SHOULD RESISTANCE TO AZOLE ANTIFUNGALS IN-VITRO BE INTERPRETED AS PREDICTING CLINICAL NONRESPONSE

Published data relating clinical treatment outcomes to susceptibility of Candida species in vitro for the triazole antifungal agents flucona zole and itraconazole show a clear association between rates of treatm ent failure and rising minimal inhibitory concentrations for the infec ting fungal isolate. However, more than 50% of patients infected with an isolate 'resistant' to a triazole by NCCLS breakpoint criteria resp ond successfully to treatment with the triazole. Data for antibacteria l agents similarly show that the association between resistance in vit ro and treatment failure in vivo is far less than perfect. Susceptibil ity testing therefore falls into a category similar to that of weather forecasting. Despite good test standardization and sophisticated tech nology, the forecasts successfully predict trends, but cannot accurate ly foresee temperatures or levels of precipitation at a specific time in a specific location.