Molecular and Growth-Based Drug Susceptibility Testing of Mycobacterium tuberculosis Complex for Ethambutol Resistance in the United States.

Ethambutol (EMB) is used as a part of drug regimens for treatment of tuberculosis (TB). Susceptibility of Mycobacterium tuberculosis complex (MTBC) isolates to EMB can be discerned by DNA sequencing to detect mutations in the embB gene associated with resistance. US Public Health Laboratories (PHL) primarily use growth-based drug susceptibility test (DST) methods to determine EMB resistance.

Concordance between molecular and phenotypic testing of Mycobacterium tuberculosis complex isolates for resistance to rifampin and isoniazid in the United States.

Multidrug-resistant (MDR) isolates of Mycobacterium tuberculosis complex (MTBC) are defined by resistance to at least rifampin (RMP) and isoniazid (INH). Rapid and accurate detection of multidrug resistance is essential for effective treatment and interruption of disease transmission of tuberculosis (TB). Overdiagnosis of MDR TB may result in treatment with second-line drugs that are more costly, less effective, and more poorly tolerated than first-line drugs.