医学部

鈴木 匡弘

スズキ マサヒロ  (Masahiro Suzuki)

基本情報

所属
藤田医科大学 医学部 医学科 准教授
学位
博士(農学)(名古屋大学)

J-GLOBAL ID
200901000682489578
researchmap会員ID
0000201773

研究キーワード

 1

経歴

 2

論文

 73
  • Taisuke Enokida, Sohei Harada, Koh Okamoto, Daisuke Ohkushi, Koichi Takeda, Kosuke Hoashi, Toshiharu Sasaki, Kazumi Takehana, Yohei Doi, Masahiro Suzuki, Brian Hayama
    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy 102656-102656 2025年2月7日  
    INTRODUCTION: Although skin and soft tissue infections (SSTIs) of the extremities are primarily caused by Gram-positive cocci (GPC), some cases are caused by Gram-negative rod (GNR). In addition, malignancy is a recognized risk factor for GNR infection. Nevertheless, information on the clinical and microbiologic characteristics of SSTIs of the extremities caused by GNR in patients with malignancy is limited. METHODS: Clinical and microbiological characteristics of patients with malignancy who developed bacteremic SSTIs of the extremities at a single cancer center over eight years were reviewed. In addition, whole-genome sequencing of the GNR isolates causing necrotizing fasciitis was conducted. RESULTS: Of 42 cases identified, 32 cases (76.2%) and 10 cases (23.8%) were caused by GPC and GNR, respectively. Four cases in the GNR group were due to Escherichia coli, and the remaining cases were caused by diverse species. The majority of cases in the GNR group were hospital-onset and the lesions were limited to a single extremity. Chronic liver disease, cellular immunodeficiency, or anatomic abnormalities of the gastrointestinal, biliary, or urinary tract underlay seven GNR cases (70%). Inappropriate empiric therapy was numerically more common in the GNR group compared to the GPC group (33.3% vs. 9.4%, p = 0.107). Whole-genome sequencing analysis revealed that two cases of GNR necrotizing fasciitis were caused by E. coli ST1193-fimH64 and Klebsiella pneumoniae K2-ST86. CONCLUSIONS: GNR organisms are a significant cause of SSTIs of the extremities in patients with malignancy and may be associated with inappropriate empiric therapy.
  • Yuka Kondo, Masahiro Suzuki, Shingo Sato, Soichi Maruyama, Akiko Sei, Xingyan Ma, Kota Nakano, Yohei Doi, Kentaro Tsukamoto
    Microbiology spectrum 13(1) e0192524 2025年1月7日  
    Bartonella henselae, a Gram-negative facultative intracellular bacterium, is the etiological agent of cat-scratch disease and also causes bacillary angiomatosis in immunocompromised individuals. Although the ability to promote vascular endothelial cell proliferation differs among Bartonella species, variations among strains within B. henselae remain unclear. Bartonella angiogenic factor A (BafA) and Bartonella adhesin A (BadA) have been identified as autotransporters of B. henselae that are involved in endothelial cell proliferation. Although strain-specific differences in the expression of BadA and the VirB/D4 type IV secretion system have been reported, BafA expression among B. henselae strains has yet to be examined. Therefore, the present study investigated the proliferation-promoting ability of 13 B. henselae strains from several sources in human umbilical vein endothelial cells (HUVECs). We identified BafA variants 1 and 2 based on the deduced amino acid sequences of its passenger domain. The recombinant proteins of both variants exhibited similar proliferation activity against HUVECs. However, BafA variant 2 strains showed cytotoxicity at a high bacterial inoculum in a direct coculture with HUVECs, which was attenuated in an indirect coculture. These strains, in contrast to BafA variant 1 strains, highly expressed BadA and exhibited bacterial aggregation. Based on a core genome SNP analysis of 50 B. henselae strains, the BafA variant types corresponded to clades 1-4. These results indicate that vasoproliferative traits differ among B. henselae clades based on the variant types. Therefore, this study provides a new conceptual framework in which the clades of B. henselae may predict their pathogenicity in humans.IMPORTANCEBartonella species including Bartonella henselae, Bartonella quintana, and Bartonella bacilliformis cause vasoproliferative lesions. Their proliferation-promoting ability in vascular endothelial cells differs among Bartonella species; however, it is unclear whether these differences exist among B. henselae strains. We herein showed that B. henselae strains exhibited variable proliferation-promoting ability and cytotoxicity in vascular endothelial cells, which corresponded to the bafA gene variants possessed by the strains. The expression levels of Bartonella angiogenic factor A (BafA) and Bartonella adhesin A, as well as the degree of proliferation-promoting ability and cytotoxicity in endothelial cells, varied among the strains. A core genome SNP analysis of strains using whole genome sequencing data divided B. henselae strains into four clades, with each clade corresponding to BafA variants 1-4. These results suggest the differential vasoproliferative potency of B. henselae, with potential implications in clinical management, including risk stratification and predictions of the clinical course.
  • Kohei Ukai, Yoshitaka Tomoda, Satoe Ishii, Satoshi Nakazato, Yohei Doi, Masahiro Suzuki, Sohei Harada
    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy 2024年12月14日  
