Comparative analysis of antifungal susceptibility testing methods for echinocandins in candidemia isolates

Despite the availability of many antifungal drugs in clinical practice, the occurrence of antifungal drug resistance is on the rise. Since the antifungal susceptibility testing (AFST) is not done routinely in many of the microbiology laboratories, it is very difficult to determine which antifungal agent is very effective for a particular infection. There is a real need for precise, reproducible and extrapolative antifungal susceptibility testing methods to aid the therapeutic management. The practice of empirical treatment for fungal infections further promotes the emergence of resistant strains. The AFST practice would essentially help the clinicians in appropriate decision making. Although conventional AFST methods are somewhat cumbersome, many novel AFST methods are currently available in many laboratory settings which would provide a quicker result many times. In essence, the application of AFST along with identification of the fungus up to species level would definitely be very helpful in selecting the primary antifungal agents for treatment especially in difficult to manage and invasive fungal infections. This review will throw light on the various AFST methods available and their issues in the current practice.

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Antifungal Susceptibility Testing: Practical Aspects and Current Challenges

Clinical Microbiology Reviews ◽

10.1128/cmr.14.4.643-658.2001 ◽

2001 ◽

Vol 14 (4) ◽

pp. 643-658 ◽

Cited By ~ 264

Author(s):

John H. Rex ◽

Michael A. Pfaller ◽

Thomas J. Walsh ◽

Vishnu Chaturvedi ◽

Ana Espinel-Ingroff ◽

...

Keyword(s):

Amphotericin B ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Antifungal Susceptibility Testing ◽

Testing Methods ◽

Clinical Value ◽

Candida Spp ◽

Testing Procedures ◽

Reference Methods ◽

Interlaboratory Reproducibility

SUMMARY Development of standardized antifungal susceptibility testing methods has been the focus of intensive research for the last 15 years. Reference methods for yeasts (NCCLS M27-A) and molds (M38-P) are now available. The development of these methods provides researchers not only with standardized methods for testing but also with an understanding of the variables that affect interlaboratory reproducibility. With this knowledge, we have now moved into the phase of (i) demonstrating the clinical value (or lack thereof) of standardized methods, (ii) developing modifications to these reference methods that address specific problems, and (iii) developing reliable commercial test kits. Clinically relevant testing is now available for selected fungi and drugs: Candida spp. against fluconazole, itraconazole, flucytosine, and (perhaps) amphotericin B; Cryptococcus neoformans against (perhaps) fluconazole and amphotericin B; and Aspergillus spp. against (perhaps) itraconazole. Expanding the range of useful testing procedures is the current focus of research in this area.

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