Methods The data for this study were collected, during the period between February 2005 and September 2007, from the alphabetical list of the commercial stores located in the geographic area of the city of Naples, in the South of Italy. From this list, 41 stores were selected using a simple random sampling selleck compound technique. Before the study, as part of the process of informed consent, all selected commercial stores received an envelope with a letter informing that a research project was being conducted and describing the study, the voluntary nature of participation, and assurance of privacy and anonymity. For each participant,
PD-1 inhibitor information about the date of installation, time since last ordinary and extraordinary maintenance of water coolers was collected with a self-administered questionnaire. The water coolers were produced LY2835219 chemical structure by different companies, all were supplied from tap water and at the sampling
time the mechanism of cooling was functioning. At the end of the study, each store received the results of the microbiological and chemical quality parameters investigated. Collection of water samples Water samples were collected from coolers (carbonated and non-carbonated water) and tap water corresponding to the tap water used for the cooler from the same store. Each sample was analyzed for total viable count (TVC), qualitative microbial indicators, and chemical parameters of organic contamination. Two litres of each water sample were collected without flushing before sampling and sterilizing the outer surfaces of the faucets. Water samples were collected C-X-C chemokine receptor type 7 (CXCR-7) in sterile sample bottles containing sodium thiosulfate (100 mg/L). Samples were transported on blue ice in an insulated, double-walled container
to the laboratory for analysis and primary isolation within 6 hours of sampling. All analyses were performed according to the current Italian  and European regulations on drinking water for human consumption . The reference values for the water in order to be declared potable are the following: Enterococcus spp., Escherichia coli, and Pseudomonas aeruginosa should not be detectable in 100 ml; TVC less than 100 and 20 colony forming units (CFU) per mm at 22°C and 37°C, respectively; nitrite and ammonium less than 0.5 mg/L; free chlorine comprised between the values of 0.2 and 0.8 mg/L; and pH between the values of 6.5 and 9.5. Microbiological parameters The microbiological analyses of all water samples were conducted as follows: 1) TVC: 1 mL of each sample was included with 20 mL of Water Plate Count agar (bioMérieux Italia) and two sets of plates were prepared for all samples with each sample diluted until 10-3 on three dishes. One set was incubated at 22°C for 72 hours and the other set at 37°C for 48 hours (prEN ISO 6222).