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Published on: May 30, 2017
Capsular polysaccharide phase variation in Vibrio vulnificus.
Tamara Hilton1, Tom Rosche, Brett Froelich
1University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA.
Applied and Environmental Microbiology
|August 29, 2006
Summary
Vibrio vulnificus alters its capsular polysaccharide (CPS) expression, impacting virulence. Environmental factors and RpoS significantly influence this conversion, with clinical strains showing less conversion than environmental ones.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Vibrio vulnificus is a dangerous pathogen, especially for immunocompromised individuals.
- Its capsular polysaccharide (CPS) is a key virulence factor.
- V. vulnificus can switch between opaque (high CPS) and translucent (low CPS) colony phenotypes.
Purpose of the Study:
- To investigate the consistency of CPS conversion in V. vulnificus.
- To determine environmental factors influencing CPS expression.
- To examine the role of RpoS and AI-2 in phenotypic switching and compare conversion rates between clinical and environmental genotypes.
Main Methods:
- Tested four V. vulnificus strains under various environmental conditions (aeration, temperature, incubation time, oxidative stress, media).
- Analyzed the influence of RpoS and AI-2 regulators on phenotypic conversion.
- Compared population conversion rates between clinical (C) and environmental (E) genotypes of V. vulnificus.
Main Results:
- Aeration, temperature, and incubation time significantly affected CPS conversion; media and oxidative stress did not.
- RpoS significantly mediated phenotypic conversion, but AI-2-based quorum sensing did not.
- Clinical strains exhibited significantly lower opaque-to-translucent conversion rates (approx. 14%) compared to environmental strains (approx. 38%).
- Biofilm formation did not correlate with increased population conversion.
Conclusions:
- V. vulnificus exhibits significant phenotypic plasticity in CPS expression influenced by environmental cues.
- RpoS plays a crucial role in regulating this switch.
- Clinical strains are less prone to conversion, suggesting adaptive strategies in host environments.
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