TABLE 4.

Bacteroides: the good and the bad

Characteristic
Beneficial effects associated with Bacteroides
Starch utilizations systems to break down complex polysaccharides
Zwitterionic polysaccharide mediates T-cell activation
Aids in development of GALT and a mature immune system
Directs Paneth cells to produce antibacterial molecules, including defensins and lectins
Deters colonization of the GI tract by pathogens
May aid in properly development of immune tolerance and avoidance of allergy and asthma
May have a role in preventing obesity
Bacteroides as pathogens
Can be involved in:
Infection after colonic contamination of the abdominal cavity and tissues
Bacteremia
Skin and soft tissue infections
Osteomyelitis
May produce enterotoxin and cause GI illness
Produces hemolysins, histolytic enzymes that cause tissue destruction
May be implicated in Crohn's disease and other IBDs
Causes abscess formation