Antimicrobial Stewardship Effects of Interpretive Comments for Faecal PCR Tests

Bacterial gastroenteritis is a common condition seen in Aotearoa New Zealand, which is typically diagnosed by PCR testing on a stool sample. Most causes of bacterial gastroenteritis (e.g. Campylobacter spp, Salmonella spp, Yersinia spp) cause a self-limiting illness and antibiotic therapy is not required. Indeed, guidelines available for community healthcare providers in Aotearoa (e.g. Community HealthPathways, recently released national antimicrobial guidelines Te Whata Kura) recommend against antibiotic therapy for the vast majority of cases. A recent internal analysis at Awanui Laboratories of community faecal pathogen PCR testing revealed that antibiotic prescribing was very common after a positive result (ranging between 20-40% for the various individual pathogens), which suggests many community healthcare providers may not be following the recommended approach for the management of these infections. Given how common infectious gastroenteritis is in Aotearoa, and the volume of tests performed (approximately 100,000 through the Awanui network per year), this prescribing behaviour may represent a large volume of unnecessary antibiotic use in our communities, with resultant potential harmful effects at the individual patient level and population level via side effects, disruption to the faecal microbiome, and impacts on antimicrobial resistance (AMR). In previous work we have demonstrated that interpretive comments, when added to laboratory reports, can have a significant positive effect on prescriber behaviour (https://doi.org/10.1093/jac/dkad384), but this has not been examined in relation to faecal pathogen testing.