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Published on: February 14, 2018
Comparative evaluation of Sensititre YeastOne and CLSI M38-Ed3 reference method for determining echinocandin minimum
Assaf Potruch1,2, Hila Elinav1,3, Matan J Cohen1,4
1Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
Abstract:
The minimum inhibitory concentration (MIC) of echinocandins against Aspergillus spp. does not represent the actual inhibition threshold of echinocandins. Therefore, the recommended method to evaluate their activity is determining the minimum effective concentration (MEC) in broth microdilution, a method that is less common in clinical settings. This study aimed to assess a user-friendly commercial method, Sensititre YeastOne (SYO), to determine the effectiveness of echinocandins (caspofungin, anidulafungin and micafungin) against Aspergillus spp. Echinocandins MEC was determined against 23 isolates of Aspergillus spp. using SYO and the reference Clinical and Laboratory Standards Institute (CLSI) method. MECs were read with an inverted microscope and a reading mirror. Essential agreement (EA) between the tested methods was defined as a ±twofold dilution difference. There was a high EA (91%-100%) between the reference method and SYO in determining echinocandins MEC against Aspergillus isolates using inverted microscopy. A high EA was also observed between SYO MEC determined by inverted microscopy and a reading mirror, but different incubation times were required. SYO is a reliable, simple method for determining the MEC of echinocandins against Aspergillus isolates, preferably with an inverted microscope, and can be easily used in clinical laboratories when echinocandin susceptibility testing is required.IMPORTANCEUsing a commercial method such as Sensititre YeastOne (SYO) to determine the minimum effective concentration (MEC) of echinocandins against Aspergillus spp. has been shown to be a reliable alternative to the Clinical and Laboratory Standards Institute (CLSI) reference method. This makes it more suitable for high-volume clinical laboratories. SYO provides accurate results comparable to the standard method and could potentially improve patient care by guiding more optimal antifungal treatment choices for patients with Aspergillus infections.
Insights
The Sensititre YeastOne (SYO) method reliably determines echinocandin effectiveness against Aspergillus species, offering a simpler alternative to standard methods for clinical labs. This approach aids in optimizing antifungal treatments for Aspergillus infections.
Area of Science:
- Medical Mycology
- Antimicrobial Susceptibility Testing
Background:
- Echinocandin minimum inhibitory concentration (MIC) does not accurately reflect inhibition thresholds against Aspergillus species.
- Minimum effective concentration (MEC) is the recommended metric but is not commonly used in clinical settings.
- A user-friendly method for MEC determination is needed for clinical laboratories.
Purpose of the Study:
- To evaluate the Sensititre YeastOne (SYO) commercial method for determining echinocandin MEC against Aspergillus species.
- To compare the performance of SYO with the Clinical and Laboratory Standards Institute (CLSI) reference method.
Main Methods:
- Echinocandin MEC was determined for 23 Aspergillus isolates using SYO and the CLSI reference method.
- Readings were performed using an inverted microscope and a reading mirror.
- Essential agreement (EA) was defined as a ±twofold dilution difference.
Main Results:
- High essential agreement (91%-100%) was observed between SYO and the CLSI method when using an inverted microscope.
- High EA was also found between SYO readings with an inverted microscope and a reading mirror, though incubation times varied.
- SYO proved to be a reliable and simple method for MEC determination.
Conclusions:
- The Sensititre YeastOne (SYO) method is a reliable and simple alternative for determining echinocandin MEC against Aspergillus isolates in clinical laboratories.
- Using an inverted microscope with SYO is preferable for accurate results.
- This method can improve antifungal treatment decisions for patients with Aspergillus infections.
