title: Molecular epidemiology and nasal carriage of Staphylococcus aureus and methicillin-resistant S. aureus among young children attending day care centers and kindergartens in Hong Kong.
abstract: OBJECTIVE
  To investigate the prevalence and molecular epidemiology of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) nasal carriage in children.
  
  
  METHODS
  We collected nasal and nasopharyngeal swabs from 2211 children aged 2-5 years attending 79 day care centers (DCCs) and 113 kindergartens (KGs) in all 18 geographical districts in Hong Kong.
  
  
  RESULTS
  The overall carriage rates of S. aureus and MRSA were 27.6% (95% confidence interval [CI], 24.8-28.5%) and 1.3% (95% CI, 0.8-1.8%), respectively. Molecular typing (staphylococcal cassette chromosome mec [SCCmec], sequence type [ST], clonal cluster [CC]) showed that all the 28 MRSA isolates had SCCmec IV (n = 13) or V (n = 15) including 12 isolates with community-associated-MRSA genotypes (ST59-IV/V, ST30-IV and ST88-V), 10 isolates with healthcare-associated-MRSA genotypes (ST45-IV/V, CC5-IV and ST630-V) and six isolates with novel genotypes (ST10-V and CC1-IV). Spa typing indicated that there was some within and between DCCs/KGs transmission of certain MRSA and methicillin-sensitive S. aureus strains but this was not extensive.
  
  
  CONCLUSIONS
  Our findings indicate the potential for DCCs to be a reservoir for emerging MRSA genotypes and highlight the need to enhance education and infection control measures to reduce their cross-transmission in this population.
authors.affiliation: Division of Infectious Diseases, Carol Yu Centre for Infection and Department of Microbiology, The University of Hong Kong, Queen Mary hospital, Hong Kong Special Administrative Region, PR China. plho@hkucc.hku.hk
authors.forename: Pak-Leung
authors.initials: PL
authors.lastname: Ho
authors.forename: Susan S
authors.initials: SS
authors.lastname: Chiu
authors.forename: Maggie Y
authors.initials: MY
authors.lastname: Chan
authors.forename: Yuki
authors.initials: Y
authors.lastname: Gan
authors.forename: Kin-Hung
authors.initials: KH
authors.lastname: Chow
authors.forename: Eileen L
authors.initials: EL
authors.lastname: Lai
authors.forename: Yu-Lung
authors.initials: YL
authors.lastname: Lau
mesh_terms: D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002656:Child Day Care Centers; D002675:Child, Preschool; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D017720:Molecular Epidemiology; D058889:Molecular Typing; D009305:Nasopharynx / Q000382:microbiology; D009666:Nose / Q000382:microbiology*; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology