Abstract
The organisms currently recognized as subspecies of Bacteroides fragilis have been shown to be genetically distinct. Species rank is therefore restored to these organisms, and type or neotype strains have been selected for the five species described. ATCC 25285 (= NCTC 9343) is designated the neotype strain of Bacteroides fragilis (Veillon and Zuber) Castellani and Chalmers; ATCC 29184 (= strain Werner E50 = NCTC 10582) is designated the neotype strain of Bacteroides thetaiotaomicron (Distaso) Castellani and Chalmers; ATCC 8503 is designated the type strain of Bacteroides distasonis Eggerth and Gagnon; ATCC 8483 is designated the type strain of Bacteroides ovatus Eggerth and Gagnon; and ATCC 8482 is designated the type strain of Bacteroides vulgatus Eggerth and Gagnon. Characteristics of these strains are presented.