title: Isolation of metronidazole-resistant Bacteroides fragilis carrying the nimA nitroreductase gene from a patient in Washington State.
abstract: Members of the Bacteroides fragilis group are among the most common anaerobic bacterial isolates in clinical specimens. Metronidazole, a 5-nitroimidazole, is often used as empirical therapy for anaerobic infections. Susceptibility testing is not routinely performed because of nearly universal susceptibility of Bacteroides spp. to this agent. We report a case of metronidazole-resistant Bacteroides fragilis in the United States and demonstrate the presence of the nimA gene, encoding a nitroreductase previously shown to mediate resistance to 5-nitroimidazole antimicrobial agents in B. fragilis strains from Europe and Africa. Because clinical failures in Bacteroides infections have been associated with the use of inactive antimicrobial agents, clinicians need to be aware of the possibility of metronidazole-resistant B. fragilis strains in the United States and the importance of susceptibility testing in selected situations.
authors.affiliation: Department of Laboratory Medicine, University of Washington Medical Center, Box 357110, 1959 NE Pacific St., Seattle, WA 98195, USA.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Schapiro
authors.forename: Rachna
authors.initials: R
authors.lastname: Gupta
authors.forename: Eric
authors.initials: E
authors.lastname: Stefansson
authors.forename: Ferric C
authors.initials: FC
authors.lastname: Fang
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Limaye
mesh_terms: D000843:Ankle Joint; D001442:Bacteroides Infections / Q000209:etiology*; D001441:Bacteroides fragilis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D050723:Fractures, Bone / Q000150:complications / Q000382:microbiology; D005869:Ghana; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009601:Nitroreductases / Q000235:genetics*; D014195:Travel; D014861:Washington
chemical_list: D009601:Nitroreductases