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CLSI Publishes Updated Reference Method for Broth Dilution Antifungal Susceptibility Testing of Filamentous Fungi

WAYNE, Pa.--(BUSINESS WIRE)--May 16, 2008 - With the increased incidence of systemic fungal infections and the growing number of antifungal agents, laboratory methods to guide the selection of antifungal therapy have gained greater attention. Clinical and Laboratory Standards Institute (CLSI) has recently published an updated standard, Reference Method for Broth Dilution Antifungal Susceptibility Testing of Filamentous Fungi; Approved Standard--Second Edition (M38-A2), which describes a method for testing the susceptibility of filamentous fungi (moulds) that cause invasive (Aspergillus spp., Fusarium spp., Rhizopus oryzae (R. arrhizus), Pseudallescheria boydii (Scedosporium apiospermum), S. prolificans, Sporothrix schenckii, and other opportunistic pathogenic moulds) and cutaneous (dermatophyte, Trichophyton, Microsporum, and Epidermophyton spp.) fungal infections to antifungal agents.

The standard discusses selection of antifungal agents; preparation of antifungal stock solutions and dilutions for testing, implementation, and interpretation of test procedures; and the purpose and implementation of quality control (QC) procedures.

This document replaces the first edition of the approved guideline, M38-A, which was published in 2002. It includes the following updates:

-- Supplemental material (QC data for mould isolates as well as echinocandin testing guidelines) has been incorporated.

-- Methods for testing dermatophyte moulds are provided based on a series of consensus studies.

-- Expanded list of relevant drug concentration to include echinocandins and other suitable drug concentration ranges for testing dermatophytes.

-- Expanded recommendations on inoculum preparation of dermatophyte species.

-- Additional recommendations on incubation of Alternaria spp. and echinocandins.

-- Modified section on reading results to include new information on echinocandins antifungal agents and MIC and MEC comparison.

-- Expanded recommendations on reading results of itraconazole and new triazoles.

This standard focuses on the fully defined synthetic medium RPMI-1640 for testing of moulds because of the suitability of this test medium for antifungal susceptibility testing of yeasts.

For additional information on CLSI or for further information regarding this release, visit the CLSI website at or call +610.688.0100.

CLSI is a global, nonprofit, membership-based organization dedicated to developing standards and guidelines for the health care and medical-testing community. CLSI's unique consensus process facilitates the creation of standards and guidelines that are reliable, practical, and achievable for an effective quality system.


Clinical and Laboratory Standards Institute (CLSI)
Amanda Holm, Marketing Manager
Phone: +610.688.0100 ext. 129

Posted: May 2008