The event will be hybrid. Please register by writing to korsbaek@cas.au.dk to get the zoom link. You are also very welcome to join the seminar at Moesgård (4235, 133).

Abstract: 

Clostridioides (formerly Clostridium) difficile is a spore-forming, obligate anaerobe bacillus. It is an enteropathogen normally found in the intestinal tract of humans and various animals, ranging from pets to livestock, but also wildlife. The ability of the vegetative cell to undergo sporulation allows this organism to resist a variety of extreme conditions, ie. UV radiations, desiccation, and many commonly used cleaners. For this reason, the spores are able to persist on contaminated surfaces for long periods and following ingestion, easily overcome the acidic environment in the stomach.

C. difficile infection (CDI) develops in connection with the use of antibiotics, which causes a disruption of the normal protective gut microbiota. The infection can range from an asymptomatic colonization, to a mild diarrhea, to the life‐threatening pseudomembranous colitis (PMC) and toxic megacolon.

In the last ten years, C. difficile has become a concern in particular in hospital settings, where it is on of the most common causes of nosocomial enteritis. Infections are also reported to be more frequent, severe and recurrent. Among the reasons for this is the emergence of two main hypervirulent strains, namely C. difficile ribotype (RT) 027 and 078. The first has been responsible for the increase in hospital-associated CDI, while the latter has been associated with the surge in community-acquired CDI. RT078 is historically known as an animal associated strain, since it is the predominant type found in livestock, in particular pigs and calves. The higher incidence of community-acquired CDI caused by this strain and the overlapping between the findings in humans and in production animals suggest the potential for a zoonotic transmission.

We aimed to better elucidate the relationship between CDI and animal husbandry while focusing on the Danish territory. We investigated the role of livestock in the spread of C. difficile and the potential for its zoonotic transmission by collecting samples from pig farms across Denmark and genetically and phylogenetically comparing the positive isolates with human isolates from patient affected by CDI, both hospital- and community-acquired.

Our results show a high prevalence of RT078 as the most common strain both in human and in animal isolates, and a high degree of genetic identity among this group. In addition to that, other ribotypes were shared between the two groups, as well as the antibiotic resistance patterns. This great similarity suggests a correlation between the strains isolated in the farms and the ones causing CDI in humans. It is however not possible to clearly determine the direction of this transmission, for which we are currently expanding our study. Nonetheless, the preliminary results we obtained add to and align with the current knowledge on a possible risk of zoonotic transmission of C. difficile.