Risk of infection associated with microbiological quality of public swimming pools in Bologna, Italy

Twelve public swimming pools in Bologna (Emilia-Romagna region, Italy) were investigated for the microbiological quality of water and surfaces of the pool edges, showers and changing rooms. At the same time a cross-sectional study was carried out on the health of 238 users (bathers) compared with 23 8 controls who practised sports other than swimming. Data regarding duratio n and frequency of exposure, behaviour and recent medical history were gath ered by means of a questionnaire. All participants also underwent a medical examination. Compliance of the pool water to the microbiological standards set by Italia n regulations was generally good; compliance was total when free chlorine r esidual was within the recommended limits. However, when analysis was exten ded to the various surfaces, potentially pathogenic bacteria such as P. aer uginosa and C. albicans were isolated. Eye burning and diarrhoea were the only declared symptoms and verrucas the only diagnosed disease showing statistically significant differences betwee n bathers and controls. Verrucas tended to increase in proportion to exposu re. Athlete's foot had a very high prevalence among both bathers (34%) and controls (27%). The environmental and epidemiological investigations both c onfirmed the risk of infection, mainly associated with the contamination of surfaces.