Dissemination of methicillin-resistant staphylococci among healthy Japanese children.
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.
Department of Bacteriology, School of Medicine, Juntendo University, Tokyo, Japan.
Ken
K
Hisata
Kyoko
K
Kuwahara-Arai
Munetaka
M
Yamanoto
Teruyo
T
Ito
Yasuo
Y
Nakatomi
Longzhu
L
Cui
Tadashi
T
Baba
Masahiko
M
Terasawa
Chie
C
Sotozono
Shigeru
S
Kinoshita
Yuichiro
Y
Yamashiro
Keiichi
K
Hiramatsu
D001426:Bacterial Proteins / Q000235:genetics; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002656:Child Day Care Centers; D002675:Child, Preschool; D003030:Coagulase / Q000378:metabolism; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016106:Methicillin Resistance / Q000235:genetics; D008969:Molecular Sequence Data; D009666:Nose / Q000382:microbiology; D015995:Prevalence; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
D001426:Bacterial Proteins; D003030:Coagulase