DEVELOPMENT AND TESTING OF MONOCLONAL ANTIBODY-BASED RAPID IMMUNODIAGNOSTIC TEST KITS FOR DIRECT-DETECTION OF VIBRIO-CHOLERAE O139 SYNONYM BENGAL

We report on the development and testing of two monoclonal antibody-ba sed rapid immunodiagnostic test kits, BengalScreen, a coagglutination test, and Bengal DFA, a direct fluorescent-antibody test, for direct d etection of Vibrio cholerae 0139 synonym Bengal in clinical and enviro nmental specimens. The BengalScreen test requires less than 5 min to c omplete and can be used in the field. Bengal DFA, being more sensitive than BengalScreen, requires only one reagent and less than 20 min for detection and enumeration of V. cholerae 0139 synonym Bengal. In test s for specificity, all 40 strains of V. cholerae 0139 reacted with bot h test kits, whereas 157 strains of heterologous species examined did not, yielding 100% specificity in this study. A field trial was conduc ted in India with both BengalScreen and Bengal DFA, and the results we re compared with those obtained by conventional culture methods. Benga lScreen demonstrated a sensitivity of 95%, a specificity of 100%, a po sitive predictive value of 100%, and a negative predictive value of 94 %. Results obtained by Bengal DFA, on the other hand, were 100% sensit ive and 100% specific and yielded 100% positive and negative predictiv e values compared with culture methods. In a second evaluation, 93 sto ol specimens from Mexico that were negative for V. cholerae 0139 by cu lture were also tested with both the BengalScreen and Bengal DFA kits. None of the 93 specimens were positive for V. cholerae 0139 by both t ests. A concentration method was optimized for screening of environmen tal water samples for V. cholerae 0139 synonym Bengal with rapid test kits. BengalScreen results were unequivocally positive when water samp les contained at least 2.0 x 10(3) CFU/ml, whereas Bengal DFA demonstr ated an unequivocally positive reaction when the water sample containe d at least 1.5 x 10(2) CFU/ml. When Bengal DFA was compared with conve ntional culture methods for enumeration of V. cholerae 0139 synonym Be ngal organisms, no difference was observed.