Faculty Profiles - SHIBAYAMA Keigo

Papers - SHIBAYAMA Keigo

Division display 61 - 80 of about 318 ／ All the affair displays >>

NHPHの基礎と臨床の新知見日本におけるNon-Helicobacter pylori Helicobacter species感染の実態調査中間報告

徳永健吾, 塚平俊久, 間部克裕, 鈴木秀和, 下山克, 杉本光繁, 沖本忠義, 松井英則, 柴山恵吾, 太田浩良, 村上和成, 加藤元嗣, 林原絵美子

日本ヘリコバクター学会学術集会プログラム・抄録集 Vol. 29回 page： 100 - 100 2023.6

Helicobacter ailurogastricus in Patient with Multiple Refractory Gastric Ulcers, Japan Reviewed International journal

Masaya Sano, Emiko Rimbara, Masato Suzuki, Hidenori Matsui, Miwa Hirai, Sae Aoki, Tsuyoshi Kenri, Keigo Shibayama, Hidekazu Suzuki

Emerging Infectious Diseases Vol. 29 ( 4 ) page： 833 - 835 2023.4

Language：English Publishing type：Research paper (scientific journal)

We report the isolation of Helicobacter ailurogastricus, a Helicobacter species that infects cats and dogs, from a person with multiple refractory gastric ulcers. In addition to H. suis, which infects pigs, Helicobacter species that infect cats and dogs should be considered as potential gastric pathogens in humans.

DOI： 10.3201/eid2904.221807

Detection of Bartonella quintana (Hyphomicrobiales: Bartonellaceae) Among Day Laborers in Osaka, Japan, 2009-2010. International journal

Toshinori Sasaki, Mayumi Matsuoka, Kyoko Sawabe, Haruhiko Isawa, Keigo Shibayama, Mutsuo Kobayashi

Journal of medical entomology Vol. 60 ( 2 ) page： 408 - 411 2023.3

Language：English Publishing type：Research paper (scientific journal)

Bartonella quintana is a gram-negative bacterium causing trench fever, an illness historically acquired by soldiers during World War I. More recently, outbreaks of trench fever have been reported in those experiencing homelessness in the United States, France, Russia, and Tokyo, as well as in children in Nepal and persons in Ethiopia. Reports of B. quintana infection outside of Tokyo are rare in Japan. The aim of this study was to examine body lice and blood obtained from people staying in shelters in Osaka (2009-2010) for B. quintana via polymerase chain reaction and enzyme-linked immunosorbent assays. Day laborers were defined as homeless individuals and shelter residents in this study. We detected genes of B. quintana in body lice by PCR and antibodies against B. quintana. The positive rate of B. quintana genes was 6/10 (60%) in body lice and the seroprevalence (IgG) of B. quintana was 4/10 (40%). This demonstrates that trench fever was endemic in people staying in shelters in Osaka in 2009-2010.

DOI： 10.1093/jme/tjad001

敗血症患者血液由来および健常者皮膚分離Bacillus cereus株芽胞のポビドンヨード感受性

石原由華, 柴山恵吾, 社本生衣, 宇佐美久枝, 太田美智男

日本環境感染学会誌 Vol. 38 ( 2 ) page： 57 - 60 2023.3

Language：Japanese Publisher：(一社)日本環境感染学会

Bacillus cereus芽胞のポビドンヨードに対する感受性を血液由来15株と健常者皮膚分離15株の芽胞を用いて作用時間と温度を変えて検討した.いずれの処理条件でも高度耐性株はなく,多くの菌株で10%ポビドンヨード処理5分で約99%の芽胞が殺菌されたが,残りの約1%の芽胞は30分処理後も生残した.皮膚由来株5株,血液由来株3株は5分処理後に生菌数が約0.1%になった.作用温度の違いによるポビドンヨードの効果には大きな差が無く,また血液由来株と皮膚由来株の間に差がほとんど見られなかった.以上によりB.cereus芽胞による皮膚汚染が軽度なら10%ポビドンヨードによる消毒が可能と考えられた.(著者抄録)

researchmap

Association between the proportion of laparoscopic approaches for digestive surgeries and the incidence of consequent surgical site infections, 2009–2019: A retrospective observational study based on national surveillance data in Japan International journal Open Access

Toshiki Kajihara, Koji Yahara, Aki Hirabayashi, Yumiko Hosaka, Norikazu Kitamura, Motoyuki Sugai, Keigo Shibayama

PLOS ONE Vol. 18 ( 2 ) page： e0281838 - e0281838 2023.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Public Library of Science (PLoS)

Background

Surgical site infections (SSIs) are among the most common healthcare-associated infections. Laparoscopy is increasingly being used in various surgical procedures. However, no study has examined the association between the proportion of laparoscopic procedures and the incidence of SSIs in digestive surgery using nationwide surveillance data.

