title: Molecular epidemiology of Staphylococcus aureus in households of children with community-associated S aureus skin and soft tissue infections.
abstract: OBJECTIVE
  Although colonization traditionally is considered a risk factor for Staphylococcus aureus infection, the relationship between contemporary S aureus colonization and infection is not well characterized. We aimed to relate the presence of colonizing and disease-causing strains of S aureus within individuals and households.
  
  
  METHODS
  In a prospective study of 163 pediatric outpatients (cases) with community-associated S aureus skin and soft tissue infections in St Louis, infection isolates were obtained from cases and colonization cultures were obtained from cases and their household contacts (n = 562). Molecular typing by repetitive sequence-based polymerase chain reaction was used to compare infecting and colonizing isolates within each case. The infecting strain from each case was compared with S aureus strains colonizing household contacts. The colonization status of cases was followed for 12 months.
  
  
  RESULTS
  A total of 27 distinct strain types were identified among the 1299 S aureus isolates evaluated. Between 1 and 6 distinct strain types were detected per household. A total of 110 cases (67%) were colonized at 1 or more body sites with the infecting strain. Of the 53 cases with an infecting strain that did not match a colonizing strain, 15 (28%) had 1 or more household contacts with a colonizing strain that matched the infecting strain. Intrafamilial strain-relatedness was observed in 105 families (64%).
  
  
  CONCLUSIONS
  One-third of cases were colonized with a different strain type than the strain causing the skin and soft tissue infection. Fewer than one-third of cases with discordant infecting and colonizing isolates could be linked to the strain from another household contact, suggesting acquisition from sources outside the household.
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St Louis, MO.
authors.forename: Marcela
authors.initials: M
authors.lastname: Rodriguez
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St Louis, MO.
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Hogan
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St Louis, MO; Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO.
authors.forename: Carey-Ann D
authors.initials: CA
authors.lastname: Burnham
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St Louis, MO.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Fritz
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000235:genetics / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics*; D005191:Family Characteristics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012307:Risk Factors; D012867:Skin / Q000382:microbiology*; D018461:Soft Tissue Infections / Q000453:epidemiology* / Q000235:genetics / Q000382:microbiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000235:genetics; D013211:Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial
keywords: CA; Community-associated; MRSA; MSSA; Methicillin-resistant Staphylococcus aureus; Methicillin-susceptible Staphylococcus aureus; PFGE; Pulsed-field gel electrophoresis; Repetitive sequence-based polymerase chain reaction; SSTI; Skin and soft tissue infection; repPCR