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Presence or absence of lipopolysaccharide O antigens affects type III secretion by Pseudomonas aeruginosa
- Source :
- Journal of Bacteriology. March, 2007, Vol. 189 Issue 5-6, p2203, 7 p.
- Publication Year :
- 2007
-
Abstract
- Pseudomonas aeruginosa is one of the major causative agents of mortality and morbidity in hospitalized patients due to a multiplicity of virulence factors associated with both chronic and acute infections. Acute P. aeruginosa infection is primarily mediated by planktonic bacteria expressing the type III secretiun system (TTSS), a surface-attached needle-like complex that injects eytotoxins directly into eukaryotic cells, causing cellular damage. Lipopolysaccharide (LPS) is the principal surface-associated virulence factor of P. aeruginosa. This molecule is known to undergo structural modification (primarily alterations in the A- and B-band O antigen) in response to changes in the mode of life (e.g., from biofilm to planktonic). Given that LPS exhibits structural plasticity, we hypothesized that the presence of LPS lacking O antigen would facilitate enkaryotic intoxication and that a correlation between the LPS O-antigen serotype and TTSS-mediated cytotoxicity would exist. Therefore, strain PAO1 ([A.sup.+] [B.sup.+] O-antigen serotype) and isogenic mutants with specific O-antigen defects ([A.sup.+] [B.sup.-], [A.sup.-] [B.sup.+], and [A.sup.-] [B.sup.-]) were examined for TTSS expression and cytotoxicity. A strong association existed in vitro between the absence of the large, structured B-band O antigen and increased cytotoxicity of these strains. In vivo, all three LPS mutant strains demonstrated significantly increased lung injury compared to PAO1. Clinical strains lacking the B-band O antigen also demonstrated increased TTSS secretion. These results suggest the existence of a cooperative association between LPS O-antigen structure and the TTSS in both laboratory and clinical isolates of P. aeruginosa.
Details
- Language :
- English
- ISSN :
- 00219193
- Volume :
- 189
- Issue :
- 5-6
- Database :
- Gale General OneFile
- Journal :
- Journal of Bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.163707216