Shakoor Sadia, Tanveer Mahnaz, Rafiq Yasraba, Hasan Zahra, Javed Arshad, Rizvi Nadeem, Rehman Nadeem, Hasan Rumina
Department of Clinical Microbiology, the Aga Khan University Hospital, Karachi, Pakistan.
Scand J Infect Dis. 2009;41(10):714-9. doi: 10.1080/00365540903147019.
Tuberculosis (TB) control is a major healthcare priority for Pakistan. We have studied Mycobacterium tuberculosis strains from the sputa of 100 treatment-naïve, smear-positive pulmonary TB cases from Karachi, Pakistan, to identify strains most responsible for active transmission in this population. DNA extracted from M. tuberculosis isolates were subjected to spacer oligotyping (spoligotyping). Sixty-six (66%) clinical isolates were grouped into 9 different clusters. The largest cluster comprised the Central Asian Strain (CAS) 1 or ST26 (n=40). The remaining isolates (34%) had unique spoligotypes. We conclude that ST26 being the most prevalent strain in smear-positive cases contributes greatly towards ongoing transmission in Karachi. Our data further suggest that ST26 may have a selection advantage not afforded by other genotypes. This conclusion is further supported by DESTUS analysis (Detecting Emerging Strains of Tuberculosis Using Spoligotypes) identifying ST26 as the only emerging spoligotype. Reasons for the spread of ST26 require further study.
结核病防控是巴基斯坦医疗保健的一项主要优先事项。我们对来自巴基斯坦卡拉奇100例未经治疗的涂片阳性肺结核病例痰液中的结核分枝杆菌菌株进行了研究，以确定该人群中导致活动性传播的主要菌株。从结核分枝杆菌分离株中提取的DNA进行间隔寡核苷酸分型（spoligotyping）。66株（66%）临床分离株被分为9个不同的簇。最大的簇包含中亚菌株（CAS）1或ST26（n = 40）。其余分离株（34%）具有独特的spoligotype。我们得出结论，ST26作为涂片阳性病例中最常见的菌株，对卡拉奇目前的传播有很大影响。我们的数据进一步表明，ST26可能具有其他基因型所没有的选择优势。DESTUS分析（使用spoligotype检测结核病新出现的菌株）将ST26确定为唯一新出现的spoligotype，进一步支持了这一结论。ST26传播的原因需要进一步研究。
