Enteric Bacterial Pathogens with Zoonotic Potential Isolated from Farm-Raised Deer

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.

Low Clostridioides difficile positivity rate in wild animal shelter in Slovenia

Here we review literature on Clostridioides difficile in captive wild animals and describe results from a single wild animal shelter in Slovenia. C. difficile was found in four out of 22 samples from animals of 15 different species (mammals n = 3; birds n = 12). Isolates were cultured only from bird samples and typed as RT 078, 002, 014 and additional unknown type. All three known ribotypes are commonly shared between humans and/or animals and environment.

Recent Updates on Outbreaks of Shiga Toxin-Producing Escherichia coli and Its Potential Reservoirs

Following infection with certain strains of Shiga toxin-producing Escherichia coli (STEC), particularly enterohemorrhagic ones, patients are at elevated risk for developing life-threatening extraintestinal complications, such as acute renal failure. Hence, these bacteria represent a public health concern in both developed and developing countries. Shiga toxins (Stxs) expressed by STEC are highly cytotoxic class II ribosome-inactivating proteins and primary virulence factors responsible for major clinical signs of Stx-mediated pathogenesis, including bloody diarrhea, hemolytic uremic syndrome (HUS), and neurological complications. Ruminant animals are thought to serve as critical environmental reservoirs of Stx-producing Escherichia coli (STEC), but other emerging or arising reservoirs of the toxin-producing bacteria have been overlooked. In particular, a number of new animal species from wildlife and aquaculture industries have recently been identified as unexpected reservoir or spillover hosts of STEC. Here, we summarize recent findings about reservoirs of STEC and review outbreaks of these bacteria both within and outside the United States. A better understanding of environmental transmission to humans will facilitate the development of novel strategies for preventing zoonotic STEC infection.

Clostridioides (Clostridium) Difficile in Food-Producing Animals, Horses and Household Pets: A Comprehensive Review

Clostridioides (Clostridium) difficile is ubiquitous in the environment and is also considered as a bacterium of great importance in diarrhea-associated disease for humans and different animal species. Food animals and household pets are frequently found positive for toxigenic C. difficile without exposing clinical signs of infection. Humans and animals share common C. difficile ribotypes (RTs) suggesting potential zoonotic transmission. However, the role of animals for the development of human infection due to C. difficile remains unclear. One major public health issue is the existence of asymptomatic animals that carry and shed the bacterium to the environment, and infect individuals or populations, directly or through the food chain. C. difficile ribotype 078 is frequently isolated from food animals and household pets as well as from their environment. Nevertheless, direct evidence for the transmission of this particular ribotype from animals to humans has never been established. This review will summarize the current available data on epidemiology, clinical presentations, risk factors and laboratory diagnosis of C. difficile infection in food animals and household pets, outline potential prevention and control strategies, and also describe the current evidence towards a zoonotic potential of C. difficile infection.

Concentrations of Campylobacter spp., Escherichia coli, Enterococci, and Yersinia spp. in the Feces of Farmed Red Deer in New Zealand

Intensive deer farming can cause environmental issues, mainly by its impact on soils and water quality. In particular, there is a risk to the microbial quality of water, as high quantities of suspended sediment and fecal bacteria can enter into water systems. The feces of farmed red deer (, = 206) from Canterbury and Southland, New Zealand, were analyzed with regard to the presence of spp., , enterococci, and spp.. Enterococci and were isolated from all samples, with mean concentrations of 4.5 × 10 (95% CI 3.5 × 10, 5.6 10) and 1.3 × 10 (95% CI 1.1 × 10, 1.5 × 10) per gram of dry feces, respectively. spp. were isolated from 27 fecal samples, giving an overall prevalence of 13.1%. isolation rates were variable within and between regions (Canterbury 7.95% [95% CI 2-14%], Southland 16.95% [95% CI 10-24%]). Five out of 42 composite samples were positive for , and one sample for The overall prevalence ranges on a per-animal basis were therefore 2.43 to 11.17% and 0.49 to 2.91%, respectively. This study is the first to quantify the concentration of spp. present in healthy deer farmed in New Zealand. Deer feces are a potential source of human campylobacteriosis, with all genotypes isolated also previously observed among human cases. The fecal outputs from deer should be regarded as potentially pathogenic to humans and therefore be appropriately managed.

