Overview of Mycobacterium churkinensis
Mycobacterium churgae is a human pathogen confirmed by Marks in 1972, and is a dark color-producing mycobacterium. it is light gas-producing when cultured at 25°C, dark color-producing when cultured at 37°C, and does not grow at 42°C. It is a slow-growing colony with an orange color. The colonies are orange in color and grow slowly. The pathogenesis is not well understood. Clinical manifestations are diverse. Skin damage is disseminated painless inflammatory nodules. Skin lesions are diagnosed by positive culture of Mycobacterium avium. A combination of three drugs, ethionamide, isoniazid and rifampicin, is effective.
Etiology
Mycobacterium churkinensis has been proved to be human pathogenic bacteria, which is a dark color-producing mycobacterium. 25℃ culture is light gas production, 37℃ culture is dark color-producing, and 42℃ does not grow. The colonies are orange in color and grow slowly. The pathogenesis is not well understood.
Symptoms
Clinical manifestations are diverse. Common symptoms are skin atrophy and hyperpigmentation, lung infection, and nodules. Most often seen in middle-aged men. Lung infection resembles tuberculosis or interstitial pneumonia, and the skin damage is disseminated painless inflammatory nodules, 2 to 4 cm in size, hard, occasionally ulcerated, scattered distribution on the trunk and limbs, with hyperpigmentation after healing, and seldom forming a scar.
Examination
1. Positive culture of Mycobacterium avium in skin lesions.
2. Histopathology: biopsy of ulcerated nodules showed ulceration and granulation tissue in the dermis, with lymphocyte, plasma cell and histiocyte infiltration around blood vessels. There are granulomas at the junction of dermis and subcutaneous tissue, consisting of histiocytes and multinucleated giant cells surrounded by lymphocytes and plasma cells.
Diagnosis
Diagnosis is made on the basis of clinical manifestations and characteristics of skin damage, histopathologic examination; positive culture of mycobacteria in the skin lesion tissue.
Treatment
Combined treatment with three drugs, ethionamide, isoniazid and rifampicin, is effective and reduces the recurrence rate.
Prognosis
The prognosis is to leave pigmentation and rarely form scar.