A review paper published in Clinical Microbiology and Infection discusses current trends in our understanding of C. difficile transmission. How much C. difficile infection we see is as a result of transmission within hospitals. How much is explained by acquisition of C. difficile prior to hospitalisation? Evidence is emerging and difficult to interpret, but it seems that more C. difficile infection that we once thought is caused by transmission within the community. However, a significant majority of cases are still linked to hospital transmission of C. difficile.

The Swiss review team identified 24 articles that reported on possible transmission pathways of C. difficile. Of the articles reviewed, the most commonly reported sources of C. difficile were symptomatic carriers (53%), the hospital environment (40%), and asymptomatic carriers (20%). The single most common hospital-based environmental reservoir of C. difficile was, unsurprisingly, in the rooms of affected patients – accounting for 25% of environmental sources. However, the majority of environmental sources were actually outside of the rooms of C. difficile patients. Therefore, one of the authors’ conclusions is to extend environmental strategies beyond the rooms or clinical spaces used to care for patients with known C. difficile. This means considering extending the use of sporicidal disinfectants, especially for toilets, bathrooms, and spaces dedicated to cleaning (such as utility rooms) – together accounting for 50% of environmental sources of C. difficile.

In the community setting, contact with symptomatic and asymptomatic carriers (including infants) was the source for 30% of cases, contact with residents of long-term care facilities accounted for 30%, and contact with environmental surfaces accounted for 20%. As in healthcare settings, the findings of this study suggest that extending the use of sporicidal disinfectants may be helpful in preventing C. difficile transmission in community settings.

The advent of whole genome sequencing has provided new insight into the transmission of C. difficile. However, it is difficult to be certain of C. difficile transmission routes in any setting. This review does a good job of navigating and simplifying a complex issue to provide some simple concluding recommendations: to focus on extending disinfection procedures beyond the immediate surroundings of symptomatic carriers in healthcare settings and to target household members and long-term care residents in the community.