Thompson Corinne N, Duy Pham Thanh, Baker Stephen
The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom; The London School of Hygiene and Tropical Medicine, London, United Kingdom.
The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.
PLoS Negl Trop Dis. 2015 Jun 11;9(6):e0003708. doi: 10.1371/journal.pntd.0003708. eCollection 2015.
Shigellosis is the major global cause of dysentery. Shigella sonnei, which has historically been more commonly isolated in developed countries, is undergoing an unprecedented expansion across industrializing regions in Asia, Latin America, and the Middle East. The precise reasons underpinning the epidemiological distribution of the various Shigella species and this global surge in S. sonnei are unclear but may be due to three major environmental pressures. First, natural passive immunization with the bacterium Plesiomonas shigelloides is hypothesized to protect populations with poor water supplies against S. sonnei. Improving the quality of drinking water supplies would, therefore, result in a reduction in P. shigelloides exposure and a subsequent reduction in environmental immunization against S. sonnei. Secondly, the ubiquitous amoeba species Acanthamoeba castellanii has been shown to phagocytize S. sonnei efficiently and symbiotically, thus allowing the bacteria access to a protected niche in which to withstand chlorination and other harsh environmental conditions in temperate countries. Finally, S. sonnei has emerged from Europe and begun to spread globally only relatively recently. A strong selective pressure from localized antimicrobial use additionally appears to have had a dramatic impact on the evolution of the S. sonnei population. We hypothesize that S. sonnei, which exhibits an exceptional ability to acquire antimicrobial resistance genes from commensal and pathogenic bacteria, has a competitive advantage over S. flexneri, particularly in areas with poorly regulated antimicrobial use. Continuing improvement in the quality of global drinking water supplies alongside the rapid development of antimicrobial resistance predicts the burden and international distribution of S. sonnei will only continue to grow. An effective vaccine against S. sonnei is overdue and may become one of our only weapons against this increasingly dominant and problematic gastrointestinal pathogen.
志贺氏菌病是全球痢疾的主要病因。宋内志贺氏菌在历史上更常见于发达国家分离得到，目前正在亚洲、拉丁美洲和中东的工业化地区经历前所未有的扩张。各种志贺氏菌物种的流行病学分布以及宋内志贺氏菌在全球范围内激增的确切原因尚不清楚，但可能是由于三种主要环境压力。首先，据推测，用类志贺邻单胞菌进行自然被动免疫可保护供水条件差的人群免受宋内志贺氏菌感染。因此，改善饮用水供应质量将导致类志贺邻单胞菌暴露减少，进而减少对宋内志贺氏菌的环境免疫。其次，无处不在的棘阿米巴属物种卡氏棘阿米巴已被证明能有效且共生地吞噬宋内志贺氏菌，从而使该细菌能够进入一个受保护的生态位，在温带国家抵御氯化和其他恶劣环境条件。最后，宋内志贺氏菌仅在相对较近的时间从欧洲出现并开始在全球传播。局部抗菌药物使用产生的强大选择压力似乎也对宋内志贺氏菌种群进化产生了巨大影响。我们假设，宋内志贺氏菌具有从共生菌和病原菌获取抗菌耐药基因的特殊能力，与福氏志贺氏菌相比具有竞争优势，尤其是在抗菌药物使用监管不力的地区。全球饮用水供应质量的持续改善以及抗菌药物耐药性的快速发展预示着宋内志贺氏菌的负担和国际分布只会继续增加。一种有效的抗宋内志贺氏菌疫苗早就该出现了，它可能会成为我们对抗这种日益占主导地位且成问题的胃肠道病原体的唯一武器之一。
