Hospital Sinks Are a Potential Nosocomial Source of Candida Infections

To the Editor—Contaminated sinks have been implicated in transmission of multidrug-resistant gram-negative bacilli [1], presumably because gram-negative bacteria colonizing sink drains can be dispersed to the sink bowl and countertop by splattering of flowing water [2]. Contaminated sinks have not previously been linked to transmission of Candida species. However, we recently reported frequent recovery of Candida species from environmental surfaces in our hospital, particularly from moist sites such as sink drains [3]. Therefore, we investigated the frequency of Candida species contamination of sinks in multiple hospitals and evaluated the potential for dispersal by splattering of water. In 4 Cleveland hospitals, we cultured sinks in patient rooms as well as in personnel work areas for Candida species. Before operation of the sink, the entire sink bowl and the adjacent countertop ≤6 inches from the sink bowl were sampled with separate Rayon swabs (BBL Culture Swabs, Becton Dickinson) premoistened with sterile water. The sink bowl and adjacent countertop were then disinfected with a commercial improved hydrogen peroxide disinfectant. Additional cultures were collected after disinfection and again after the sink hot and cold water faucets were run for 30 seconds. The swabs were plated onto Sabouraud dextrose agar and incubated for 96 hours at 37°C. Water samples from the faucet and swabs from the sink drain were also cultured. Colonies consistent with Candida species were subjected to identification using matrix-assisted laser desorption/ionization–time of flight. A total of 194 sets of cultures were collected from the 4 hospitals (range, 44–50 cultures per hospital). As shown in the figure, Candida species were frequently recovered from the sink bowls and countertops at baseline (Figure 1A). No cultures were positive after disinfection, but dissemination to the sink bowl and countertop occurred frequently after running the faucet (Figure 1B). Candida parapsilosis was the most frequent Candida species recovered. All sink drain cultures were positive for the same Candida species that was recovered from the bowl and countertop, but cultures of water were negative. Frequency of recovery of Candida species from sink bowls and countertops at baseline (A) and after running the hot and cold water faucets for 30 seconds (B). The sink bowl and countertop were disinfected after the baseline cultures but before running the water. Candida species recovered were identified using matrix-assisted laser desorption/ionization–time of flight. Candida species are a common cause of invasive infections in hospitalized patients, and strains causing infection may be acquired exogenously, including from the environment [4, 5]. A better understanding of the sources of acquisition of Candida species is urgently needed, particularly given evidence of transmission of the emerging multidrug-resistant Candida auris in healthcare settings [6]. Our results demonstrate that hospital sinks are frequently contaminated with Candida species and splattering of water from the sink drain results in dispersal to the sink bowl and countertop. Such dispersal could result in transmission due to contamination of medical supplies or equipment or the hands of personnel and patients. Our study findings provide evidence that contaminated sinks could be an important and heretofore unrecognized source for dissemination of Candida species in healthcare facilities. Additional studies that include molecular typing are needed to determine the relatedness of Candida species recovered from sinks and clinical isolates. In addition, there is a need to develop effective interventions to reduce contamination of sinks with Candida species and gram-negative bacterial pathogens. Financial support. This work was supported by the Department of Veterans Affairs. Potential conflicts of interest.