Distribution of lag-1 Alleles and Sequence-Based Types among Legionella pneumophila Serogroup 1 Clinical and Environmental Isolates in the United States
- 1 August 2009
- journal article
- research article
- Published by American Society for Microbiology in Journal of Clinical Microbiology
- Vol. 47 (8), 2525-2535
- https://doi.org/10.1128/jcm.02410-08
Abstract
Approximately 84% of legionellosis cases are due to Legionella pneumophila serogroup 1. Moreover, a majority of L. pneumophila serogroup 1 clinical isolates react positively with monoclonal antibody 2 (MAb2) of the international standard panel. Over 94% of the legionellosis outbreaks investigated by the Centers for Disease Control and Prevention are due to this subset of L. pneumophila serogroup 1. To date, there is no complete explanation for the enhanced ability of these strains to cause disease. To better characterize these organisms, we subtyped 100 clinical L. pneumophila serogroup 1 isolates and 50 environmental L. pneumophila serogroup 1 isolates from the United States by (i) reactivity with MAb2, (ii) presence of a lag-1 gene required for the MAb2 epitope, and (iii) sequence-based typing analysis. Our results showed that the MAb2 epitope and lag-1 gene are overrepresented in clinical L. pneumophila serogroup 1 isolates. MAb2 recognized 75% of clinical isolates but only 6% of environmental isolates. Similarly, 75% of clinical isolates but only 8% of environmental isolates harbored lag-1 . We identified three distinct lag-1 alleles, referred to as Philadelphia, Arizona, and Lens alleles, among 79 isolates carrying this gene. The Arizona allele is described for the first time in this study. We identified 59 different sequence types (STs), and 34 STs (58%) were unique to the United States. Our results support the hypothesis that a select group of STs may have an enhanced ability to cause legionellosis. Combining sequence typing and lag-1 analysis shows that STs tend to associate with a single lag-1 allele type, suggesting a hierarchy of virulence genotypes. Further analysis of ST and lag-1 profiles may identify genotypes of L. pneumophila serogroup 1 that warrant immediate intervention.Keywords
This publication has 29 references indexed in Scilit:
- PCR-based ‘serotyping’ of Legionella pneumophilaJournal of Medical Microbiology, 2009
- Occurrence and distribution of sequence types among Legionella pneumophila strains isolated from patients in Germany: common features and differences to other regions of the worldEuropean Journal of Clinical Microbiology & Infectious Diseases, 2007
- Addition of neuA , the Gene Encoding N -Acylneuraminate Cytidylyl Transferase, Increases the Discriminatory Ability of the Consensus Sequence-Based Scheme for Typing Legionella pneumophila Serogroup 1 StrainsJournal of Clinical Microbiology, 2007
- Comparison of clinical and environmental isolates of Legionella pneumophila obtained in the UK over 19 yearsClinical Microbiology & Infection, 2007
- Sequence-Based Typing of Legionella pneumophila Serogroup 1 Offers the Potential for True Portability in Legionellosis Outbreak InvestigationJournal of Clinical Microbiology, 2003
- A Hospital-Associated Outbreak of Legionnaires' Disease Caused by Legionella pneumophila Serogroup 1 Is Characterized by Stable Genetic Fingerprinting but Variable Monoclonal Antibody PatternsJournal of Clinical Microbiology, 2003
- Pan-European Study on Culture-Proven Legionnaires' Disease: Distribution of Legionella pneumophila Serogroups and Monoclonal SubgroupsEuropean Journal of Clinical Microbiology & Infectious Diseases, 2002
- A point mutation in the active site of Legionella pneumophila O-acetyltransferase results in modified lipopolysaccharide but does not influence virulenceInternational Journal of Medical Microbiology, 2001
- Molecular characterization of a virulence-associated epitope on the lipopolysaccharide ofLegionella pneumophilaserogroup 1Epidemiology and Infection, 1995
- Legionella pneumophilaserogroup 1 population in Italy by monoclonal subtypingEpidemiology and Infection, 1990