Planet Paul J, Diaz Lorena, Kolokotronis Sergios-Orestis, Narechania Apurva, Reyes Jinnethe, Xing Galen, Rincon Sandra, Smith Hannah, Panesso Diana, Ryan Chanelle, Smith Dylan P, Guzman Manuel, Zurita Jeannete, Sebra Robert, Deikus Gintaras, Nolan Rathel L, Tenover Fred C, Weinstock George M, Robinson D Ashley, Arias Cesar A
Division of Pediatric Infectious Diseases, Department of Pediatrics, Columbia University, College of Physicians and Surgeons Sackler Institute for Comparative Genomics, American Museum of Natural History.
Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Bogotá, Colombia.
J Infect Dis. 2015 Dec 15;212(12):1874-82. doi: 10.1093/infdis/jiv320. Epub 2015 Jun 5.
The community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) epidemic in the United States is attributed to the spread of the USA300 clone. An epidemic of CA-MRSA closely related to USA300 has occurred in northern South America (USA300 Latin-American variant, USA300-LV). Using phylogenomic analysis, we aimed to understand the relationships between these 2 epidemics.
We sequenced the genomes of 51 MRSA clinical isolates collected between 1999 and 2012 from the United States, Colombia, Venezuela, and Ecuador. Phylogenetic analysis was used to infer the relationships and times since the divergence of the major clades.
Phylogenetic analyses revealed 2 dominant clades that segregated by geographical region, had a putative common ancestor in 1975, and originated in 1989, in North America, and in 1985, in South America. Emergence of these parallel epidemics coincides with the independent acquisition of the arginine catabolic mobile element (ACME) in North American isolates and a novel copper and mercury resistance (COMER) mobile element in South American isolates.
Our results reveal the existence of 2 parallel USA300 epidemics that shared a recent common ancestor. The simultaneous rapid dissemination of these 2 epidemic clades suggests the presence of shared, potentially convergent adaptations that enhance fitness and ability to spread.
美国社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）的流行归因于USA300克隆株的传播。南美洲北部出现了与USA300密切相关的CA-MRSA疫情（USA300拉丁美洲变种，USA300-LV）。我们旨在通过系统基因组分析来了解这两种疫情之间的关系。
我们对1999年至2012年间从美国、哥伦比亚、委内瑞拉和厄瓜多尔收集的51株MRSA临床分离株的基因组进行了测序。系统发育分析用于推断主要分支的分歧关系和时间。
系统发育分析揭示了两个主要分支，它们按地理区域划分，在1975年有一个假定的共同祖先，分别于1989年起源于北美洲，1985年起源于南美洲。这些平行疫情的出现与北美分离株中精氨酸分解代谢移动元件（ACME）的独立获得以及南美分离株中一种新型的铜和汞抗性（COMER）移动元件的出现相吻合。
我们的结果揭示了存在两个具有近期共同祖先的平行USA300疫情。这两个疫情分支同时快速传播表明存在共同的、可能趋同的适应性变化，这些变化增强了适应性和传播能力。
