结核病实验室诊断技术及其进展 - 结核病防治网.ppt

积极治疗传染源可以减少结核病的传播 涂阳病人的传染性是涂阴病人的 4-20 倍 如果不给予治疗一个涂阳病人可以传染10-15人/年 如果不给予治疗涂阳病人更容易死亡 传染途径 结核病的传染系由细小飞沫而发生 饮用来自病牛的牛奶而罹患肠结核 传统的结核病实验室检查方法 # Capacity to detect when ≥10,000 bacilli per ml sputum * Capacity to detect when ≥ 102-3 CFU per ml sputum 痰涂片显微镜检查 Z-N 萋尼二氏染色, 需要 5,000-10,000 个CFU/毫升 100x 油镜看完300个视野大概需要15分钟 40-70% 灵敏度, 90%特异性 FM 荧光染色 灵敏度较ZN染色高10% Culture of the organisms Liquefaction, decontamination, concentration Soild media- Egg-based (Lowenstein-Jensen), agar-based (Middlebrook 7H10 and 7H11), biphasic media Liquid media- Middlebrook 7H9, 7H12 Identification by biochemical tests The entire process: 4 to 6 weeks Drug susceptibility test: add 3 to 6 weeks BACTEC TB system Tubes with a fluorescent compound in silicone bottom, which is sensitive to oxygen presence Comparison of the BACTEC MGIT 960 with Lowenstein-Jensen medium (1-2w vs 6-8w) The recovery rates- 94% (117/124) vs 75.8% (94/124); TTDs (time to detection) - 10.7 vs 30.6 d Disadvantage- inability to observe colonial morpgology, mixture culture, high cost Serodiagnosis of Tuberculosis Factors Contributing to the Increase in TB Cases HIV epidemic Increased immigration from high-prevalence countries Transmission of TB in congregate settings (e.g., correctional facilities, long-term care) Deterioration of the public health care infrastructure Transmission and Pathogenesis of TB Caused by Mycobacterium tuberculosis (M. tuberculosis) Spread person to person through airborne particles that contain M. tuberculosis, called droplet nuclei Transmission occurs when an infectious person coughs, sneezes, laughs, or sings Prolonged contact needed for transmission 10% of infected persons will develop TB disease at some point in their lives Sites of TB Disease Pulmonary TB occurs in the lungs 85% of all TB cases are pulmonary Extrapulmonary TB occurs in places other than the lungs, including the: Larynx Lymph nodes Pleura (membrane surrounding each lung) Brain and sp