PURPOSE: The usefulness of bronchial washing for early and differential diagnoses of pulmonary mycobacteriosis was investigated.
METHODS: Pulmonary mycobacteriosis was suspected by chest X-ray radiography, but sputum sampling was difficult or sputum smear was negative for acid-fast bacteria, and, thus, bronchial washing was performed and pulmonary mycobacteriosis was identified by culture in 54 patients over the last 5 years (January 2006-December 2010). These 54 cases were retrospectively investigated.
RESULTS: Acid-fast bacteria were identified in bronchial washing fluid by culture in 54 patients (tuberculosis: 29, nontuberculous mycobacteriosis: 25). Sputum could be collected, but smears were negative for acid-fast bacteria in 34 cases, and 17 of these were negative on sputum MGIT culture. Only 2 of these 17 cases were positive on PCR, and, thus, bronchial washing was necessary to make a diagnosis in 15 (44.1%). Sputum could be subjected to PCR of acid-fast bacteria in 31 cases, and 9 of these were positive, showing that the sputum-based early diagnosis rate was only 29.0%. Bronchial washing fluid was positive for acid-fast bacteria on PCR in 24 of 34 cases (TB-PCR-positive: 17), and the early diagnosis rate was high (70.6%). Sputum sampling was difficult in 20 cases, and bronchial washing fluid was positive for acid-fast bacteria on PCR in 15 (TB-PCR-positive: 5).
CONCLUSIONS: Combining cases with difficulty in sputum sampling and cases negative for acid-fast bacteria in sputum smears as well as on PCR and culture, a final diagnosis could be made only in 36 cases (65.5%) even though the sputum test was performed, showing the importance of bronchial washing. Bronchial washing may also be useful for making an early diagnosis (positive PCR rate) compared to that in sputum-sampled cases.
CLINICAL IMPLICATIONS: Bronchial washing is useful for early and differential diagnoses of tuberculosis and nontuberculous mycobacteriosis.
DISCLOSURE: The following authors have nothing to disclose: Tadashi Takao, Yu Enomoto, Hiroshi Igei
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