This study aimed at characterizing the phenotypic and toxigenic status of circulating strains of cholera
during outbreaks in Nigeria, employing molecular typing techniques. Two hundred and one samples
of rectal swabs, stool, vomitus, water (from the well, borehole, sachet, stream, and tap) and disinfectants
(sodium hypochlorite) were collected from three states in the country. The samples were inoculated
on thiosulphate-citrate bile salt-sucrose (TCBS), Cary-Blair transport medium and smeared on glass slides
for direct examination. The
Vibrio cholerae
isolates were serotyped, biotyped, and characterized using
PCR of the cytotoxin gene A (
ctxA),
wbeO1, and
wbfO139 gene primer. Of the 201 samples screened, 96
were positive for
V. cholerae O1 (48%), with 69 (72%) positive for
ctxA gene. The results from this study
showed that the circulating strains of cholera in Nigeria were of Ogawa serotype, also observed in other
outbreaks in Nigeria (1991, 1992, and 1996). However, the strains were of the Classical biotype and were
mainly (72%)
ctxA gene-positive. This current investigation has confirmed the production of cholera
toxin by the circulating strains, and this could be harnessed for possible cholera vaccine production in
Nigeria.
