Detection of culturable and nonculturable Legionella species from hot water systems of public buildings in Japan.
J Appl Microbiol
; 105(6): 2104-14, 2008 Dec.
Article
em En
| MEDLINE
| ID: mdl-19120656
ABSTRACT
AIMS:
To investigate the prevalence of culturable and nonculturable Legionella species in hot water systems of public buildings in Japan and assess the risk factors associated with Legionella contamination in hot water systems. METHODS ANDRESULTS:
Legionella species were detected by conventional culture and molecular methods in 130 water samples collected from 40 buildings. A total of 26 (20.0%) water samples from 17 (42.5%) buildings were positive by culture, qualitative PCR or bothmethods:
Legionella pneumophila and Leg. anisa were detected in four samples by a culture method, whereas 23 samples were positive by qualitative PCR, with the presence of various Legionella species confirmed by sequencing. Of these 23 samples, bacterial counts were quantifiable in 21 by real-time PCR (from 1.7 x 10(5) to 2.6 x 10(11) cells per litre). Phylogenetic analysis of amplified partial 16S rRNA gene showed close relations to various species of Legionella, including Leg. anisa and Leg. micdadei, all of which have been associated with respiratory diseases or increased antibody titres in human sera. Assessment of risk factors showed that turbidity, free chlorine concentration, iron concentration and heterotrophic plate count (HPC) were significantly associated with Legionella contamination (P < 0.05).CONCLUSIONS:
Contamination of hot water systems of public buildings with culturable and nonculturable Legionella species may be a potential risk factor for Legionella infection in Japan. Adequate levels of chlorine, low levels of iron and HPC are important maintenance measures in the reduction of Legionella contamination in hot water systems. SIGNIFICANCE AND IMPACT OF THE STUDY More than 40% of hot water systems in the Japanese public buildings examined were contaminated by not only culturable Leg. pneumophila and Leg. anisa but also by nonculturable pathogenic species. To our knowledge, this is the first report of both culturable and nonculturable Legionella contamination in hot water systems of public buildings in Japan.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluição da Água
/
Abastecimento de Água
/
Legionella
/
Água Doce
/
Temperatura Alta
Tipo de estudo:
Diagnostic_studies
/
Etiology_studies
/
Qualitative_research
/
Risk_factors_studies
País/Região como assunto:
Asia
Idioma:
En
Revista:
J Appl Microbiol
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Japão