[A case of pulmonary tuberculosis in which diagnosis was delayed because of prior treatment with fluoroquinolone and metronidazole].

We report the case of a patient with pulmonary tuberculosis, whose diagnosis was delayed because of prior treatment with fluoroquinolone and metronidazole. A 35-year-old woman developed productive cough, fever, and back pain, which lasted for 3 weeks before admission to hospital. She had been diagnosed with lower respiratory infection and was treated with garenoxacin mesilate hydrate for 7 days before admission. As her symptoms did not improve, she was referred to our hospital for further evaluation. A chest computed tomography scan revealed confluent consolidation in the right lower lung, predominantly in segment 7, and lung abscess was initially suspected. Since chemotherapy with ceftriaxone and minomycin did not reduce her symptoms, metronidazole was added on day 4. Her symptoms improved dramatically and she was discharged on day 15. Metronidazole was given for a total of 3 weeks, and 2 weeks after discontinuation of metronidazole, she presented with recurrent chest pain and was diagnosed with active pulmonary tuberculosis. In addition to the atypical imaging findings in this patient, the use of chemotherapeutics such as garenoxacin mesilate hydrate and metronidazole, which have anti-tuberculosis effects, meant that the diagnosis of tuberculosis was complicated and hence delayed. We should keep in mind that some general chemotherapy agents, including linezolid, also have anti-tuberculosis effects and may cause similar problems with diagnosis.