Toma Claudia



Associate Professor

Researcher Number(JSPS Kakenhi)


Homepage URL

Current Affiliation Organization 【 display / non-display

  • Duty   University of the Ryukyus   Graduate School of Medicine   Associate Professor  

Academic degree 【 display / non-display

  • University of the Ryukyus -  PhD

External Career 【 display / non-display

  • 2007.04

    University of the Ryukyus, Graduate School of Medicine, Research Associate  

  • 2017.04


Affiliated academic organizations 【 display / non-display

  • 1993.07

    Japanese Society for Bacteriology 

  • 2016.04

    Japanese Society of Tropical Medicine 

Research Interests 【 display / non-display

  • Bacterial Pathogenesis

Research Areas 【 display / non-display

  • Life Science / Bacteriology

Research Theme 【 display / non-display

  • Identification of Shiga Toxin-Producing Escherichia Coli (STEC) Adhesins

Published Papers 【 display / non-display

  • Analysis of human clinical and environmental Leptospira to elucidate the eco-epidemiology of leptospirosis in Yaeyama, subtropical Japan.

    Sato Y, Hermawan I, Kakita T, Okano S, Imai H, Nagai H, Kimura R, Yamashiro T, Kajita T, Toma C

    PLoS neglected tropical diseases ( PLoS Neglected Tropical Diseases )  16 ( 3 ) e0010234 - e0010234   2022.03 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    Background Leptospirosis, a zoonosis caused by species in the spirochete genus Leptospira, is endemic to the Yaeyama region in Okinawa, subtropical Japan. Species of the P1 subclade “virulent” group, within the genus Leptospira, are the main etiological agents of leptospirosis in Okinawa. However, their environmental persistence is poorly understood. This study used a combination of bacterial isolation and environmental DNA (eDNA) metabarcoding methods to understand the eco-epidemiology of leptospirosis in this endemic region. Findings Polymerase chain reaction (PCR) characterized twelve human clinical L. interrogans isolates belonging to the P1 subclade “virulent” subgroup and 11 environmental soil isolates of the P1subclade “low virulent” subgroup (genetically related to L. kmetyi, n = 1; L. alstonii, n = 4; L. barantonii, n = 6) from the Yaeyama region targeting four virulence-related genes (lipL32, ligA, ligB and lpxD1). Clinical isolates were PCR positive for at least three targeted genes, while all environmental isolates were positive only for lipL32. Analysis of infected renal epithelial cells with selected clinical and environmental strains, revealed the disassembly of cell-cell junctions for the Hebdomadis clinical strain serogroup. Comparison of leptospiral eDNA during winter and summer identified operational taxonomic units corresponding to the species isolated from soil samples (L. kmetyi and L. barantonii) and additional P2 subclade species (L. licerasiae, L. wolffii-related, among others) that were not detected by soil cultivation. Total Leptospira read counts were higher in summer than in winter and the analysis of leptospiral/animal eDNA relationship suggested Rattus spp. as a potential reservoir animal. Conclusion Our study demonstrated high environmental Leptospira diversity in the Yaeyama region, particularly during summer, when most of the leptospirosis cases are reported. In addition, several Leptospira species with pathogenic potential were identified that have not yet been reported in Yaeyama; however, the environmental persistence of P1 subclade species previously isolated from human clinical cases in this region was absent, suggesting the need of further methodology development and surveillance.

  • Disassembly of the apical junctional complex during the transmigration of Leptospira interrogans across polarized renal proximal tubule epithelial cells.

    Sebastián I, Okura N, Humbel BM, Xu J, Hermawan I, Matsuura C, Hall M, Takayama C, Yamashiro T, Nakamura S, Toma C

    Cellular microbiology ( Cellular Microbiology )  23 ( 9 ) e13343   2021.09 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

  • Understanding leptospirosis eco-epidemiology by environmental DNA metabarcoding of irrigation water from two agro-ecological regions of Sri Lanka

    Chandika D. Gamage, Yukuto Sato, Ryosuke Kimura, Tetsu Yamashiro, Claudia Toma

    PLOS Neglected Tropical Diseases   14 ( 7 ) e0008437   2020.07 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

  • Evaluation of Intracellular Trafficking in Macrophages.

    Toma C, Suzuki T

    Methods in molecular biology (Clifton, N.J.) ( Methods in Molecular Biology )  2134   199 - 206   2020 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

  • Environmental DNA metabarcoding to detect pathogenic Leptospira and associated organisms in leptospirosis-endemic areas of Japan.

    Sato Y, Mizuyama M, Sato M, Minamoto T, Kimura R, Toma C

    Scientific reports ( Springer Science and Business Media LLC )  9 ( 1 ) 6575   2019.04 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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Other Papers 【 display / non-display

  • Vibrio cholerae type IV pili

    Toma C., Nakasone N., and Iwanaga M

    Recent Res. Devel. Infection ( その他の出版社 )  1 ( 1 ) 167 - 178   2003.03



Presentations 【 display / non-display

  • Environmental DNA metabarcoding to understand the ecology of leptospirosis

    Claudia Toma

    World Congress on Leptospirosis  (Port Blair, Andaman and Nicobar Islands, India)  2019.11  -  2019.11 

  • Leptospira interrogans translocation across renal proximal tubule epithelial cells

    Toma C, Sebastian I, Okura N.

    The 18th International Forum on Infection and Immunity  (Awaji Yumebutai International Conference Center, Hyogo, Japan)  2019.09  -  2019.10 

  • Evaluation of a leptospiral enzyme for diagnosis of acute leptospirosis

    Toma C, Koizumi N, Kakita T, Kyan H, Hermawan I, Higa N, Yamashiro T.

    10th International Leptospirosis Society Conference  (Parlmerston North, New Zealand)  2017.11  -  2017.12 

  • Analysis of the bacterial factors involved in Leptospira interrogans-macrophage interactions

    Toma C, Murray GL, Higa N, Nakasone N, Nohara T, Takaesu G, Koizumi N, Adler B, Suzuki T.

    8th Scientific Meeting of International Leptospirosis Society  (Fukuoka, Japan)  2013.10  -  2013.10 

  • Mechanism of macrophage infection by Leptospira interrogans

    Toma C, Koizumi Y, Okura N, Nakasone N, Higa N, Ogura Y, Takayama C, Suzuki T.

    Gordon Research Conference, Biology of Spirochetes,   (Ventura, CA, USA)  2010.01  -  2010.02 

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Industrial Property 【 display / non-display

  • Antibodies to detect a leptospiral antigen for the diagnosis of leptospirosis

    Industrial Property No 2017-226148  (2017.11.24)

    Unexpectedly No 2018-127442  (2020.07.02)

    Claudia Toma

SDGs 【 display / non-display

  • 感染症の対策