1224. Factors Associated with Aerosolization of Gammaproteobacteria from Intensive Care Unit (ICU) Sinks in a Randomized Trial of Copper Alloy vs. Standard Chrome Sink Drains

Background Hospital wastewater environments are recognized as reservoirs for multi-drug-resistant bacteria, and sink drains in ICUs have been implicated in numerous outbreaks. The mechanism of pathogen transmission to patients, and the best approach to risk mitigation remains unclear. We tested a new copper alloy sink drain for its effect on detection of gammaproteobacteria in sink drains and adjacent aerosols. Methods We randomized 90 sinks in 76 ICU rooms/bedspaces in 7 ICUs to new standard chrome or copper alloy drains. We sampled sinks on 4 occasions over 4 months. Drain tailpieces were sampled using cotton swabs of 140 cm2 of the interior surface, inserted into 1mL of Dey-Engley neutralizing broth, and cultured semi-quantitatively for gammaproteobacteria on Mac3CV. 850L samples of air adjacent to sinks were obtained by impaction onto Mac3CV. Faucet swabs were also cultured. Multivariable analysis adjusting for factors associated with growth in air and drains used conditional logistic regression, GEE with an exchangeable correlation matrix, a robust estimate of variance, negative binomial distribution and log link function. Results Gammaproteobacteria were detected in 247/424 (58%) tailpiece swabs, 137/456 (30%) air samples, and 31/456 (7%) faucet swabs. In multivariable analysis, growth was less likely from air adjacent to sinks with copper vs. chrome drains [IRR 0.50 (95% CI 0.35, 0.73), P < 0.0001], with reduced effect size observed when drain growth was included in the model [IRR 0.64 (95% CI 0.43, 0.94)], P = 0.025]. Growth in air was more likely when drain growth was 1–899 cfu/cm2 [IRR 2.38 (95% CI 1.46, 3.88), P = 0.001] or ≥900 cfu/cm2 [IRR 3.55 (95% CI 1.87, 6.86), P < 0.001] vs. no growth. Tailpiece swab growth was more likely if rooms were occupied compared with empty [IRR 1.85 (95% CI 1.25, 2.76), P = 0.002], and less likely from copper drains compared with swabs from chrome drains [IRR 0.51 (95% CI 0.47, 0.75), P ≤ 0.001]. Conclusion Sinks with new copper drains are less likely to have detectable gammaproteobacteria in adjacent air when compared with standard chrome drains, and results suggest this is mediated through reduced bacterial growth in the drains. Ongoing study is needed to determine whether this influences patient risk for hospital-acquired infection. Disclosures All authors: No reported disclosures.