Use of automated sequencing of polymerase chain reaction-generated amplicons to identify three types of cholera toxin subunit B in Vibrio cholerae O1 strains.
Cholera toxin is the principal factor causing the profuse intestinal fluid secretion that is characteristic of cholera. The DNA sequences of the cholera toxin subunit B structural genes from 45 Vibrio cholerae O1 strains isolated in 29 countries over a period of 70 years were determined by automated DNA sequencing of polymerase chain reaction-generated amplicons. Three types of cholera toxin B subunit gene (ctxB) were identified. Genotype 1 was found in strains of classical biotype worldwide and El Tor biotype strains associated with the U.S. Gulf Coast, genotype 2 was found in El Tor biotype strains from Australia, and genotype 3 was found in El Tor biotype strains from the seventh pandemic and the recent Latin American epidemic. All base changes correspond to an amino acid substitution in the B subunit of the cholera toxin. Heterogenicity in the B subunit could have implications for vaccine development and diagnostic tests for cholera toxin and antitoxin. We conclude that this technology provides timely and potentially useful epidemiological information.
Olsvik
O
O
Division of Bacterial and Mycotic Diseases, Centers for Disease Control, Atlanta, Georgia 30333.
Wahlberg
J
J
Petterson
B
B
Uhlén
M
M
Popovic
T
T
Wachsmuth
I K
IK
Fields
P I
PI
D000349:Africa / Q000453:epidemiology; D000569:Americas / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D001315:Australia / Q000453:epidemiology; D001483:Base Sequence; D002771:Cholera / Q000453:epidemiology; D002772:Cholera Toxin / Q000737:chemistry / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA / Q000379:methods; D014734:Vibrio cholerae / Q000145:classification* / Q000235:genetics*
D004269:DNA, Bacterial; D002772:Cholera Toxin