Mycobacterium ulcerans infection
Introduction
Introduction to Mycobacterium tuberculosis infection Mycobacterium ulcerans infection (mycobacteriumulceransinfection) is found all over the world, mainly in tropical rain forests. The natural host and human transmission pathways of this bacterium are still unclear, and insects may be the vector of transmission. Skin lesions occur in the forearms and calves. At first, it is a solid and painless subcutaneous nodule. After rupture, it forms a necrotizing ulcer. The edge is slowly and chiseled. The surrounding skin is bulged, with infiltration and pigmentation. The surface is dry. The bottom of the ulcer is an adhesive gray pseudomembrane. Superficial, individual can be deep and periosteum. Can be divided into pre-ulcer (early), ulcer, and late ulcers. Histopathology is different. The diagnosis requires culture and animal vaccination, and systemic treatment of clofazimine is effective. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of transmission: insect vector transmission Complications: sarcoidosis
Cause
Causes of Mycobacterium ulcerative infection
Causes:
The pathogen of the disease is saprophytic parasitic bacteria, which grow slowly, and is a non-chromophoric bacterium, and the growth temperature after cultivation is 24 to 31 ° C, and colonies are formed at 3 to 5 weeks. The natural host and human transmission pathway of this bacterium is still unclear. It may be infected by damaged skin by contact with contaminated water, soil or plants. Insects in the water can also be infected after biting. The droplet spread between humans has not been confirmed. Mycobacterium ulcerans produce a soluble polypeptide toxin that destroys tissues and inhibits monocyte and T cell responses.
Pathogenesis:
The pathogenesis is still inaccurate and there are no other relevant descriptions at present.
Prevention
Mycobacterium tuberculosis infection prevention
Medical institutions should attach great importance to the prevention and control of mycobacterial nosocomial infections, strengthen organizational leadership, strengthen safety awareness, strictly implement the "Hospital Infection Management Measures" and relevant hospital infection control technologies and standards, and clarify and implement prevention and control of various departments. The responsibility of hospital infection, establish a hospital infection management responsibility system. In accordance with the epidemiological characteristics of non-tuberculous mycobacteria and the prevention and control of hospital infections, the corresponding rules and regulations and work norms are formulated and improved, and effective measures are taken from management and technology to strengthen management.
Complication
Mycobacterium tuberculosis infection complications Complications
After entering the human body from damaged skin and mucous membranes or digestive tract and respiratory tract, the bacterium is first swallowed by phagocytic cells and enters lymph nodes. Sometimes it can survive and grow and form infections. It can enter the blood circulation bacteria after about 2 to 3 weeks. Blood.
Symptom
Mycobacterium ulcerative symptoms common symptoms nodular subcutaneous nodules
Skin lesions occur in the forearms and calves. They are solid and painless subcutaneous nodules at first. After rupture, they form necrotizing ulcers. The edges are slowly and chiseled. The surrounding skin is bulged, with infiltration and pigmentation. The surface is dry and the bottom of the ulcer is Adhesive gray pseudomembrane, general ulcer is superficial, individual can be deep and periosteum, patients have no systemic symptoms, local lymph nodes are not swollen, no fever, general lesions are single, but can also see satellite lesions around, a few After a month, it can heal itself. It can last for several years. The longer the course of the disease, the larger the skin lesions and the severe deformity caused by scar contracture.
Lesions are single nodules or ulcers, local lymph nodes are not swollen, no systemic symptoms, a large number of acid-fast bacilli can be seen in the ulcer smear or tissue section, and the diagnosis requires culture and animal inoculation.
Examine
Examination of mycobacterial ulcer infection
Histopathology:
1. Early ulceration (early stage): subcutaneous adipose tissue necrosis, nuclear nucleus disappears, fibrin deposition, fine calcium deposits can be seen in the necrotic site, reticular fibers increase, the center of the lesion has bacillus colonies, and large colonies are visible by acid-fast staining. , leaving the necrotic site of the bacillus to reduce, no significant inflammatory reaction, no congestion and cell infiltration at and around the necrosis site.
2. Ulcer period: dermis collagen fibrosis, edema around the sweat glands, inflammatory cell infiltration around small blood vessels; epidermal degeneration to form ulcers.
3. Late ulceration: After about 3 weeks of ulcer formation, giant cells and foam cells were observed in some lesions, and lymphocytes infiltrated under the epidermis. Tuberculous nodular granulation tissue appeared above the necrotic tissue.
Diagnosis
Diagnosis and identification of Mycobacterium tuberculosis infection
Attention to identification: With Brucella first infected with livestock, the clinical performance of livestock is not obvious, but the pregnant female animal is very likely to cause miscarriage or stillbirth. The discharged amniotic fluid, placenta and secretion contain a large amount of Brucella, especially infectious. The bacteria are found in fur, urine, and milk. The bacteria can be used for more than 3 months. People who use contaminated milk and meat through contact with livestock, inhaled bacteria-containing dust or bacteria into the conjunctiva, can cause infection. The age of onset is mostly over 30 years old.
