CLSI Publishes Standard For Antimicrobial Disk And Dilution Susceptibility Tests For Bacteria Isolated From Animals

Main Category: Veterinary
Article Date: 10 Mar 2008 - 3:00 PDT

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In order to have a positive impact on clinical outcomes, help maintain antimicrobial effectiveness, assist clinicians in using antimicrobials safely, and minimize selection of resistant pathogens, laboratories must use a standardized, well-defined method for performing antimicrobial susceptibility testing (AST).

In response to this need, Clinical and Laboratory Standards Institute (CLSI) recently published an updated document, Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated From Animals; Approved Standard-Third Edition (M31-A3), which is predicated on providing AST methods that give accurate, reproducible, clinically relevant results for veterinary pathogens.

Jeffrey L. Watts, PhD, RM(AAM), M(ASCP), Director, Livestock Pharmaceuticals, Pfizer Animal Health, who served as chairholder for the committee that developed the document, says, "M31 is the only standard available in the world specifically addressing the antimicrobial susceptibility testing of animal pathogens. This latest version, M31-A3, incorporates the latest information for detecting resistance mechanisms in bacterial pathogens as well as veterinary-specific clinical breakpoints for over 18 agents."

This document provides veterinary diagnostic laboratories with currently recommended antimicrobial agent disk and dilution susceptibility test methods for bacteria isolated from animals; criteria for quality control (QC) testing; and interpretive criteria.

This document is a revision of M31-A2, and includes the following updates:

- changes derived from CLSI documents Performance Standards for Antimicrobial Disk Susceptibility Tests (M2) and Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically (M7);

- a separate section lists QC strain entries in various international repositories;

- a workflow sheet for QC testing and a troubleshooting checklist;

- development of specific test methods and QC values for several antimicrobial agents effective against Campylobacter;

- veterinary-specific interpretive criteria for additional antimicrobial agents;

- designate CLSI Approved Human Interpretive Criteria, Primary Test, Selectively Report (Group B); No Veterinary Species-Specific or Human-Specific Interpretive Criteria, Primary Test, Selectively Report (Group C); and Supplemental "AMDUCA-use" (US Animal Medicinal Drug Use Clarification Act) products, Selectively Test, Selectively Report (Group D); and

- refinements to definitions for "susceptible" and "resistant" designations.

For additional information on CLSI or for further information regarding this release, visit the CLSI website at http://www.clsi.org.

CLSI, formerly NCCLS, 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.

http://www.clsi.org