Subboiling Moist Heat Favors the Selection of Enteric Pathogen Clostridium difficile PCR Ribotype 078 Spores in Food

Emerging enteric pathogens could have not only more antibiotic resistance or virulence traits; they could also have increased resistance to heat. We quantified the effects of minimum recommended cooking and higher temperatures, individually on a collection of C. difficile isolates and on the survival probability of a mixture of emerging C. difficile strains. While minimum recommended cooking time/temperature combinations (63–71°C) allowed concurrently tested strains to survive, higher subboiling temperatures reproducibly favored the selection of newly emerging C. difficile PCR ribotype 078. Survival ratios for “ribotypes 078” :  “other ribotypes” (n = 49 : 45 isolates) from the mid-2000s increased from 1 : 1 and 0.7 : 1 at 85°C (for 5 and 10 minutes, resp.) to 2.3 : 1 and 3 : 1 with heating at 96°C (for 5 and 10 minutes, resp.) indicating an interaction effect between the heating temperature and survival of C. difficile genotypes. In multistrain heating experiments, with PCR ribotypes 027 and 078 from 2004 and reference type strain ATCC 9689 banked in the 1970s, multinomial logistic regression (P < 0.01) revealed PCR ribotype 078 was the most resistant to increasing lethal heat treatments. Thermal processes (during cooking or disinfection) may contribute to the selection of emergent specific virulent strains of C. difficile. Despite growing understanding of the role of cooking on human evolution, little is known about the role of cooking temperatures on the selection and evolution of enteric pathogens, especially spore-forming bacteria.

Clostridium difficile infection: Early history, diagnosis and molecular strain typing methods

Recognised as the leading cause of nosocomial antibiotic-associated diarrhoea, the incidence of Clostridium difficile infection (CDI) remains high despite efforts to improve prevention and reduce the spread of the bacterium in healthcare settings. In the last decade, many studies have focused on the epidemiology and rapid diagnosis of CDI. In addition, different typing methods have been developed for epidemiological studies. This review explores the history of C. difficile and the current scope of the infection. The variety of available laboratory tests for CDI diagnosis and strain typing methods are also examined.

Listeria monocytogenes in Different Specimens from Healthy Red Deer and Wild Boars

In the past, Listeria monocytogenes has been isolated from game feces and meat. However, less information is available on the occurrence of L. monocytogenes in other specimens originating from game animals. Hence, the aim of this study was to get an overview of the occurrence and distribution of L. monocytogenes in game animals by characterization of isolates from different matrices. For that purpose, samples were collected from red deer (Cervus elaphus), wild boars (Sus scrofa), and feed during the hunting season 2011-2012 in three different regions of Germany and Austria. Six samples from each animal were examined: tonsils, content of the rumen or the stomach, liver, intestinal lymph nodes, cecum content, and feces. Nineteen of 45 red deer and 12 of 49 wild boars were found to be positive for L. monocytogenes as well as 4 of 22 pooled feed samples. L. monocytogenes was isolated most frequently from the rumen of red deer (14 of 19) and the tonsils of wild boars (7 of 12). Serotypes 1/2a, 1/2b, 4a, and 4b were detected in samples of game animals and feed, and serotypes 1/2a and 4b were the most prevalent serotypes. The presence of L. monocytogenes serotype 4a had not yet been described in red deer. This might be due to the fact that it was only isolated from the content of rumen and that no other study has yet examined ruminal content. Pulsed-field gel electrophoresis showed a wide variety of strains. Some strains occurred in both species and feed samples, but one strain was dominant in one region. The results show that red deer and wild boars can be carriers of L. monocytogenes in different matrices, although the feces samples can be negative.

Clostridium difficile in Food and Animals: A Comprehensive Review

Zoonoses are infections or diseases that can be transmitted between animals and humans through direct contact, close proximity or the environment. Clostridium difficile is ubiquitous in the environment, and the bacterium is able to colonise the intestinal tract of both animals and humans. Since domestic and food animals frequently test positive for toxigenic C. difficile, even without showing any signs of disease, it seems plausible that C. difficile could be zoonotic. Therefore, animals could play an essential role as carriers of the bacterium. In addition, the presence of the spores in different meats, fish, fruits and vegetables suggests a risk of foodborne transmission. This review summarises the current available data on C. difficile in animals and foods, from when the bacterium was first described up to the present.

Clostridium difficile with Moxifloxacin/Clindamycin Resistance in Vegetables in Ohio, USA, and Prevalence Meta-Analysis

We (i) determined the prevalence of Clostridium difficile and their antimicrobial resistance to six antimicrobial classes, in a variety of fresh vegetables sold in retail in Ohio, USA, and (ii) conducted cumulative meta-analysis of reported prevalence in vegetables since the 1990s. Six antimicrobial classes were tested for their relevance as risk factors for C. difficile infections (CDIs) (clindamycin, moxifloxacin) or their clinical priority as exhaustive therapeutic options (metronidazole, vancomycin, linezolid, and tigecycline). By using an enrichment protocol we isolated C. difficile from three of 125 vegetable products (2.4%). All isolates were toxigenic, and originated from 4.6% of 65 vegetables cultivated above the ground (n = 3; outer leaves of iceberg lettuce, green pepper, and eggplant). Root vegetables yielded no C. difficile. The C. difficile isolates belonged to two PCR ribotypes, one with an unusual antimicrobial resistance for moxifloxacin and clindamycin (lettuce and pepper; 027-like, A⁺B⁺CDT⁺; tcdC 18 bp deletion); the other PCR ribotype (eggplant, A⁺B⁺ CDT⁻; classic tcdC) was susceptible to all antimicrobials. Results of the cumulative weighted meta-analysis (6 studies) indicate that the prevalence of C. difficile in vegetables is 2.1% and homogeneous (P < 0.001) since the first report in 1996 (2.4%). The present study is the first report of the isolation of C. difficile from retail vegetables in the USA. Of public health relevance, antimicrobial resistance to moxifloxacin/clindamycin (a bacterial-associated risk factor for severe CDIs) was identified on the surface of vegetables that are consumed raw.

