THE USE OF GENE PROBES, IMMUNOASSAYS AND TISSUE-CULTURE FOR THE DETECTION OF TOXIN IN VIBRIO-CHOLERAE NON-O1

Vibrio cholerae non-Ol strains were screened for the presence of chole ra enterotoxin (CT) genes by means of digoxigenin-labelled polynucleot ide CTA and CTB probes. In-vitro production of CT was investigated by the Y1 mouse adrenal cell assay, enzyme-linked immunosorbent assay (EL ISA) and a commercial, reversed passive latex agglutination (RPLA) kit . Only two (0.25 %) of 790 strains tested gave positive results with t he CTA and CTB probes. The production of other bacterial cytotoxin(s) made it impossible to use the characteristic cell-rounding effect on Y 1 cells for the detection of CT. CT production by the probe-positive s trains was confirmed by the immunoassays. Two hundred and fifty-two of the 788 probe-negative strains were tested by both cell assay and imm unoassays. Of these, 90 % produced cytotoxin(s) in the cell assay. In addition, 37 % gave positive results in CT-ELISA, but negative results with LT-ELISA and VET-RPLA. These results indicate the presumed prese nce of a toxin in V. cholerae non-Ol that is able to bind GM(1) and re act with antisera to CT, but which is not identical to CT.