Effective risk assessments and measures for community-acquired MRSA, are urgently necessary from the spread situation in the hospital

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K08358
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental and hygienic pharmacy
• Research Institution: Shujitsu University
• Principal Investigator: Shiota Sumiko 就実大学, 薬学部, 教授 (00368698)
• Research Collaborator: Yamada Youichi 就実大学, 薬学部, 助教
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: MRSA / 院内感染 / 市中感染型MRSA / バイオフィルム

Outline of Final Research Achievements

Analysis of MRSA clinically isolated in a cooperative hospital was conducted from year of 2011(Phase I),from January 2015 to March 2016 (Phase II) and year of 2018 (Phase III). The prevailing type of MRSA in the hospital is replaced hospital-acquired (HA-MRSA) with community-acquired (CA-MRSA) from 2011 to 2018. CA-MRSA was isolated from lower age patients than HA-MRSA, and the biofilm formation ability was extremely high compared to HA-MRSA. Although the number of HA-MRSA isolates has been reduced by the conventional measures against nosocomial infections, instead CA-MRSA has been brought in from the outpatients. CA-MRSA is considered to be spread and colonized in the hospital because of the high ability to form a biofilm. The number of isolates of CA-MRSA producing strong toxins is increasing. We screened and found effective inhibitors of biofilm formation of MRSA, and examined its mechanism of action and clinical application.

Free Research Field

病原微生物学

Academic Significance and Societal Importance of the Research Achievements

2011年～18年の間にMRSAの主流はHA-MRSAからCA-MRSAに置き換わった。CA-MRSAはバイオフィルム形成能が極めて高く、院内に拡散し定着した。CA-MRSAは低年齢層から分離され、Ⅱ・Ⅲ期では皮膚感染症に関わる毒素であるedn, eta遺伝子を同時に保有する株が小児の皮膚科領域で複数株検出たのに加え、PVLを産生株も複数個見出された。特にⅢ期ではpvlとacme遺伝子を同時に保有する強毒株のUSA300株が今回の調査では初めて検出された。新たなリスクファクターを有するCA-MRSAが小児科・皮膚科で拡大することが懸念され、CA-MRSA有効な院内感染対策の構築が求められる。