Clinical and Laboratory Standards Institute (CLSI) recently published a document, "Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria; Approved Guideline — Second Edition" (M45-A2).
This document provides guidance to clinical or public health microbiology laboratories for standardized susceptibility testing of infrequently isolated or fastidious bacteria that are not presently included in CLSI documents "Performance Standards for Antimicrobial Disk Susceptibility Tests" (M02) or "Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically" (M07).
Franklin R. Cockerill, III, MD, Mayo Clinic College of Medicine, and chairholder of the Subcommittee on Antimicrobial Susceptibility Testing, says, "This important document compiles a number of guidelines for antimicrobial testing of fastidious or rarely encountered bacteria that cause human disease. Because no other document like this has existed, it fills a significant void in laboratory practice that has existed for many years."
James H. Jorgensen, PhD, The University of Texas Health Science Center, and chairholder of the working group that developed the guideline, explains, "This second edition of the guideline includes several organisms and groups previously included in the main CLSI M100 supplement tables published each year. In the future, those less common or fastidious organisms will be found only in M45. This document provides the microbiologist with expert advice regarding when and how to test organisms that may only be recovered from certain patients or on an infrequent basis. This update allows us to include the revised cephalosporin interpretive breakpoints from the Enterobacteriaceae from M100 for testing and reporting with Aeromonas and Vibrio species."
The tabular information in the document presents the most current information for drug selection, interpretation, and quality control for the infrequently isolated or fastidious bacterial pathogens included in the guideline.