Ultrashort-course chemotherapy for culture-negative pulmonary tuberculosis--a qualified success.

A group of 250 patients with new or enlarging apical lung lesions which were thought to be tuberculous, and who had positive tuberculin tests but negative sputum smears and cultures for Mycobacterium tuberculosis, were treated with an ultrashort (3-month), 4-drug (rifampicin, isoniazid, pyrazinamide and ethambutol) regimen. One patient developed bacteriologically positive pulmonary tuberculosis (PTB) during the treatment period and 35 others (14%) developed bacteriologically positive PTB after completing the drug regimen.