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Objective To investigate molecular characterization of streptococcus pyogenes isolates involved in an outbreak of scarlet fever in China in 2011.
Methods Seventy-four Streptococcal pyogenes involved in an outbreak of scarlet fever were isolated from pediatric patients in the areas with high incidence in China from May to August of 2011. Emm genotyping, pulsed-field gel electrophoresis (PFGE), superantigen (SAg) genes and antimicrobial susceptibility profiling were analyzed for these isolates.
Results A total of 4 different emm types were identified. Emm12 was the most prevalent type which contained four predominating PFGE patterns corresponding to four different virulence and superantigen profiles. Emm12 (79.7%) and emml (14.90 accounted for approximately 94} of all the isolates. The speA gene was all negative in emm12 isolates and positive in emml isolates. All strains were resistant to erythromycin, and 89.4% of them were resistant to erythromycin, tracycline, and clindamycin simultaneously.
Conclusion Several highly diversified clones with a high macrolide resistance rate comprise a predominant proportion of circulating strains, though no new emm type was found in this outbreak. The data provide a baseline for further surveillance of scarlet fever, which may contribute to the explanation of the outbreak and development of a GAS vaccine in China. -
分子流行病学在低收入、高负担国家的作用
分子流行病学的出现已经有约20年的历史,其出现的标志是1991年第1个分子菌株分型技术的问世.之后,很多种用于分型的替代技术被开发出来,并被不同程度的应用,其中基于IS6110的RFLP指纹技术、spoligotyping和MIRU-VNTR分型技术已经成功地发展为非常有价值的工具,用于监测和了解疾病在宿主人群中的发病过程.
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原发性高血压候选基因多态性的分子流行病学研究进展
原发性高血压(EH)是遗传物质与环境因素共同作用的多基因遗传性疾病,发病机制尚不明确.遗传流行病学研究表明:人群中个体血压水平的差异30%~70%归因于遗传因素,遗传背景是EH发病的重要原因.随着人类基因组单核苷酸多态性检测和分型技术的不断完善,近年来人们广泛开展EH候选基因多态性研究,以阐明EH的关键基因,从分子水平来认识其发病机制.本文主要针对近几年来研究的一些热点基因及多态性成果予以综述.