原发性耐药是耐药结核病产生的重要原因

目的 研究原发性耐药在产生耐药结核病中的作用。方法对上海市疾病预防控制中心收集保存的1996年至2004年结核分枝杆菌临床菌株进行分析统计，计算原发性耐药和获得性耐药的比例；并对16例复发耐药患者前后发病菌株进行结核分枝杆菌散在分布重复单位（mycobacterial interspersed repetitive units，MIRU）基因型比较分析。结果在保存的初治患者的8120株结核分枝杆菌中，耐药菌株707株，耐药率为8．7％；复治患者的菌株610株，耐药菌株150株，耐药率为24．6％。初治和复治患者中耐药率均有上升趋势。以初治患者耐药代表原发性耐药，复治患者耐药代表获得性耐药，其原发性耐药占总耐药菌株的82．5％。在16例复发耐药患者中，13例患者在两次发病时分离的菌株基因型不一致，可能是由于重新感染了耐药菌株所致，属于原发性耐药。结论原发性耐药是目前耐药结核病产生的重要原因，该结果提示有效控制结核病的传染源是减少耐药结核病产生的关键。

Primary drug-resistance is the main cause of drug-resistant tuberculosis

Objective To investigate the main cause of drug-resistant tuberculosis. Methods Clinic isolates of Mycobacterium tuberculosis from 1996 to 2004 in Shanghai were analyzed and the proportion of isolates from new cases (the proxy of primary drug-resistance) and retreatment cases (the proxy of acquired drug-resistance) were calculated. Mycobacterial interspersed repetitive units(MIRU)genotyping was performed and analyzed on pairs of isolates of Mycobacterium tuberculosis from 16 recurrent patients with drug-resistant tuberculosis. Results Of all 8 120 isolates of Mycobacterium tuberculosis from new cases, 707 isolates (8.7%) were drug resistant. Of all 610 isolates from retreatment cases, 150 isolates (24.6%) were drug resistant. Primary drug resistance accounted for 82.5% (707/857) of all drug resistant isolates. Based on the MIRU genotypes, 13 of all 16 recurrent drug-resistant patients were reinfected with new drug-resistant strain of Mycobacterium tuberculosis. Conclusion Primary drug-resistance is the main cause of drug-resistant tuberculosis.