[Genetic diversity of Legionella pneumophila serogroup 1 in hospital water distribution systems in Shanghai].

Objective: To classify Legionella pneumophila serogroup 1 (LP1) isolated from the water distribution systems in hospitals of Shanghai by using genotying methods, and therefore to explore the genetic relationship between different genotypes.

Methods: LP1 was isolated from 8 hospitals in Shanghai, and strains of LP1 were subtyped using pulse field gel electrophoresis (PFGE). Genotyping results of PFGE were classified as dendrogram, and cluster analysis was used to compare the genetic characteristics of different strains.

Results: Twenty-four strains of LP1 were isolated from 193 water specimens. LP1 belonged to 6 PFGE genotypes, of which 21 belonged to 3 predominant genotypes. Different hospitals shared the same genotype, while some strains isolated from the same hospital had different genotypes.

Conclusion: The genetic characteristics are stable in environmental LP1. Molecular biology techniques should be added to epidemiological study for hospital acquired legionellosis due to the genetic diversity in one hospital.