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CLSI’s Publishes 30th Edition of M100


Wayne, Pennsylvania, USAThe Clinical and Laboratory Standards Institute announces the publication of its annually updated antimicrobial susceptibility testing (AST) supplement M100—Performance Standards for Antimicrobial Susceptibility Testing, 30th Ed. M100 is available as part of a package with either M02—Performance Standards for Antimicrobial Disk Susceptibility, 13th Ed.or M07— Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically, 11th Ed., or all three documents together.  

M02 covers the current recommended methods for disk susceptibility testing and criteria for quality control testing and includes the M02 Quick Guide.M07 covers reference methods for determining minimal inhibitory concentrations of aerobic bacteria by broth macrodilution, broth microdilution, and agar dilution. M100 includes annually updated tables for M02, M07, and M11. 

Romney Humphries, PhD, D(ABMM) member of the CLSI Subcommittee on AST Testing, said of the changes in the 30th Edition,

“In the 2020 edition of M100, we’ve taken the important step of setting, for the first time, colistin and polymyxin B breakpoints for the Enterobacterales. These breakpoints address a major global health need, with the emergence of more and more Gram-negative bacteria that are only susceptible to the polymyxin class of antibiotics. However, use of these drugs is not without substantial risk, as they are associated with high toxicity. As a result, the AST Subcommittee decided to designate only two interpretive categories for colistin: intermediate and resistant. The reason for this is that the clinical data did not support designating a “susceptible” category, which implies probable clinical success. Along with this breakpoint update, in M100, we describe two new methods for colistin testing: a disk broth elution method and an agar dilution method. Together, these two advances will allow laboratories to test and report these drugs.”

In addition to publishing M100, on Wednesday, February 26, 2020, 1:00–2:30 PM Eastern (US) Time and Thursday, February 27, 2020, 3:00–4:30 PM Eastern (US) Time CLSI will host the Annual AST Updates Webinar. This webinar will focus on changes and updates to M100 followed by a question and answer session. For more information and to register, click here.

CLSI sets the standard for quality in medical laboratory testing. A not-for-profit membership organization, CLSI brings together the global laboratory community for the advancement of a common cause: to foster excellence in laboratory medicine.   For over 50 years, our members, volunteers, and customers have made CLSI a respected, transformative leader in the development and implementation of medical laboratory testing standards. Through our unified efforts, we will continue to set and uphold the standards that drive quality test results, enhance patient care delivery, and improve health care around the world.    

By using CLSI standards, laboratorians can improve process quality, speed the development of standard operating procedures, and implement safer practices with greater ease and efficiency.    


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