Detection of heat-stable enterotoxin in a cholera toxin gene-positive strain of Vibrio cholerae 01

DNA colony hybridization with a polynucleotide clonal DNA probe for heat-stable enterotoxin of Vibrio cholerae non-01 (NAG-ST) was used to screen 197 isolates of V. cholerae 01. Under stringent hybridizing and washing conditions, one strain (GP156) reacted with the probe. The concentrated supernatant from V. cholerae 01 GP156, heated at 100°C for 5 min, elicited fluid accumulation in the suckling mice and that could be completely netralized by an anti-NAG-ST monoclonal antibody (mAb2F). The preparation from V. cholerae 01 GP156 also inhibited the binding of mAb2F to NAG-ST in a competitive ELISA. V. cholerae 01 GP156 was confirmed to possess a gene encoding cholera toxin (CT). The results indicate that a heat-stable enterotoxin is produced by certain strains of CT-producing V. cholerae 01.