title: Mechanisms of beta-lactam resistance in anaerobic bacteria.
abstract: The known mechanisms of beta-lactam resistance in anaerobic bacteria involve production of beta-lactamases, alteration of penicillin-binding proteins, and blocking of the penetration of beta-lactams through the outer membranes. The most important factor in beta-lactam resistance is the production of beta-lactamase. beta-Lactamases in various Bacteroides, Fusobacterium, and Clostridium species have been described. beta-Lactam resistance in Bacteroides fragilis is most commonly mediated by the production of beta-lactamase, primarily of the cephalosporinase type. Studies have also shown that B. fragilis can produce a penicillinase that inactivates piperacillin and carbenicillin. Enzymes that inactivate cefoxitin and imipenem have also been found in B. fragilis. The nonfragilis Bacteroides species produce beta-lactamases mainly of the penicillinase type. Recently a penicillinase from Fusobacterium nucleatum has been characterized. Among the clostridia, Clostridium butyricum, clostridium clostridiiforme and Clostridium ramosum have been shown to produce penicillinases.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001421:Bacteria, Anaerobic / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D001426:Bacterial Proteins; D001439:Bacteroides / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002473:Cell Wall / Q000187:drug effects; D003013:Clostridium / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D004352:Drug Resistance, Microbial; D005673:Fusobacterium / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase / Q000378:metabolism; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D001618:beta-Lactamases / Q000378:metabolism*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D047090:beta-Lactams; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D001618:beta-Lactamases