CHARACTERIZATION OF AEROMONAS-TROTA STRAINS THAT CROSS-REACT WITH VIBRIO-CHOLERAE O139 BENGAL

It has previously been shown that Vibrio cholerae O139 Bengal shares a ntigens with V. cholerae serogroups O22 and O155. We detected six surf ace water isolates of Aeromonas tr ota that agglutinated in polyclonal antisera to V. cholerne O139 and V. cholerae O22 but not in antiserum to V. cholerae O155. On the basis of agglutinin-absorption studies, t he antigenic relationship between the cross-reacting bacteria were fou nd to be in an a,b-a,c fashion, where a is the common antigenic epitop e and b and c are unique epitopes, The antigen sharing between A. trot a strains and V. choler ae O139 was confirmed in immunoblot studies. H owever, A. tr ota strains did not react with two monoclonal antibodies specific for V. cholerae O139 and, consequently, tested negative in t he Bengal SMART rapid diagnostic test for V. cholerae O139 which uses one of the monoclonal antibodies. A polyclonal antiserum to a cross re acting A. trota strain cross-protected infant mice against cholera on challenge with virulent V. cholerae O139. All A. trota strains were cy totoxic for HeLa cells, positive for adherence to HEp-2 cells, and wea kly invasive for HEp-2 cells; one strain was heat-stable toxin positiv e in the suckling mouse assay; however, all strains were negative for cholera toxin-like enterotoxin, Studies on bacteria that share somatic antigen with V. cholerae O139 may shed further light on the genesis o f V. cholel ae O139.