Animal Reservoirs of Shiga Toxin-Producing Escherichia coli

Shiga toxin-producing Escherichia coli (STEC) strains have been detected in a wide diversity of mammals, birds, fish, and several insects. Carriage by most animals is asymptomatic, thus allowing for dissemination of the bacterium in the environment without detection. Replication of the organism may occur in the gastrointestinal tract of some animals, notably ruminants. Carriage may also be passive or transient, without significant amplification of bacterial numbers while in the animal host. Animals may be classified as reservoir species, spillover hosts, or dead-end hosts. This classification is based on the animal's ability to (i) transmit STEC to other animal species and (ii) maintain STEC infection in the absence of continuous exposure. Animal reservoirs are able to maintain STEC infections in the absence of continuous STEC exposure and transmit infection to other species. Spillover hosts, although capable of transmitting STEC to other animals, are unable to maintain infection in the absence of repeated exposure. The large diversity of reservoir and spillover host species and the survival of the organism in environmental niches result in complex pathways of transmission that are difficult to interrupt.

Bioserotypes and virulence markers of Y. enterocolitica strains isolated from roe deer (Capreolus capreolus) and red deer (Cervus elaphus)

Free-living animals are an important environmental reservoir of pathogens dangerous for other animal species and humans. One of those is Yersinia (Y.) enterocolitica, the causative agent of yersiniosis--foodborne, enzootic disease, significant for public health. The purpose of the study was to identify bioserotypes and virulence markers of Y enterocolitica strains isolated from roe deer (Capreolus capreolus) and red deer (Cervus elaphus) obtained during the 2010/2011 hunting season in north-eastern Poland. From among 48 rectal swabs obtained from 24 roe deer, two strains of Y enterocolitica from one animal were isolated. Although both belonged to biotype 1A they were identified as different serotypes. The strain obtained from cold culture (PSB) belonged to serotype 0:5, while the strain isolated from warm culture (ITC) was regarded as nonidentified (NI), what may suggest mixed infection in that animal. The presence of ystB gene, coding for YstB enterotoxin, directly related to Y enterocolitica pathogenicity was detected in both strains using triplex PCR. The effect of the examination of 32 swabs obtained from 16 red deer was the isolation of two Y enterocolitica strains from two different animals. Both belonged to biotype 1A with NI serotype, but were originated from different types of culture. They gave positive results in case of products of a size corresponding to the ystB gene. No amplicons corresponding to ail and ystA genes were found. Roe deer and red deer may carry and shed Y. enterocolitica, what seems to be important in aspect of an environmental reservoir of this pathogen. The Y enterocolitica strains isolated from wild ruminants had the amplicons of the ystB gene, what suggest they can be potential source of Y enterocolitica infection for humans.

Transmission of Clostridium difficile in foods

Clostridium difficile is a human intestinal pathogen most frequently involved in diarrheal illnesses following the administration of antibiotics. There is growing concern that some C difficile infections (CDI) may be acquired from ingestion of C difficile spores in contaminated foods. The number of CDI cases is increasing with a heightening in the severity of disease symptoms and an increasing number of community-associated infections not connected to health care-associated risk. This article provides an overview of information related to assessing the risk of foodborne transmission of CDI, highlighting studies on C difficile relevant to food safety in health care settings.

Clostridium difficile in foods and animals: history and measures to reduce exposure

Many articles have summarized the changing epidemiology of Clostridium difficile infections (CDI) in humans, but the emerging presence of C. difficile in foods and animals and possible measures to reduce human exposure to this important pathogen have been infrequently addressed. CDIs have traditionally been assumed to be restricted to health-care settings. However, recent molecular studies indicate that this is no longer the case; animals and foods might be involved in the changing epidemiology of CDIs in humans; and genome sequencing is disproving person-to-person transmission in hospitals. Although zoonotic and foodborne transmission have not been confirmed, it is evident that susceptible people can be inadvertently exposed to C. difficile from foods, animals, or their environment. Strains of epidemic clones present in humans are common in companion and food animals, raw meats, poultry products, vegetables, and ready-to-eat foods, including salads. In order to develop science-based prevention strategies, it is critical to understand how C. difficile reaches foods and humans. This review contextualizes the current understanding of CDIs in humans, animals, and foods. Based on available information, we propose a list of educational measures that could reduce the exposure of susceptible people to C. difficile. Enhanced educational efforts and behavior change targeting medical and non-medical personnel are needed.

