Open AccessConstruction of genetically marked Vibrio cholerae O1 vaccine strains
Author(s) -
Ketley J.M.,
Michalski J.,
Galen J.,
Levine M.M.,
Kaper J.B.
Publication year - 1993
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1993.tb06355.x
Subject(s) - vibrio cholerae , microbiology and biotechnology , cholera , cholera toxin , biology , strain (injury) , virology , vector (molecular biology) , gene , bacteria , genetics , recombinant dna , anatomy
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 environment 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.