[A case of multidrug-resistant tuberculosis who acquired additional resistance to ethambutol before the result of the initial drug sensitivity test was reported].

On December 6, 2008, a 52-year-old man presented to a clinic with chronic cough, sputum, and chest discomfort, which had lasted since mid-November. Since the chest radiograph showed a small cavity with small nodules and granular shadows, he was referred to another hospital. On TB-PCR, the gastric juice was positive. Therefore, on December 16, 2008, treatment for pulmonary tuberculosis was initiated with isoniazid, rifampicin, ethambutol, and pyrazinamide. However, on February 4, 2009, a drug susceptibility test revealed that the bacilli were resistant to isoniazid and rifampicin. Therefore, he was referred to our hospital. At that time, he had no symptoms and his sputum smear was negative. We performed a right upper lobectomy. The smear result of the surgical specimen was heavily positive (equivalent to Gaffky 6), and the drug susceptibility test showed resistance to ethambutol in addition to isoniazid and rifampicin. After surgery, we treated him with pyrazinamide, streptomycin, para-aminosalicylate, ethionamide, and levofloxacin. We report this case of multidrug-resistant tuberculosis without past treatment who acquired additional resistance to ethambutol during the first 2 months of chemotherapy. When treating multidrug-resistant tuberculosis, very careful consideration of susceptibility to other drugs is warranted.