Dataset Information

Consensus sequence-based scheme for epidemiological typing of clinical and environmental isolates of Legionella pneumophila.

ABSTRACT: A previously described sequence-based epidemiological typing method for clinical and environmental isolates of Legionella pneumophila serogroup 1 was extended by the investigation of three additional gene targets and modification of one of the previous targets. Excellent typeability, reproducibility, and epidemiological concordance were determined for isolates belonging to both serogroup 1 and the other serogroups investigated. Gene fragments were amplified from genomic DNA, and PCR amplicons were sequenced by using forward and reverse primers. Consensus sequences are entered into an online database, which allows the assignment of individual allele numbers. The resulting sequence-based type or allelic profile comprises a string of the individual allele numbers separated by commas, e.g., 1,4,3,1,1,1, in a predetermined order, i.e., flaA, pilE, asd, mip, mompS, and proA. The index of discrimination (D) obtained with these six loci was calculated following analysis of a panel of 79 unrelated clinical isolates. A D value of > 0.94 was obtained, and this value appears to be sufficient for use in the epidemiological investigation of outbreaks caused by L. pneumophila. The D value rose to 0.98 when the results of the analysis were combined with those of monoclonal antibody subgrouping. Sequence-based typing of L. pneumophila is epidemiologically concordant and discriminatory, and the data are easily transportable. This consensus method will assist in the epidemiological investigation of L. pneumophila infections, especially travel-associated cases, by which it will allow a rapid comparison of isolates obtained in more than one country.

SUBMITTER: Gaia V

PROVIDER: S-EPMC1153775 | biostudies-literature | 2005 May

REPOSITORIES: biostudies-literature

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Consensus sequence-based scheme for epidemiological typing of clinical and environmental isolates of Legionella pneumophila.

Gaia Valeria V Fry Norman K NK Afshar Baharak B Lück P Christian PC Meugnier Hélène H Etienne Jerome J Peduzzi Raffaele R Harrison Timothy G TG

Journal of clinical microbiology 20050501 5

A previously described sequence-based epidemiological typing method for clinical and environmental isolates of Legionella pneumophila serogroup 1 was extended by the investigation of three additional gene targets and modification of one of the previous targets. Excellent typeability, reproducibility, and epidemiological concordance were determined for isolates belonging to both serogroup 1 and the other serogroups investigated. Gene fragments were amplified from genomic DNA, and PCR amplicons we ...[more]

PMID: 15872220

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Project description:The aim of this study is to explore the dispersion, clonality, and virulence of Legionella pneumophila serogroups 2 to 14 in the Greek environment. Eighty L. pneumophila serogroup 2 to 14 strains isolated from water distribution systems of hotels, hospitals, athletic venues, and ferries in Greece were tested by monoclonal antibodies (MAbs) for serogroup discrimination and molecularly by amplified fragment length polymorphism (AFLP) for genetic diversity. Fifty-six of 80 strains were also typed by the sequence-based typing (SBT) method. ?ll strains were further analyzed for detection of two pathogenicity loci: Legionella vir homologue (lvh) and repeats in structural toxin (rtxA). Thirty-seven strains (46.2%) belonged to serogroup 6, 26 strains (32.5%) to serogroup 3, and 7 (8.8%) to other serogroups (4, 5, 8, and 10). Ten strains (12.5%) were nontypeable (NT) into the known serogroups. Thirty-nine different AFLP types were found among the 80 L. pneumophila serogroup 2 to 14 strains, and 24 different SBT types were found among the 56 strains tested. Among the 80 strains, the lvh locus was present in 75 (93.8%), the rtxA locus was found in 76 (95%), and both loci were found in 73 (91.3%) strains. This study showed that there is genetic variability of L. pneumophila serogroups 2 to 14 in the Greek environment as well as a high percentage of the pathogenicity loci. ?ntroducing an effective diagnostic test for L. pneumophila serogroups 2 to 14 in urine and promoting the examination of respiratory specimens from patients hospitalized for pneumonia in Greek hospitals are essential.In this study, the dispersion, clonality, and virulence of environmental isolates of Legionella pneumophila serogroups 2 to 14 (Lp2-14) in Greece were investigated. Genetic variability of Lp2-14 in the Greek environment was identified together with the presence of the pathogenicity loci in a high percentage of the isolates. Despite the high prevalence of Lp2-14 in the Greek environment, no clinical cases were reported, which may be due to underdiagnosis of the disease. Almost all the legionellosis cases are diagnosed in Greece by using the urine antigen test, which is specific for Lp1. There is an urgent need to improve the clinical diagnosis of legionellosis by introducing an effective diagnostic test for Lp2-14 in urine and by promoting the PCR examination of respiratory specimens from patients with compatible clinical symptoms.

Dataset Information

Consensus sequence-based scheme for epidemiological typing of clinical and environmental isolates of Legionella pneumophila.

Publications

Consensus sequence-based scheme for epidemiological typing of clinical and environmental isolates of Legionella pneumophila.

Similar Datasets

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