Article in Japanese

Methicillin-resistant Staphylococcus aureus USA300 strain infections in children in Japan

Takuya FUJII^1）, Hanako FUNAKOSHI^2）, Chiaki TAO^{3, 4）}, Kensuke SHOJI^3）, Hiroshi HATAYA^1）, Yuho HORIKOSHI^2）

Methicillin-resistant Staphylococcus aureus (MRSA) USA300 has been a major cause of skin and soft tissue infections (SSTIs) in the United States of America. The USA300 strain carries Panton Valentine Leukocidin and causes invasive infection. The strain is thought to be relatively rare in Japan. This was a retrospective study aimed to elucidate the clinical features of pediatric cases diagnosed with MRSA USA300 strain infection at the Tokyo Metropolitan Children’s Medical Center and National Center for Child Health and Development between January 2020 and August 2021. Based on medical history and microbiology results, MRSA was investigated further for USA300 strain by genome sequencing. This study identified 16 cases. Their median age and boy’s ratio were 4.0 (Interquartile range, IQR: 1.0-6.5) years old and 69％, respectively. Skin soft tissue infections and invasive infections such as osteomyelitis and empyema were identified in 12 and 4 cases, respectively. Among them, one case was admitted to the pediatric intensive care unit. Treatment with antimicrobial agents included vancomycin, teicoplanin and clindamycin. The median duration of treatment for SSTIs and invasive infections was 7.0 (IQR: 5.0-14.5) and 148 (IQR: 79.3-206) days, respectively. In that time, surgical drainage for abscess was performed in 7 cases. In this study, SSTIs requiring surgical drainage was common, and one critical case with intensive care also was observed. These characteristics are similar to those in reports on USA300 in the United States of America.

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1）Department of General Pediatrics, Tokyo Metropolitan Children’s Medical Center
2）Division of Infectious Diseases, Department of Pediatrics, Tokyo Metropolitan Children’s Medical Center
3）Division of Infectious Diseases, National Center for Child Health and Development
4）Department of Pediatrics, Hiroshima University

Key words	MRSA (methicillin-resistant Staphylococcus aureus), USA300, PVL
Received	March 10, 2023
Accepted	November 18, 2023

36 (1)：3─11,2024