LES PRINCIPES BACTERIOLOGIQUES DES TRAITEMENTS DE LA TUBERCULOSE

The efficacy of treatment against tuberculosis depends on the activity of the antibiotics prescribed on the 3 main bacillar populations found in tuberculous lesions. On the abundant bacillar population which actively grows in the walls of cavities, streptomycin, isoniazid and rifampicin are bactericidal, ethambutol bacteriostatic and pyrazinamide inactive. For the small population which grows at a slow rate in macrophages, pyrazinamide, isoniazid and rifampicin are bactericidal, ethambutol bacteriostatic and streptomycin inactive. For the small bacillar population which intermittently grows inside caseous foci, rifampicin only is bactericidal, the other antibiotics being all inactive. The association of rifampicin and isoniazid, which is bactericidal on all the bacilli in the various types of lesions, is therefore the basis of modern treatment. Because of the present prevalence of primary and acquired resistance however, ethambutol should be added as a third antibiotic in the association.