Susceptibility Testing of Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) have emerged as important human pathogens and there are increasing reports of NTM infections worldwide. Both immunosuppressed as well as immunocompetent patients may be affected by these pathogens. Treatment options are mostly guided by antimicrobial susceptibility testing (AST) of the involved NTM. However, since choice of therapy is dependent on NTM species, identification of NTM in a patient is paramount prior to susceptibility testing. Treatment duration may be prolonged and frequently includes using multiple antimicrobials. Currently, however, AST guidelines are limited to select NTM. Additional information is also required on correlation of susceptibility breakpoints with the clinical outcomes; an area that is not well documented in the literature. This chapter provides a summary of available AST guidelines for NTM and explores clinical outcome data with the available AST breakpoints.