Comparative evaluation of Sensititre YeastOne® and CLSI M38-A2 reference method for antifungal susceptibility testing of Aspergillus spp. against echinocandins.


Siopi M, Pournaras S, Meletiadis J.
J Clin Microbiol. 2017 Mar 22. pii: JCM.00044-17.


Sensititre YeastOne® (YO) panels were assessed for in vitro susceptibility testing of echinocandins against 39 isolates of A. fumigatus, A. flavus and A. terreus, including two echinocandin-resistant A. fumigatus, using different inocula (103, 104 and 105 cfu/mL), incubation times (16-48h) and endpoints (first blue or purple) and compared with CLSI M38-A2. The best agreement was found with inoculum of 104 cfu/mL, incubation time of 20h for A. flavus and 30h for A. fumigatus and A. terreus and reading the first purple well. The reproducibility within ±1 two-fold dilution was 100% for all three echinocandins. The essential agreement (±2 log2 dilutions) between the two methods was good for anidulafungin (67-100%) and micafungin (77-100%), but poor for caspofungin (0-54%). Nevertheless, resistant isolates were detected after 24h of incubation.