CLSI Publishes 2009 Antimicrobial Susceptibility Testing Standards.

WAYNE, Pa. -- CLSI recently published updated editions of its antimicrobial susceptibility testing (AST) standards, Performance Standards for Antimicrobial Disk Susceptibility Tests; Approved Standard--Tenth Edition (M02-A10), and Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard--Eighth Edition (M07-A8). In addition, the annual update of the well-known Performance Standards for Antimicrobial Susceptibility Testing; Nineteenth Informational Supplement (M100-S19) is available with the purchase of M02-A10 and M07-A8.

Matthew A. Wikler, MD, MBA, FIDSA, President and CEO, Pacific Beach BioSciences, Inc., and chairholder of the CLSI AST subcommittee, says, "The ultimate mission of the subcommittee on AST is to provide useful information to enable laboratories to assist the clinician in the selection of appropriate antimicrobial therapy for patient care. With the need to better identify resistant bacterial strains and resistance mechanisms, we believe that these updated documents will provide the laboratory with the most up-to-date methods and interpretive criteria to assist the physician in providing benefit to the patient."

Dr. Wikler adds, "The AST subcommittee recommends that all microbiology laboratories performing AST testing should now begin using the 2009 versions, M02-A10, M07-A8, and M100-S19, as these versions contain the most up to date information."

M100-S19 provides updates of the latest recommendations for detecting emerging resistance of aerobic bacteria--arranged in tabular format. The "breakpoints" included in the supplement are defined as specific values on the basis of which bacteria can be assigned to the clinical categories of susceptible, intermediate, or resistant.

Updates include:

* new antimicrobial agents and quality control (QC) ranges;

* improved and expanded for ease of use:

* appendixes for detection of resistance for several organism groups were clarified and combined into one table for each organism,

* merged disk diffusion and minimal inhibitory concentration (MIC) tables for suggested groupings of antimicrobial agents; and

* appendix for screening and confirmatory tests for suspected carbapenemase production in Enterobacteriaceae.

Every three years, the CLSI M02 and M07 standards are updated by the CLSI consensus development committee to ensure that new methodology is included in the documents. This methodology is essential to correctly interpret and use the annual M100 supplement.

Jana M. Swenson, MMSc, Centers for Disease Control and Prevention, and volunteer who worked on the subcommittee that developed the documents, says, "Because they not only explain the 'hows' but the 'whys' of susceptibility testing, these documents are critically important resources for all clinical microbiology laboratories. Together with M100, the core tables that are updated every year, M02 and M07 provide the knowledge needed to perform the testing correctly and with understanding."

Performance Standards for Antimicrobial Disk Susceptibility Tests; Approved Standard--Tenth Edition (M02-A10) describes the standard agar disk diffusion techniques utilized to determine the in vitro susceptibility of aerobic bacteria to antimicrobial agents.

Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard--Eighth Edition (M07-A8) outlines reference methods for the determination of MICs of aerobic bacteria by broth macrodilution, broth microdilution, and agar dilution.

Updates of the M02-A10 and M07-A8 standards include:

* guidance for reading zone diameters;

* tables and sections for organisms requiring special consideration;

* sections and appendixes outlining QC responsibilities; and

* listed subgroups of antimicrobials for the macrolide group.

Antimicrobial Susceptibility Testing Searchable CD-ROM, AST QC Flowchart Quick Guides, M02 and M07 Quick Guides for Tables 1 and 1A, and Wallchart-Glossary of Antimicrobial Terms and Abbreviations for implementing CLSI's highly acclaimed AST standards and guidelines have also been updated.

For additional information on CLSI or the documents and products in this release, visit the CLSI website at www.clsi.org or call +610.688.0100.

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.