Microbiological cultures
Rectal swabs for ESBL-E surveillance cultures were collected on the day of admission or the following 2 days, once a week thereafter, and on the day of discharge or the prior and/or following 2 days. Swabs were processed at the local microbiological laboratories following a standardized protocol. Chromogenic agar plates were used for detection of ESBL-E (bioMérieux, Marcy l’Etoile, France). Disk diffusion, Vitek2 (bioMérieux), or MicroScan (Beckman Coulter, Brea, CA) was used to confirm ESBL-E production. Swab results were reported back to the wards as part of routine laboratory notification procedures.