Echinocandins and Their Activity against Aspergillus terreus Species Complex: a Novel Agar Screening Method

We evaluated the newly proposed agar screening method for echinocandin susceptibility testing of 144 Aspergillus section Terre( isolates compared with the Etest method. Both methods defined the isolates to be wild-type strains for anidulafungin and micafungin, with Etest minimal effective concentrations (MECs) of <= 0.004 mg/L. For caspofungin, the novel agar screening method identified 37 isolates to be caspofungin non-wild type based on their fluffy colony appearance on caspofungin agar. Etest MECs for caspofungin for these isolates were scattered widely from 0.002 to 0.750 mg/L, showing only partial accordance between the two methods.

Automated summary

We evaluated a newly proposed agar screening method for testing the susceptibility of 144 Aspergillus section Terre isolates to echinocandins, and compared it with the Etest method. The results showed that the new method accurately identified wild-type and non-wild type isolates, but there was some discrepancy between the two methods in caspofungin testing.