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Featured researches published by Hiroki Namikawa.


BMC Infectious Diseases | 2016

Two unusual cases of successful treatment of hypermucoviscous Klebsiella pneumoniae invasive syndrome

Hiroki Namikawa; Koichi Yamada; Hiroki Fujimoto; Ken-Ichi Oinuma; Yoshihiro Tochino; Yasuhiko Takemoto; Yukihiro Kaneko; Taichi Shuto; Hiroshi Kakeya

BackgroundA few Japanese cases of hypermucoviscous Klebsiella pneumoniae (K. pneumoniae) invasive syndrome have recently been reported. Although extrahepatic complications from bacteremic dissemination have been observed, infected aneurysms are rare. Furthermore, the primary source of infection is generally a liver abscess, and is rarely the prostate. Therefore, we report two atypical cases of hypermucoviscous K. pneumoniae invasive syndrome.Case presentationThe first case was an 81-year-old Japanese man with no significant medical history, who was referred to our hospital for vision loss in his right eye. Contrast-enhanced whole-body computed tomography revealed abscesses in the liver and the prostate, and an infected left internal iliac artery aneurysm. Contrast-enhanced head magnetic resonance imaging revealed brain abscesses. Cultures of the liver abscess specimen and aqueous humor revealed K. pneumoniae with the hypermucoviscosity phenotype, which carried the magA gene (mucoviscosity-associated gene A) and the rmpA gene (regulator of mucoid phenotype A). We performed enucleation of the right eyeball, percutaneous transhepatic drainage, coil embolization of the aneurysm, and administered a 6-week course of antibiotic treatment. The second case was a 69-year-old Japanese man with diabetes mellitus, who was referred to our hospital with fever, pollakiuria, and pain on urination. Contrast-enhanced whole-body computed tomography revealed lung and prostate abscesses, but no liver abscesses. Contrast-enhanced head magnetic resonance imaging revealed brain abscesses. The sputum, urine, prostate abscess specimen, and aqueous humor cultures revealed K. pneumoniae with the hypermucoviscosity phenotype, which carried magA and rmpA. We performed enucleation of the left eyeball, percutaneous drainage of the prostate abscess, and administered a 5-week course of antibiotic treatment.ConclusionsHypermucoviscous K. pneumoniae can cause infected aneurysms, and the prostate can be the primary site of infection. We suggest that a diagnosis of hvKP invasive syndrome should be considered in all patients who present with K. pneumoniae infection and multiple organ abscesses.


Internal Medicine | 2017

Clinical Characteristics of Bacteremia Caused by Extended-spectrum Beta-lactamase-producing Escherichia coli at a Tertiary Hospital

Hiroki Namikawa; Koichi Yamada; Hiroki Fujimoto; Ken-Ichi Oinuma; Yoshihiro Tochino; Yasuhiko Takemoto; Yukihiro Kaneko; Taichi Shuto; Hiroshi Kakeya

Objective In recent years, infection caused by extended-spectrum beta-lactamase (ESBL)-producing organisms has become an important issue. However, comparative studies of the bacteremia caused by ESBL Enterobacteriaceae and non-ESBL Enterobacteriaceae are extremely rare in Japan. This study aimed to assess the risk factors and prognosis of patients with bacteremia due to ESBL Escherichia coli (E. coli). Methods The medical records of 31 patients with ESBL E. coli bacteremia and 98 patients with non-ESBL E. coli bacteremia who had been admitted to Osaka City University Hospital between January 2011 and June 2015 were retrospectively reviewed. The patient backgrounds, risk factors for infection, and prognosis were evaluated. Results The male-to-female ratio, mean age, underlying disease, leukocyte count, and C-reactive protein (CRP) level did not differ between the patients in the ESBL E. coli bacteremia and non-ESBL E. coli bacteremia groups. The mean Sequential Organ Failure Assessment (SOFA) score for patients with ESBL and non-ESBL E. coli bacteremia were 3.6 and 3.8, respectively. Further, the mortality did not differ between the two groups (9.7% vs 9.2%). However, the independent predictors associated with ESBL E. coli bacteremia according to a multivariate analysis were the use of immunosuppressive drugs or corticosteroids (p=0.048) and quinolones (p=0.005) prior to isolation. The mortality did not differ between the carbapenem and tazobactam/piperacillin (TAZ/PIPC) or cefmetazole (CMZ) groups for the patients with ESBL E. coli bacteremia. Conclusion Whenever we encountered patients with a history of immunosuppressive drug, corticosteroid, quinolone administration, it was necessary to perform antibiotic therapy while keeping the risk of ESBL E. coli in mind.


