In 2014 the Advisory Committee on Antimicrobial Resistance and Healthcare Associated Infection recommended updating the definitions used to attribute/apportion C. difficile infections (CDIs) to align them with recognised international definitions. From April 2019, CDIs will be categorised by PHE as hospital onset healthcare-associated, community onset healthcare associated, community onset indeterminate association, or community onset community associated.

These changes are not expected to increase the total number of CDIs, but there will be a shift in the proportion of cases that are trust assigned, particularly as healthcare associated cases will include those with recent (last four weeks) hospitalisation. PHE estimates that the proportion of healthcare associated CDI cases will increase to around 65% of the total number of cases. The changes in apportionment should increase the potential for learning and interventions around preventing further CDIs, particularly noting that investigation of the root causes of community-associated CDI has been less complete than that of healthcare-associated cases.

From 2020, data on faecal sampling and CDI testing rates for all NHS providers will be reviewed. PHE already collects data on such sampling and testing rates on a quarterly basis. Preliminary analyses of these data show marked variations, which need to be explained/addressed to minimise the risk of ascertainment bias on CDI rates. Failure to diagnose CDI raises the possibility of poor outcomes for patients and missed opportunities for CDI control. Going forwards, there will be a particular focus on providers with high CDI rates but low sampling/testing rates relative to their peers.

Professor Mark Wilcox, Leeds Teaching Hospitals NHS Trust