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Alterations in Vibrio cholerae motility phenotypes correlate with changes in virulence factor expression
1Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Infection and Immunity
|June 1, 1996
Summary
Vibrio cholerae motility influences virulence. Nonmotile mutants showed increased toxin production but poor colonization, while hypermotile mutants had defects in key virulence factors and colonization.
Area of Science:
- Microbiology
- Molecular Biology
- Pathogenesis
Background:
- Motility is a key factor in Vibrio cholerae virulence, but its precise role in pathogenesis remains unclear.
- Understanding the interplay between motility and virulence gene expression is crucial for comprehending cholera disease progression.
Purpose of the Study:
- To investigate the impact of Vibrio cholerae motility on virulence gene expression and intestinal colonization.
- To characterize mutants with altered swarming abilities to elucidate the function of motility in pathogenesis.
Main Methods:
- Isolation of spontaneous hyperswarmer and nonmotile mutants of Vibrio cholerae strain 0395.
- Analysis of autoagglutination, virulence factor production (TCP, cholera toxin, hemolysins, protease, hemagglutinin), and intestinal colonization in mutant strains.
- Genetic characterization of mutants, including analysis of insertions in motB homologous sequences.
Main Results:
- Hyperswarmer mutants exhibited defects in autoagglutination, toxin-coregulated pili (TCP) production, cholera toxin, and cell-associated hemolysin, but increased protease and fucose-sensitive hemagglutinin.
- Nonmotile mutants showed increased expression of TCP pilin, cholera toxin, and cell-associated hemolysin, but decreased fucose-sensitive hemagglutinin and HEp-2 adhesins.
- Nonmotile mutants had minimal defects in intestinal colonization, whereas class I hyperswarmer mutants were significantly impaired in colonization.
Conclusions:
- Vibrio cholerae motility is intrinsically linked to the expression of multiple virulence determinants, both ToxR-regulated and non-ToxR-regulated.
- Altered motility significantly impacts the balance of virulence factor production and intestinal colonization capabilities.
- Motility plays a complex, multifaceted role in Vibrio cholerae pathogenesis, influencing both colonization and the expression of key toxins and factors.