Objective To investigate the molecular characteristics and intracellular growth ability of Legionella pneumophila(L. pneumophila) strains from 1989 to 2016 in Sichuan Province, China. Methods Seventy-nine isolates of ...Objective To investigate the molecular characteristics and intracellular growth ability of Legionella pneumophila(L. pneumophila) strains from 1989 to 2016 in Sichuan Province, China. Methods Seventy-nine isolates of L. pneumophila were collected from environmental and clinical sources, including cooling towers, hot springs, bath water, fountains, and patients, and identified with 16 S rRNA gene analysis and serum agglutination assay. The isolates were then typed by Sequence-Based Typing(SBT), and Genotyping of forty-two LP1 strains were analyzed by means of multiple-locus VNTR analysis with 8 loci(MLVA-8). All strains were further analyzed for two virulence genes: Legionella vir homologue(lvh) and repeats in structural toxin(rtx A). The intracellular growth ability of 33 selected isolates was determined by examining their interaction with J774 cells. Results All isolates were identified to L. pneumophila including 11 serogroups, among which the main serogroup were LP1, accounting for 54.43%. Thirty-three different sequence types(STs) from five main clonal groups and five singletons were identified, along with 8 different MLVA patterns. Both the lvh and rtx A loci were found in all 79 strains. Thirty isolates showed high intracellular growth ability in J774 cells. Conclusion L. pneumophila is a potential threat to public health, and effective control and prevention strategies are urgently needed.展开更多
基金supported by grants from the National Natural Science Foundation of China [81672048]the Youth Innovation Project of Sichuan Medical Association Foundation [Q15081]the Priority Project on Infectious Disease Control and Prevention [2018ZX10714002]
文摘Objective To investigate the molecular characteristics and intracellular growth ability of Legionella pneumophila(L. pneumophila) strains from 1989 to 2016 in Sichuan Province, China. Methods Seventy-nine isolates of L. pneumophila were collected from environmental and clinical sources, including cooling towers, hot springs, bath water, fountains, and patients, and identified with 16 S rRNA gene analysis and serum agglutination assay. The isolates were then typed by Sequence-Based Typing(SBT), and Genotyping of forty-two LP1 strains were analyzed by means of multiple-locus VNTR analysis with 8 loci(MLVA-8). All strains were further analyzed for two virulence genes: Legionella vir homologue(lvh) and repeats in structural toxin(rtx A). The intracellular growth ability of 33 selected isolates was determined by examining their interaction with J774 cells. Results All isolates were identified to L. pneumophila including 11 serogroups, among which the main serogroup were LP1, accounting for 54.43%. Thirty-three different sequence types(STs) from five main clonal groups and five singletons were identified, along with 8 different MLVA patterns. Both the lvh and rtx A loci were found in all 79 strains. Thirty isolates showed high intracellular growth ability in J774 cells. Conclusion L. pneumophila is a potential threat to public health, and effective control and prevention strategies are urgently needed.
