DIFFERENTIATION OF VIBRIO-CHOLERAE-01 ISOLATES WITH BIOCHEMICAL FINGERPRINTING AND COMPARISON WITH RIBOTYPING

The Phene Plate (PhP) system is a commercially available typing system based on the measurements of kinetics of selected biochemical reactio ns of bacteria grown in liquid medium in 96-well microplates. The syst em uses numerical analysis to identify biochemical phenotypes among th e tested strains, In the present study, a set of 16 discriminatory tes ts were used to differentiate 117 strains of Vibrio cholerae O1 from M exico and Bangladesh, The stability of PhP types of 16 isolates under different storage temperatures and after repeated subcultures were als o evaluated. The PhP system had a reproducibility of 95%. Storage eith er at +4 degrees C or 70 degrees C, did not affect the reactions of th e isolates, whereas 4 strains (25%) stored at room temperature and 5 s trains (31%) subjected to 30 consecutive subcultures, exhibited minor changes in their biochemical reactions. Endemic isolates of V. cholera e O1 from Bangladesh were more diverse (diversity index = 0.84 to 0.93 ) than epidemic isolates from Mexico (diversity index = 0.73), Using a collection of 33 heterogeneous isolates of classical biotype of vibri os, PhP typing and ribotyping were compared. PhP typing discriminated more types (n=23) than ribotyping (n=5), whereas a combination of both yielded 27 types, The PhP system appears to be a simple, reliable and highly discriminating method for typing of V. cholerae, and may prove especially useful as a first screening method in epidemiological stud ies of V. cholerae.