2182. Molecular epidemiology of community-associated and hospital-associated methicillin-resistant Staphylococcus aureus in a Japanese university hospital
Session: Poster Abstract Session: HAI: MRSA, MSSA, and Other Gram Positives
Saturday, October 7, 2017
Room: Poster Hall CD
  • poster#2182_NaokatsuFukukawa.pdf (219.0 kB)
  • Background: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been reported in healthcare facilities worldwide. But details of CA-MRSA in Japanese healthcare facilities are rarely reported. The aims of this study are to know the distribution of CA-MRSA and healthcare-associated MRSA (HA-MRSA) with detailed molecular typing, and to assess the efficacy of infection control practice in a Japanese hospital.

    Methods: From July to October in 2015, first MRSA isolate from each patient was collected in Juntendo University Hospital, Tokyo, Japan. MRSA strains were categorized as CA-MRSA and HA-MRSA according to the clinical definition of CDC. Detection of toxin genes and SCCmec typing were performed by PCR. Genetic relatedness among isolates was determined by pulsed-field gel electrophoresis (PFGE). Multilocus sequence typing was performed using whole genome sequencing data.

    Results: A total of 102 MRSA strains were collected in the study period, and categorized as 34 CA-MRSA (33.3 %) and 68 HA-MRSA (66.7 %), respectively. Among the 73 strains isolated from hospitalized patients, 10 were CA-MRSA (13.7 %). Whereas among the 29 strains isolated in clinic, 5 were HA-MRSA (17.2 %). Three major types were as follows: ST8-SCCmec IV (n= 26, 25.5 %, CA: HA= 10: 16), ST5-SCCmec IIa (n= 17, 16.7 %, CA: HA= 5: 12), and ST1-SCCmec IVa (n= 13, 12.7 %, CA: HA= 6: 7). Among ST8-SCCmec IV strains, SCCmec IVl, originally reported in Japanese CA-MRSA, was found both in CA-MRSA and HA-MRSA (n= 11, 10.8 %, CA: HA= 5: 6). Only one ST772-SCCmec V strain carried Panton-Valentine leukocidin (PVL) gene. Two ST765-SCCmec IIa strains in CCU, 2 ST765-SCCmec IIa strains in a general ward, and 6 ST2764-SCCmec IVa strains in NICU showed genetic relatedness by PFGE, respectively. Especially, ST2764-SCCmec IVa was a clone originally reported as HA-MRSA in another Juntendo-affiliated hospital.

    Conclusion: CA-MRSA and HA-MRSA were comparably found both in hospital and clinic. Unique Japanese clones were found in this study, but it seemed impossible to distinguish CA-MRSA and HA-MRSA simply by ST-SCCmec typing. In contrast, transmission of MRSA rarely happened in hospital. This heterogenous population structure of MRSA suggested that conventional HA-MRSA had lost its predominance by sufficient infection control, resulting in relative increase of CA-MRSA in hospital environment.

    Naokatsu Fukukawa, RN, MMS1,2, Yuki Uehara, MD, PhD1,3, Takashi Sasaki, DVM, PhD1,4, Masayoshi Chonan, MT5, Ayako Nakamura, PhD5, Shigeki Misawa, PhD5, Naomi Komatsuzaki, RN, CICN6, Satoshi Hori, MD, PhD1,6, Akimichi Ohsaka, MD, PhD5,7 and Keiichi Hiramatsu, MD, PhD1, (1)Department of Infection Control Science, Juntendo University Graduate School of Medicine, Tokyo, Japan, (2)Department of Nursing, Kyorin University Hospital, Tokyo, Japan, (3)Department of General Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan, (4)Animal Research Center, Sapporo Medical University School of Medicine, Sapporo, Japan, (5)Department of Clinical Laboratory, Juntendo University Hospital, Tokyo, Japan, (6)Infection Control Office, Juntendo University Hospital, Tokyo, Japan, (7)Department of Transfusion Medicine and Stem Cell Regulation, Juntendo University Faculty of Medicine, Tokyo, Japan


    N. Fukukawa, None

    Y. Uehara, None

    T. Sasaki, None

    M. Chonan, None

    A. Nakamura, None

    S. Misawa, None

    N. Komatsuzaki, None

    S. Hori, None

    A. Ohsaka, None

    K. Hiramatsu, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 4th with the exception of research findings presented at the IDWeek press conferences.