Biochemical identification and characterization of DNA groups within the Proteus vulgaris complex

We placed 43 isolates belonging to the Proteus vulgaris complex into proposed DNA groups (genomovars) using five previously recommended tests (tests for esculin hydrolysis, production of acid from salicin, L-rhamnose fermentation, and elaboration of DNase and lipase). On the basis of the results of these five tests, 49% of the isolates fell into DNA groups 5 and 6, 37% fell into DNA group 2, and the remaining 14% fell into DNA groups 3 and 4. Sequencing of the 16S rRNA genes of 11 members of DNA groups 5 and 6 indicated that 10 of these isolates (91%) could be unambiguously assigned to one of these two genomospecies. Overall expression of selected enzymatic and virulence-associated characteristics did not differ significantly among DNA groups.