The organism appears to be a derivative of El Tor O1
but has a distinct LPS and an immunologically related Oantigen polysaccharide capsule.
Prolonged colonization of mice by Vibrio cholerae El Tor O1
depends on accessory toxins.
Two genotypes (ctxB1 and ctxB3) of the El Tor O1
The Asian reference strains, regardless of their biotypes and serogroups (classical O1, El Tor O1
, O139, or O151), showed a genetic resemblance, but had different patterns from the strains collected during the two outbreaks in Thailand.
The official records state that the cholera epidemic in Brazil was caused by an El Tor O1
cholerae El Tor O1
strains, isolated in Calcutta, before, during, and after the O139 outbreak.