Antimycobacterial activity of rifaximin (L/105) in experimental tuberculosis in the guinea pig.

The antimycobacterial activity of rifaximin was studied in the guinea pig, after oral administration. The experiment confirmed the scanty absorption of rifaximin in the gastrointestinal tract, as the two dosages used (60 and 30 mg/kg) did not modify the tubercular illness after four months of therapy. Furthermore, sensitivity to rifaximin of the callenging Mycobacterium tuberculosis isolated at the end of the study from the spleen, lung, liver and lymph nodes of the guinea pigs that received rifaximin did not change.