Methods

We retrospectively investigated national SSI surveillance data from the Japan Nosocomial Infections Surveillance between 2009 and 2019. The annual trend of the SSI rate and the proportion of laparoscopic procedures were assessed, focusing on five major digestive surgeries. This was based on data from 109,544 (appendix surgery), 206,459 (gallbladder surgery), 60,225 (small bowel surgery), 363,677 (colon surgery), and 134,695 (rectal surgery) procedures. The effect of a 10% increase in the proportion of laparoscopic procedures on the reduction of the SSI rate was estimated using mixed-effect logistic regression.

Findings

The average SSI rate of the five digestive surgeries decreased from 11.8% in 2009 to 8.1% in 2019. The proportion of laparoscopic procedures in each of the five digestive surgeries increased continuously (p<0.001). The SSI rate for laparoscopic procedures was always lower than that for open procedures. The results were consistent between all and core hospitals participating in the surveillance. The odds ratios of the 10% increase in the proportion of laparoscopic procedures for five digestive surgeries were always <0.950 (p<0.001).

Conclusion

An increase in the proportion of laparoscopic procedures was associated with a reduction in the SSI rate in digestive surgeries.

DOI： 10.1371/journal.pone.0281838

黄色ブドウ球菌における多剤耐性表現型のサーベイランスとWGS所見との相関性(Surveillance of multidrug resistance phenotypes in S. aureus and correlation with WGS findings)

矢原耕史, 保阪由美子, Clarck Adam, 北川浩樹, 久恒順三, 菅井基行, 柴山恵吾, Stelling John

日本細菌学雑誌 Vol. 78 ( 1 ) page： 105 - 105 2023.2

Helicobacter cinaediの新規オートトランスポーター蛋白質HcaAの特徴(Characterization of novel autotransporter protein HcaA in Helicobacter cinaedi)

青木沙恵, 森茂太郎, 松井英則, 柴山恵吾, 見理剛, 林原絵美子

日本細菌学雑誌 Vol. 78 ( 1 ) page： 87 - 87 2023.2

ヘリコバクター・スイスとヘリコバクター・ピロリ感染の世界初の同時診断(The world's first simultaneous diagnostic approach of H. suis and H. pylori infection)

松井英則, 林原絵美子, 青木沙恵, 柴山恵吾, 鈴木仁人

日本細菌学雑誌 Vol. 78 ( 1 ) page： 68 - 68 2023.2

今月の主題 Non-H. pylori Helicobacter胃炎と周辺疾患主題症例除菌にて完全寛解したHelicobacter suis感染胃MALTリンパ腫の1例

徳永健吾, 大野亜希子, 井田陽介, 三好佐和子, 神保陽子, 林原絵美子, 松井英則, 柴山恵吾, 鈴木仁人, 大崎敬子, 太田浩良, 二階雪野, 長濱清隆, 柴原純二, 岡本晋, 久松理一

胃と腸 Vol. 58 ( 1 ) page： 87 - 94 2023.1

胃MALTリンパ腫とNon-Helicobacter pylori Helicobacterの関連

徳永健吾, 林原絵美子, 柴山恵吾, 鈴木仁人, 松井英則, 太田浩良, 井田陽介, 三好佐和子, 岡本晋, 楠原光謹, 大野亜希子, 久松理一, 大崎敬子

日本ヘリコバクター学会誌 Vol. 24 ( 2 ) page： 154 - 159 2023.1

Language：Japanese Publisher：(一社)日本ヘリコバクター学会

近年、H.pylori(H.p.)感染者の多くが除菌を受け、また衛生環境が良くなったことでH.p.感染者は減少したが、一方でH.p.以外のHelicobacter(NHPH)による胃疾患が相対的に増加している。胃型NHPHには、H.suis、H.felis、H.heilmannii、H.salomonisなどが存在する。1)H.p.感染の胃MALTリンパ腫、2)H.p.未感染の胃MALTリンパ腫、3)胃MALTリンパ腫とNHPH感染、4)NHPH感染胃MALTリンパ腫の内視鏡像、5)H.p.未感染胃MALTリンパ腫に対する除菌効果、6)NHPH感染胃MALTリンパ腫に対する除菌効果、について概説した。

researchmap

Other Link： https://search.jamas.or.jp/default/link?pub_year=2023&ichushi_jid=J05115&link_issn=&doc_id=20230216410011&doc_link_id=%2Fdy6jahel%2F2023%2F002402%2F019%2F0154-0159%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdy6jahel%2F2023%2F002402%2F019%2F0154-0159%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

