Ethics

The study protocol conformed to the ethical guidelines of the Declaration of Helsinki and the Ethical Guidelines for Medical and Health Research involving Human Subjects by the Ministry of Health, Labor and Welfare of Japan. Ethical approval was obtained from the Institutional Review Boards (IRB) of Nagasaki University Hospital (#20081722). Informed consent to participate was obtained in writing from patients who underwent bacteriological search by real-time PCR. Because part of this study is a retrospective one, patient identifiable information was removed, and the research plan was published on the homepages of Nagasaki University Hospital websites, along with an opt-out option in accordance with IRB instructions.