title: Susceptibility of anaerobic bacteria to beta-lactam antibiotics and beta-lactamase production.
abstract: We examined the susceptibility of various anaerobes to four beta-lactamase susceptible (ampicillin, amoxycillin, cyclacillin, and penicillin G) and two beta-lactamase resistant (moxalactam, and N-F-thienamycin) beta-lactam antibiotics and measured beta-lactamase production. Members of the Bacteroides groups were most resistant to the six antibiotics. N-F-thienamycin was the most effective antimicrobial agent against all the test strains, moxalactam the next most effective, and penicillin G the least. Beta-lactamase production was mainly confined to Bacteroides species. Cephalosporinase was the most common beta-lactamase produced; penicillinase was detected less often. About two thirds of the penicillin-resistant isolates produced cephalosporinase. N-F-thienamycin and moxalactam were the most active agents against those anaerobes that were resistant to many beta-lactam antibiotics.
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology; D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000201:enzymology; D001439:Bacteroides / Q000187:drug effects; D002513:Cephamycins / Q000494:pharmacology; D003493:Cyclacillin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009070:Moxalactam; D013845:Thienamycins / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; D002513:Cephamycins; D013845:Thienamycins; D003493:Cyclacillin; D000667:Ampicillin; D000658:Amoxicillin; D001618:beta-Lactamases; D009070:Moxalactam; C015537:thienamycin