DETECTION OF FRUCTOSE-6-PHOSPHATE PHOSPHOKETOLASE (F6PPK), A KEY ENZYME OF THE BIFID-SHUNT, IN GARDNERELLA-VAGINALIS

The detection of Fructose-6-phosphate phosphoketolase (F6PPK) in cellu lar extracts, is considered to be the most reliable indication that Gr am-positive rod-shaped bacteria belong to the genus Bifidobacterium. R ecent phylogenetic studies using 16S rRNA sequencing highlighted the c lose taxonomic relationship between the species Gardnerella vaginalis and a group containing most of the Bifidobacterium species. In order t o further investigate this relationship, we have searched for F6PPK ac tivity in strains identified as 'true' G. vaginalis and in other catal ase-negative coryneform bacteria, recently described as Actinomyces tu ricensis-like. Our data show that (i) the enzyme is only present in th e G. vaginalis sensu stricto strains (ii) F6PPK can be considered as a taxonomic criterion of both Bifidobacterium and G. vaginalis strains, and not as the specific enzyme of the 'Bifid-shunt'. (C) 1996 Academi c Press