Neonatal piglet losses associated with Escherichia coli and Clostridium difficile infection in a Slovakian outdoor production unit

The Environment, Farm Animals and Foods as Sources of Clostridioides difficile Infection in Humans

The recent discovery of the same Clostridioides difficile ribotypes associated with human infection in a broad range of environments, animals and foods, coupled with an ever-increasing rate of community-acquired infections, suggests this pathogen may be foodborne. The objective of this review was to examine the evidence supporting this hypothesis. A review of the literature found that forty-three different ribotypes, including six hypervirulent strains, have been detected in meat and vegetable food products, all of which carry the genes encoding pathogenesis. Of these, nine ribotypes (002, 003, 012, 014, 027, 029, 070, 078 and 126) have been isolated from patients with confirmed community-associated C. difficile infection (CDI). A meta-analysis of this data suggested there is a higher risk of exposure to all ribotypes when consuming shellfish or pork, with the latter being the main foodborne route for ribotypes 027 and 078, the hypervirulent strains that cause most human illnesses. Managing the risk of foodborne CDI is difficult as there are multiple routes of transmission from the farming and processing environment to humans. Moreover, the endospores are resistant to most physical and chemical treatments. The most effective current strategy is, therefore, to limit the use of broad-spectrum antibiotics while advising potentially vulnerable patients to avoid high-risk foods such as shellfish and pork.

Seasonality of Clostridium difficile in the natural environment

Clostridium difficile is considered the leading cause of antibiotic-associated disease worldwide. In the past decade, a large number of studies have focused on identifying the main sources of contamination in order to elucidate the complete life cycle of the infection. Hospitals, animals and retail foods have been considered as potential vectors. However, the prevalence of C. difficile in these types of samples was found to be rather low, suggesting that other contamination routes must exist. This study explores the presence of C. difficile in the natural environment and the seasonal dynamics of the bacterium. C. difficile was isolated from a total of 45 samples out of 112 collected (40.2%) on 56 sampling points. A total of 17 points were positive only during the winter sampling (30.4%), 10 were positive only during the summer sampling (17.9%) and 9 sampling points (16.1%) were positive in both summer sampling and winter sampling. Spore counts in soil samples ranged between 50 and 250 cfu/g for 24.4% of the positive samples, with the highest concentrations detected in samples collected in the forest during winter campaign (200-250 cfu/g). A total of 17 different PCR ribotypes were identified, and 15 of them had the genes coding for toxins A and B. Most of those ribotypes had not previously been found or had been isolated only sporadically (<1% of samples) from hospitals in Belgium. Regarding antimicrobial susceptibility, most of the resistant strains were found during the summer campaign. These findings bear out that C. difficile is present in the natural environment, where the bacterium undergoes seasonal variations.

Genomic Delineation of Zoonotic Origins of Clostridium difficile

Clostridium difficile is toxin-producing antimicrobial resistant (AMR) enteropathogen historically associated with diarrhea and pseudomembranous colitis in hospitalized patients. In recent years, there have been dramatic increases in the incidence and severity of C. difficile infection (CDI), and associated morbidity and mortality, in both healthcare and community settings. C. difficile is an ancient and diverse species that displays a sympatric lifestyle, establishing itself in a range of ecological niches external to the healthcare system. These sources/reservoirs include food, water, soil, and over a dozen animal species, in particular, livestock such as pigs and cattle. In a manner analogous to human infection, excessive antimicrobial exposure, particularly to cephalosporins, is driving the expansion of C. difficile in livestock populations worldwide. Subsequent spore contamination of meat, vegetables grown in soil containing animal feces, agricultural by-products such as compost and manure, and the environment in general (households, lawns, and public spaces) is contributing to a persistent community source/reservoir of C. difficile and the insidious rise of CDI in the community. The whole-genome sequencing era continues to redefine our view of this complex pathogen. The application of high-resolution microbial genomics in a One Health framework (encompassing clinical, veterinary, and environment derived datasets) is the optimal paradigm for advancing our understanding of CDI in humans and animals. This approach has begun to yield critical insights into the genetic diversity, evolution, AMR, and zoonotic potential of C. difficile. In Europe, North America, and Australia, microevolutionary analysis of the C. difficile core genome shows strains common to humans and animals (livestock or companion animals) do not form distinct populations but share a recent evolutionary history. Moreover, for C. difficile sequence type 11 and PCR ribotypes 078 and 014, major lineages of One Health importance, this approach has substantiated inter-species clonal transmission between animals and humans. These findings indicate either a zoonosis or anthroponosis. Moreover, they challenge the existing paradigm and the long-held misconception that CDI is primarily a healthcare-associated infection. In this article, evolutionary, and zoonotic aspects of CDI are discussed, including the anthropomorphic factors that contribute to the spread of C. difficile from the farm to the community.

