Parallel Epidemics of Community-Associated Methicillin-Resistant Staphylococcus aureus USA300 Infection in North and South America

• Published in: The Journal of infectious diseases 2015-12, Vol.212 (12), p.1874-1882
• Main Authors: 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.
• Format: Article
• Language: English
• Subjects: BACTERIA; Community-Acquired Infections - epidemiology; Community-Acquired Infections - microbiology; Epidemics; Epidemiological Monitoring; Genome, Bacterial; Genotype; Humans; Major and Brief Reports; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Molecular Epidemiology; Molecular Typing; North America - epidemiology; Phylogeography; Sequence Analysis, DNA; South America - epidemiology; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcus aureus
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/jiv320

Background. 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. Methods. 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. Results. 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. Conclusions. 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.