title: Nasal carriage of methicillin-resistant Staphylococcus aureus during the first 2 years of life in children in northern Taiwan.
abstract: BACKGROUND
  Most reported studies of methicillin-resistant Staphylococcus aureus (MRSA) carriage have represented 1 time point. To better understand dynamic changes of nasal MRSA carriage, we conducted this longitudinal study in Taiwan.
  
  
  METHODS
  We recruited 304 newborn babies and obtained samples from nares for detection of S. aureus within 3 days of life, and obtained further samples periodically up to 2 years of age. A total of 12 samplings were attempted to be obtained.
  
  
  RESULTS
  Totally, 273 subjects with ≥9 samples were included for analysis. One hundred and ten subjects (40%) harbored MRSA, on one or more occasions; of these 82 (75%) had ≥2 positive specimens and 84 (76%) had colonization ≤4 months of age. Fourteen infants (5.1%) carried MRSA within 3 days of life, the rate peaked at the age of 2 months (21%) and it was lowest (3.1%) at the age of 18 months. All but 4 first MRSA isolates from the colonized subjects carried either staphylococcal cassette chromosome (SCCmec) IV or V(T). Of 32 subjects with ≥4 MRSA isolates, all isolates from the same subject were genetically indistinguishable in 17 (53%) and genetically related in an additional 9 (28%). Five episodes of skin and soft tissue infections (SSTIs) were identified in 4 subjects.
  
  
  CONCLUSIONS
  In Taiwan, during the first 2 years of life, two-fifths of the children ever harbored MRSA, whereas fewer than 2% of them had SSTIs. Three-fourths of the colonization occurred within the first 4 months and were persistent. More than half of the persistent colonizing isolates were genetically indistinguishable.
authors.affiliation: From the *Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Memorial Hospital; and †Chang Gung University College of Medicine, Kweishan, Taoyuan, Taiwan.
authors.forename: Yhu-Chering
authors.initials: YC
authors.lastname: Huang
authors.forename: Chih-Jung
authors.initials: CJ
authors.lastname: Chen
mesh_terms: D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D009297:Nasal Mucosa / Q000382:microbiology*; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013624:Taiwan / Q000453:epidemiology