Standardization of antifungal susceptibility testing

Area of Science:

• Medical Microbiology
• Clinical Mycology
• Pharmacology

Background:

• In vitro antifungal susceptibility testing (AFST) has faced challenges in reproducibility and clinical relevance.
• Limited standardization has hindered the reliable application of AFST in clinical research and therapy guidance.

Purpose of the Study:

• To address the limitations of AFST by developing and evaluating standardized methods.
• To establish reproducible and clinically relevant in vitro testing protocols for antifungal agents.

Main Methods:

• Development and validation of a standardized method (M27-P) by the National Committee for Clinical Laboratory Standards.
• Evaluation of alternative methods like microdilution broth and stable gradient technology against the standard.
• Assessment of a disc diffusion method and modification for filamentous fungi.

Main Results:

• Multi-laboratory studies confirmed the intra- and inter-laboratory reproducibility of the proposed standard method.
• Alternative methods demonstrated a defined relationship to the standard, offering convenience.
• A modified standard method for filamentous fungi showed promise.

Conclusions:

• The availability of standardized and validated alternative AFST methods facilitates meaningful analysis of clinical relevance.
• Emerging correlations between in vitro minimum inhibitory concentrations (MICs) and clinical outcomes are evident.
• This progress is particularly notable for fluconazole in treating HIV-associated oropharyngeal candidosis.