beta-lactamases in bacteroides.

Bacteroides fragilis is responsible for most anaerobic infections in man. Most isolates of B. fragilis show resistance to beta-lactam antibiotics. This resistance might be due to beta-lactamase production or permeability barrier in the cell wall. B. fragilis produce beta-lactamase with mainly cephalosporinase activity. Other Bacteroides species such as B. clostridiformis, B. melaninogenicus and B. oralis also produce beta-lactamase but with different biochemical characteristics.