Virulence Factors Encoded by Legionella longbeachae Identified on the Basis of the Genome Sequence Analysis of Clinical Isolate D-4968
- 15 February 2010
- journal article
- case report
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 192 (4), 1030-1044
- https://doi.org/10.1128/jb.01272-09
Abstract
Legionella longbeachae causes most cases of legionellosis in Australia and may be underreported worldwide due to the lack of L. longbeachae -specific diagnostic tests. L. longbeachae displays distinctive differences in intracellular trafficking, caspase 1 activation, and infection in mouse models compared to Legionella pneumophila , yet these two species have indistinguishable clinical presentations in humans. Unlike other legionellae, which inhabit freshwater systems, L. longbeachae is found predominantly in moist soil. In this study, we sequenced and annotated the genome of an L. longbeachae clinical isolate from Oregon, isolate D-4968, and compared it to the previously published genomes of L. pneumophila . The results revealed that the D-4968 genome is larger than the L. pneumophila genome and has a gene order that is different from that of the L. pneumophila genome. Genes encoding structural components of type II, type IV Lvh, and type IV Icm/Dot secretion systems are conserved. In contrast, only 42/140 homologs of genes encoding L. pneumophila Icm/Dot substrates have been found in the D-4968 genome. L. longbeachae encodes numerous proteins with eukaryotic motifs and eukaryote-like proteins unique to this species, including 16 ankyrin repeat-containing proteins and a novel U-box protein. We predict that these proteins are secreted by the L. longbeachae Icm/Dot secretion system. In contrast to the L. pneumophila genome, the L. longbeachae D-4968 genome does not contain flagellar biosynthesis genes, yet it contains a chemotaxis operon. The lack of a flagellum explains the failure of L. longbeachae to activate caspase 1 and trigger pyroptosis in murine macrophages. These unique features of L. longbeachae may reflect adaptation of this species to life in soil.Keywords
This publication has 86 references indexed in Scilit:
- Legionella pneumophila Dot/Icm translocated substrates: a sum of partsCurrent Opinion in Microbiology, 2009
- The Legionella pneumophila replication vacuole: making a cosy niche inside host cellsNature Reviews Microbiology, 2008
- Critical function for Naip5 in inflammasome activation by a conserved carboxy-terminal domain of flagellinNature Immunology, 2008
- Enzymatic Properties of an Ecto-nucleoside Triphosphate Diphosphohydrolase from Legionella pneumophilaOnline Journal of Public Health Informatics, 2008
- A primer on ankyrin repeat function in TRP channels and beyondMolecular BioSystems, 2007
- Protein secretion systems and adhesins: The molecular armory of Gram-negative pathogensInternational Journal of Medical Microbiology, 2007
- Legionella pneumophila type II secretome reveals unique exoproteins and a chitinase that promotes bacterial persistence in the lungProceedings of the National Academy of Sciences of the United States of America, 2006
- Does using potting mix make you sick? Results from a Legionella longbeachae case-control study in South AustraliaEpidemiology and Infection, 2006
- Cytosolic recognition of flagellin by mouse macrophages restricts Legionella pneumophila infectionThe Journal of Experimental Medicine, 2006
- Evidence in the Legionella pneumophila genome for exploitation of host cell functions and high genome plasticityNature Genetics, 2004