Abstract
This study made it clear that for the initial isolation and subculture of Bacteroides melaninogenicus CO2 gas at a concentration of 50% or more was needed in addition to the standard conditions. With regard to black colony formation, laked rabbit blood agar was superior to an agar preparation containing blood of any other animal (sheep, horse, man, or chicken). When ovine, equine or human blood was used, many strains, even those of B. melaninogenicus, failed to form black colonies.
To isolate B. melaninogenicus from various specimens, Brucella agar (BBL) with 5% laked rabbit blood cultured by the steelwool method (CO2 50%, N2 50%) for 1 week was used. The isolated strains were subcultured in PRAS-semisolid GAM medium (Nissui) and identified according to the VPI Manual and Bergey's Manual (8th edition).
B. melaninogenicus ss. asaccharolyticus was isolated from vaginal swabs, B. melaninogenicus ss. intermedius from the gingival sulcus (58.3%), vaginal swabs (33.3%), and feces (8.4%), and B. melaninogenicus ss. melaninogenicus from the gingival sulcus alone.
Biochemicral characteristics of all the isolates were determined. A scheme was developed for the subspecific classification of B. melaninogenicus.