Tohoku Journal of Experimental Medicine | 2017

Clinical Characteristics and Low Susceptibility to Daptomycin in Enterococcus faecium Bacteremia

Hiroki Namikawa; Koichi Yamada; Wataru Shibata; Hiroki Fujimoto; Etsuko Takizawa; Makoto Niki; Kiyotaka Nakaie; Yasutaka Nakamura; Ken-Ichi Oinuma; Mamiko Niki; Yasuhiko Takemoto; Yukihiro Kaneko; Taichi Shuto; Hiroshi Kakeya

Enterococcus faecium has high levels of resistance to multiple antibiotics, and the mortality due to E. faecium bacteremia is high. Accordingly, E. faecium strains with low susceptibility to daptomycin are a concern in clinical practice. This study assessed the predictive factors and prognosis of patients with bacteremia due to E. faecium as well as the antimicrobial susceptibility, particularly to daptomycin, among E. faecium isolates. The medical records of patients admitted to Osaka City University Hospital with E. faecalis (n = 60) and E. faecium (n = 48) bacteremia between January 2011 and March 2016 were retrospectively reviewed. The E. faecalis group (mean age: 62.0 years) included 22 women, and the E. faecium group (mean age: 59.1 years) included 19 women. Predictive factors for infection, prognosis, and isolate antimicrobial susceptibilities were evaluated. The mean Sequential Organ Failure Assessment score and mortality rate did not differ between the two groups. The independent predictors of E. faecium bacteremia in multivariate analysis included quinolone use (p = 0.025), malignancy (p = 0.021), and prolonged hospitalization (p = 0.016). Cardiovascular disease was associated with a reduced risk of E. faecium bacteremia (p = 0.015). Notably, the percentage of E. faecium isolates with low daptomycin susceptibility was higher than that of E. faecalis (8.5% vs. 0%, p = 0.036). Thus, E. faecium should be considered when administering antibiotic therapy to patients with a history of these predictors. Furthermore, the use of daptomycin should be avoided in case of E. faecium with low susceptibility to daptomycin.


Journal of General and Family Medicine | 2017

Favorable effects of motivational interviewing and support in a patient with schizophrenia and alcohol abuse

Ayako Makuuchi; Yasuhiko Takemoto; Hiroshi Okamura; Takahiko Nakane; Hiroki Namikawa; Kazuo Fukumoto; Masanori Kobayashi; Shigeki Kinuhata; Mina Morimura; Kazuhiro Hirohashi; Masayuki Hino; Taichi Shuto

A 42‐year‐old man with schizophrenia was referred to our hospital after 2 weeks of worsening fatigue. His hemoglobin level was 2.8 g/dL owing to folic acid deficiency stemming from alcohol abuse and consumption of unbalanced meals. We induced behavioral changes in the patient by motivational interviewing. We had direct methodical conversations with medical staff involved with the patient as well as his family, and established new social support for him as well as public assistance. These have resulted in the patient maintaining a favorable lifestyle ever since.


