Vibrio cholerae is part of the Vibronaceae family and can cause syndromes ranging from asymptomatic to cholera gravis. Serogroups O1 and O139 are primarily responsible for cholera outbreaks. Pathogenic serogroups produce cholera toxin (CT). Vibrio cholerae serougroup O75 strains possessing the cholera toxin gene were isolated from patients with severe diarrhoea, and serogroup O141 has been associated with sporadic cholera-like diarrhoea and bloodstream infections. Serotypes that do not produce cholera toxin can still cause enteritis in humans.