[THE GENETIC EXAMINATION OF BRONCHIAL LAVAGE ENABLES THE PROMPT DIAGNOSIS OF PULMONARY MYCOBACTERIUM KANSASII--A CASE REPORT].

A 59-year-old man with chronic obstructive pulmonary disease and bronchial asthma presented at our hospital with an abnormal shadow on the chest radiograph, which was obtained as part of a routine medical examination. Computed tomography of the chest revealed two nodules in the right upper lung with the longest diameter measuring 29 mm and 10 mm, respectively. A granulomatous disease was strongly suspected based on the histological features of the transbronchial lung biopsy specimen. Results of smear examination for mycobacteria and genetic examination of the bronchial lavage aspirate by the transcription reverse transcription concerted (TRC) reaction method for Mycobacterium tuberculosis and M. avium complex (MAC), were both negative. However, three days after the bronchoscopic examination, an additional genetic examination by the TRC method confirmed the diagnosis of M. kansasii infection. About two weeks later, the culture results were positive and M. kansasii infection was re-confirmed with the DNA probe method. The patient responded well to treatment with a combination of isoniazid, rifampicin, and ethambutol. In Japan, among the nontuberculous mycobacterial infections, the prevalence of pulmonary M.kansasii disease is second only to infection with MAC. However, it is often difficult to distinguish this disease from pulmonary tuberculosis. In this patient, a genetic examination with the TRC method enabled a prompt diagnosis of M. kansasii infection. The TRC method appears to be a useful tool for diagnosing nontubercular mycobacterial infections.