Imputation Methods and Modeling of Environmental Reservoirs of Nosocomial Carbapenum-Resistant Bacteria

The transmission of hospital-acquired Carbapenem-resistant Enterobacteriaceae (CRE) is a serious and growing problem in hospitals worldwide. Carbapenem - the antibiotic typically used as a last resort to fight bacterial infections - is being rendered useless against some strains of bacteria that cause high rates of mortality among critically ill patients. Previous research of CRE found that traditional patient-to-patient transmission can only account for 20 percent of transmission of this bacteria in hospital settings and it is unknown through what means the remaining 80 percent of cases are transmitted. Recent e↵orts to better understand other means 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 uses clinical data from a major U.S. hospital to evaluate imputation methods for understanding CRE presence in sinks between known cultures and uses the selected imputation method as the response variable in modeling sink positivity over time as a factor of positive patient presence, use of clinical interventions, and sink characteristics. This study found that an ad hoc imputation method based on expert knowledge provided the best representation of sink positivity. Modeling results indicated that the cumulative presence of positive patients in the same room as a sink, the distance from the patient bed to the sink, and sink design are significant predictors of sink positivity.