Clostridium difficile colitis and zoonotic origins—a narrative review

Abstract

Clostridium difficile is a major cause of hospital-associated diarrhoea, and in severe cases leads to pseudomembranous colitis and toxic megacolon. The frequency of C. difficile infection (CDI) has increased in recent decades, with 453 000 cases identified in 2011 in the USA. This is related to antibiotic-selection pressure, disruption of normal host intestinal microbiota and emergence of antibiotic-resistant C. difficile strains. The burden of community-acquired CDI has been increasingly appreciated, with disease identified in patients previously considered low-risk, such as young women or patients with no prior antibiotic exposure. C. difficile has been identified in livestock animals, meat products, seafood and salads. It has been postulated that the pool of C. difficile in the agricultural industry may contribute to human CDI. There is widespread environmental dispersal of C. difficile spores. Domestic households, turf lawns and public spaces are extensively contaminated, providing a potential reservoir for community-acquired CDI. In Australia, this is particularly associated with porcine-derived C. difficile UK PCR ribotype 014/020. In this article, the epidemiological differences between hospital- and community-acquired CDI are discussed, including some emerging evidence for community-acquired CDI being a possible zoonosis.

The adaptive immune response toClostridioides difficile: A tricky balance between immunoprotection and immunopathogenesis

“…[10][11][12] Moreover, C. difficile has been identified in livestock animals, meat products, seafood, and salads, and there is widespread environmental dispersal of C. difficile spores that are potential reservoirs for community-acquired CDI. 10,13 Even more, C. difficile is also found as a commensal or pathogen microorganism in the intestinal tract of most mammals, including polar bears, evidence pointing to a zoonotic potential for this bacteria. 13,14 Interestingly, in a recent report, toxigenic isolates were recovered from dog nasal discharge suggesting a new route of transmission for C. difficile.…”

Diarrhoea in critical care is rarely infective in origin, associated with increased length of stay and higher mortality

“…This is in contrast to reports in the literature, which report increased rates of C. difficile infection. 19,20 The comparatively low number of samples sent for virological analysis (two samples) is a reflection of laboratory policy; diarrhoea samples are not routinely tested for norovirus or rotavirus. Samples are run on the basis of clinical suspicion.…”

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“…Infections occurred in hospitals are mainly transmitted between patients and between patients and medical staff, but also after contact with medical equipments, medical protective clothing, healthcare furniture or contaminated floors (20,21). Community-acquired infections may be associated with various exposures in outer environment (dust, navigable waters, sewage, irrigation ditches), domestic environment (kitchen surfaces, refrigerators) and contact with animals or foods of animal origin (22,23). Clostridium difficile, especially ribotype 078 and ribotype 027, which was isolated in cattles, pigs or domesticated poultries, but also pets and wild animals (22).…”