Mycobacterium kansasii infection

　　Mycobacterium kansasii is a slow-growing, photopigmenting mycobacterium. The optimal growth temperature is 37°C, and colonies can form in about 1-3 weeks. It cannot grow at 45°C, and can form S-shaped colonies on egg solid media, occasionally R-shaped, and is easy to emulsify. It does not produce pigments in the dark, but can produce red crystalline-like carotene-like pigments after light exposure, which is a characteristic of this bacterium. Acid-fast staining of smears shows cross-staff-shaped coccobacilli, often containing one to several acid-fast granules. Nitrate reduction test and hydrolysis test are positive, while niacin test, catalase, and neutral red test are all negative. Mouse inoculation is sensitizing, and intraperitoneal inoculation can cause self-limiting granulomas in the liver, spleen, and lymph nodes.

　　The main complications of Mycobacterium kansasii infection are invasion of the lungs, occasionally affecting the skin and causing skin lesions. Lesions are prone to occur in areas easily injured, such as the limbs and face. They present as irregular nodules with warty protuberances, some resembling sporotrichosis, starting on the back of the hand and then spreading to the extensor side of the forearm. Facial lesions may present as hyperpigmented crusts, revealing shallow ulcers upon removal of the crust. Lower limb lesions can gradually expand into large疣状 granulomatous plaques over several years, with mild edema in the lower limbs. Local lymph nodes are not enlarged, and there are no systemic symptoms.

　　Mycobacterium kansasii infection mainly invades the lungs, occasionally affecting the skin and causing skin lesions. Lesions are prone to occur in areas easily injured, such as the limbs and face, presenting as irregular nodules with warty protuberances. Some may resemble sporotrichosis, starting on the back of the hand and then spreading to the extensor side of the forearm. Facial lesions may present as hyperpigmented crusts, revealing shallow ulcers upon removal of the crust. Lower limb lesions can gradually expand into large疣状 granulomatous plaques over several years, with mild edema in the lower limbs. Local lymph nodes are not enlarged, and there are no systemic symptoms.

　　Standardize the use of medical water, sterile liquids, and liquid chemical disinfectants. When liquid chemical disinfectants are needed, ensure that their use methods, concentrations, and disinfection times meet relevant regulations. At the same time, strengthen the concentration monitoring of liquid chemical disinfectants in use.

　　Medical institutions should follow sterile technique operation procedures, standardize the use of medical water, sterile liquids, and liquid chemical disinfectants, etc., to prevent secondary contamination. Various infused drugs or solvents should be marked with time after opening, standardized use, and avoid patient sharing. It is not allowed to use sterile liquids opened for more than 24 hours.

　　Antacid bacilli can be found in abscesses and necrotic tissues in Mycobacterium kansasii infection.

　　The epidermis thickens, keratin hyperplasia with incomplete keratinization, chronic granulomatous inflammation in the dermis, with mononuclear or multinuclear giant cells, which may be accompanied by small abscesses or necrosis. Acid-fast staining of smears shows Corynebacterium cross, often containing one to several metachromatic granules, nitrate reduction test and thermolysis test are positive, niacin test, peroxidase and neutral red test are negative, mouse inoculation has sensitization, intraperitoneal inoculation can cause liver, spleen, and lymph node self-limitingGranuloma..

　　Mycobacterium kansasii infection should have a light and nutritious diet, pay attention to dietary balance. Avoid spicy and刺激性 food. In order to avoid the recurrence of the disease, for example: seafood, chicken, dog meat, etc. At the same time, do not eat stimulating foods. Eat more fresh vegetables and fruits. Eat more immune-enhancing foods: patients with postoperative body weakness and low immunity should eat more immune-enhancing foods, such as mushrooms, kiwi, figs, apples, milk, pork liver, etc., to enhance the body's resistance to diseases.

　　Clinical drugs that are more sensitive include minocycline (minocycline), pyrazinamide, crotamiton, and ethionamide, etc. It is advisable to use long-term combined medication for Mycobacterium kansasii infection, and there are also reports that freeze-dried BCG vaccine and this strain vaccine are effective, and transfer factor can also be tried.