title: Changes in the molecular epidemiological characteristics of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit.
abstract: OBJECTIVE
  To determine whether the molecular epidemiological characteristics of methicillin-resistant Staphylococcus aureus (MRSA) had changed in a level III neonatal intensive care unit (NICU).
  
  
  METHODS
  Retrospective review of medical records.
  
  
  METHODS
  Level III NICU of a university-affiliated children's hospital in New York, New York.
  
  
  METHODS
  Case patients were neonates hospitalized in the NICU who were colonized or infected with MRSA.
  
  
  METHODS
  Rates of colonization and infection with MRSA during the period from 2000 through 2008 were assessed. Staphylococcal chromosomal cassette (SCC) mecA analysis and genotyping for S. aureus encoding protein A (spa) were performed on representative MRSA isolates from each clonal pulsed-field gel electrophoresis pattern.
  
  
  RESULTS
  Endemic MRSA infection and colonization occurred throughout the study period, which was punctuated by 4 epidemiologic investigations during outbreak periods. During the study period, 93 neonates were infected and 167 were colonized with MRSA. Surveillance cultures were performed for 1,336 neonates during outbreak investigations, and 115 (8.6%) neonates had MRSA-positive culture results. During 2001-2004, healthcare-associated MRSA clones, carrying SCC mec type II, predominated. From 2005 on, most MRSA clones were community-associated MRSA with SCC mec type IV, and in 2007, USA300 emerged as the principal clone.
  
  
  CONCLUSIONS
  Molecular analysis demonstrated a shift from healthcare-associated MRSA (2001-2004) to community-associated MRSA (2005-2008).
authors.affiliation: Department of Pediatrics, Division of Neonatology, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, Pennsylvania 19134, USA. alison.carey@drexelmed.edu
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Carey
authors.forename: Phyllis
authors.initials: P
authors.lastname: Della-Latta
authors.forename: Richard
authors.initials: R
authors.lastname: Huard
authors.forename: Fann
authors.initials: F
authors.lastname: Wu
authors.forename: Phillip L
authors.initials: PL
authors.lastname: Graham
authors.forename: Diane
authors.initials: D
authors.lastname: Carp
authors.forename: Lisa
authors.initials: L
authors.lastname: Saiman
mesh_terms: D003428:Cross Infection / Q000453:epidemiology / Q000517:prevention & control; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008485:Medical Audit; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification; D017720:Molecular Epidemiology; D009519:New York City / Q000453:epidemiology; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013205:Staphylococcal Protein A / Q000235:genetics
chemical_list: D013205:Staphylococcal Protein A