Efficacy of a Sink Tailpiece Heating Device to Decrease Microbial Colonization of Sink Drains

Background: Many institutions have reported transmission of multidrug-resistant organisms to patients from colonized sinks. Prior data have shown that bacterial colonization of the sink drain, which can occur via biofilm from a colonized p-trap or via seeding from above, results in dispersion of bacteria in the area of the sink when water from the faucet comes in contact with the drain. Heat disruption of biofilm formation between the p-trap and sink drain is a potential strategy in preventing colonization of sink drains. Methods: In an academic center hospital, 54 tail-piece heaters were installed in 3 intensive care units and 2 acute-care units in an associated regional hospital. Half of the installed devices were sham (no heat). The devices were programmed to heat the tail piece to 72C for 1 hour every fourth hour. Rooms were randomized to heating or sham devices on a 1:1 basis within each unit. Sink drains and p-traps were sampled biweekly. Samples were assessed for semiquantitative growth of gram-negative bacteria on MacConkey agar, looking especially for Pseudomonas aeruginosa and Stenotrophomonas maltophilia. Carbapenemase-producing Enterobacterales (CPE) was detected by broth enrichment followed by growth on Colorex KPC agar. Frontline personnel were blinded to device assignment. Results: Linear mixed modeling revealed reduced risk of detectable gram-negative bacteria (OR, 0.16; 95% CI, 0.037–0.536) and Enterobacterales (OR, 0.17; 95% CI, 0.368–0.668) in sink drains with a heating device (Fig. 1), but no difference in risk of detectable P. aeruginosa or S. maltophilia (Table 1). We detected a trend toward reduction in CPE that did not reach statistical significance, and there was no difference in risk for detection of any bacteria in the p-trap between heating and sham devices. Audits of devices demonstrated that few reached the target heating temperature of 72C (median, 65.9C; range, 50.1–73.7C). Conclusions: Disruption of biofilm between the p-trap and the sink drain is a promising strategy for the prevention of sink-drain colonization with clinically important bacteria. The presence of a heating device was associated with reduced risk of detectable gram-negative organisms, specifically Enterobacterales, in sink drains. The limitations of this study included low overall rates of positivity for certain pathogens, including CPE, and suboptimal, inconsistent performance across heating devices. Further work with a larger sample size and more consiste