ABSTRACT
Bifidobacteria are normal flora in the mouth, the ileum, the colon, the vagina, and the cervix of man. As such they may become opportunistic pathogens when these anatomic structures are injured or disrupted. Bifidobacteria are anaerobes and are most liable to cause disease under conditions which predispose to an anaerobic environment in the tissues. Bifidobacterial species have been described as occasional pathogens in four anatomic sites: the head and neck area, the lung, the genitourinary system, and the gastrointestinal tract. Bifidobacterium dentium has been isolated from cervicofacial abscesses, dental plaque, cervical lymphadenitis, acute and chronic otitis media, chronic maxillary sinusitis, peritonsillar abscesses, and postoperative infections following major head and neck surgery for malignant disease. Most clinical laboratories will be able to identify bifidobacteria only to the genus level. Isoenzyme patterns are needed to definitively identify species, and this is neither practical nor necessary for the routine clinical laboratory.
