GLUCOSE-6-PHOSPHATE-DEHYDROGENASE AND 6-PHOSPHOGLUCONATE DEHYDROGENASE-ACTIVITIES AND GLUCOSE-UTILIZATION BY SPECIES WITHIN THE GENERA BACTEROIDES, PREVOTELLA, AND PORPHYROMONAS

Members of the genera Bacteroides, Prevotella, and Porphyromonas were investigated for their glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activities by using spectro-photometric (SP) and alloenzyme elecrophoresis (AE) detection methods. When the SP and AE methods were compared, the AE method failed to detect activity in two of the six strains which exhibited G6PDH and 6PGDH activities as determined by the SP detection method. On the basis of the results of SP detection, Bacteroides levii ATCC 29147(T) (T = type strain) (G6PDH and 6PGDH negative) is not a member of the genus Bacteroides as currently defined, which reflects recent 16S rRNA placement, nor do Prevotella heparinolytica ATCC 35895(T), Prevotella zoogleoformans ATCC 33285(T), Porphyromonas canoris 12835(T), and Porphyromonas salivosa NCTC 11632(T) (all G6PDH and 6PGDH positive) conform to their respective genus descriptions. When these organisms were grown in prereduced peptone-yeast extract broth containing 10% (wt/vol) glucose, the amounts of glucose remaining after 5 days were less than the amounts present initially for members of the genus Bacteroides (Bacteroides fragilis ATCC 25285(T) and B. levii) and members of the genus Prevotella (Prevotella melaninogenica ATCC 25845(T), Prevotella buccae ATCC 33574(T), Prevotella heparinolytica, and Prevotella zoogleo-formans). In addition, the glucose levels were lower after 5 days of incubation in broth media containing Porphyromonas asaccharolytica ATCC 25845(T) and Porphyromonas salivosa, but not in media containing the other members of the genus Porphyromonas tested (Porphyromonas canoris, Porphyromonas circumdentaria NCTC 12469(T), Porphyromonas endodontalis ATCC 35406(T), and Porphyromonas gingivalis ATCC 33277(T)). The reductions in glucose levels were not directly related to the final pH values. Our results suggest that the descriptions of the genera Bacteroides, Prevotella, and Porphyromonas may require emendation to reflect variability in G6PDH and 6PGDH activities and glucose utilization.