Publications by authors named "Masao Kuwabara"

Article Synopsis
  • * Phylogenetic analysis identified the outbreak was predominantly caused by sequence type (ST) 80, which originated from an Indian strain and was actively spreading across hospitals in the area.
  • * The research underscores the need for early interventions at a central hospital known to be the main hub of infection transmission to curb further spread, especially to smaller facilities with vulnerable populations.
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More than 200 million COVID-19 survivors have lasting symptoms after recovering, but the duration and related risk factors remain uncertain. This study focused on all 6551 patients diagnosed with COVID-19 at a medical institution in Hiroshima from March 2020 to July 2022. In November 2022, a questionnaire survey was conducted regarding post-COVID symptoms and their duration.

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Objectives: The present study investigates the diagnosis and prediction of COVID-19 based on clinical symptoms, and corresponding difference between the Delta- and Omicron-dominant periods, using data collected at polymerase chain reaction (PCR) centers in Hiroshima Prefecture, Japan.

Methods: Data was collected using a J-SPEED-style COVID-19 standard data collection form. The analysis was done in two directions: calculating the likelihood ratio that clinical symptoms will manifest in "infected" versus "non-infected" individuals and calculating the diagnostic odds ratio (OR) of infection for those who have symptoms compared to those without symptoms.

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Perceived discrimination and work impairment are commonly observed in COVID-19 survivors, but their relationship has not been well understood. We aimed to evaluate the role of discrimination in the development of psychological distress and work impairment in COVID-19 survivors. From April 2020 to November 2021, 309 patients were recruited at two designated COVID-19 hospitals in Japan.

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This study aimed to exercise the Sanger sequencing strategy for screening of variants among confirmed COVID-19 cases and validate our strategy against NGS strains in Hiroshima retrieved from GISAID. A total of 660 samples from confirmed COVID-19 cases underwent screening for variants by Sanger-based partial sequencing to the targeted spike gene (nt22,735~nt23,532) using an in-house-developed primer set. The identification of variants was done by unique checkpoints of base nucleotide changes in the targeted spike gene.

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This study aimed to develop the feasible and effective universal screening strategy of the notable SARS-CoV-2 variants by Sanger Sequencing Strategy and then practically applied it for mass screening in Hiroshima, Japan. A total of 734 samples from COVID-19 confirmed cases in Hiroshima were screened for the notable SARS-CoV-2 variants (B.1.

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With the widespread and increasing number of cases of Coronavirus Disease (2019) globally, countries have been taking preventive measures against this pandemic. However, there is no universal agreement across cultures on whether wearing face masks are an effective physical intervention against disease transmission. We investigated the relationship between mask wearing and COVID-19 among close contacts of COVID-19 patients in the Hiroshima Prefecture, Japan.

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Background: In this study, we performed molecular characterization of SARS-CoV-2 strains in Hiroshima and its mutation pattern between the first and second waves of the outbreak.

Method: A total of 55 nasal swab samples from the first wave in Hiroshima and 13 from the second wave were examined quantitatively by RT-qPCR and qualitatively by nested PCR using specific primers. Four samples from each wave underwent next-generation sequencing and phylogenetic tree analysis including controls and all sequences retrieved in Japan from GISAID and GenBank.

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Article Synopsis
  • A nationwide surveillance study on the antimicrobial susceptibility of bacterial respiratory pathogens in Japan was conducted between January 2014 and April 2015 by three medical societies.
  • The study evaluated 1534 bacterial strains obtained from diagnosed adult patients with respiratory infections, focusing on various pathogens like Staphylococcus aureus and Streptococcus pneumoniae.
  • Results indicated high resistance rates, with 43.6% of Staphylococcus aureus being methicillin-resistant and significant percentages of Haemophilus influenzae showing resistance to ampicillin.
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Article Synopsis
  • A nationwide study in Japan in 2012 focused on monitoring the antibiotic resistance of bacterial pathogens responsible for respiratory infections in adult patients.
  • A total of 1,236 bacterial strains were tested, revealing high resistance rates, including 51.3% methicillin-resistant Staphylococcus aureus and concerning levels of antibiotic resistance in other bacteria like Klebsiella pneumoniae and Pseudomonas aeruginosa.
  • The findings highlight the importance of ongoing surveillance to understand and address the increasing resistance of bacterial respiratory pathogens to antimicrobial treatments.
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The 2014/15 influenza season started earlier than usual, and intense activity was reflection of circulation of antigenically-drifted and vaccine-mismatched dominant A(H3N2) viruses. Although inpatients and health-care workers (HCWs) had a high influenza vaccination coverage rate well prior to the beginning of influenza season, numerous outbreaks of influenza A(H3N2) infection with fatal cases were reported in long-term care facilities (LTCFs) in Japan during 2014/15 influenza season. In January 2015, we were given opportunity to conduct outbreak investigation of influenza A at facility A (LTCF attached with hospital) in Western part of Japan.

