Objective To measure the association between phenotypic drug resistance and the risk of tuberculosis infection and disease among household contacts of patients with pulmonary tuberculosis.
Setting 106 district health centers in Lima, Peru between September 2009 and September 2012.
Design Prospective cohort study.
Participants 10 160 household contacts of 3339 index patients with tuberculosis were classified on the basis of the drug resistance profile of the patient: 6189 were exposed to drug susceptible strains of Mycobacterium tuberculosis, 1659 to strains resistant to isoniazid or rifampicin, and 1541 to strains that were multidrug resistant (resistant to isoniazid and rifampicin).
Main outcome measures Tuberculosis infection (positive tuberculin skin test) and the incidence of active disease (diagnosed by positive sputum smear or chest radiograph) after 12 months of follow-up.
Results Household contacts exposed to patients with multidrug resistant tuberculosis had an 8% (95% confidence interval 4% to 13%) higher risk of infection by the end of follow-up compared with household contacts of patients with drug sensitive tuberculosis. The relative hazard of incident tuberculosis disease did not differ among household contacts exposed to multidrug resistant tuberculosis and those exposed to drug sensitive tuberculosis (adjusted hazard ratio 1.28, 95% confidence interval 0.9 to 1.83).
Conclusion Household contacts of patients with multidrug resistant tuberculosis were at higher risk of tuberculosis infection than contacts exposed to drug sensitive tuberculosis. The risk of developing tuberculosis disease did not differ among contacts in both groups. The evidence invites guideline producers to take action by targeting drug resistant and drug sensitive tuberculosis, such as early detection and effective treatment of infection and disease.
Trial registration ClinicalTrials.gov NCT00676754.

目的探讨表型耐药与肺结核患者家庭接触者的结核感染和疾病风险之间的关系。
设置在秘鲁首都利马106个区卫生服务中心2009年9月和2012年9月间
设计前瞻性队列研究。
参与者10 160户3339名索引结核病患者接触者分类的患者的耐药性简档的基础上：6189暴露于的药物敏感菌株结核分枝杆菌，1659至菌株耐异烟肼或利福平，和1541到菌株具有多药耐药性（对异烟肼和利福平有耐药性）。
主要观察指标随访12个月后，结核感染（阳性结核菌素皮肤试验）和活动性疾病的发生率（通过阳性痰涂片或胸部X线片诊断）。
结果：与药物敏感性结核患者的家庭接触相比，在随访结束时与多药耐药性结核患者接触的家庭接触的感染风险增加了8％（95％置信区间为4％至13％）。接触耐多药结核病的家庭接触者和接触药物敏感性结核病的家庭接触者之间发生结核病的相对危险性没有差异（调整后的危险比1.28，95％置信区间为0.9至1.83）。
结论与暴露于药物敏感性结核病的接触者相比，耐多药结核病患者的家庭接触者患结核病的风险更高。两组接触者之间发生结核病的风险没有差异。证据邀请指南制定者针对耐药性和药物敏感性结核病采取行动，例如及早发现和有效治疗感染和疾病。
试用注册ClinicalTrials.gov NCT00676754。