Dissemination of methicillin-resistant staphylococci among healthy Japanese children

J Clin Microbiol. 2005 Jul;43(7):3364-72. doi: 10.1128/JCM.43.7.3364-3372.2005.

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA), regarded as a tenacious pathogen in the hospital, has recently become increasingly prevalent as a community pathogen. We evaluated the prevalence and characteristics of methicillin-resistant staphylococci in the Japanese community by testing nasal samples of 818 children of five day care centers and two kindergartens in three districts. We found that methicillin-resistant staphylococci are already prevalent among healthy children. Among 818 children, 35 children (4.3%) carried MRSA and 231 children (28.2%) carried methicillin-resistant coagulase-negative staphylococci (MRC-NS). The types of staphylococcal cassette chromosome mec (SCCmec) found among 44 MRSA isolates were as follows: type IIa, 11 isolates; type IIb, 19 isolates; and type IV, 14 isolates. The type IIb SCCmec element was a new SCCmec element found in this study. Eleven (25%) strains which belonged to clonal complex 5 (CC5) carried type IIa SCCmec, and they produced type 2 coagulase and toxic shock syndrome toxin 1. They were indistinguishable from health care-associated MRSA (H-MRSA) strains in Japan, represented by strain N315. On the other hand, 33 (75%) strains, most of which belonged to CC78 or CC91, carried small SCCmec elements, such as type IIb or type IV, and they produced type 1 or type 3 coagulase and exfoliative toxin. The data indicated that MRSA clones distinct from H-MRSA have disseminated in healthy children. The fact that MRC-NS strains were prevalent in the community suggested that they might serve as a reservoir for the SCCmec element carried by MRSA strains disseminated in the community.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Child Day Care Centers*
  • Child, Preschool
  • Coagulase / metabolism
  • Community-Acquired Infections / epidemiology*
  • Community-Acquired Infections / microbiology
  • Humans
  • Japan / epidemiology
  • Methicillin Resistance* / genetics
  • Molecular Sequence Data
  • Nose / microbiology
  • Prevalence
  • Sequence Analysis, DNA
  • Staphylococcal Infections / epidemiology*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification

Substances

  • Bacterial Proteins
  • Coagulase

Associated data

  • GENBANK/AB127982