The Assessment of the Risk Factors on Legionella spp. Presence in Public Supply Water in Permanently vs. Seasonally Open Facilities

Microbiological, physical and chemical analysis of domestic hot water in two accommodation sites with year-round operation and two accommodation sites with seasonal work in Split and Dalmatian County was conducted during 2009-2012. From seasonally open facilities 206 hot water samples were analyzed for the presence of Legionella spp. as well as 219 samples from facilities with year-round operation. Analysis also included water temperature, free residual chlorine, and concentrations of iron, zinc and copper. Legionella spp. was found in 116 (27.3%) samples. There was no statistical significance between positive samples from the year round facilities (57) and seasonal accommodation sites (59). Differences in metal concentrations were negligible, except for zinc, which was higher in year round (0.110 mg/L) compared with seasonal facilities (0.090 mg/L). This study showed that there was no difference between full-time or seasonal work of the facilities in terms of the isolation of Legionella spp. from hot water.