Prevalence of Shiga toxin-, intimin- and haemolysin genes in Escherichia coli isolates from drinking water supplies in a rural area of Austria

Literature harbours several reports of potable water-associated outbreaks. We studied the prevalence of Shiga toxin- (stx1/2), intimin- (eae) and haemolysin (hlyA) genes in Escherichia coli isolates from drinking water of private and public water supplies in a rural area of Upper Austria; 2633 water samples were gained between November 2000 and December 2003. Two hundred and eighty of these water samples were positive for E. coli (10.6%). Of these, 101 samples were drawn from drilled wells (36%), 96 from dug wells (34%), 61 from springs (22%) and 22 from water supplies without available information on technical details (8%); 141 of the samples were from public water supplies, 139 from private water supplies. Eleven of the E. coli isolates were found to be positive for one of the investigated virulence genes (3.9%): one isolate yielded stx2, seven eae, and three isolates had hlyA. The presence of these genes underlines the importance of control of water quality in public and also private water supplies.

Non-touch fittings in hospitals: a possible source of Pseudomonas aeruginosa and Legionella spp

Non-touch fittings are gradually becoming very common in the bathrooms and toilets of public facilities and restaurants. Hospitals and other healthcare facilities have recently started to install these types of water taps to lower water consumption, thus saving costs, and to prevent healthcare workers from touching the tap, thus promoting hygiene. This study analysed the bacteriological water quality of 38 non-touch water taps in different settings in a 450-bed secondary-care hospital in Upper Austria. Two different tap types were installed: 23 taps were without temperature selection and 15 were with temperature selection (cold and warm). A membrane filtration method was used, and the authors screened for both indicator organisms and Pseudomonas aeruginosa in 100 ml water samples. In 10 non-touch taps without temperature selection, the authors also screened for Legionella spp. in 500 ml water samples. Seventy four percent of the taps without temperature selection and 7% of the taps with temperature selection showed contamination with P. aeruginosa (P<0.001). None of the taps showed contamination with indicator organisms. Detailed analysis of the source of contamination revealed that the magnetic valve and the outlet itself were heavily contaminated, whereas the junction from the central pipe system was free of contamination. All 10 analysed taps showed contamination with Legionella spp. It was concluded that the local contamination of non-touch fittings is a result of the low amount of water that flows through the outlet, the low water pressure and the column of water, which is 'still-standing' and has a temperature of about 35 degrees C, thus providing nearly ideal growth conditions for P. aeruginosa. Additionally, the presence of materials such as rubber, PVC, etc. in the fittings enhances the adhesion of P. aeruginosa and thus the production of biofilms. In conclusion, the authors wish to encourage infection control teams to evaluate the use of non-touch fittings in hospitals, especially when they are installed in risk areas.