Identification of two Vibrio metschnikovi strains cross-agglutinating with Vibrio cholerae O139

ObjectiveTo identify two strains suspected of Vibrio cholerae O139 to exclude or confirm cholera. MethodsTube agglutination and cross-absorption tests were performed to review the results of slide agglutination. Biochemical experiments featuring BIOFOSUN microbial identification system were conducted, and PCR was applied to detect the Vibrio cholerae O139-specific LPS gene. ResultsThe slide agglutination test was positive. Tube agglutination of one stains demonstrated 1/4 titer of the original serum, and the other 1/2. However, cross-absorption confirmed non-specific agglutination. No Vibrio cholerae O139-specific LPS gene was detected. The biochemical identification system showed that the strains were Vibrio metschnikovi. ConclusionThe two strains were not Vibrio cholerae but Vibrio metschnikovi.