The Clinical and Laboratory Standards Institute operates as a non-profit organization that develops standards through a consensus process.
M45 does not replace M100 for common pathogens like Staphylococcus or E. coli , nor does it cover anaerobes (see CLSI M11).
The document underscores the "rule of thumb" that the yield of blood culture increases proportionally with the volume of blood cultured. M45 provides specific volume recommendations for adults, pediatric patients, and neonates, noting that collecting too little blood is a common cause of false-negative results.
Unlike M100, M45 does not always provide “S/I/R” (Susceptible/Intermediate/Resistant) breakpoints for every drug-organism pair due to limited clinical data. Instead, you may find: clsi document m45 pdf
Incubation in a 5% CO2 environment rather than ambient air for specific capnophilic species. Reading and Interpreting Results
Categorized into Susceptible (S), Intermediate (I), Resistant (R), or Susceptible-Dose Dependent (SDD) where applicable.
: Includes specialized guidance for public health laboratories testing bacteria potentially associated with bioterrorism Modern Taxonomic Updates The Clinical and Laboratory Standards Institute operates as
: The third edition (M45-Ed3) features updated nomenclature and new tables for organisms typically identified via MALDI-TOF mass spectrometry or sequencing. : Assists clinical laboratories in determining when and how
Comparison guides between and M100 for your bench techs.
: Detailed instructions for performing broth microdilution and agar disk diffusion for specific "non-standard" organisms. The document underscores the "rule of thumb" that
The document, titled Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria , is a specialized guideline developed by the Clinical and Laboratory Standards Institute (CLSI) . It serves as a critical extension to the primary antimicrobial susceptibility testing (AST) standards, specifically covering organisms that are not included in the more common CLSI M100 supplement. Core Purpose and Scope
Regular revisions ensure that the guidelines reflect the current epidemiology and resistance patterns. Key Organisms and Testing Methods in M45
Maintain validation records for specialized media formulations, ensuring they support the growth of control strains.