Specimens.

From January 2016 to June 2017, consecutive rectal ESwabs (Copan Diagnostics, Murrieta, CA) from patients in the medical intensive care unit (MICU) and solid organ transplant unit at The Johns Hopkins Hospital were collected at unit admission and weekly thereafter. The swabs were collected as part of a long-standing vancomycin-resistant Enterococcus (VRE) surveillance program. At the completion of standard-of-care testing, and prior to disposal, the swabs were deidentified and held at 4°C for up to 4 days prior to further testing. This study was approved by The Johns Hopkins University School of Medicine Institutional Review Board, with a waiver of informed consent.