Susceptibility Test Methods: Mycobacteria, <i>Nocardia</i> , and Other Actinomycetes

Abstract This chapter includes a description of the main laboratory tools for the detection of antimicrobial resistance (drug resistance) in tuberculosis (TB), other mycobacterial infections, and aerobic actinomycetes. Nontuberculous mycobacteria (NTM) and aerobic actinomycetes can also cause substantial disease in humans. The incidence of NTM infection continues to increase, particularly in certain patient populations, and AST for NTM and aerobic actinomycetes is an important component of optimal patient care. The chapter discusses the antimicrobial agents that are used in treating mycobacterial infections. It discusses antimicrobial agents in alphabetical order. For TB, first‐line drugs are less toxic, can be given orally using short‐course therapy, and are used to treat pulmonary TB disease susceptible to those agents. Nocardia spp. and other aerobic actinomycetes can cause serious disease in immunocompromised and occasionally even healthy hosts. In vitro susceptibility testing should be performed on all clinically significant isolates to serve as a guide for therapy and to monitor for resistance.