Evaluation of the phenol-induced flagellar agglutination test for the identification of the cholera group of vibrios

Abstract

Applied routinely to 1081 recently isolated cultures, the phenol-induced slide-agglutination test (standard procedure) with flagellar antiserum corrently identified 98.9% of Vibrio cholerae strains of O type-I and NAG serotypes; 1.0% of cultures were unstable in phenol-saline. The incidence of instability and other types of defect was higher (7.3%) in older stock cultures. The majority of such strains were successfully tested by one of the three modified procedures. No cross-reactions were observed in 47 cultures of other species including the halophilic vibrios. Only one out of the 1205 cultures of V. cholerae tested by all procedures reacted negatively; this strain was found to lack functional flagella. These results establish the significance of flagellar specificity as a classificatory determinant in V. cholerae, and the fidelity and utility of the phenol test in routine bacteriology.