Pathogens
Bacteroides fragilis

Bacteroides fragilis

General Information

Anaerobic gram negative rod.

Most common anaerobic infection "below the diaphragm."

Colonizes GI tract of humans, colon>small bowel.

Other Bacteroides spp. such as B. thetaiotaomicron and B. ovatus are less frequently isolated, but may occur in similar infections.  

Metronidazole and piperacillin-tazobactam remain drug of choice for non-B. frag Bacteroides spp.