Environmental Reservoirs of Nosocomial Infection: Imputation Methods for Linking Clinical and Environmental Microbiological Data to Understand Infection Transmission

The transmission of hospital-acquired Carbapenem-resistant Enterobacteriaceae (CRE) is a serious and growing concern in hospitals worldwide. Previous research of CRE found that traditional patient-to-patient transmission of the bacteria does not fully account for all cases of transmission. Recent efforts to further understand modes of transmission found identical genomes of CRE in patient sinks as was found in cultures collected from patients, indicating that environmental reservoirs could be playing a larger role in transmission than was first realized. This study evaluated imputation methods for linking multiscale clinical and environmental microbiological data. We then utilized the imputed data set to model the risk of CRE presence in sinks between culture dates. We demonstrated that imputation based on expert knowledge of the unique factors of the physical hospital layout and patterns of occurrence throughout hospital sinks provided the best representation of sink positivity and also identified several significant risk factors for explaining environmental contamination. This work helps to more clearly define the mechanism and risk of transmission from a wastewater source to hospitalized patients in a world with increasingly antibiotic-resistant bacteria which can thrive in wastewater environments and cause infections in vulnerable patients.