title: Dissemination of methicillin-resistant Staphylococcus aureus USA300 sequence type 8 lineage in Latin America.
abstract: BACKGROUND
  Methicillin-resistant Staphylococus aureus (MRSA) is an important nosocomial and community-associated (CA) pathogen. Recently, a variant of the MRSA USA300 clone emerged and disseminated in South America, causing important clinical problems.
  
  
  METHODS
  S. aureus isolates were prospectively collected (2006-2008) from 32 tertiary hospitals in Colombia, Ecuador, Peru, and Venezuela. MRSA isolates were subjected to antimicrobial susceptibility testing and pulsed-field gel electrophoresis and were categorized as health care-associated (HA)-like or CA-like clones on the basis of genotypic characteristics and detection of genes encoding Panton-Valentine leukocidin and staphylococcal cassette chromosome (SCC) mec IV. In addition, multilocus sequence typing of representative isolates of each major CA-MRSA pulsotype was performed, and the presence of USA300-associated toxins and the arcA gene was investigated for all isolates categorized as CA-MRSA.
  
  
  RESULTS
  A total of 1570 S. aureus were included; 651 were MRSA (41%)--with the highest rate of MRSA isolation in Peru (62%) and the lowest in Venezuela (26%)--and 71%, 27%, and 2% were classified as HA-like, CA-like, and non-CA/HA-like clones, respectively. Only 9 MRSA isolates were confirmed to have reduced susceptibility to glycopeptides (glycopeptide-intermediate S. aureus phenotype). The most common pulsotype (designated ComA) among the CA-like MRSA strains was found in 96% of isolates, with the majority (81%) having a < or =6-band difference with the USA300-0114 strain. Representative isolates of this clone were sequence type 8; however, unlike the USA300-0114 strain, they harbored a different SCCmec IV subtype and lacked arcA (an indicator of the arginine catabolic mobile element).
  
  
  CONCLUSIONS
  A variant CA-MRSA USA300 clone has become established in South America and, in some countries, is endemic in hospital settings.
authors.affiliation: Molecular Genetics and Antimicrobial Resistance Unit, Universidad El Bosque, Bogota, Colombia.
authors.forename: Jinnethe
authors.initials: J
authors.lastname: Reyes
authors.forename: Sandra
authors.initials: S
authors.lastname: Rincón
authors.forename: Lorena
authors.initials: L
authors.lastname: Díaz
authors.forename: Diana
authors.initials: D
authors.lastname: Panesso
authors.forename: Germán A
authors.initials: GA
authors.lastname: Contreras
authors.forename: Jeannete
authors.initials: J
authors.lastname: Zurita
authors.forename: Carlos
authors.initials: C
authors.lastname: Carrillo
authors.forename: Adele
authors.initials: A
authors.lastname: Rizzi
authors.forename: Manuel
authors.initials: M
authors.lastname: Guzmán
authors.forename: Javier
authors.initials: J
authors.lastname: Adachi
authors.forename: Shahreen
authors.initials: S
authors.lastname: Chowdhury
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Murray
authors.forename: Cesar A
authors.initials: CA
authors.lastname: Arias
mesh_terms: D016521:Electrophoresis, Gel, Pulsed-Field; D007843:Latin America; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D010641:Phenotype; D011446:Prospective Studies