In vitro activity of rifamycin derivatives against nontuberculous mycobacteria, including macrolide- And amikacin-resistant clinical isolates

We evaluated the in vitro activity of rifamycin derivatives, including rifampin, rifapentine, rifaximin, and rifabutin, against clinical nontuberculous mycobacteria (NTM) isolates. Of the rifamycin derivatives, rifabutin showed the lowest MICs against all NTM species, including Mycobacterium avium complex, M. abscessus, and M. kansasii. Rifabutin also had effective in vitro activity against macrolideand aminoglycoside-resistant NTM isolates. Rifabutin could be worth considering as a therapeutic option for NTM disease, particularly drug-resistant disease.