Division of Tuberculosis Control, British Columbia Centre for Disease Control, Vancouver, BC, Canada.
BMC Infect Dis. 2012 Oct 22;12:266. doi: 10.1186/1471-2334-12-266.
Studies examining the transmission of multidrug-resistant tuberculosis (MDR-TB) strains have yielded conflicting results.
We examined transmission of MDR-TB strains using contact tracing data from a low incidence setting. Contacts of MDR-TB cases diagnosed in British Columbia, Canada, from 1990-2008 were identified through a provincial tuberculosis (TB) registry. Tuberculin skin test (TST) results and TB disease incident rates were determined for contacts. For comparison, TB disease incident rates and TST results were measured in close contacts of isoniazid mono-resistant (HMR-TB) and drug susceptible TB (DS-TB) cases.
Of 89 identified close contacts of MDR-TB patients, 5 patients (6%) developed TB disease and 42 (47%) were TST positive. The incidence rate of TB disease (3%, p = 0.31) and TST positivity (49%, p = 0.82) were similar in contacts of HMR-TB cases. Compared with MDR-TB contacts, DS-TB contacts had lower incidence rate of TB disease (2%, p = 0.04) and TST positivity (32%, p < 0.01). All MDR-TB contacts with culture positive TB diagnosed in follow-up were drug-susceptible; three of six HMR-TB contacts with culture positive TB were HMR-TB. Multivariate analysis demonstrated that contact with MDR-TB (adjusted OR 1.72; 95%CI 1.05-2.81) and HMR-TB (adjusted OR 1.99; 95%CI 1.48-2.67) was associated with TST positivity. In addition, adult age, male gender, BCG positivity, source case sputum smear positivity, foreign birth and fewer contacts per source case were significantly associated with TST positivity in the multivariate model.
Contacts of MDR-TB and HMR-TB patients in a low incidence setting show high rates of TST positivity and TB disease but low rates of drug resistance.
研究多药耐药结核病（MDR-TB）菌株的传播得出了相互矛盾的结果。
我们使用来自低发病率环境的接触者追踪数据来检查 MDR-TB 菌株的传播。通过不列颠哥伦比亚省结核病（TB）登记处确定了加拿大不列颠哥伦比亚省 1990-2008 年诊断为 MDR-TB 病例的接触者。为接触者确定结核菌素皮肤试验（TST）结果和结核病发病率。为了比较，还测量了异烟肼单耐药（HMR-TB）和药物敏感结核病（DS-TB）病例的密切接触者的结核病发病率和 TST 结果。
在 89 名确定的 MDR-TB 患者的密切接触者中，有 5 名（6％）发生结核病，42 名（47％）TST 阳性。HMR-TB 病例接触者的结核病发病率（3％，p=0.31）和 TST 阳性率（49％，p=0.82）相似。与 MDR-TB 接触者相比，DS-TB 接触者的结核病发病率（2％，p=0.04）和 TST 阳性率（32％，p<0.01）较低。所有在随访中诊断为培养阳性结核病的 MDR-TB 接触者均对药物敏感；六名培养阳性结核病的 HMR-TB 接触者中有三名是 HMR-TB。多变量分析表明，接触 MDR-TB（调整后的 OR 1.72；95％CI 1.05-2.81）和 HMR-TB（调整后的 OR 1.99；95％CI 1.48-2.67）与 TST 阳性相关。此外，成人年龄、男性、BCG 阳性、来源病例痰涂片阳性、外国出生和每个来源病例的接触者较少在多变量模型中与 TST 阳性显著相关。
在低发病率环境中，MDR-TB 和 HMR-TB 患者的接触者 TST 阳性和结核病发病率较高，但耐药率较低。
