[The role of simultaneous combination culture with solid and liquid media for diagnosis of pulmonary tuberculosis].

PURPOSE To study the usefulness of simultaneous combination culture with egg-based Ogawa medium (1 slant) and MGIT (Mycobacterium growth indicator tube/Becton-Dickinson) for detection of M. tuberculosis from sputum in sputum-culture proven pulmonary tuberculosis patients. OBJECT AND METHOD Retrospective study of sputum-culture-positive pulmonary tuberculosis cases in our hospital (with tuberculosis ward) from Jan. 2002 to Sept. 2003. RESULT In 1103 sputum culture for the diagnosis of 370 sputum-culture proven pulmonary tuberculosis cases, 86.0% were MGIT positive and 79.5% were Ogawa positive. Among sputa contaminated on MGIT, 56.1% (23/41) were positive on Ogawa. Among sputa culture-negative on MGIT, 2.7% (3/113) were positive on Ogawa. Those 3 sputa were obtained from 3 different patients, and in 2 of them, other sputa were positive on MGIT. Frequency of "M. tuberculosis strain which can be cultured only by Ogawa" was supposed to be at maximum 0.27% (1/370). Of 41 sputa contaminated on MGIT, 15 sputum specimens were re-treated and re-cultured by MGIT. Of these specimens 46.7% (7/15) were positive on Ogawa, and 73.3% (11/15) were positive on re-treated MGIT, and the difference was not statistically different. CONCLUSION From the standpoint of detection of M. tuberculosis from sputum in sputum-culture proven pulmonary tuberculosis patients, simultaneous combination culture of Ogawa medium with MGIT is useful, mainly for risk management of MGIT contamination. But, if re-treated MGIT is done for cases of contaminated on MGIT, simultaneous combination culture of Ogawa medium with MGIT is not necessary.