366. Possible Spreading of Exfoliative Toxin A-Positive Methicillin-Resistant Staphylococcus aureus (MRSA) in Japan as the Dominant Clone of Community-Associated MRSA among Children
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • IDWeek2013 #366.pdf (115.0 kB)
  • Background: Community-associated methicillin-resistant Staphylococcus aureus(CA-MRSA) has emerged an important pathogen among children. Although USA300, which harbors Panton-Valentine leukocidin (PVL), has been the dominant clone in the United States, the clonality of CA-MRSA in Japan has not been well understood.

    Methods: We collected MRSA isolates recovered from outpatients younger than 10 years of age from 15 hospitals throughout Ishikawa and Toyama Prefecture, an area of 8,433 km². We selected the isolates which fulfilled the Centers for Disease Control and Prevention (CDC) definition of CA-MRSA. The genes of virulence factors, PVL, arginine catabolic mobile element (ACME), exfoliative toxin A, exfoliative toxin B, and toxic shock syndrome toxin-1, were detected by polymerase chain reaction (PCR). Phage-derived open reading frames typing (POT), which is a multiplex PCR-based technique, was performed as a genotyping method.

    Results: Among 82 isolates we collected, 62 (75.6%) isolates met the CDC criteria of CA-MRSA. Of these, only 1 (1.6%) isolate was PVL positive but ACME negative. In the genotyping analysis, 30 (48.4%) isolates were classified into a cluster with similar POT types which are associated with clonal complex 121. Twenty-three of 30 isolates harbored exfoliative toxin A gene and showed an identical POT type although they were isolated in 10 hospitals geographically apart from each other.

    Conclusion: Our data suggested that an exfoliative toxin A-positive MRSA clone might be dominantly spreading among the community of our region although PVL-positive strains including USA300 were rare.

    Hisashi Baba, MD, PhD1, Masahiro Suzuki, PhD2, Yoshitsugu Iinuma, MD, PhD1 and Surveillance Study Group of Antimicrobial Resistance in Hokuriku District, (1)Department of Infectious Diseases, Kanazawa Medical University, Uchinada, Japan, (2)Aichi Prefectural Institute of Public Health, Nagoya, Japan


    H. Baba, None

    M. Suzuki, None

    Y. Iinuma, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.