Quality controls for antimicrobial disk diffusion testing on Leptospira Vanaporn Wuthiekanun agar

BACKGROUND Disk diffusion susceptibility testing for Leptospira spp. on Leptospira Vanaporn Wuthiekanun (LVW) solid agar was reported recently. However, it was unclear whether the zone sizes obtained on LVW agar were comparable with those of other bacteria on Mueller-Hinton agar. METHODS Here, we evaluate the disk diffusion assay on LVW agar using the standard quality control (QC) bacterial strains for 22 antimicrobials. RESULTS All antimicrobials provided zone sizes within the standard range for each QC bacterial strain, except for fosfomycin. CONCLUSIONS In conclusion, the simple disk diffusion assay can be used to assess antimicrobial activity against Leptospira on LVW agar using standard bacterial strains for QC with the standard breakpoints (except for fosfomycin).