Background The gradual replacement of the Streptococcus pyogenes M1global genotype by a newly emergent M1UK variant is a global public health threat warranting increased surveillance. M1UK differs from progenitor M1global genotype by 27 single-nucleotide polymorphisms and is characterized by increased speA superantigen expression in vitro. Methods An allele-specific real-time polymerase chain reaction assay was developed for the rapid detection of M1UK strains. The assay was used in combination with whole genome sequencing to determine emm (sub)type distribution for 51 invasive (n = 9) and noninvasive (n = 42) S pyogenes clinical isolates. Results Emm1 was the most prevalent S pyogenes emm serotype (n = 11) in this set of clinical isolates, with M1UK being the dominant emm1 genotype (4/5 invasive, 3/6 noninvasive isolates). The assay accurately detected M1UK strains. Whole genome sequencing revealed continued presence of Australian M1UK sublineages associated with epidemic scarlet fever–causing S pyogenes in Asia. Conclusions Our study establishes a suitable target for detection of the toxigenic M1UK and confirms the maintenance of M1UK strains in Queensland, Australia. This assay can be deployed in laboratories and provides a valuable, cost-effective tool to enhance surveillance of the expanding M1UK clone.

中文翻译：

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产毒 M1UK 化脓性链球菌的快速分子检测工具


背景 新出现的 M1UK 变体逐渐取代化脓性链球菌 M1global 基因型是一个全球公共卫生威胁，需要加强监测。M1UK 与祖细胞 M1global 基因型的不同之处在于 27 个单核苷酸多态性，其特征是体外 speA 超抗原表达增加。方法 建立一种等位基因特异性实时聚合酶链反应检测法，用于 M1UK 菌株的快速检测。该测定与全基因组测序结合使用，以确定 51 种侵袭性 （n = 9） 和非侵袭性 （n = 42） 化脓性链球菌临床分离株的 emm（亚）型分布。结果 Emm1 是这组临床分离株中最普遍的化脓性链球菌 emm 血清型 （n = 11），其中 M1UK 是主要的 emm1 基因型 （4/5 侵袭性，3/6 无侵袭性分离株）。该检测准确检测到 M1UK 菌株。全基因组测序显示，澳大利亚 M1UK 亚系与亚洲流行的猩红热引起的化脓性链球菌相关。结论 我们的研究建立了检测产毒 M1UK 的合适靶点，并证实了澳大利亚昆士兰州 M1UK 菌株的维持。该检测试剂盒可部署在实验室中，为加强对不断扩增的 M1UK 克隆的监测提供了一种有价值、经济高效的工具。