Use of Whole Genome Sequencing to Investigate the Risk for Transmission of Clostridioides difficile From Prior Room Occupants: A Single-Center Study.
BACKGROUND: Admission to a room previously occupied by a patient with Clostridioides difficile infection (CDI) has been identified as a risk factor for CDI. However, previous studies have not included molecular typing to definitively link healthcare-associated CDI (HA-CDI) cases to prior room occupants. METHODS: In a hospital and affiliated long-term care facility, we conducted a 1-year cohort study to determine if exposure to a room previously occupied by a CDI patient and/or with environmental contamination after cleaning and disinfection in the past 3 months was associated with an increased risk of HA-CDI. Multivariable logistic regression was used to assess risk factors for HA-CDI. Whole genome sequencing was used to determine the relatedness of HA-CDI isolates and isolates from prior CDI cases or environmental surfaces. RESULTS: Of 5,746 admitted patients, 55 were diagnosed with HA-CDI. Exposure to a room previously occupied by a CDI patient and/or with a positive post-discharge culture was not associated with an increased risk of HA-CDI (adjusted odds ratio 1.15, 95% confidence interval 0.65-1.98; P=0.62). None of the 21 HA-CDI patients with prior room-level exposures were infected with isolates genomically related to isolates from prior room occupants with CDI or from room surfaces. Five HA-CDI cases were linked to prior CDI patients or environmental isolates on the same ward or without ward-level exposure. CONCLUSION: Despite frequent exposure to rooms previously occupied by CDI patients or contaminated with C. difficile, no HA-CDI cases were linked to prior room exposures in a facility using sporicidal disinfectants in CDI rooms.