A Prospective Cohort Multicenter Study of Molecular Epidemiology and Phylogenonnics of Staphylococcus aureus Bacterennia in Nine Latin American Countries

<jats:title>ABSTRACT</jats:title> <jats:p> <jats:named-content content-type="genus-species">Staphylococcus aureus</jats:named-content> is an important pathogen causing a spectrum of diseases ranging from mild skin and soft tissue infections to life-threatening conditions. Bloodstream infections are particularly important, and the treatment approach is complicated by the presence of methicillin-resistant <jats:named-content content-type="genus-species">S. aureus</jats:named-content> (MRSA) isolates. The emergence of new genetic lineages of MRSA has occurred in Latin America (LA) with the rise and dissemination of the community-associated USA300 Latin American variant (USA300-LV). Here, we prospectively characterized bloodstream MRSA recovered from selected hospitals in 9 Latin American countries. All isolates were typed by pulsed-field gel electrophoresis (PFGE) and subjected to antibiotic susceptibility testing. Whole-genome sequencing was performed on 96 MRSA representatives. MRSA represented 45% of all (1,185 <jats:named-content content-type="genus-species">S. aureus</jats:named-content> ) isolates. The majority of MRSA isolates belonged to clonal cluster (CC) 5. In Colombia and Ecuador, most isolates (≥72%) belonged to the USA300-LV lineage (CC8). Phylogenetic reconstructions indicated that MRSA isolates from participating hospitals belonged to three major clades. Clade A grouped isolates with sequence type 5 (ST5), ST105, and ST1011 (mostly staphylococcal chromosomal cassette <jats:italic>mec</jats:italic> [SCC <jats:italic>mec</jats:italic> ] I and II). Clade B included ST8, ST88, ST97, and ST72 strains (SCC <jats:italic>mec</jats:italic> IV, subtypes a, b, and c/E), and clade C grouped mostly Argentinian MRSA belonging to ST30. In summary, CC5 MRSA was prevalent in bloodstream infections in LA with the exception of Colombia and Ecuador, where USA300-LV is now the dominant lineage. Clonal replacement appears to be a common phenomenon, and continuous surveillance is crucial to identify changes in the molecular epidemiology of MRSA. </jats:p>