Epidemiology and Risk Factors for Community-Associated Clostridium difficile Infection: A Narrative Review

Clostridium difficile infection (CDI) was once considered a primarily nosocomial concern. Emerging evidence from the last 20 years has highlighted a drastic shift in the known epidemiology of CDI, with disease outside of hospitals apparently occurring more frequently and causing severe disease in populations that were thought to be at low risk. This narrative review summarises potential pathways for infection outside of the hospital environment and highlights likely routes of transmission. Further, evidence is presented on potential risk factors for development of disease. Understanding the epidemiology of CDI outside of hospitals is essential to the ability to prevent and control disease in vulnerable populations.

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.

Prevalence and genotypic characteristics of Clostridium difficile in a closed and integrated human and swine population

Recently, an apparent rise in the number of cases attributed to community-acquired Clostridium difficile infection has led researchers to explore additional sources of infection. The finding of C. difficile in food animals and retail meat has raised concern about potential food-borne and occupational exposures. The objective of this study was to compare C. difficile isolated from a closed population of healthy individuals consisting of both humans and swine in order to investigate possible food safety and occupational risks for exposure. Using a multistep enrichment isolation technique, we identified 11.8% of the human wastewater samples and 8.6% of the swine samples that were positive for C. difficile. The prevalences of C. difficile in swine production groups differed significantly (P < 0.05); however, the prevalences in the two human occupational group cohorts did not differ significantly (P = 0.81). The majority of the human and swine isolates were similar based on multiple typing methods. The similarity in C. difficile prevalence in the human group cohorts suggests a low occupational hazard, while a greatly decreased prevalence of C. difficile in later-stage swine production groups suggests a diminished risk for food-borne exposure. The similarity of strains in the two host species suggests the possibility of a common environmental source for healthy individuals in a community setting.

Prevalence of Clostridium difficile in diarrhoeic and non-diarrhoeic piglets

Clostridium difficile is considered to be an important causative agent of porcine neonatal diarrhoea, having taken over from classic bacterial pathogens. However, there are currently no clear data concerning the prevalence of this microorganism in piglets, or about its relative distributions among diarrhoeic and non-diarrhoeic animals. In the present study, we analyzed the presence of C. difficile in rectal swabs from 780 piglets from two age groups (newborn and 1-2-month-old pigs) by means of molecular and microbiological procedures. Furthermore DNA was isolated from the bacteria in order to identify toxin A and toxin B genes.C. difficile was not found in any of the 239 samples taken from 1- to 2-month-old pigs. Bacteria were, however, recovered from 140 out of 541 newborn piglets (25.9%), including both diarrhoeic and non-diarrhoeic animals, and animals from control farms (free of diarrhoeic animals). Genes for the production of both toxins A and B were identified in 132 of the 140 isolates (A(+)B(+)). Only seven isolates, all from the same farm and from non-diarrhoeic animals, lacked both toxin genes (A(-)B(-)), while one isolate from this same group of animals was A(-)B(+).This study provides the first report comparing the prevalence of C. difficile in large numbers of diarrhoeic and non-diarrhoeic animals. There was no clear link between bacterial isolation and neonatal porcine diarrhoea.

A new periparturient disease in Eastern Europe, Clostridium difficile causes postparturient sow losses

Postparturient sow losses caused by Clostridium difficile have not been reported in the veterinary literature. Recently in Croatia, in a large outdoor production unit with suboptimal environmental conditions, a sudden increase in postparturient sow mortality was diagnosed. After postpartal application of enrofloxacine to postparturient mastitis metritis agalactia (MMA) suffering sows, diarrhea, respiratory distress, and mortality of these sows were recorded. While 13% of MMA suffering and treated sows died, only 0.4% of the non-treated (no MMA suffering) sows died postpartum. Gross pathology revealed mesocolonic edema, hydrothorax, and ascites. Microscopic examination showed scattered foci of suppuration in the colonic lamina propria and accumulation of neutrophils and fibrin on colonic mucosa. Anaerobic cultures of the colon yielded heavy growth of C. difficile. Enzyme immunoassay revealed C. difficile toxins A and B. C. difficile infections of postparturient MMA suffering sows may be associated with environmental stress, the application of antibiotics, or both. C. difficile infections are an impending danger in Eastern Europe and does not only raise animal welfare issues, but seriously inflict the economical well being of outdoor production units.