Effectiveness of foam disinfectants in reducing sink-drain gram-negative bacterial colonization

Background: Sink drainage systems are not amenable to standard methods of cleaning and disinfection. Disinfectants applied as a foam might enhance efficacy of drain decontamination due to greater persistence and increased penetration into sites harboring microorganisms. Objective: To examine the efficacy and persistence of foam-based products in reducing sink drain colonization with gram-negative bacilli. Methods: During a 5-month period, different methods for sink drain disinfection in patient rooms were evaluated in a hospital and its affiliated long-term care facility. We compared the efficacy of a single treatment with 4 different foam products in reducing the burden of gram-negative bacilli in the sink drain to a depth of 2.4 cm (1 inch) below the strainer. For the most effective product, the effectiveness of foam versus liquid-pouring applications, and the effectiveness of repeated foam treatments were evaluated. Results: A foam product containing 3.13% hydrogen peroxide and 0.05% peracetic acid was significantly more effective than the other 3 foam products. In comparison to pouring the hydrogen peroxide and peracetic acid disinfectant, the foam application resulted in significantly reduced recovery of gram-negative bacilli on days 1, 2, and 3 after treatment with a return to baseline by day 7. With repeated treatments every 3 days, a progressive decrease in the bacterial load recovered from sink drains was achieved. Conclusions: An easy-to-use foaming application of a hydrogen peroxide- and peracetic acid-based disinfectant suppressed sink-drain colonization for at least 3 days. Intermittent application of the foaming disinfectant could potentially reduce the risk for dissemination of pathogens from sink drains.