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The objective of this study was to identify factors related to the expansion of infection and prevention of influenza A(H1N1)pdm09. A retrospective non-randomized cohort study (from June 2009 to May 2010) on influenza A(H1N1)pdm09 was conducted in a sample of residents from Hiroshima Prefecture, Japan. The cumulative incidence of the influenza A(H1N1)pdm09 and the pandemic vaccine effectiveness (VE) were estimated.

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The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, was conducted by Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases and Japanese Society for Clinical Microbiology in 2010. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period from January and April 2010 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical and Laboratory Standard Institutes using maximum 45 antibacterial agents.

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Mycoplasma pneumoniae is one of the common pathogens of the community-acquired pneumonia in adults and children. Macrolide antibiotics are considered to be the first-choice drug for M. pneumoniae infections.

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For the purpose of nationwide surveillance of antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, the Japanese Society of Chemotherapy (JSC) started a survey in 2006. From 2009, JSC continued the survey in collaboration with the Japanese Association for Infectious Diseases and the Japanese Society for Clinical Microbiology. The fourth-year survey was conducted during the period from January and April 2009 by the three societies.

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Recently, there have been reports concerning an increased frequency of isolation of multi-drug resistant Pseudomonas aeruginosa (MDRP) strains in hospitals and other clinical settings as well as the associated risk of their hospital-acquired infections; in such a situation, it has been a major challenge to establish methods of managing and treating the infections. In order to investigate the trend of P. aeruginosa, the Infection Forum in the Chugoku Region has conducted to a multi-center collaborative study to isolate P.

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For the purpose of nationwide surveillance of the antimicrobial susceptibility of bacterial respiratory pathogens collected from patients in Japan, the Japanese Society of Chemotherapy conducted a third year of nationwide surveillance during the period from January to April 2008. A total of 1,097 strains were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections. Susceptibility testing was evaluable with 987 strains (189 Staphylococcus aureus, 211 Streptococcus pneumoniae, 6 Streptococcus pyogenes, 187 Haemophilus influenzae, 106 Moraxella catarrhalis, 126 Klebsiella pneumoniae, and 162 Pseudomonas aeruginosa).

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Article Synopsis
  • The tumor was diagnosed as a mixed-type germ cell tumor after a CT-guided biopsy showed necrotizing tissue and immature cartilage-like tissue.
  • He underwent 4 cycles of combination chemotherapy, leading to a decrease in tumor size and AFP levels, followed by successful surgical resection with no signs of viable cells or recurrence for over 9 months.
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We have reported in this journal in vitro susceptibilities of clinical isolates to antibiotics every year since 1992. In this paper, we report the results of an analysis of in vitro susceptibilities of 12,919 clinical isolates from 72 centers in Japan to selected antibiotics in 2007 compared with the results from previous years. The common respiratory pathogens, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae maintained a high susceptibility to fluoroquinolones (FQs).

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There have been few studies on cancer incidence and survival among children in Japan. Childhood cancer cases in Hiroshima City can be ascertained almost perfectly in terms of completeness and validity as both a population-based cancer registry and a tissue registry cover the whole area. We report here recent incidence and survival of childhood cancer in Hiroshima City.

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To characterize the PK/PD of biapenem (BIPM) in critically ill patients under continuous venovenous hemodiafiltration (CVVHDF), we conducted a prospective, open-label study in nine adult CVVHDF patients with acute renal failure at the Critical Care Medical Center, Hiroshima Prefectural Hospital. Plasma and filtrate samples were obtained at six time points. The concentrations of BIPM in plasma and filtrate were determined by HPLC.

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Background: A pharmacokinetic-pharmacodynamic (PK-PD) target attainment analysis to build a dosing strategy for biapenem in adult patients has not been conducted.

Methods: A total of 321 plasma concentration samples from 68 adult patients (1-6 samples per patient) were assayed biologically and chromatographically, and used for a population PK modeling and Monte Carlo simulation to assess the probability of attaining the PK-PD target (40% of the time above the minimum inhibitory concentration).

Results: The population PK model was based on the standard two-compartment model, and creatinine clearance (Cl(cr)) was the most significant covariate that affected the drug clearance.

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Objectives: The susceptibility of clinical isolates of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), to host-derived cationic antimicrobial peptides was investigated.

Methods: We examined the susceptibility of 190 clinical strains of methicillin-susceptible S.

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A 44-year-old man presented with difficulties in gripping a ball with the left hand upon playing tennis. He developed muscle weakness involving the left limbs, as well as memory decline, with subsequent gradual worsening of such symptoms. Cranial MRI showed multiple high intensity lesions in the white matter on T2-weighted imaging and FLAIR imaging.

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Background And Aim: Proton pump inhibitor (PPI) monotherapy cannot cure all cases of gastroesophageal reflux disease (GERD), and combination therapy with prokinetics and PPI achieves symptomatic improvement for some GERD patients. Few studies have been performed to predict the need for prokinetics.

Methods: Subjects were 163 patients (64 male, mean age 53.

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