Changes in epidemic methicillin-resistant Staphylococcus aureus strains in a Japanese hospital in Tokyo, Japan
- 1Department of Clinical Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
- 2Department of Infectious Diseases, Tokyo Medical University Hachioji Medical Centre, Hachioji, Tokyo, Japan
Abstract
Objectives: In recent years, methicillin-resistant Staphylococcus aureus (MRSA) isolates from Japanese hospitals have predominantly comprised community-acquired MRSA (CA-MRSA) carrying staphylococcal cassette chromosome mec (SCCmec) type IV in most regions. Certain CA-MRSA strains produce toxins, notably, Panton–Valentine leukocidin (PVL), a leukocyte-lytic toxin, and may cause infections in otherwise healthy individuals. This study aimed to clarify the current epidemiologic status of MRSA in a Japanese hospital.
Methods: In total, 1479 MRSA isolates collected from a Japanese university hospital between 2016 and 2023 were analyzed. SCCmec types and various genes were detected using polymerase chain reaction. Molecular epidemiologic analyses were performed using multilocus sequence typing and pulsed-field gel electrophoresis. Antimicrobial susceptibility was tested using the agar dilution method.
Results: The proportion of SCCmec type IV MRSA cases increased from 45.9% to 86.4% over 8 years. The PVL-positive MRSA isolation rate ranged from 6.4% to 15.9%. PVL-negative strains predominated throughout the study period. Among the PVL-negative SCCmec type IV strains, the USA400/J clone belonging to sequence type 1 accounted for 40.6% of the isolates, whereas the sequence type 8 CA-MRSA/J clone carrying SCCmec type IVl accounted for 15.1%. The USA400/J clone exhibited high resistance to levofloxacin but remained susceptible to clindamycin and minocycline, displaying a characteristic antimicrobial susceptibility pattern.
Conclusion: The USA400/J clone of CA-MRSA was predominant in the studied hospital. Strains with characteristics consistent with the USA400/J clone have also been reported in other regions of Japan, suggesting that this clone may be widely disseminated in Japan.
Related
- Isolation and Evaluation of a Lytic Staphylophage Specific to Methicillin Resistant Staphylococcus Aureus from Postsurgical Wound Infections in Surgical Wards at Mzuzu Central Hospital, Malawi.
- High prevalence and multidrug resistance of Methicillin-resistant Staphylococcus aureus at a provincial referral hospital in Zambia: A 5-year retrospective study
- Chlorhexidine MIC distribution, efflux pump gene profiles, and genotypic characteristics among clinical methicillin-resistant and methicillin-susceptible Staphylococcus aureus isolates
- Improving Antibiotic Stewardship Through a Retrospective Study of the Diagnostic Value of Nasal Methicillin-Resistant Staphylococcus aureus Polymerase Chain Reaction for Pneumonia in Intensive Care Unit Settings
- From Heart Murmur to Bone Involvement: Tricuspid Valve Endocarditis With First-Rib Osteomyelitis in a Patient With Methicillin-Resistant Staphylococcus aureus (MRSA) Bacteremia
BibTeX
@article{yoshida2026changes,
title = {{Changes in epidemic methicillin-resistant Staphylococcus aureus strains in a Japanese hospital in Tokyo, Japan}},
author = {Takuma Yoshida and Rika Sawara and Yuma Tomida and Mayu Sato and Yuki Okura and Hidetoshi Masuda and Taiga Natori and Takemi Ozeki and Tatsuya Numadate and Natsuki Oda and Megumi Sakaihori and Rika Watanabe and Hinako Kawasaki and Natsuki Fukuda and Tomomi Akasu and Shunsuke Takadama and Hiroshi Kaneko and Norihisa Noguchi and Yuji Hirai and Hidemasa Nakaminami},
journal = {IJID Regions},
year = {2026},
month = sep,
doi = {10.1016/j.ijregi.2026.101024},
url = {https://doi.org/10.1016/j.ijregi.2026.101024},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Changes in epidemic methicillin-resistant Staphylococcus aureus strains in a Japanese hospital in Tokyo, Japan
AU - Takuma Yoshida
AU - Rika Sawara
AU - Yuma Tomida
AU - Mayu Sato
AU - Yuki Okura
AU - Hidetoshi Masuda
AU - Taiga Natori
AU - Takemi Ozeki
AU - Tatsuya Numadate
AU - Natsuki Oda
AU - Megumi Sakaihori
AU - Rika Watanabe
AU - Hinako Kawasaki
AU - Natsuki Fukuda
AU - Tomomi Akasu
AU - Shunsuke Takadama
AU - Hiroshi Kaneko
AU - Norihisa Noguchi
AU - Yuji Hirai
AU - Hidemasa Nakaminami
PY - 2026
DA - 2026/09/29
JO - IJID Regions
DO - 10.1016/j.ijregi.2026.101024
UR - https://doi.org/10.1016/j.ijregi.2026.101024
AB - Objectives: In recent years, methicillin-resistant Staphylococcus aureus (MRSA) isolates from Japanese hospitals have predominantly comprised community-acquired MRSA (CA-MRSA) carrying staphylococcal cassette chromosome mec (SCCmec) type IV in most regions. Certain CA-MRSA strains produce toxins, notably, Panton–Valentine leukocidin (PVL), a leukocyte-lytic toxin, and may cause infections in otherwise healthy individuals. This study aimed to clarify the current epidemiologic status of MRSA in a Japanese hospital. Methods: In total, 1479 MRSA isolates collected from a Japanese university hospital between 2016 and 2023 were analyzed. SCCmec types and various genes were detected using polymerase chain reaction. Molecular epidemiologic analyses were performed using multilocus sequence typing and pulsed-field gel electrophoresis. Antimicrobial susceptibility was tested using the agar dilution method. Results: The proportion of SCCmec type IV MRSA cases increased from 45.9% to 86.4% over 8 years. The PVL-positive MRSA isolation rate ranged from 6.4% to 15.9%. PVL-negative strains predominated throughout the study period. Among the PVL-negative SCCmec type IV strains, the USA400/J clone belonging to sequence type 1 accounted for 40.6% of the isolates, whereas the sequence type 8 CA-MRSA/J clone carrying SCCmec type IVl accounted for 15.1%. The USA400/J clone exhibited high resistance to levofloxacin but remained susceptible to clindamycin and minocycline, displaying a characteristic antimicrobial susceptibility pattern. Conclusion: The USA400/J clone of CA-MRSA was predominant in the studied hospital. Strains with characteristics consistent with the USA400/J clone have also been reported in other regions of Japan, suggesting that this clone may be widely disseminated in Japan.
SN - 2772-7076
ER -