title: New findings in beta-lactam and metronidazole resistant Bacteroides fragilis group.
abstract: Beta-lactam antibiotics and 5-nitroimidazoles have been extensively used against anaerobic bacteria. However, antibiotic resistance is increasingly common among anaerobic Gram-negative bacilli. The classical mechanisms of resistance to beta-lactams are, (1) production of beta-lactamases; (2) alteration of penicillin-binding proteins (PBPs); and (3) changes in outer membrane permeability to beta-lactams. The 5-nitroimidazole molecule is a prodrug whose activation depends upon reduction of the nitro group in the absence of oxygen. Decreased uptake and altered reduction are believed to be responsible for metronidazole resistance. Five nim genes (A, B, C, D and E) have been identified in Bacteroides fragilis group spp. that confer resistance to 5-nitroimidazole antibiotics. Knowledge of the status and the mechanisms of resistance is critical for both the selection of antimicrobial therapy and the design of new antimicrobial agents. The purpose of this article is to review the mechanisms for and the prevalence of beta-lactam and metronidazole resistance in strains belonging to the B. fragilis group.
authors: Department of Microbiology, Pathology and Immunology, Karolinska Institute, Huddinge University Hospital, SE-141 86, Stockholm, Sweden. carl.erik.nord@impi.ki.se
authors: Hong
authors: H
authors: Fang
authors: Charlotta
authors: C
authors: Edlund
authors: Maria
authors: M
authors: Hedberg
authors: Carl Erik
authors: CE
authors: Nord
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001442:Bacteroides Infections / Q000382:microbiology; D001441:Bacteroides fragilis / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D008795:Metronidazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D008795:Metronidazole; D001618:beta-Lactamases