Tuberculosis is caused by a bacterium called Mycobacteria tuberculosis, a part of a large family of mycobacteria, some strains of which can cause lung disease. The most common pathogenic, nontubercular mycobacteria are collectively known as M.avium complex (MAC).
Researchers have shown that a new diagnostic kit can effectively differentiate between MAC pulmonary disease and TB in just a few hours. It was found that serum antibody levels specific to the MAC antigen were higher in patients with MAC pulmonary disease as compared to those with other respiratory diseases, including TB. The new diagnostic test is based on these findings.
“There are more cases [of MAC] being reported,” says Alvin Teirstein, MD, professor of medicine at Mount Sinai School of Medicine. “We are not sure where it was hiding 25 years ago, but there appears to be a growing epidemic over the last 20 years.”
Although the diagnostic kit was tested in a multicenter study, its effectiveness in different locations and populations must be proven, as MAC strains can vary from place to place.
The current process to distinguish between TB and MAC pulmonary disease takes from 4 to 8 weeks and is often unreliable. Often times, patients with MAC are immediately isolated and started on anti-TB medication —an incorrect diagnosis that can drain resources needed to treat actual TB infections, and also create a burden on patients.