BACKGROUND The epidemiology of invasive meningococcal disease (IMD) is continuously changing in incidence, age distribution and/or the expansion of new strains of Neisseria meningitidis. The epidemiology of IMD due to group W (IMDW) has changed recently at a global level with the emergence of isolates belonging to the clonal complex ST-11 (CC11) derived from the South America-UK strain. A more recent change has been detected in France with the emergence of a new genotype distinct from CC11 that we aimed to analyse. METHODS Epidemiological and microbiological surveillance data in France were used in combination with whole genome sequencing (WGS) to detect emerging phenotypes and genotypes of IMD causing strains, and their susceptibility to immunity induced by the 4CMenB vaccine. Transgenic mice expressing the human transferrin were used to analyse the virulence of emerging strain isolates by direct comparison with CC11 isolates. FINDINGS Our data showed a local increase of IMDW isolates in north France since 2013. The isolates belonged to ST-9316 and few were ST-11 isolates. WGS clustered ST-9316 isolates together and were distantly separated from the isolates of the clonal complex ST-11 (CC11). Unlike cases due to W/CC11 isolates, cases due to W/ST-9316 isolates were mostly observed amongst infants under the age of 1 year but with lower mortality compared to W/CC11 cases. Genomic comparison showed that the W/ST-9316, unlike W/CC11 isolates, lacked the hmbR gene encoding the haemoglobin receptor that is a virulence factor involved in the acquisition of iron from haemoglobin. W/ST-9316 further showed lower virulence in mice compared to W/CC11 isolates. INTERPRETATION We report the emergence of a novel sequence type (ST-9316) mostly associated with serogroup W, and exhibiting a lower virulence and a distinct age specific incidence profile than W/CC11 isolates. Surveillance requires powerful approaches combining WGS and pathophysiological analysis to adapt control measures.

中文翻译：

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2013-2018年法国上豪斯地区脑膜炎奈瑟氏球菌W组新遗传谱系ST-9316的出现。

背景技术侵袭性脑膜炎球菌病（IMD）的流行病学在脑膜炎奈瑟氏球菌新菌株的发病率，年龄分布和/或扩展中不断变化。由于W组（IMDW）引起的IMD流行病学最近在全球范围内发生了变化，出现了源自南美-英国菌株的克隆复合体ST-11（CC11）分离株。在法国，随着我们旨在分析的不同于CC11的新基因型的出现，在法国发现了最新的变化。方法将法国的流行病学和微生物学监测数据与全基因组测序（WGS）结合使用，以检测引起IMD的菌株的新兴表型和基因型，以及它们对4CMenB疫苗诱导的免疫力的敏感性。通过与CC11分离株直接比较，使用表达人转铁蛋白的转基因小鼠来分析新出现的分离株的毒力。结果我们的数据显示，自2013年以来，法国北部的IMDW分离株有所增加。分离株属于ST-9316，很少是ST-11分离株。WGS将ST-9316分离株聚在一起，并与克隆复合体ST-11（CC11）的分离株远距离分离。与W / CC11分离株不同，W / ST-9316分离株引起的病例多见于1岁以下婴儿，但死亡率比W / CC11病例低。基因组比较表明，W / ST-9316与W / CC11分离株不同，缺少编码血红蛋白受体的hmbR基因，该基因是从血红蛋白中获取铁的一种致病因子。与W / CC11分离株相比，W / ST-9316在小鼠中的毒力更低。解释我们报道了一种新的序列类型（ST-9316）的出现，该序列类型与W血清群最相关，并且比W / CC11分离株具有更低的毒力和不同的年龄特异性发病率。监视需要强有力的方法，将WGS和病理生理分析相结合以适应控制措施。