Behr M A, Hopewell P C, Paz E A, Kawamura L M, Schecter G F, Small P M
Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305-5107, USA.
Am J Respir Crit Care Med. 1998 Aug;158(2):465-9. doi: 10.1164/ajrccm.158.2.9801062.
Contact tracing, the evaluation of persons who have been in contact with patients having tuberculosis, is an important component of tuberculosis control. We used DNA fingerprinting to test the assumption that tuberculosis in contacts to active cases represents transmission from that person. Cases of tuberculosis in San Francisco between 1991 and 1996 with positive cultures who had been previously identified as contacts ("contact cases") to active cases ("index cases") were studied. Of 11,211 contacts evaluated, there were 66 pairs of culture-positive index and contact cases. DNA fingerprints were available for both members of these pairs in 54 instances (82%). The index and contact cases were infected with the same strain of Mycobacterium tuberculosis in 38 instances (70%; 95% CI: 56 to 82%); 16 pairs (30%) were infected with unrelated strains. Unrelated infections were more common among foreign-born (risk ratio [RR] = 5.22, p < 0.001), particularly Asian (RR = 3.89, p = 0.002) contacts. Contact investigation is an imperfect method for detecting transmission of M. tuberculosis, particularly in foreign-born persons. However, because such investigations target a group with a high prevalence of tuberculosis and tuberculous infection, these efforts remain an important activity in the control of tuberculosis.
接触者追踪，即对曾与结核病患者有过接触的人员进行评估，是结核病控制的一个重要组成部分。我们采用DNA指纹技术来检验一个假设，即活动性病例的接触者中的结核病是由该患者传播而来的。对1991年至1996年间旧金山那些之前被确定为活动性病例（“索引病例”）的接触者（“接触病例”）且培养结果呈阳性的结核病病例进行了研究。在评估的11211名接触者中，有66对培养结果呈阳性的索引病例和接触病例。在其中54例（82%）中，这两对病例的DNA指纹均可用。索引病例和接触病例在38例（70%；95%置信区间：56%至82%）中感染了同一株结核分枝杆菌；16对（30%）感染的是不相关菌株。不相关感染在外国出生者中更为常见（风险比[RR]=5.22，p<0.001），尤其是亚洲接触者（RR=3.89，p=0.002）。接触者调查是检测结核分枝杆菌传播的一种不完善方法，尤其是在外国出生者中。然而，由于此类调查针对的是结核病和结核感染患病率较高的群体，这些努力仍然是结核病控制中的一项重要活动。
