Source http://www.denniskunkel.com/DK/Bacteria/24704B.html

Bifidobacterium sp. - Gram-positive, anaerobic, rod prokaryote. Bifidobacterium spp. are a large group of probiotic
bacteria that are present in the mammalian gastrointestinal tract, mouth and vagina. They are responsible for
suppressing pathogenic microorganisms and are rarely pathogenic.
Infections due to some species of
Bifidobacterium include obstetric and gynecological sepsis, peritonitis, pulmonary infections, urinary
tract infections, bacteremia and endocarditis.
Bifidobacterium spp. are used as a form of probiotic that is
thought to have health promoting properties for humans. Probiotic bacteria favorably alter the intestine microflora
balance, inhibit the growth of harmful bacteria, promote good digestion, boost immune function, and increase
resistance to infection.

Postgrad Med, 1978 Mar, 63(3), 187 - 8, 190, 192
Case report: fatal anaerobic pulmonary infection due to Bifidobacterium eriksonii; Green SL; This case illustrates
progressive anaerobic pleuropulmonary infection caused by Bifidobacterium eriksonii that eventually was fatal .
Aspiration pneumonia, lung abscess, empyema, and finally
necrotizing pneumonia characterized the clinical
course . The organism is difficult to recover, but there is reason to suspect that it may be of greater etiologic
importance than heretofore recognized in debilitated patients with pleuropulmonary infections . This patient was a
52-year-old alcoholic with periodontal disease . Both conditions are well-known factors underlying anaerobic
pleuropulmonary infection . Alcoholism probably predisposed the patient to aspiration of oral secretions, the likely
source of the infection.
http://www.bionewsonline.com/w/2/bifidobacteria_c.htm