How Frequently Does Hospitalization of Patients Colonized with Carbapenemase-Producing Enterobacteriaceae (CPE) Result in Contamination of Hospital Sink Drains?

Background: There is growing evidence that hospital sinks and drains may be reservoirs for gram negative bacteria, which can be transmitted to patients. A report from Toronto implicating a sink drain in transmission of CPE to a hospitalized patient led us to systematically culture sinks after they were exposed to patients colonized with CPE.

Methods: At Mount Sinai Hospital (MSH), patients with risk factors for CPE are screened for colonization on admission with rectal swabs. Patients identified as colonized/infected with CPE are managed in private rooms with contact precautions and additional environmental disinfection. Beginning in 2013, we swabbed sink drains and overflows in rooms in which a patient with CPE had been present.

Results: From 10/2007-5/2016 18 patients colonized/infected with CPE have been identified at MSH (some with multiple strains/organisms); 16 were hospitalized including 1 who acquired CPE in hospital. There were 7 Klebsiella spp. (1 KPC, 1 OXA48, 1 NDM, 2 VIM, 2 OXA48+NDM); 6 E. coli (3 OXA48, 2 NDM, 1 KPC); 3 E. cloacae (1 KPC, 1 VIM, 1 NMC); and 4 other (1 KPC, 1 NDM, 1 VIM, 1 OXA24+OXA143). Since 2013, 14 hospitalized cases resulted in the exposure of 39 sinks to CPE. Swabs of five (12.8%) of these sinks, exposed to 3 different cases yielded CPE after discharge cleaning [3 E. coli (2 KPC, 1 OXA48); 1 E. cloacae (KPC); and 1 Klebsiella spp. (VIM)]. In all cases, the organism and the enzyme from the sink matched that of the patient previously admitted to the room. The median room exposure was 9 days (range 2-76) for patients whose sinks became contaminated, and 5 days (range 1-81) for patients whose sinks were negative for CPE on discharge (P=0.56) . Targeted cleaning of drains and was not successful in removing CPE. In three cases, removal of the sink drain from outlet to wall resulted in subsequent cultures from the sink being negative. In one sink with an overflow, replacement of the sink was also required before negative cultures were achieved. Another sink with an overflow remained culture negative after steam cleaning.

Conclusion: In our hospital, 13% of sink drains were contaminated after exposure to CPE colonized patients. Procedures to protect hospital drains from CPE contamination are needed.