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Updated: Sep 13, 2025
Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Genomic and phenotypic characterization of methicillin-resistant Staphylococcus aureus ST965: an emerging
Jianbo Lv1,2, Zhixuan Chen2, Can Yang1,2
1School of Public Health, Nanchang University, Nanchang, Jiangxi, China.
Abstract:
Staphylococcus aureus sequence type 965 (ST965) represents a significant member of clonal complex 5. However, there are still significant gaps in research regarding the resistance, virulence, and distribution characteristics of methicillin-resistant S. aureus (MRSA) ST965. Here, we conducted a comprehensive analysis of 27 ST965-MRSA genomes from three different countries, including 20 genomes sequenced in this study and 7 genomes retrieved from public databases. Our results indicate that ST965-MRSA mainly originates from China (92.6%, 25 out of 27) and was first reported in 2013. SCCmec IV typing (75%, 21 out of 27) and spa t062 typing (75%, 21 out of 27) constituted its predominant clonal characteristics. Among ST965-MRSA clinical isolates, bloodstream infection samples accounted for 35%. A novel multidrug-resistant plasmid (pYF965) was identified in ST965-MRSA, which contains erm genes integrated via Tn551 into pTZ2162 and simultaneously contains aac(6')-Ie and blaI-blaR-blaZ. Through the acute pathogenicity model, ST965-MRSA exhibited higher hemolytic activity and mortality rates compared to N315 (ST5), yet their overall virulence remained significantly lower than the highly virulent strain USA300-LAC (ST8) (P < 0.0001). Notably, in terms of persistent infection, the bacterial colonization levels of ST965-MRSA in the heart, lungs, and spleen in vivo were significantly higher than those of N315 (ST5) and USA300-LAC (ST8) (P < 0.05). Particularly, its immune evasion ability and intracellular survival ability were superior to those of ST5 and ST8 (P < 0.05). This study elucidated the biological characteristics of ST965-MRSA for the first time, expanding our understanding of the molecular epidemiology of the ST965 clone.
Importance:
As an emerging clonal lineage, ST965 has been predominantly discovered in Asian regions. However, research regarding the ST965-MRSA remains highly limited at present. Therefore, we conducted a detailed analysis of the genomic characteristics of ST965-MRSA and, combined with phenotypic experiments, further revealed their potential pathogenic risks. This study initially uncovers the potential global transmission and genetic and phenotypic features of ST965-MRSA and offers valuable insights for controlling and preventing persistent hospital infections.
Insights
Methicillin-resistant Staphylococcus aureus ST965 (MRSA ST965) exhibits enhanced immune evasion and persistent infection capabilities. This study reveals its genetic traits and pathogenic risks, offering insights for infection control.
Area of Science:
- Microbiology
- Genomics
- Epidemiology
Background:
- Staphylococcus aureus sequence type 965 (ST965) is an emerging clonal lineage within clonal complex 5.
- Limited research exists on the resistance, virulence, and distribution of methicillin-resistant S. aureus (MRSA) ST965.
- ST965 MRSA has been primarily identified in Asian regions, with scarce data on its global spread and characteristics.
Purpose of the Study:
- To conduct a comprehensive genomic and phenotypic analysis of ST965-MRSA.
- To elucidate the genetic features, resistance mechanisms, virulence factors, and distribution of ST965-MRSA.
- To assess the pathogenic potential and implications for persistent hospital infections.
Main Methods:
- Genome sequencing and analysis of 27 ST965-MRSA isolates from China and public databases.
- SCCmec IV and spa t062 typing to determine clonal characteristics.
- Acute pathogenicity models and in vivo colonization studies to evaluate virulence and persistence.
Main Results:
- ST965-MRSA predominantly originates from China (92.6%) and was first reported in 2013.
- Predominant clonal characteristics include SCCmec IV (75%) and spa t062 (75%).
- A novel multidrug-resistant plasmid (pYF965) carrying erm genes was identified.
- ST965-MRSA showed higher hemolytic activity and mortality than N315 (ST5) but lower overall virulence than USA300-LAC (ST8).
- ST965-MRSA exhibited significantly higher in vivo colonization, immune evasion, and intracellular survival compared to N315 (ST5) and USA300-LAC (ST8).
Conclusions:
- This study provides the first comprehensive elucidation of ST965-MRSA's biological characteristics.
- ST965-MRSA possesses distinct genetic traits, including a novel multidrug-resistant plasmid.
- Its superior ability to cause persistent infections and evade the immune system highlights potential clinical significance.
- Findings offer valuable insights for controlling and preventing ST965-MRSA-associated infections.
