Cholera in north Brazil: on the occurrence of strains of Vibrio cholerae O1 which fail to ferment sucrose during routine plating on thiosulphate-citrate-bile salt-sucrose agar (TCBS). A new problem in diagnosis and control?

The occurrence is recorded from a biochemical strain variant of Vibrio cholerae O1 originating from the municipality of Oiapoque, Amapá State, north Brazil and responsible for an epidemic outbreak of cholera in that region in August, 1994. The principal characteristic of the strain is its incapacity of break down sucrose on T.C.B.S. agar plates, and its delayed utilization of that sugar only after 48 hs. when cultivated in liquid medium. The strain spread rapidly in north Brazil, becoming responsible for most of the cases of cholera reported in Amazonian Brazil. The importance of this observation in laboratory diagnosis and the control of cholera is discussed.