非HP非NSAID・難治性胃・十二指腸潰瘍の診断と治療非H.pylori非NSAIDs特発性胃・十二指腸潰瘍におけるNHPH含む成因の検討

徳永健吾, 大野亜希子, 楠原光謹, 林原絵美子, 松井英則, 鈴木仁人, 柴山恵吾, 大崎敬子, 三好佐和子, 井田陽介, 岡本晋, 久松理一

日本消化管学会雑誌 Vol. 7 ( Suppl. ) page： 164 - 164 2023.1

Genotyping of Mycoplasma pneumoniae strains isolated in Japan during 2019 and 2020: spread of p1 gene type 2c and 2j variant strains. International journal Open Access

Tsuyoshi Kenri, Tsutomu Yamazaki, Hitomi Ohya, Michio Jinnai, Yoichiro Oda, Sadasaburo Asai, Rikako Sato, Nobuhisa Ishiguro, Tomohiro Oishi, Atsuko Horino, Hiroyuki Fujii, Toru Hashimoto, Hiroshi Nakajima, Keigo Shibayama

Frontiers in microbiology Vol. 14 page： 1202357 - 1202357 2023

Language：English Publishing type：Research paper (scientific journal)

We characterized 118 Mycoplasma pneumoniae strains isolated from three areas of Japan (Saitama, Kanagawa, and Osaka) during the period of 2019 and 2020. Genotyping of the p1 gene in these strains revealed that 29 of them were type 1 lineage (29/118, 24.6%), while 89 were type 2 lineage (89/118, 75.4%), thereby indicating that type 2 lineage was dominant in this period. The most prevalent variant of type 2 lineage was type 2c (57/89, 64%), while the second-most was type 2j, a novel variant identified in this study (30/89, 33.7%). Type 2j p1 is similar to type 2 g p1, but cannot be distinguished from reference type 2 (classical type 2) using the standard polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) with HaeIII digestion. Thus, we used MboI digestion in the PCR-RFLP analysis and re-examined the data from previous genotyping studies as well. This revealed that most strains reported as classical type 2 after 2010 in our studies were actually type 2j. The revised genotyping data showed that the type 2c and 2j strains have been spreading in recent years and were the most prevalent variants in Japan during the time-period of 2019 and 2020. We also analyzed the macrolide-resistance (MR) mutations in the 118 strains. MR mutations in the 23S rRNA gene were detected in 29 of these strains (29/118, 24.6%). The MR rate of type 1 lineage (14/29, 48.3%) was still higher than that of type 2 lineage (15/89, 16.9%); however, the MR rate of type 1 lineage was lower than that found in previous reports published in the 2010s, while that of type 2 lineage strains was slightly higher. Thus, there is a need for continuous surveillance of the p1 genotype and MR rate of M. pneumoniae clinical strains, to better understand the epidemiology and variant evolution of this pathogen, although M. pneumoniae pneumonia cases have decreased significantly since the COVID-19 pandemic.

DOI： 10.3389/fmicb.2023.1202357

Genomic Epidemiological Analysis of Antimicrobial-Resistant Bacteria with Nanopore Sequencing. International journal

Masato Suzuki, Yusuke Hashimoto, Aki Hirabayashi, Koji Yahara, Mitsunori Yoshida, Hanako Fukano, Yoshihiko Hoshino, Keigo Shibayama, Haruyoshi Tomita

Methods in molecular biology (Clifton, N.J.) Vol. 2632 page： 227 - 246 2023

Language：English Publishing type：Research paper (scientific journal)

Antimicrobial-resistant (AMR) bacterial infections caused by clinically important bacteria, including ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) and mycobacteria (Mycobacterium tuberculosis and nontuberculous mycobacteria), have become a global public health threat. Their epidemic and pandemic clones often accumulate useful accessory genes in their genomes, such as AMR genes (ARGs) and virulence factor genes (VFGs). This process is facilitated by horizontal gene transfer among microbial communities via mobile genetic elements (MGEs), such as plasmids and phages. Nanopore long-read sequencing allows easy and inexpensive analysis of complex bacterial genome structures, although some aspects of sequencing data calculation and genome analysis methods are not systematically understood. Here we describe the latest and most recommended experimental and bioinformatics methods available for the construction of complete bacterial genomes from nanopore sequencing data and the detection and classification of genotypes of bacterial chromosomes, ARGs, VFGs, plasmids, and other MGEs based on their genomic sequences for genomic epidemiological analysis of AMR bacteria.

