Partition of heat-labile-enterotoxin genes between human and animal Escherichia coli isolates.

Heat-labile toxin (LT) genes from human and animal Escherichia coli isolates from a restricted geographical region (Thailand) exhibited a segregated pattern of dissemination that was revealed by a restriction enzyme site polymorphism. The results suggest an exclusion of LT genes from or a low transfer rate for LT genes between E. coli strains infectious for humans and those infectious for animals in natural settings.