title: Reassessment of Clostridium difficile susceptibility to metronidazole and vancomycin.
abstract: Clostridium difficile is the most frequently identified enteric pathogen in patients with nosocomially acquired, antibiotic-associated diarrhea. The drugs most commonly used to treat diseases associated with C. difficile are metronidazole and vancomycin. Most clinical laboratories assume that all C. difficile isolates are susceptible to metronidazole and vancomycin. We report on the antimicrobial susceptibilities of 415 C. difficile isolates to metronidazole and vancomycin over an 8-year period (1993 to 2000). The overall rate of resistance to metronidazole at the critical breakpoint (16 microg/ml) was 6.3%. Although full resistance to vancomycin was not observed, the overall rate of intermediate resistance was 3.1%. One isolate had a combination of resistance to metronidazole and intermediate resistance to vancomycin. Rates of resistance to metronidazole and vancomycin were higher among isolates from human immunodeficiency virus-infected patients. Molecular typing methods proved the absence of clonality among the isolates with decreased susceptibilities to the antimicrobials tested.
authors.affiliation: Microbiology and Infectious Diseases Service, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Peláez
authors.forename: L
authors.initials: L
authors.lastname: Alcalá
authors.forename: R
authors.initials: R
authors.lastname: Alonso
authors.forename: M
authors.initials: M
authors.lastname: Rodríguez-Créixems
authors.forename: J M
authors.initials: JM
authors.lastname: García-Lechuz
authors.forename: E
authors.initials: E
authors.lastname: Bouza
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016360:Clostridioides difficile / Q000187:drug effects*; D004352:Drug Resistance, Microbial; D004761:Enterocolitis, Pseudomembranous / Q000382:microbiology; D015658:HIV Infections / Q000150:complications / Q000382:microbiology; D006801:Humans; D008795:Metronidazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013997:Time Factors; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D014640:Vancomycin