[How to recover live mycobacteria from smear-positive and culture-negative specimens of mycobacteriosis patients].
There are two kinds of smear-positive and culture-negative (SPCN) cases. One takes place temporarily when patients are under healing process and another takes place fro a long period of time. In the latter situation, probability of detecting live mycobacteria in the SPCN specimens seems to be high. To detect live mycobacteria, we examined 27 specimens which had been designated as SPCN previously, and could recover colonies from 14 specimens. Ten strains of M. tuberculosis and 4 strains of M. chelonae were identified. We analyzed factors of false results of SPCN specimens in routine examination. Nine out of 10 strains of M. tuberculosis were multi-drug resistant, and most of these strains were inhibited their growth on the media by added glycerol. Therefore we concluded that glycerol affected the proliferation of M. tuberculosis in SPCN specimens. Moreover, treatment of specimens by NaOH also affected the growth of mycobacteria. The number of colony which we recovered, decreased dramatically after the treatment by 4% NaOH (M. tuberculosis) and by 1% NaOH (M> chelonae).