The Role of Sensor-Activated Faucets in Surgical Handwashing Environment as a Reservoir of Legionella

Abstract

Surgical handwashing is a mandatory practice to protect both surgeons and patients in order to control Healthcare-Associated Infections (HAIs). The study is focused on Legionella and Pseudomonas aeruginosa contamination in Surgical Handwashing Outlets (SHWOs) provided by sensor-activated faucets with Thermostatic Mixer Valves (TMVs), as correlated to temperature, technologies, and disinfection used. Samples were analyzed by standard culture techniques, comparing hot- and cold-water samples. Legionella isolates were typed by an agglutination test and by mip sequencing. Legionella contamination showed the same distribution between hot and cold samples concerning positive samples and mean concentration: 44.5% and 1.94 Log10 cfu/L vs. 42.6% and 1.81 Log10 cfu/L, respectively. Regarding the distribution of isolates (Legionella pneumophila vs. Legionella non-pneumophila species), significant differences were found between hot- and cold-positive samples. The contamination found in relation to ranges of temperature showed the main positive samples (47.1%) between 45.1–49.6 °C, corresponding to high Legionella concentrations (2.17 Log10 cfu/L). In contrast, an increase of temperature (>49.6 °C) led to a decrease in positive samples (23.2%) and mean concentration (1.64 Log10 cfu/L). A low level of Pseudomonas aeruginosa was found. For SHWOs located in critical areas, lack of consideration of technologies used and uncorrected disinfection protocols may lead to the development of a high-risk environment for both patients and surgeons.

Legionella and the Role of Dissolved Oxygen in Its Growth and Inhibition: A Review

“…Increased water age consumes residual chlorine and results in lower disinfectant levels [2,20]. Low flow faucets and electronic eye (automatic) fixtures create microhabitats that harbor biofilm and Legionella growth [22,23].…”

Causes, Factors, and Control Measures of Opportunistic Premise Plumbing Pathogens—A Critical Review

“…Notably, since the introduction of WELS in Australia, every tap now includes a mesh capture point on its outlet, which is suspected to be an ideal breeding ground for bacteria. The mechanisms driving these trends in outlet flow control devices in tap need to be better studied [71].…”

Editorial Comments to the Special Issue: “Legionella Contamination in Water Environment”

“…The Italian Guidelines support the development of a risk assessment plan and emphasize the need for an adequate environmental surveillance plan. The study of Mazzotta et al [12] highlighted, during a Legionella environmental Surveillance Program in different hospitals, the critical role of Surgical and Washing Outlets (SHWO) with Thermostatic Mixer Valves (TMV) in bacterial growth and Health Care-Associated Infections (HAIs) risk. A non significant difference of Legionella contamination between hot and cold samples demonstrated a continuous mixing between two pipelines that create an environment capable of supporting Legionella growth.…”