ABSTRACT
BACKGROUND: The development of novel antibiotics to treat multidrug-resistant (MDR) tuberculosis is time-consuming and expensive. Multiple immune modulators, immune suppressants, anti-inflammatories, and growth enhancers, and vitamins A and D, inhibit Mycobacterium avium subspecies paratuberculosis (MAP) in culture. We studied the culture inhibition of Mycobacterium tuberculosis complex by these agents. METHODS: Biosafety level two M. tuberculosis complex (ATCC 19015 and ATCC 25177) was studied in radiometric Bactec or MGIT culture. Agents evaluated included clofazimine, methotrexate, 6-mercaptopurine, cyclosporine A, rapamycin, tacrolimus, monensin, and vitamins A and D. RESULTS: All the agents mentioned above caused dose-dependent inhibition of the M. tuberculosis complex. There was no inhibition by the anti-inflammatory 5-aminosalicylic acid, which causes bacteriostatic inhibition of MAP. CONCLUSIONS: We conclude that, at a minimum, studies with virulent M. tuberculosis are indicated with the agents mentioned above, as well as with the thioamide 5-propothiouricil, which has previously been shown to inhibit the M. tuberculosis complex in culture. Our data additionally emphasize the importance of vitamins A and D in treating mycobacterial diseases.
