Background: Blood culture is the gold standard diagnostic method in candidemia in spite of long result time and low sensitivity rate. Early diagnosis is crucial for management of candidemia because a delay in treatment is related with increased mortality. We aimed to evaluate the direct applicability of antifungal susceptibility testing methods from positive blood culture bottles to save at least 24 hours.
Methods: Blood culture bottles were inoculated with 62 Candida isolates. Etest and broth microdilution (BMD) methods for six antifungals, disk diffusion (DD) method for two antifungals were performed, both directly from bottles and standardly.
Results: Essential agreements between direct and standard Etest methods were 87.1% for caspofungin and >90% for other antifungals, but the agreements of them with reference BMD were relatively low. Essential agreement between direct and standard BMD was >93%. Correlation between direct and standard DD methods was very high, negative correlations were observed between reference BMD and DD methods.
Conclusion: BMD is a reference method to evaluate the antifungal susceptibility, direct application of BMD might provide reliable results at least 24 hours earlier. Direct DD method may be a qualitative alternative. Direct susceptibility testing methods may be very useful to initiating the appropriate treatment on time.
Keywords: Candida; Etest; blood culture; broth microdilution; direct antifungal susceptibility; disk diffusion.
© 2017 Wiley Periodicals, Inc.