DOI： 10.1007/978-1-0716-2996-3_16

Scopus

PubMed

researchmap

A Nationwide Plasmidome Surveillance in Thailand Reveals a Limited Variety of New Delhi Metallo-β-Lactamase-Producing Carbapenem-Resistant Enterobacteriaceae Clones and Spreading Plasmids International journal

Ryuichiro Abe, Yukihiro Akeda, Noriko Sakamoto, Dan Takeuchi, Yo Sugawara, Norihisa Yamamoto, Anusak Kerdsin, Yuki Matsumoto, Daisuke Motooka, Warawut Laolerd, Pitak Santanirand, Masato Suzuki, Keigo Shibayama, Kazunori Tomono, Tetsuya Iida, Shigeyuki Hamada

Journal of Clinical Microbiology Vol. 60 ( 12 ) page： e0108022 2022.11

Language：English Publishing type：Research paper (scientific journal) Publisher：American Society for Microbiology

Despite frequent identification of plasmids carrying carbapenemase genes, the transfer of plasmids carrying carbapenemase genes is not well recognized in clinical settings because of technical limitations. To investigate the detailed mechanisms of the spread of carbapenem-resistant Enterobacteriaceae (CRE), we performed multifaceted genomic surveillance of CRE isolates in Thailand and analyzed their plasmidome.

DOI： 10.1128/jcm.01080-22

Scopus

PubMed

researchmap

Characterization of HcaA, a novel autotransporter protein in Helicobacter cinaedi, and its role in host cell adhesion

Sae Aoki, Shigetarou Mori, Hidenori Matsui, Keigo Shibayama, Tsuyoshi Kenri, Emiko Rimbara

bioRxiv 2022.11

Development of a serological assay to simultaneously identify Helicobacter suis and Helicobacter pylori infection International journal Open Access

Hidenori Matsui, Emiko Rimbara, Masato Suzuki, Kengo Tokunaga, Hidekazu Suzuki, Masaya Sano, Takashi Ueda, Hitoshi Tsugawa, Sohachi Nanjo, Akira Takeda, Makoto Sasaki, Shuichi Terao, Tsuyoshi Suda, Sae Aoki, Keigo Shibayama, Hiroyoshi Ota, Katsuhiro Mabe

iScience Vol. 26 ( 4 ) page： 106522 - 106522 2022.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Cold Spring Harbor Laboratory

BackgroundHelicobacter suis hosted by hogs is the most-prevalent gastric non-Helicobacter pylori Helicobacter species (NHPH) found in humans with gastric diseases. However, there is no reliable method for diagnosing H. suis infection in clinical practice without gastric biopsy specimens.MethodsHelicobacter infection was diagnosed by using routine methods for detecting H. pylori infection and three other methods (PCR, culture accompanied by genomic analyses, and microscopy) for detecting NHPH and H. pylori infection using gastric biopsy specimens. Then, an ELISA was developed to detect serum anti-H. suis and anti-H. pylori antibody titers. Findings The serum specimens (n=101) were divided into specimens with (n=20) and without H. suis infection (n=81), or into specimens with (n=17) or without H. pylori infection (n=64) after excluding H. pylori infection-eradicated specimens (n=20). The cut-off values of the optical density in the ELISA were used to judge Helicobacter infections. The sensitivity and specificity were 100% and 92.5%, respectively, for identifying H. suis infection, or 88.2% and 87.5%, respectively, for identifying H. pylori infection, and these levels were considered acceptable for clinical application. We detected no other NHPH infections by PCR or culture in this study.Interpretation We developed the world′s first ELISA to simultaneously diagnose H. suis and H. pylori infection, which is available for large-scale medical examination. The eradication of H. suis was confirmed by the time-dependent decline of anti-H. suis antibody titers. Funding This work was supported by MEXT/JSPS KAKENHI (JP19H03474, JP20K08365) and AMED (JP20fk0108148, JP20fk0108133).

