distance from wastewater treatment plants was a significant risk factor for tetracycline resistance in E. coli from red deer but not from roe deer. Data indicated that AMR E. coli can occur in wild deer populations that are not directly exposed to the selective pressure exerted by antimicrobial treatment. Overall, resistance to critically important antimicrobials was found to be low in the studied population, suggesting no immediate cause for concern regarding human health. Utilising existing culling frameworks, wild deer in Scotland could function well as a sentinel species for the surveillance of AMR in the Scottish environment.

Evidence of on-going transmission of Shiga toxin-producing Escherichia coli O157:H7 following a foodborne outbreak

In August 2019, public health surveillance systems in Scotland and England identified seven, geographically dispersed cases infected with the same strain (defined as isolates that fell within the same five single nucleotide polymorphism single linage cluster) of Shiga toxin-producing Escherichia coli O157:H7. Epidemiological analysis of enhanced surveillance questionnaire data identified handling raw beef and shopping from the same national retailer (retailer A) as the common exposure. Concurrently, a microbiological survey of minced beef at retail identified the same strain in a sample of minced beef sold by retailer A, providing microbiological evidence of the link. Between September and November 2019, a further four primary and two secondary cases infected with the same strain were identified; two cases developed haemolytic uraemic syndrome. None of the four primary cases reported consumption of beef from retailer A and the transmission route of these subsequent cases was not identified, although all four primary cases visited the same petting farm. Generally, outbreaks of STEC O157:H7 in the UK appear to be distinct, short-lived events; however, on-going transmission linked to contaminated food, animals or environmental exposures and person-to-person contact do occur. Although outbreaks of STEC caused by contaminated fresh produce are increasingly common, undercooked meat products remain a risk of infection.

Fallow Deer (Dama dama) as a Reservoir of Shiga Toxin-Producing Escherichia coli (STEC)

Shiga toxin-producing Escherichia (E.) coli (STEC) are responsible for the outbreaks of serious diseases in humans. Only a few reports on fallow deer as a reservoir of foodborne pathogens have been published to date. The purpose of this study was to determine the occurrence of STEC strains in the fallow deer population in Poland. In all, 94 fallow deer swabs were tested. Polymerase chain reaction (PCR) was performed to detect the virulence profile of stx1, stx2 and eae or aggR genes, to identify the subtypes of stx1 and stx2 genes and to perform O and H serotyping. STEC and attaching and effacing (AE)-STEC were identified in 13 isolates (13.83%). The most hazardous virulence profile was detected in three strains, namely stx2d serotype O103:HNM, eae/stx1a serotype O26:HNM and eae/stx1a serotype O157:H7. The predominant stx gene was stx2, which was identified in 76.92% of isolates. E. coli O157 was detected in 4/94 (4.26%). Other E. coli serogroups, O26, O103, O111 and O145, were identified in 14/94 fallow deer (14.89%). The present findings suggest that fallow deer are carriers of STEC/AE-STEC that are potentially pathogenic to humans.