ERJ：XDR-TB可显著提高TB的家庭传播

根据报道，多药耐药（MDR）-结核病（TB）和广泛耐药（XDR）-TB已导致家庭传输的增加。来自香港卫生署卫生防护中心胸肺科的Eric Chung Ching Leung等人针对家庭接触中发生MDR-TB暴露的活动性结核病进行了一项回顾性队列研究。结果于2013年4月1日发表在European Respiratory Journal。研究人员发现MDR-TB患者中的XDR-TB感染使得普通TB病例出现的可能性显著增加至4.8，而继发性TB病例的发现风险则增加至4.7。因此其得出结论认为XDR-TB可显著提高TB的家庭传播，并可能存在长期的/更高的传染性。
研究人员在246户的704位联系人中，初步筛选确定了12例（1.7％）TB病例（普通病例）和17例（2.4％）接触后发生活动性TB病例（继发性病例），接触的中位（范围）持续时间为17（5-62.5）个月。
结果发现其中8例流行病例和3例继发病例为MDR-TB。每100000人-年的结核病发病率为254.9，而其中MDR-TB为45.0。MDR-TB患者中的XDR-TB感染使得普通TB病例出现的可能性显著增加至4.8（95％CI为1.02-22.5），而继发性TB病例的发现风险则增加至4.7（95％CI为1.7-13.5）。分子指纹确认了MDR-TB的家庭传播。对来自27例XDR-TB原发病例的20种可恢复分离株进行限制性片段长度多态性分析，其结果显示13例（65％）存在聚集现象，而其中11（55％）例是经由n-1途径近期传播，同时在这11例患者中有3（27.2％）例存在明确的家庭来源。
研究人员由此认为相对于MDR-TB，XDR-TB显著提高了TB的家庭传播，可能表明其存在长期的/更高的传染性，同时显示了长期家庭监测的必要性。XDR-TB可能会在家庭环境以外大量传播。
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Transmission of multidrug-resistant and extensively drug-resistant
Abstract
Multidrug-resistant (MDR)- tuberculosis (TB) and extensively drug resistant (XDR)-TB reportedly lead to increased household transmission. This is a retrospective cohort study of active TB occurring among household contacts exposed to MDR-TB. Of 704 contacts in 246 households, initial screening identified 12 (1.7%) TB cases (prevalent cases) and 17 (2.4%) contacts that subsequently developed active TB (secondary cases) after a median (range) duration of 17 (5-62.5) months. Eight prevalent cases and three secondary cases had MDR-TB. TB incidence rates per 100 000 person-years were 254.9 overall and 45.0 for MDR-TB. XDR-TB in the index MDR-TB patient significantly increased the odds of identifying a prevalent TB case to 4.8 (95% CI 1.02-22.5), and the hazard of finding a secondary TB case to 4.7 (95% CI 1.7-13.5). Molecular fingerprinting confirmed household transmission of MDR-TB. Of 20 retrievable isolates from 27 XDR-TB index cases, restriction fragment length polymorphism analysis showed clustering among 13 (65%), with 11 (55%) due to recent transmission by n-1 method and an identifiable household source in only three (27.2%) of the 11 cases. XDR-TB relative to MDR-TB significantly increases household transmission of TB, probably reflecting prolonged/higher infectivity, and indicating a need for prolonged household surveillance. XDR-TB may largely transmit outside of the household settings.