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Updated: Dec 25, 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
Characterization of an ST5-SCCmec II-t311 methicillin-resistant Staphylococcus aureus strain with a widespread
Dandan Wu1, Haiping Wang2, Feiteng Zhu2
1Department of Infectious Diseases, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China.
Purpose:
To determine the genetic characteristics of the Chinese epidemic ST5-SCCmec II-t311 methicillin-resistant Staphylococcus aureus (MRSA) clone and to investigate the transmission characteristics of the cfr-positive plasmid.
Methods:
The complete genome of SR153 was sequenced. Genomic comparison with MRSA strains of other lineages was performed. The cfr-positive plasmid was investigated and compared with other cfr-positive plasmids from different origins and different areas.
Results:
The cfr-positive MRSA strain SR153 was a Chinese epidemic ST5-SCCmec II-t311 strain. It clustered much closer to the Japanese ST5-SCCmec II clone than to the European and American ST5-SCCmec II clones. The genome of SR153 contains one circular chromosome and three plasmids. It harbors the genomic islands νSaα, νSaβ, νSaγ, ΦSa1 and ΦSa3, the pathogenicity island νSa4, and genes encoding virulence factors such as tst and many enterotoxins. The SR153 genome also contains several resistance genes and mutations, such as ermA, aadD, spc, aacA-aphD, lnuA, tetK, blaZ and mutations in grlA and gyrA. SR153 harbors a cfr-positive plasmid, pSR01, which is highly similar to pSX01 from a Staphylococcus xylosus of pig origin from Henan Province. pSR01 was also highly similar to pXWZ from a Staphylococcus capitis and pLRSA417 from S. aureus. Both were obtained from geographically separated hospitals in Zhejiang Province.
Conclusions:
SR153, which clustered closely to the Japanese ST5-SCCmec II clone, is more resistant than N315. A pSR01-like cfr-positive plasmid was widespread among different Staphylococcus species of both human and animal origin in different hospitals and areas.
