Prevalence of Legionella in premise plumbing in Hungary

Legionella Survey in the Plumbing System of a Sparse Academic Campus: A Case Study at the University of Perugia

“…These data confirm that water temperature represents a key risk factor for Legionella colonization and further support the international recommended value of 55 • C for hot-water temperature [9]. Nevertheless, in public buildings it often happens that the temperature of hot water is found below 50 • C, because of energy-saving measures, to prevent the risk of burns, or due to malfunctions in the water-heating and distribution systems [15,21]. Our results also indicate the occurrence of this microorganism in cold-water samples.…”

“…Our data indicated that the contamination rate recorded in the University of Perugia buildings was lower than that found in offices or schools in other countries, ranging from more than 30% in Germany [16] to 60% in Japan and Hungary [14,15], and even lower than the 30.5% rate recorded in private apartments in Italy [13]. Moreover, even if many of the buildings at the University of Perugia are very ancient (ranging in age from the 1960s back to the 13th century) and it has been previously shown that the rate of positive samples increases with the age of the building [15], we found that only 1 of the 12 contaminated buildings was older than one century, while all the others were very recent (i.e., less than 30 years-old). It is important to underline that the age of a building's water distribution system is often difficult to assess because pipelines may undergo partial or complete reconstruction.…”

“…It is important to underline that the age of a building's water distribution system is often difficult to assess because pipelines may undergo partial or complete reconstruction. In any case, it was reported that new plumbing systems were significantly less likely to be contaminated by Legionella only when they were less than 9 years old [15].…”

“…It is well established that the type of hot-water production system has a strong influence on the potential threat of microbial contaminations in plumbing [15,20]. In this respect, the buildings of the University of Perugia, even within the same campus, were very heterogeneous (Table 1).…”

“…This corresponded to a 22% contamination rate, with 12% and 10% of low and high levels of contamination, respectively. It is well known that Legionella is more likely to be found in hot-water mains and, furthermore, the production of hot water by centralized systems has been often associated with higher rates of contamination [13][14][15]21]. Stagnation, low circulation efficiency, and temperature drop within the hot-water network are also considered typical risk factors of large buildings with extensive plumbing systems [15].…”