Home Microbiological Sampling in a Pediatric Cystic Fibrosis Population: Pandemic Implementation and Ongoing Use.

BACKGROUND: During the coronavirus disease 2019 (COVID19) pandemic, restrictions on in-person care threatened to disrupt in-clinic airway sampling for microbiological surveillance, a vital aspect of cystic fibrosis (CF) care. In response, institutions developed home airway sampling strategies to allow continued guidelines-based microbiological surveillance. The validity of this sampling technique and its ongoing use has not been reviewed. Our aim is to characterize the frequency of home versus in-clinic airway sampling at our institution before, during, and after COVID19 and to compare the positivity rates of significant CF pathogens in both sampling methods. METHODS: This single center, retrospective cohort study included children with CF with at least one airway culture between January 1st, 2019, and May 16th, 2023. Culture data were extracted from an electronic microbiological database and individual culture locations (home or clinic) were confirmed manually from patient charts. RESULTS: Two thousand six hundred and thirty eight cultures were included from 170 patients (52.4% male, mean age 6.2 years). Of these, 2080 were collected by healthcare providers at BCCH and 558 were collected at home by parents or caregivers. Overall, the positivity rate of all pathogens was higher in home collected samples (rate ratio: 1.46, 95%CI: 1.32-1.61, p < 0.001) than in-clinic collected samples. However, on a species-by-species analysis, only the positivity rate of other gram-negative bacilli had significantly higher positivity in home-collected samples (rate ratio: 1.69, 95%CI: 1.16-2.46, p = 0.01). CONCLUSION: The similar positivity rates of clinically significant CF pathogens suggest that home sampling is comparable to clinic sampling, though future prospective studies are needed to confirm this hypothesis.