Distribution of monoclonal antibody subgroups and sequence-based types among Legionella pneumophila serogroup 1 isolates derived from cooling tower water, bathwater, and soil in Japan.

Legionella pneumophila serogroup (SG) 1 is the most frequent cause of legionellosis. This study analyzed environmental isolates of L. pneumophila SG 1 in Japan using monoclonal antibody (MAb) typing and sequence-based typing (SBT). Samples were analyzed from bathwater (BW; n = 50), cooling tower water (CT; n = 50), and soil (SO; n = 35). The distribution of MAb types varied by source, with the most prevalent types being Bellingham (42%), Oxford (72%), and OLDA (51%) in BW, CT, and SO, respectively. The ratios of MAb 3/1 positive isolates were 26, 2, and 14% from BW, CT, and SO, respectively. The environmental isolates from BW, CT, and SO were divided into 34 sequence types (STs; index of discrimination [IOD] = 0.973), 8 STs (IOD = 0.448), and 11 STs (IOD = 0.879), respectively. Genetic variation among CT isolates was smaller than seen in BW and SO. ST1 accounted for 74% of the CT isolates. The only common STs between (i) BW and CT, (ii) BW and SO, and (iii) CT and SO were ST1, ST129, and ST48, respectively, suggesting that each environment constitutes an independent habitat.

[Occurrence of Legionella bacteria in a variety of environmental waters--from April, 1996 to November, 2000].

The present paper deals with the occurrence of Legionella bacteria in a variety of man-made environmental waters, including whirlpool bathes, cooling towers and others, from April 1996 to November 2000 in the eastern part of Japan around Tokyo area. A total of 2,895 water samples were examined for the possible occurrence of Legionella, and 904 (31%) were demonstrated to be positive. Among the various water sources, Legionella were frequently detected both in whirlpool bathes and in cooling towers, of which detection rates were 48% and 46%, respectively. More precisely, occurrence of Legionella was higher in private-use whirlpool bathes than those for public-use; namely, the positive rate was 71% in bathes accommodated in private houses, 63% in company's club houses, 62% in company dormitories for employees, and 51% in old-people's homes. Occurrence of Legionella, on the other hand, was less common (< or = 30%) in bathes for public-use such as those installed in hotels and in hot spring facilities. Typing of L. pneumophila serogroups revealed that SG5 (34%) was dominant in whirlpool bath waters followed by SG3 (22%), whereas SG1 (32%) was dominantly found in cooling tower waters.

Distinct difference of flaA genotypes of Legionella pneumophila between isolates from bath water and cooling tower water.

To investigate the genetic difference of Legionella pneumophila in human-made environments, we collected isolates of L. pneumophila from bath water (n = 167) and cooling tower water (n = 128) primarily in the Kanto region in 2001 and 2005. The environmental isolates were serogrouped and sequenced for a target region of flaA. A total of 14 types of flaA genotypes were found: 10 from cooling tower water and nine from bath water. The flaA genotypes of isolates from cooling tower water were quite different from those of bath water.