Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
PLoS One. 2013;8(2):e55598. doi: 10.1371/journal.pone.0055598. Epub 2013 Feb 1.
The phylogeographical structure of Mycobacterium tuberculosis is generally bimodal in low tuberculosis (TB) incidence countries, where genetic lineages of the isolates generally differ with little strain clustering between autochthonous and foreign-born TB patients. However, less is known on this structure in Saudi Arabia-the most important hub of human migration as it hosts a total population of expatriates and pilgrims from all over the world which is equal to that of its citizens.
We explored the mycobacterial phylogenetic structure and strain molecular clustering in Saudi Arabia by genotyping 322 drug-resistant clinical isolates collected over a 12-month period in a national drug surveillance survey, using 24 locus-based MIRU-VNTR typing and spoligotyping.
In contrast to the cosmopolitan population of the country, almost all the known phylogeographic lineages of M. tuberculosis complex (with noticeable exception of Mycobacterium africanum/West-African 1 and 2) were detected, with Delhi/CAS (21.1%), EAI (11.2%), Beijing (11.2%) and main branches of the Euro-American super-lineage such as Ghana (14.9%), Haarlem (10.6%) and Cameroon (7.8%) being represented. Statistically significant associations of strain lineages were observed with poly-drug resistance and multi drug resistance especially among previously treated cases (p value of < = 0.001 for both types of resistance), with relative over-representation of Beijing strains in the latter category. However, there was no significant difference among Saudi and non-Saudi TB patients regarding distribution of phylogenetic lineages (p = 0.311). Moreover, 59.5% (22/37) of the strain molecular clusters were shared between the Saudi born and immigrant TB patients.
Specific distribution of M. tuberculosis phylogeographic lineages is not observed between the autochthonous and foreign-born populations. These observations might reflect both socially favored ongoing TB transmission between the two population groups, and historically deep-rooted, prolonged contacts and trade relations of the peninsula with other world regions. More vigorous surveillance and strict adherence to tuberculosis control policies are urgently needed in the country.
在结核病（TB）发病率较低的国家，结核分枝杆菌的系统地理结构通常呈双峰模式，即分离株的遗传谱系通常存在差异，且本地和外国出生的 TB 患者之间的菌株聚类现象很少。然而，关于沙特阿拉伯的这种结构的了解较少，因为它是人类迁移的最重要枢纽，其总人口中包括来自世界各地的侨民和朝圣者，与本国公民人数相当。
我们通过对全国药物监测调查中收集的 12 个月内的 322 例耐药临床分离株进行 24 位基因 MIRU-VNTR 分型和 spoligotyping，探讨了沙特阿拉伯的分枝杆菌系统地理结构和菌株分子聚类。
与该国的世界性人口不同，几乎检测到了结核分枝杆菌复合群的所有已知系统地理谱系（有一个明显的例外是非洲分枝杆菌/西非 1 型和 2 型），其中德里/卡斯（21.1%）、EAI（11.2%）、北京（11.2%）和欧洲-美洲超级谱系的主要分支，如加纳（14.9%）、哈雷姆（10.6%）和喀麦隆（7.8%）。在多药耐药和耐多药患者中观察到菌株谱系与多药耐药之间存在统计学显著关联，尤其是在先前治疗的病例中（p 值均为<0.001），在后一类患者中，北京菌株的相对过度表达更为明显。然而，在沙特和非沙特 TB 患者之间，关于系统地理谱系的分布没有显著差异（p=0.311）。此外，37 例中的 59.5%（22/37）的菌株分子聚类在沙特出生和移民的 TB 患者之间共享。
在本地和外国出生的人群之间，没有观察到结核分枝杆菌系统地理谱系的特定分布。这些观察结果可能反映了两组人群之间社会上有利于持续传播的结核病，以及半岛与世界其他地区之间长期的、根深蒂固的联系和贸易关系。该国迫切需要更有力的监测和严格遵守结核病控制政策。
