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Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
09:03

Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus

Published on: September 5, 2013

The emerging ST8 methicillin-resistant Staphylococcus aureus clone in the community in Japan: associated infections,

Yasuhisa Iwao1, Rumiko Ishii, Yusuke Tomita

  • 1Division of Bacteriology, Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.

Journal of Infection and Chemotherapy : Official Journal of the Japan Society of Chemotherapy
|February 22, 2012
PubMed

Insights

A new Japanese strain of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), ST8 CA-MRSA/J, has emerged. It causes skin infections and severe invasive diseases, similar to USA300, posing a significant public health threat.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Genomics

Background:

  • Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a global health concern.
  • USA300 (ST8 CA-MRSA with SCCmecIVa) is the predominant strain in the United States.
  • A distinct Japanese CA-MRSA strain, ST8 CA-MRSA/J, emerged in 2003.

Purpose of the Study:

  • To investigate the characteristics and clinical significance of the emerging Japanese ST8 CA-MRSA/J strain.
  • To compare ST8 CA-MRSA/J with the predominant US strain, USA300.
  • To understand the genetic diversity and genomic features of ST8 CA-MRSA/J.

Main Methods:

  • Epidemiological surveillance of CA-MRSA genotypes in Japan.
  • Clinical data analysis of infections associated with ST8 CA-MRSA/J.
  • Pulsed-field gel electrophoresis (PFGE) for strain typing.
  • Genomic analysis comparing ST8 CA-MRSA/J and USA300.

Main Results:

  • ST8 CA-MRSA/J was prevalent (16.2-34.4%) in Japan, causing skin and soft tissue infections (SSTIs), colitis, and invasive infections.
  • The strain spread internationally via a Japanese family.
  • Genomic analysis revealed similarities to USA300 but distinct accessory genes, including enhanced cytolytic peptides and a novel SaPIj50 carrying a highly expressed toxic shock syndrome toxin-1 gene.
  • ST8 CA-MRSA/J lacked the Panton-Valentine leukocidin phage and arginine catabolic mobile element found in USA300.
  • A specific subtype, ST8 Jβ, was linked to severe invasive infections.

Conclusions:

  • ST8 CA-MRSA/J is a successful, native CA-MRSA clone in Japan.
  • It causes a spectrum of infections, including severe invasive diseases, similar to USA300.
  • The strain's unique genomic features, including salvaged virulence factors, contribute to its success and pose a significant threat requiring attention.

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