The microbiological conditions of carcasses from large game animals in Italy

This study investigates the microbiological conditions of large game animal carcasses following evisceration. Carcasses of animals (N=291) hunted in the Upper Susa Valley (Italian Alps) were analysed for pH, Aerobic Viable Count (AVC), Enterobacteriaceae, Yersinia spp., Listeria monocytogenes and Salmonella spp. After shooting, evisceration occurred within 60 min in 90.7% of animals and sampling within 90 min in 88.3% of animals. Mean pH values (5.97: ruminants; 5.77: wild boar) were similar to those of regularly slaughtered domestic species. AVC values were highest in animals shot in the abdomen. Within species, AVC and Enterobacteriaceae values did not differ across different shooting-evisceration/sampling times. However, these counts exceeded 5 and 2.5 log, respectively, in 18% of wild boar and 39% of ruminants; the highest values were detected in wild boar. No pathogens were detected in any species. These results reveal inadequate hygiene in game meat handling/harvesting, implicating the need for improved practices.

Prevalence, enumeration, and antimicrobial agent resistance of Clostridium difficile in cattle at harvest in the United States

To assess the potential for food contamination with Clostridium difficile from food animals, we conducted a cross-sectional fecal prevalence study in 944 randomly selected cattle harvested at seven commercial meat processing plants, representing four distant regions (median distance of 1,500 km) of the United States. In all, 944 animals were sampled in the summer of 2008. C. difficile was isolated from 1.8% (17 of 944) of cattle, with median fecal shedding concentration of 2.2 log CFU/g (range = 1.6 to 4.8, 95% confidence interval = 1.6, 4.3). Toxigenic C. difficile isolates were recovered from only four (0.4%) cattle. One of these isolates was emerging PCR ribotype 078/toxinotype V. The remaining toxigenic isolates were toxinotype 0, one of which was an isolate with resistance to linezolid, clindamycin, and moxifloxacin (by the E-test). All isolates were susceptible to vancomycin, metronidazole, and tigecycline, but the MICs against linezolid were as high as the highest reported values for human-derived isolates. The source of the linezolid-clindamycin-moxifloxacin resistance in a toxigenic C. difficile isolate from cattle is uncertain. However, since the use of these three antimicrobial agents in cattle is not allowed in North America, it is possible that resistance originated from an environmental source, from other species where those antimicrobial agents are used, or transferred from other intestinal bacteria. This study confirms that commercial cattle can carry epidemiologically relevant C. difficile strains at the time of harvest, but the prevalence at the time they enter the food chain is low.

Transient fecal shedding and limited animal-to-animal transmission of Clostridium difficile by naturally infected finishing feedlot cattle

To longitudinally assess fecal shedding and animal-to-animal transmission of Clostridium difficile among finishing feedlot cattle as a risk for beef carcass contamination, we tested 186 ± 12 steers (mean ± standard deviation; 1,369 samples) in an experimental feedlot facility during the finishing period and at harvest. Clostridium difficile was isolated from 12.9% of steers on arrival (24/186; 0 to 33% among five suppliers). Shedding decreased to undetectable levels a week later (0%; P < 0.001), and remained low (< 3.6%) until immediately prior to shipment for harvest (1.2%). Antimicrobial use did not increase fecal shedding, despite treatment of 53% of animals for signs of respiratory disease. Animals shedding C. difficile on arrival, however, had 4.6 times higher odds of receiving antimicrobials for respiratory signs than nonshedders (95% confidence interval for the odds ratio, 1.4 to 14.8; P = 0.01). Neither the toxin genes nor toxin A or B was detected in most (39/42) isolates based on two complementary multiplex PCRs and enzyme-linked immunosorbent assay testing, respectively. Two linezolid- and clindamycin-resistant PCR ribotype 078 (tcdA+/tcdB+/cdtB+/39-bp-type deletion in tcdC) isolates were identified from two steers (at arrival and week 20), but these ribotypes did not become endemic. The other toxigenic isolate (tcdA+/tcdB+/cdtB+/classic tcdC; PCR ribotype 078-like) was identified in the cecum of one steer at harvest. Spatio-temporal analysis indicated transient shedding with no evidence of animal-to-animal transmission. The association between C. difficile shedding upon arrival and the subsequent need for antimicrobials for respiratory disease might indicate common predisposing factors. The isolation of toxigenic C. difficile from bovine intestines at harvest highlights the potential for food contamination in meat processing plants.