Nonculturable acid-fast forms in the sputum of patients with tuberculosis and chronic pulmonary disease.

Abstract

Nonculturable acid-fast forms occurred in the sputum of 24 per cent of patients with active pul­ monary tuberculosis, in 3 per cent of patients with quiescent or inactive disease, and in one per cent of persons with nontuberculous conditions. Eight per cent of sputum specimens from patients with active pulmonary tuberculosis were microscopically positive but culturally negative (MPCN). The incidence in patients with in­ active tuberculosis was one per cent, and in nontuberculous patients it was 0.2 per cent. Thirty-two hospitalized patients and one clinic patient had three or more MPCN specimens. The pattern of MPCN specimens is described with emphasis on the 32 hospital patients with multiple MPCN sputums. Nonculturable acid-fast forms occurring as pulmonary tuberculosis was becoming quiescent or inactive were considered to be excreted tubercle bacilli. Isolated MPCN specimens from patients with nontuberculous pulmonary disease and appearing late in the treat­ ment of pulmonary tuberculosis were more likely to be other bacteria. The fate of 2 of the patients with multiple MPCN specimens lent support to the theory of bac­ terial persistence during long-term chemotherapy. The writers are of the opinion that drug therapy should be altered when multiple MPCN speci­ mens occur as the tuberculosis is becoming quiescent or inactive.