scope:

M24 includes antimicrobial susceptibility testing (AST) protocols for three major categories of mycobacterial species:

• Mycobacterium tuberculosis complex (MTBC)

• The slowly growing nontuberculous mycobacteria (SGM)

• The rapidly growing mycobacteria (RGM)

Also provided are:

• AST recommendations for Nocardia spp. and other aerobic actinomycetes

• Guidance on selecting first-line and, for some organisms, second-line antimicrobial agents for testing and reporting

• Instructions for performing the standard agar proportion (AP) method for MTBC and broth microdilution for mycobacteria and aerobic actinomycetes

• Molecular methods for detecting mutations associated with MTBC drug resistance

• QC protocols for each organism category

Testing and reporting recommendations and QC procedures apply to both reference methods and commercial shorter-incubation broth systems that have been regulatory organization cleared or approved for testing MTBC. This standard does not cover identification methods, nor does it provide an in-depth discussion of molecular test procedures. This standard is intended for use by hospital, public health, and referral laboratories that perform AST on MTBC, nontuberculous mycobacteria (NTM), Nocardia spp., and/or other aerobic actinomycetes.