DOI： 10.1101/2022.10.10.22280809

Strand-biased circularizing integrative elements spread tmexCD-toprJ gene clusters encoding RND-type multidrug efflux pumps by repeated transpositions

Trung Duc Dao, Hirokazu Yano, Taichiro Takemura, Aki Hirabayashi, Le Thi Trang, Hoang Huy Tran, Keigo Shibayama, Futoshi Hasebe, Ikuro Kasuga, Masato Suzuki

bioRxiv 2022.9

Language：English Publisher：Cold Spring Harbor Laboratory

Antimicrobial resistance genes (ARGs) are associated with mobile genetic elements (MGEs) that conscript useful genes into the human-microbe and microbe-microbe battlefields. Thus, under intense selective pressure, ARGs have been constantly adapting and evolving, spreading among microbes. tmexCD-toprJ gene clusters, which encode resistance-nodulation-cell division (RND)-type efflux pumps, confer multidrug-resistance to clinically important antimicrobials, including tigecycline. Noteworthily, these gene clusters have emerged in gram-negative bacteria in humans, animals, and the environment worldwide by MGE-mediated transfer. Here we show a hidden MGE, strand-biased circularizing integrative element (SE), that is recently recognized to mediate transpositions of ARGs, associated with the spread of tmexCD-toprJ gene clusters. We identified multidrug-resistant isolates of Aeromonas species in a water environment in Vietnam that harbored multiple copies of tmexCD-toprJ in their chromosomes that were associated with SEs. In particular, Aeromonas hydrophila NUITM-VA1 was found to harbor two copies of a novel variant of tmexC3.3D3.3-topJ1 within cognate SEs, whereas Aeromonas caviae NUITM-VA2 harbored four copies of a novel variant of tmexC2D2.3-topJ2 within cognate SEs. Based on the nature of SE to incorporate a neighboring sequence into the circular form and reinsert it into target sites during transposition, we identified the order of intragenomic movements of tmexCD-toprJ gene clusters. Altogether, our findings suggest that most known subgroups of tmexCD-toprJ and their subvariants underwent transpositions among bacterial chromosomes and plasmids via SEs. Hence, a tmexCD-toprJ gene cluster ancestor may have been initially mobilized via SE, subsequently spreading among bacteria and evolving in new hosts.

DOI： 10.1101/2022.09.22.508988

researchmap

Emergence of plasmid-mediated RND-type efflux pump gene cluster tmexCD-toprJ in Shewanella xiamenensis in a water environment

Trung Duc Dao, Taichiro Takemura, Ikuro Kasuga, Aki Hirabayashi, Nguyen Thi Nga, Pham Hong Quynh Anh, Nguyen Dong Tu, Le Thi Trang, Hoang Huy Tran, Keigo Shibayama, Futoshi Hasebe, Masato Suzuki

bioRxiv 2022.9

Language：English Publisher：Cold Spring Harbor Laboratory

The emergence of the mobile resistance-nodulation-division (RND)-type efflux pump tmexCD-toprJ gene cluster that confers multidrug resistance (MDR), including tigecycline resistance, in gram-negative bacteria poses a global public health threat. However, the spread of such clinically important antimicrobial resistance genes (ARGs) in the natural environment has not yet been well investigated. In this study, we investigated MDR aquatic bacteria in Vietnam. A carbapenem- and tigecycline-resistant Shewanella xiamenensis isolate NUITM-VS2 was obtained from urban drainage in Hanoi, Vietnam, in October 2021. S. xiamenensis NUITM-VS2 showed resistance to most antimicrobials tested, including tigecycline, tetracyclines, carbapenems, cephalosporins, fluoroquinolone, and aminoglycosides. Whole-genome analysis was performed by long- and short-read sequencing, resulting in the complete genome sequence consisting of one chromosome and five plasmid sequences. ARGs and plasmid replicons in the genome were detected using ResFinder with the custom ARG database, including all known tigecycline resistance genes, and PlasmidFinder, respectively. A 152.2-kb IncC plasmid, pNUITM-VS2_2, co-carried two mobile tigecycline resistance genes, tet(X4) and tmexC3.1D3.1-toprJ1. In addition, a 24.8-kb untypeable plasmid, pNUITM-VS2_4, carried the carbapenemase gene blaNDM-1. pNUITM-VS2_2 was transferred to Escherichia coli by conjugation, which simultaneously conferred high-level resistance against many antimicrobials, including tigecycline. To the best of our knowledge, this is the first report of the detection of the mobile RND-type efflux pump gene cluster tmexCD-toprJ in Shewanella species. Our results provide genetic evidence of the complexity of the dynamics of clinically important ARGs among aquatic bacteria, which could be important reservoirs for ARGs in the natural environment.