Internal Medicine | 2017

Addison's Disease Caused by Tuberculosis with Atypical Hyperpigmentation and Active Pulmonary Tuberculosis

Hiroki Namikawa; Yasuhiko Takemoto; Shigeto Kainuma; Sakurako Umeda; Ayako Makuuchi; Kazuo Fukumoto; Masanori Kobayashi; Shigeki Kinuhata; Yoshihiro Isaka; Hiromitsu Toyoda; Noriko Kamata; Yoshihiro Tochino; Yoshikazu Hiura; Mina Morimura; Taichi Shuto

We herein report a case of Addisons disease caused by tuberculosis characterized by atypical hyperpigmentation, noted as exacerbation of the pigmentation of freckles and the occurrence of new freckles, that was diagnosed in the presence of active pulmonary tuberculosis. The clinical condition of the patient was markedly ameliorated by the administration of hydrocortisone and anti-tuberculosis agents. When exacerbation of the pigmentation of the freckles and/or the occurrence of new freckles are noted, Addisons disease should be considered as part of the differential diagnosis. In addition, the presence of active tuberculosis needs to be assumed whenever we treat patients with Addisons disease caused by tuberculosis, despite its rarity.


Journal of General and Family Medicine | 2015

Cronkhite-Canada Syndrome with Complete Remission after Four Months of Prednisolone Therapy and Polypectomy

Hiroki Namikawa; Yasuhiko Takemoto; Noriko Kamata; Masakazu Yashiro; Kazuhiro Hirohashi; Taichi Shuto

The etiology of and optimal treatments for Cronkhite‐Canada syndrome (CCS) are still undetermined. Fewer than 5% of CCS patients experience complete remission and 15% of CCS patients develop malignancies. Here, we present a case of CCS involving autoimmune disorders, in which rapid diagnosis, rapid commencement of therapy, and complete remission were achieved after 4 months of prednisolone therapy and polypectomy, although biopsy specimens from all residual colonic polyps revealed adenocarcinoma in one polyp 4 months after prednisolone therapy. It is important to identify gastrointestinal or colonic polyps harboring malignant changes and to examine the involvement of autoimmune mechanisms for better outcomes in CCS patients.


Internal Medicine | 2017

Clinical Characteristics of Methicillin-resistant Coagulase-negative Staphylococcal Bacteremia in a Tertiary Hospital

Koichi Yamada; Hiroki Namikawa; Hiroki Fujimoto; Kiyotaka Nakaie; Etsuko Takizawa; Yasuyo Okada; Akiko Fujita; Hiroyoshi Kawaguchi; Yasutaka Nakamura; Junko Abe; Yukihiro Kaneko; Hiroshi Kakeya


BMC Cancer | 2016

Disseminated carcinomatosis of the bone marrow from pancreatic cancer: a case report

Hiroki Namikawa; Yasuhiko Takemoto; Ayako Makuuchi; Masanori Kobayashi; Shigeki Kinuhata; Mina Morimura; Takashi Ikebe; Hiromu Tanaka; Taichi Shuto


Japanese Journal of Infectious Diseases | 2018

A Case of Imported Taenia asiatica Infection in Japan

Hiroki Namikawa; Yasuhiko Takemoto; Ikuji Shimazaki; Ayako Makuuchi; Masanori Kobayashi; Shigeki Kinuhata; Koichi Yamada; Hiroki Fujimoto; Hiromitsu Toyoda; Noriko Kamata; Yoshihiro Tochino; Isao Teramoto; Niichiro Abe; Mina Morimura; Hiroshi Kakeya; Taichi Shuto


Asia Pacific Family Medicine | 2018

The 1-min animal test as a mental status screening examination in patients with diabetes

Shigeki Kinuhata; Yasuhiko Takemoto; Mariko Senda; Shiho Nakai; Erika Tsumura; Tatsuyuki Otoshi; Sadahiko Hiratani; Kazuo Fukumoto; Hiroki Namikawa; Yoshihiro Tochino; Mina Morimura; Taichi Shuto; Sadahiko Uchimoto

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Masanori Kobayashi

Nippon Veterinary and Life Science University

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