Breakpoints for susceptibility testing should not divide wild-type distributions of important target species.
The fluconazole MIC distributions for Candida glabrata from testing 34 different clinical isolates and performing 51 tests on a single isolate mirrored each other. Since what is perceived as biological variation in isolates without resistance mechanisms is mainly methodological variation, breakpoints which divide this distribution not only lack a sound biological basis but also result in poor reproducibility of susceptibility characterization. This makes 2, 4, 8, and possibly 16 microg/ml unsuitable breakpoints for C. glabrata and fluconazole.
Arendrup
Maiken Cavling
MC
Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark. mad@ssi.dk
Kahlmeter
Gunnar
G
Rodriguez-Tudela
Juan Luis
JL
Donnelly
J Peter
JP
D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects*; D015725:Fluconazole / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*
D000935:Antifungal Agents; D015725:Fluconazole