Intensive Care Unit Wastewater Interventions to Prevent Transmission of Multi-species Klebsiella pneumoniae Carbapenemase (KPC) Producing Organisms.

Background: Increasing prevalence of nosocomial carbapenemase-producing Enterobacteriaceae is a concern; however, the role of the environment in multispecies outbreaks remains poorly understood. There is increasing recognition that hospital wastewater plumbing may play a role. Methods: Covers were installed on all hoppers in adult intensive care units (ICUs) of a university hospital; in the surgical ICU (SICU) both hopper covers and sink trap heating/vibration devices were installed. Patient acquisitions (measured by perirectal colonization or clinical culture) of Klebsiella pneumoniae carbapenemase (KPC)-producing organisms (KPCO) for patients who were admitted to an intervention unit were compared for 18-month pre-intervention and intervention periods. Results: Sixty hopper covers and 23 sink trap devices were installed. A total of 56 new multispecies KPCO acquisitions occurred pre-intervention compared to 30 during the intervention. Decreases for all KPCO acquisitions (odds ratio [OR] 0.51; 95% confidence interval [CI]: 0.31-0.81; p=0.003) and KPCO-positive clinical cultures (OR 0.29; CI:0.17-0.48; p<0.001) per admission in patients exposed to an intervention unit were observed. The incidence rate ratio was 0.51 [0.43-0.61 95% CI] fold lower for all KPCO acquisitions during the intervention. The effect of the sink trap devices alone could not be determined, although the proportion of sink drain cultures positive for KPCO decreased (12/15 [80%] sites sampled pre-intervention versus 40/840 [5%] sampled during the intervention; p=0.001). Conclusions: An intervention targeting wastewater hospital plumbing fixtures by installing hopper covers in adult ICUs demonstrated a decrease in patient KPCO acquisitions. Considering wastewater reservoirs in nosocomial transmission of multispecies carbapenemase-producing Enterobacteriaceae may be critical.