Distribution of bacteria causing Legionnaires' disease at potable water in Istanbul

Abstract

Legionella pneumophila (especially L. pneumophila serogroup 1) known as causing Legionnaires' disease inhabits surface waters, such as rivers, lakes, and streams. Hence, these bacteria can easily infect man-made water systems. It is known that these bacteria cause various infections and even death in men. Therefore, to assess the role of potable water systems in buildings (especially hotels) around Istanbul as possible sources for Legionella infection, this study was performed during the period of 1996 to 2001. A total of 701 potable water samples (hot-cold water faucets and shower heads) collected from 162 buildings were concentrated by filtration, and inoculated onto buffered charcoal yeast extract agar (BCYE) added glycine, vancomycin, polymyxin, cycloheximide and incubated at 37degreesC for 14 days. Colonies consistent with Legionella morphology were subcultured to tryptone soy agar (TSA). Definitive identification was performed by latex agglutination (OXOID). The results were recorded as the highest number of confirmed Legionella (CFU/L). The water systems of 63 (38.8%) of the buildings tested were found to be positive for Legionella. It was found that 32 (24%) of the 134 strains determined as Legionella pneumophila were L. pneumophila serogroup 1; 102 strains (76%) were L. pneumophila serogroup 2-14. Generally, hot water circulating systems of buildings, such as hot water faucets and shower heads, were found to be the major sites for growth of L. pneumophila. According to the results, it is suggested that the large number of buildings (hotels) around Istanbul exhibit a low risk as a source of Legionnaires' disease.