Construction of genetically marked Vibrio cholerae O1 vaccine strains

FEMS Microbiol Lett. 1993 Jul 15;111(1):15-21. doi: 10.1111/j.1574-6968.1993.tb06355.x.

Abstract

Attenuated Vibrio cholerae O1 vaccine strains lacking the gene encoding the A subunit of cholera toxin have proven efficacious in preventing experimental cholera. As these strains move from closed, contained testing environments to large-scale field trials, a readily assayable phenotypic trait to distinguish a vaccine strain from wild-type V. cholerae O1 is desirable. We have constructed three derivatives of the attenuated V. cholerae strain CVD 103 which carry a mercury resistance or urease marker in the hlyA gene. CVD 103-HgR was constructed using a protracted marker-exchange procedure; this strain was found to have somewhat lowered colonisation efficiency in infant mice in comparison to its parent strain, CVD 103. The insertion of the resistance marker was repeated using a suicide vector system; CVD 103-HgR2 was found to colonise infant mice as efficiently as CVD 103. Strain CVD 103-UR, in which sequences encoding urease were inserted using a suicide vector, also colonised infant mice as well as CVD 103. The genetically marked strains CVD 103-HgR, CVD 103-HgR2 and CVD 103-UR form the basis for a generation of defined oral vaccines that may give single-dose, long-lasting protection to populations at risk from cholera.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cholera / microbiology
  • Cholera Toxin / genetics*
  • Diarrhea / microbiology
  • Drug Resistance, Microbial / genetics
  • Escherichia coli / genetics
  • Genetic Markers
  • Genetic Vectors
  • Macromolecular Substances
  • Mice
  • Mutagenesis, Insertional
  • Rabbits
  • Vaccines, Attenuated / biosynthesis
  • Vaccines, Attenuated / genetics*
  • Vibrio cholerae / genetics*
  • Vibrio cholerae / immunology*
  • Vibrio cholerae / pathogenicity
  • Viral Vaccines / biosynthesis
  • Viral Vaccines / genetics*
  • Virulence

Substances

  • Genetic Markers
  • Macromolecular Substances
  • Vaccines, Attenuated
  • Viral Vaccines
  • Cholera Toxin