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Jingjing Zhong, Ming Wei, Chunxia Yang, Yudong Yin, Yu Bai, Ran Li, Li Gu Department of Infectious Diseases and Clinical Microbiology, Beijing Institute of Respiratory Medicine and Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People’s Republic of ChinaCorrespondence: Li Gu, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100000, People’s Republic of China, Email guli2013227@foxmail.comPurpose: Since community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized, the molecular epidemiology of CA-MRSA in China has been diverse. It is unclear whether different sites of CA-MRSA infection differ in antimicrobial resistance and clinical characteristics. The purpose of this study was to identify the molecular types, virulence factors and antimicrobial resistance of CA-MRSA strains and to analyze the clinical characteristics of different sites of CA-MRSA infection.Methods: 26 CA-MRSA strains were screened from Beijing Chao-Yang Hospital from 2014 to 2022. SCCmec type, MLST type, spa type, Panton–Valentine leukocidin (PVL), hemolysin α (Hla), phenolic soluble regulatory protein α (PSMα), toxic shock syndrome toxin-1 (TSST-1), and enterotoxin (SE) A to E were detected by PCR and gene sequencing. Antimicrobial susceptibility tests and the clinical features of CA-MRSA infection cases were collected for statistical analysis.Results: The predominant type of CA-MRSA was ST59-t437-IV. New non-epidemic types, SCCmec VII, were also found. PVL was seen in 65.4% of CA-MRSA strains and TSST-1 was only be detected in 3.8% of CA-MRSA strain which caused poor prognosis. There were three types of infections: pneumonia (61.5%), infective endocarditis (7.7%), and skin and soft tissue infections (SSTIs) (30.8%). CA-MRSA pneumonia cases were secondary to influenza infection (37.5%). Patients with CA-MRSA-associated infective endocarditis were more likely to have underlying cardiac diseases. Patients with CA-MRSA-associated SSTIs were more likely to have a history of diabetes mellitus, and strains in this group were more susceptible to erythromycin and clindamycin.Conclusion: ST59-t437-IV was the primary CA-MRSA type in our research and in China. We proposed that TSST-1 might be one of the indicators to predict the severity and prognosis of CA-MRSA infection. Different sites of CA-MRSA infection had difference in antibiotics susceptibility testing and underlying diseases of patients. It could provide a new perspective on treating different types of CA-MRSA infection.Keywords: community, acquired methicillin, resistant Staphylococcus aureus, staphylococcal chromosomal cassette mec type, Panton-Valentine leukocidin, antibiotic resistance, pneumonia |