title: Routine disc diffusion antimicrobial susceptibility testing of Clostridium difficile and association with PCR ribotype 027.
abstract: Reduced susceptibility to metronidazole and vancomycin in Clostridium difficile has been reported, which emphasises the need for simple antimicrobial susceptibility testing methods. The aim of this study was to apply a published disc diffusion method and zone diameter breakpoint correlates to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological minimum inhibitory concentration (MIC) cut-off values in a routine setting. Metronidazole and vancomycin zone diameters from 2702 isolates were recorded. Fifteen isolates had a metronidazole zone diameter below the published breakpoint (<23 mm) and five isolates had a vancomycin zone diameter below the published breakpoint (<19 mm), most of which were polymerase chain reaction (PCR) ribotype 027. The total number of PCR ribotype 027 was 29 (1.1 %). Overall, C. difficile PCR ribotype 027 isolates had smaller zone diameters than non-027 isolates. The disc diffusion method is very simple and inexpensive, and the published zone diameter breakpoints will detect C. difficile isolates with reduced susceptibility to metronidazole and vancomycin.
authors: Department of Clinical Microbiology, Odense University Hospital, Winsloewparken 21, 2, 5000, Odense C, Denmark.
authors: H M
authors: HM
authors: Holt
authors: Department of Clinical Microbiology, Odense University Hospital, Winsloewparken 21, 2, 5000, Odense C, Denmark.
authors: T K
authors: TK
authors: Danielsen
authors: Department of Clinical Microbiology, Odense University Hospital, Winsloewparken 21, 2, 5000, Odense C, Denmark. ujustesen@health.sdu.dk.
authors: U S
authors: US
authors: Justesen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016360:Clostridioides difficile / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification; D003015:Clostridium Infections / Q000382:microbiology*; D003967:Diarrhea / Q000382:microbiology; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial; D006801:Humans; D008795:Metronidazole / Q000494:pharmacology*; D021521:Ribotyping; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D014640:Vancomycin