title: Molecular analysis of the carbapenem and metronidazole resistance mechanisms of Bacteroides strains reported in a Europe-wide antibiotic resistance survey.
abstract: Here we examine the carbapenem and metronidazole resistance mechanisms of 640 Bacteroides strains reported in the 2008-2009 European antibiotic susceptibility survey. Of the 22 strains with elevated imipenem minimum inhibitory concentrations (≥4 μg/mL), 10 were cfiA-positive and out of these 5 carried activating insertion sequence (IS) elements in the upstream regions of the cfiA genes. However, resistant strains with cfiA genes but with no activating IS elements were found (n=2) as well as a resistant strain with no cfiA gene. In the former the resistance phenotypes by Etest were heterogeneous, whilst in the latter no carbapenemase production was seen; both mechanisms have been rarely observed, examined and characterised. Interestingly, few (n=3) nim-positive strains were found, including one metronidazole-resistant strain harbouring nimE activated by ISBf6, and two susceptible strains harbouring chromosomally located nim genes.
authors.affiliation: Institute of Clinical Microbiology, Faculty of Medicine, University of Szeged, Semmelweis 6, H-6725 Szeged, Hungary. soki.jozsef@med.u-szeged.hu
authors.forename: József
authors.initials: J
authors.lastname: Sóki
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Eitel
authors.forename: Edit
authors.initials: E
authors.lastname: Urbán
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Nagy
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D001439:Bacteroides / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D001442:Bacteroides Infections / Q000382:microbiology; D015780:Carbapenems / Q000494:pharmacology*; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005060:Europe; D006801:Humans; D008795:Metronidazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D008795:Metronidazole