Validation of commercial dry-form broth microdilution panels and test reproducibility for susceptibility testing of dalbavancin, a new very long-acting glycopeptide.

Results from dalbavancin dry-form commercial broth microdilution MIC panels (Sensititre, TREK Diagnostics) were compared with reference frozen-form MIC values to assure the validity and reproducibility of the extended shelf-life product. A collection of 402 organisms from four major organism groups were used in the validation trial and 10 strains for reproducibility replicate tests. A total of 98.6% commercial dalbavancin MIC results were within +/-1 log(2) dilution of reference values (76.2% were identical) and reproducibility trials produced identical MIC results in 88.9-92.2% of dalbavancin MIC comparisons. These dalbavancin MIC results demonstrated the acceptable accuracy of commercially-prepared broth microdilution products for use in subsequent clinical trials.