    A 70-year-old Japanese man with well-controlled diabetes mellitus and chronic kidney disease was hospitalized for an examination of acute renal failure and elevated inflammatory reactions. He had a history of Klebsiella pneumoniae bacteremia without extended-spectrum β-lactamase (ESBL) production five months earlier. The patient was found to have bacteremia due to hypermucoviscous ESBL-producing Klebsiella pneumoniae, and developed septic shock, multiple cerebral infarctions, and an abscess in the left masticatory muscle space. The causative organism was resistant to ampicillin-sulbactam and piperacillin-tazobactam, which were used for empiric therapy, and the patient died despite subsequent definitive treatment with meropenem. Whole genome sequencing analysis showed that the strain of K. pneumoniae was ST412 with capsular genotype K57 and carried virulence genes iroBCDN, iucABCD, iutA, mrkABCDFHIJ, rmpA2, ybtAEPQSTUX. The strain also carried the blaCTX-M-15 ESBL gene. Although the antimicrobial susceptibility of the causative organisms of hvKp infections in Japan has been favorable in most cases, severe infections caused by ESBL-producing hvKp may increase in the near future considering the recent increase in ESBL-producing K. pneumoniae.
  • Miyu Isogai, Kumiko Kawamura, Tetsuya Yagi, Shizuo Kayama, Motoyuki Sugai, Yohei Doi, Masahiro Suzuki
    Microbial genomics 10(9) 2024年9月  
    Klebsiella pneumoniae is a Gram-negative bacterium that causes both community- and healthcare-associated infections. Although various virulence factors and highly pathogenic phenotypes have been reported, the pathogenicity of K. pneumoniae is still not fully understood. In this study, we utilized whole-genome sequencing data of 168 clinical K. pneumoniae strains to assess pathogenicity. This work was based on the concept that the genetic composition of individual genomes (referred to as holistic gene content) of the strains may contribute to their pathogenicity. Holistic gene content analysis revealed two distinct groups of K. pneumoniae strains ('major group' and 'minor group'). The minor group included strains with known highly pathogenic clones (ST23, ST375, ST65 and ST86). The minor group had higher rates of capsular genotype K1 and presence of nine specific virulence genes (rmpA, iucA, iutA, irp2, fyuA, ybtS, iroN, allS and clbA) compared to the major group. Pathogenicity was assessed using Galleria mellonella larvae. Infection experiments revealed lower survival rates of larvae infected with strains from the minor group, indicating higher virulence. In addition, the minor group had a higher string test positivity rate than the major group. Holistic gene content analysis predicted possession of virulence genes, string test positivity and pathogenicity as observed in the G. mellonella infection model. Moreover, the findings suggested the presence of as yet unrecognized genomic elements that are either involved in the acquisition of virulence genes or associated with pathogenicity.
  • Ryota Hase, Aki Sakurai, Masahiro Suzuki, Naoya Itoh, Kayoko Hayakawa, Kohei Uemura, Yasufumi Matsumura, Hideaki Kato, Takuma Ishihara, David van Duin, Norio Ohmagari, Yohei Doi, Sho Saito
    The Journal of antimicrobial chemotherapy 2024年6月6日  
    BACKGROUND: Stenotrophomonas maltophilia is a carbapenem-resistant Gram-negative pathogen increasingly responsible for difficult-to-treat nosocomial infections. OBJECTIVES: To describe the contemporary clinical characteristics and genome epidemiology of patients colonized or infected by S. maltophilia in a multicentre, prospective cohort. METHODS: All patients with a clinical culture growing S. maltophilia were enrolled at six tertiary hospitals across Japan between April 2019 and March 2022. The clinical characteristics, outcomes, antimicrobial susceptibility and genomic epidemiology of cases with S. maltophilia were investigated. RESULTS: In total, 78 patients were included representing 34 infection and 44 colonization cases. The median age was 72.5 years (IQR, 61-78), and males accounted for 53 cases (68%). The most common comorbidity was localized solid malignancy (39%). Nearly half of the patients (44%) were immunosuppressed, with antineoplastic chemotherapy accounting for 31%. The respiratory tract was the most common site of colonization (86%), whereas bacteraemia accounted for most infection cases (56%). The 30 day all-cause mortality rate was 21%, which was significantly higher in infection cases than colonization cases (35% versus 9%; adjusted HR, 3.81; 95% CI, 1.22-11.96). Susceptibility rates to ceftazidime, levofloxacin, minocycline and sulfamethoxazole/trimethoprim were 14%, 65%, 87% and 100%, respectively. The percentage of infection ranged from 13% in the unclassified group to 86% in genomic group 6A. The percentage of non-susceptibility to ceftazidime ranged from 33% in genomic group C to 100% in genomic groups 6 and 7 and genomic group geniculate. CONCLUSIONS: In this contemporary multicentre cohort, S. maltophilia primarily colonized the respiratory tract, whereas patients with bacteraemia had the highest the mortality from this pathogen. Sulfamethoxazole/trimethoprim remained consistently active, but susceptibility to levofloxacin was relatively low. The proportions of cases representing infection and susceptibility to ceftazidime differed significantly based on genomic groups.

MISC

 65

Works(作品等)

 1
  • Masahiro Suzuki
    2023年1月 - 現在 ソフトウェア
    GIGAdoc offers a graphical user interface (GUI) for bioinformatics software, facilitating microbial genome analysis on Docker. It's developed for use on Linux but is also compatible with Windows through WSL2. GIGAdoc simplifies the process of using advanced genomic analysis tools by providing a user-friendly interface. The latest version introduces several enhancements, including default settings for folders, support for fastANI and cgMLST, alongside other minor corrections, improving overall usability and functionality. The update on 28th February 2024 focuses on bug fixes, further stabilizing the application and enhancing user experience. Currently Supported Software

共同研究・競争的資金等の研究課題

 5