Duration of carriage of carbapenem-resistant Enterobacteriaceae following hospital discharge

BackgroundHospitalized carriers of carbapenem-resistant Enterobacteriaceae (CRE) are cohorted under contact precautions, including in the days between rehospitalization and surveillance culture results. This study investigates duration of CRE carriage to define populations requiring precautions upon readmission.MethodsPatients with CRE-positive culture during 2009-2010 were followed up by rectal swab cultures taken retrospectively and prospectively for the study or as part of clinical follow-up.ResultsOne hundred thirty-seven patients met the inclusion criteria, with follow-up cultures obtained from 97. Mean time to CRE negativity was 387 days (95% confidence interval: 312-463). Seventy-eight percent of patients (64/82) had positive culture at 3 months, 65% (38/58) at 6 months, and 39% (12/30) at 1 year. Duration of carriage was affected by repeat hospitalization (P = .001) and clinical, as opposed to surveillance, culture (P = .002).ConclusionCRE carriers from a previous hospitalization have a lower probability of CRE carriage upon readmission if the index specimen was a surveillance culture and 1 year passed without further hospitalization. Multiple hospitalizations and CRE disease extend duration of carriage. This study better defines patients requiring cohorting and isolation, thus limiting spread of CRE and allowing for improved allocation of infection control measures.