POTENTIAL PATHOGENIC FACTORS PRODUCED BY A CLINICAL NONTOXIGENIC VIBRIO-CHOLERAE 01

A clinical isolate of nontoxigenic Vibrio cholerae O1 that caused inte stinal fluid accumulation (FA) in adult mice produced proteolytic, hem olytic, and cytotoxic activities in in vitro assays. The linkage of th ese secreted factors to the FA activity was studied by transposon (Tnp hoA) mutagenesis. Ten of the 12 TnphoA insertion mutants that were def ective for proteolytic activity produced FA, hemolytic and cytotoxic a ctivities; the remaining two mutants lost these latter three activitie s. These results indicate that FA activity is independent of proteolyt ic activity but closely associated with cytotoxic and hemolytic activi ties. Our results with the adult mouse model and a nontoxigenic V. cho lerae 01 are in general agreement with previous studies that demonstra ted linkage of cytotoxin and hemolysin of toxigenic V. cholerae O1 and non-O1 with FA activity in rabbit ileal loops.