Recent and Rapid Emergence of W-Beijing Strains of Mycobacterium tuberculosis in Cape Town, South Africa
Recent and Rapid Emergence of W-Beijing Strains of Mycobacterium tuberculosis in Cape Town, South Africa
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DOI：
10.1086/592575
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发表时间：
2008-11-15
影响因子：
11.8
通讯作者：
Nicol, Mark P.
中科院分区：
文献类型：
--
作者：
Cowley, Donna;Govender, Dhirendra;Nicol, Mark P.
背景。越来越多的证据表明，结核分枝杆菌毒力的菌株相关变异可能对某些菌株具有选择性优势。W-Beijing毒株家族分布全球，在动物模型中具有高毒力，与人类免疫缺陷病毒感染和耐药性有关，可能是一个新兴毒株家族。我们的目标是确定W-Beijing菌株是否在世界上结核病发病率最高的南非地区扩张。我们使用spoligotyping和单核苷酸多态性分析对南非开普敦主要儿科转诊医院4年期间的所有儿童结核菌株进行基因分型，并对76年期间352份存档组织学样本中的菌株进行基因分型。2000 ~ 2003年儿童W-Beijing菌株比例由13%上升至33% （P = 0.026）。组织学标本中，1930 ~ 1965年未见W-Beijing菌株，1966 ~ 1995年极少见（2.8%），1996 ~ 2005年呈上升趋势（20%,P = .001）。W-Beijing菌株在结核病背景发病率非常高的地区迅速扩张，表明这些菌株具有显著的选择优势。这种观察的生物学原因尚不清楚，但值得进一步研究。这一毒株谱系的迅速传播可能给结核病控制带来额外的挑战。
Background. There is increasing evidence of a strain-related variation in the virulence in Mycobacterium tuberculosis that may afford a selective advantage to certain strains. The W-Beijing strain family is globally distributed, highly virulent in animal models, associated with human immunodeficiency virus infection and drug resistance, and may be an emerging strain family. Our goal was to determine whether W-Beijing strains are expanding in a region of South Africa where rates of tuberculosis are among the highest in the world.Methods. We used spoligotyping and single nucleotide polymorphism analysis to genotype all strains of tuberculosis from children presenting to the major pediatric referral hospital in Cape Town, South Africa over a period of 4 years and strains present in 352 archived histological samples from over a 76-year period.Results. The proportion of W-Beijing strains from children increased from 13% to 33% from 2000 to 2003 (P = .026). With regard to the histological samples, W-Beijing strains were absent in the samples from the period 1930-1965 and rare in the samples from the period 1966-1995 (2.8% of samples), but they were increasingly common in samples from the period 1996-2005 (20% of samples; P = .001).Conclusions. The rapid expansion of W-Beijing strains in a region with a very high background incidence of tuberculosis suggests that these strains have a significant selective advantage. The biological reasons for this observation remain unclear but warrant further study. The rapid spread of this virulent strain lineage is likely to present additional challenges for tuberculosis control.