DOI： 10.1101/2022.09.15.508154

researchmap

Clonal dissemination of carbapenem-resistant Klebsiella pneumoniae ST16 co-producing NDM-1 and OXA-232 in Thailand Reviewed International journal Open Access

Ryuichiro Abe, Yukihiro Akeda, Dan Takeuchi, Noriko Sakamoto, Yo Sugawara, Norihisa Yamamoto, Anusak Kerdsin, Yuki Matsumoto, Daisuke Motooka, Warawut Leolerd, Pitak Santanirand, Masato Suzuki, Keigo Shibayama, Kazunori Tomono, Tetsuya Iida, Shigeyuki Hamada

JAC-Antimicrobial Resistance Vol. 4 ( 4 ) page： dlac084 2022.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

Abstract

Background

Klebsiella pneumoniae ST258 and ST11 carrying blaKPC are among the most widespread carbapenem-resistant K. pneumoniae strains worldwide. Our carbapenem-resistant Enterobacteriaceae surveillance in Thailand revealed a nationwide dissemination of K. pneumoniae ST16 isolates carrying blaNDM-1 and blaOXA-232.

Objectives

To analyse the genomic details of this nationwide dissemination by focusing on plasmids and virulence factors.

Methods

Using WGS data of 119 K. pneumoniae ST16 isolates carrying blaNDM-1 obtained in our previous surveillance study, clonality of chromosomes and plasmids of the isolates with carriage of virulence factors was evaluated.

Results

Of the 119 isolates, 111 carried plasmid pKP151_NDM1, and all 104 isolates harbouring blaOXA-232 carried plasmid pKP151_OXA232. These 104 K. pneumoniae ST16 isolates showing chromosomal clonality possessed both pKP151_NDM1 and pKP151_OXA232, demonstrating clonal dissemination of K. pneumoniae ST16 with these plasmids. The isolates had essentially similar virulence factors as those of K. pneumoniae ST16 clones carrying blaKPC, which were recently reported as highly invasive clones in Brazil.

Conclusions

The potential global dissemination of these invasive clones with resistance to several antibiotics highlights the importance of appropriate monitoring and strict standard precautions.

DOI： 10.1093/jacamr/dlac084

Helicobacter suis胃粘膜感染と病態発症

鈴木仁人, 林原絵美子, 松井英則, 徳永健吾, 柴山恵吾

日本ヘリコバクター学会誌 Vol. 24 ( 1 ) page： 2 - 9 2022.5

Language：Japanese Publisher：(一社)日本ヘリコバクター学会

Helicobacter suisはブタが自然宿主と考えられている細菌で、ヒト胃での持続感染は胃粘膜関連リンパ組織(MALT)リンパ腫などの胃関連疾患の発症に関連していることが指摘されている。H.suisは過去にブタから単離培養されていたが、ヒトからの分離はなされていなかったため、ヒトにおいてH.suis感染と胃関連疾患発症の因果関係の証明は不完全なままとなっていた。本研究では、われわれはヒト胃から直接的にH.suisを分離し、in vitroで培養することに成功した。H.suisはHelicobacter pyloriと異なり、中性pHで著しく生存率が低下するため、胃生検の輸送には低pH培地を用いた。最終的に胃MALTリンパ腫を含む胃関連疾患患者3名からH.suisを分離することができた。患者全員において抗菌治療によりH.suisの除菌に成功し、内視鏡所見、病理組織学的所見が有意に改善された。H.suis臨床分離株をマウスに経口感染させると、胃粘膜で持続感染し、胃局所および全身性の炎症反応が惹起され、感染4ヵ月後には胃粘膜上皮化生が進行することが確認された。また、感染マウスの胃からH.suisが分離されたことから、本菌はヒトの胃関連疾患の起因菌としてコッホの原則を満たす形で初めて証明された。臨床分離株を用いたH.suisの比較ゲノム解析により、各分離株の染色体にはIV型分泌機構関連遺伝子などの株特異的な病原因子をコードする可塑性の高い領域が存在していること、ヒトとブタの分離株は遺伝的に非常に似ており、ブタ-ヒト感染の可能性があることが示唆された。(著者抄録)

researchmap

　 PREV - NEXT 　

<SHIBAYAMA Keigo>

Papers - SHIBAYAMA Keigo