title: Genotypes, intrafamilial transmission, and virulence potential of nasal methicillin-resistant Staphylococcus aureus from children in the community.
abstract: Pediatric outpatients and healthy children in the community were examined for nasal methicillin-resistant Staphylococcus aureus (MRSA) in Japan. MRSA isolation frequencies were 0.7% (3/426) and 3.7% (5/136), respectively, in pediatric outpatients and healthy children in the community (overall frequency, 1.4%). The frequency of MRSA isolation was higher in children 5-9 years of age compared with the other age groups. All eight MRSA strains isolated were Panton-Valentine leukocidin-negative. Of these, three with the genotype multilocus sequence type (ST) 8/spa606/SCCmecIV (2 cases) and ST88/spa999/SCCmecIV/exfoliative toxin A gene (eta) were identical or similar to MRSA from bullous impetigo, determined by pulsed-field gel electrophoresis. One strain with ST764 (ST5 variant)/spa2/SCCmecII/staphylococcal enterotoxin B gene seb2 (seb variant) was similar to MRSA from bacteremia, and one with ST5/spa2/SCCmecII was the Pandemic New York/Japan clone. The remaining three strains, with ST22/spa998/SCCmecI, ST380/spa799/SCCmecIV, and ST857/spa416/SCCmecII, have not been identified. All MRSA strains were resistant to one or more non-beta-lactam antibiotics, and the ST5 and ST764 strains were multidrug-resistant. Family analysis demonstrated parent-to-child transmission (for ST8 and ST764), as well as acquisition from outside the family (for ST8 and ST380). The data suggest that young school-age children have a higher carriage rate of nasal MRSA than children of other ages, and that not only community-acquired MRSA strains but also MRSA strains with characteristics of hospital-acquired MRSA are spreading in the community.
authors.affiliation: Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, 757 Ichibanchou, Asahimachidori, Niigata, 951-8510, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ozaki
authors.forename: Misao
authors.initials: M
authors.lastname: Takano
authors.forename: Wataru
authors.initials: W
authors.lastname: Higuchi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Takano
authors.forename: Shizuka
authors.initials: S
authors.lastname: Yabe
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Nitahara
authors.forename: Akihito
authors.initials: A
authors.lastname: Nishiyama
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D001427:Bacterial Toxins / Q000235:genetics; D002353:Carrier State / Q000382:microbiology* / Q000635:transmission; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000382:microbiology; D004768:Enterotoxins / Q000235:genetics; D005098:Exotoxins / Q000235:genetics; D005190:Family; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D007223:Infant; D007956:Leukocidins / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D009296:Nasal Cavity / Q000382:microbiology; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000635:transmission
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; C031818:enterotoxin B, staphylococcal