Related Experiment Video
Updated: Jul 15, 2026
Broth Microdilution In Vitro Screening: An Easy and Fast Method to Detect New Antifungal Compounds
Published on: February 14, 2018
Posaconazole susceptibility testing against Candida species: comparison of broth microdilution and E-test methods
G Sóczó1, G Kardos, P M McNicholas
1Department of Medical Microbiology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.
Abstract:
Posaconazole (POS) is a newer triazole with activity against yeasts and moulds. POS and fluconazole were tested in vitro against 32 Candida albicans, 30 C. glabrata, 21 C. tropicalis, 29 C. krusei, 28 C. parapsilosis, 50 C. inconspicua, 13 C. kefyr and 5 C. famata isolates using CLSI broth microdilution method (BMD). We compared E-test and a modified BMD using polyethylene-glycol (PEG) as solvent to the CLSI method. BMDs and E-test were performed according to CLSI and the manufacturer's instructions respectively. Geometric means of POS MICs using BMD were 0.71, 0.22 and 0.21 microg ml(-1) against C. glabrata, C. krusei and C. inconspicua, respectively, and remained below 0.1 microg ml(-1) against all other species tested. One of two C. albicans and two of three C. glabrata isolates resistant to fluconazole showed MICs above 8 microg ml(-1) to POS. The impact of using PEG instead of DMSO had only a minor effect (agreements above 95% with the exception of C. parapsilosis). E-tests read after 24 h showed good agreement with the BMD. POS exhibited excellent in vitro activity against Hungarian Candida strains. E-test showed good correlation with the CLSI method, but to facilitate the comparability of results we believe that DMSO should be used as solvent in the BMD.
Insights
Posaconazole demonstrates potent in vitro antifungal activity against various Candida species, including fluconazole-resistant strains. This study confirms its efficacy and compares testing methods for reliable results.
Area of Science:
- Mycology
- Infectious Diseases
- Pharmacology
Background:
- Posaconazole (POS) is a newer triazole antifungal agent.
- Candida species are a significant cause of opportunistic fungal infections.
- Fluconazole resistance in Candida necessitates alternative treatment options.
Purpose of the Study:
- To evaluate the in vitro activity of posaconazole against a panel of clinical Candida isolates.
- To compare the performance of E-test and modified broth microdilution (BMD) methods with the CLSI standard.
- To assess the impact of different solvents (PEG vs. DMSO) on POS MIC determination.
Main Methods:
- Broth microdilution (BMD) and E-test methods were used according to CLSI guidelines.
- Testing was performed against 8 different Candida species.
- Modified BMD using polyethylene-glycol (PEG) was compared to the standard DMSO solvent.
Main Results:
- Posaconazole exhibited excellent in vitro activity against all tested Candida species, with low minimum inhibitory concentrations (MICs).
- POS demonstrated potent activity even against fluconazole-resistant Candida albicans and Candida glabrata isolates.
- E-test showed good agreement with BMD, and PEG solvent had minimal impact on POS MICs.
Conclusions:
- Posaconazole is a highly effective antifungal agent against a broad spectrum of Candida species.
- The E-test is a reliable method for determining POS susceptibility, correlating well with BMD.
- Standardization of solvent use (DMSO) in BMD is recommended for optimal comparability of results.
More Related Videos
08:45Whole Genome Sequencing of Candida glabrata for Detection of Markers of Antifungal Drug Resistance
Published on: December 28, 2017
07:19A 96 Well Microtiter Plate-based Method for Monitoring Formation and Antifungal Susceptibility Testing of Candida albicans Biofilms
Published on: October 21, 2010