Details of a Researcher - YOKOTA Shinichi

Papers - YOKOTA Shinichi

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A Hydroxypropyl Methylcellulose Plaque Assay for Human Respiratory Syncytial Virus.

Yuka Takumi-Tanimukai, Soh Yamamoto, Noriko Ogasawara, Sayaka Nakabayashi, Katsumi Mizuta, Keisuke Yamamoto, Ryo Miyata, Takuya Kakuki, Sumito Jitsukawa, Toyotaka Sato, Hiroyuki Tsutsumi, Takashi Kojima, Kenichi Takano, Shin-Ichi Yokota

Journal of virological methods 114528 - 114528 2022.03 [International journal]

Quantifying proliferative virus particles is one of the most important experimental procedures in virology. Compared with classical overlay materials, newly developed cellulose derivatives enable a plaque-forming assay to produce countable clear plaques easily. HEp-2 cells are widely used in plaque assays for human respiratory syncytial virus (RSV). It is crucial to use an overlay material to keep HEp-2 cell proliferation and prevent RSV particles from spreading over the fluid. Among four cellulose derivatives, carboxymethyl cellulose sodium salt (CMC), hydroxypropyl methylcellulose (HPMC), microcrystalline cellulose (MCC), and hydroxyethyl cellulose (HEC), we found that HPMC was the optimal overlay material because HPMC maintained HEp-2 cell proliferation and RSV infectivity. Although MCC was unsuitable for RSV, it assisted the plaque-forming by human metapneumovirus in TMPRSS2-expressing cells. Therefore, depending on the cells and viruses, it is necessary to use different overlay materials at varying concentrations.

DOI PubMed

Solid-Phase Total Synthesis of Plusbacin A3.

Kazuki Takashina, Akira Katsuyama, Rintaro Kaguchi, Kazuki Yamamoto, Toyotaka Sato, Satoshi Takahashi, Motohiro Horiuchi, Shin-Ichi Yokota, Satoshi Ichikawa

Organic letters 24 ( 11 ) 2253 - 2257 2022.03 [International journal]

DOI PubMed

Corrigendum to "Design, synthesis and biological evaluation of simplified analogues of MraY inhibitory natural product with rigid scaffold" Bioorganic & Medicinal Chemistry 55 (2021) 116556.

Kazuhiro Okamoto, Aoi Ishikawa, Ryotaro Okawa, Kazuki Yamamoto, Toyotaka Sato, Shin-Ichi Yokota, Kazuhiro Chiba, Satoshi Ichikawa

Bioorganic & medicinal chemistry 61 116689 - 116689 2022.03 [Refereed] [International journal]

DOI PubMed

Establishment of a reference panel of Helicobacter pylori strains for antimicrobial susceptibility testing.

Kenji Yokota, Takako Osaki, Shunji Hayashi, Shin-Ichi Yokota, Hiroaki Takeuchi, Emiko Rimbara, Hinako Ojima, Toyotaka Sato, Hideo Yonezawa, Keigo Shibayama, Kengo Tokunaga, Shigeru Kamiya, Kazunari Murakami, Mototsugu Kato, Toshiro Sugiyama

Helicobacter e12874 2022.03 [International journal]

BACKGROUND: Eradication treatment for Helicobacter pylori gastritis is covered by national health insurance since 2013 in Japan. However, eradication failure due to the increase of antimicrobial resistance has become a serious problem. The present study aims to establish a reference panel of Japanese H. pylori strains for antimicrobial susceptibility testing. METHOD: A total of 28 strains were collected from 4 medical facilities in Japan. Antimicrobial susceptibility tests (ASTs) to clarithromycin (CLR), amoxicillin (AMX), and metronidazole (MNZ), were used to select standard reference strains. Complete genome sequences were also determined. RESULTS: Three H. pylori strains (JSHR3, JSHR6 and JSHR31) were selected as standard reference strains by the Japanese Society for Helicobacter Research (JSHR). The minimum inhibitory concentrations (MICs) of the antibiotics against these 3 strains by agar dilution method with Brucella-based horse-serum-containing agar medium were as follows: JSHR3 (CLR 16 μg/ml, AMX 0.032 μg/ml and MNZ 4 μg/ml), JSHR6 (CLR 0.016 μg/ml, AMX 0.032 μg/ml and MNZ 4 μg/ml), and JSHR31 (CLR 16 μg/ml, AMX 1 μg/ml and MNZ 64 μg/ml). CONCLUSIONS: A reference panel of H. pylori JSHR strains was established. The panel consisted of JSHR6, which was antibiotic-susceptible, JSHR3, which was CLR-resistant, and JSHR31, which was multi-resistant. This reference panel will be essential for standardized ASTs before the optimal drugs are selected for eradication treatment.

DOI PubMed

アメーバによる共生細菌依存的な細菌運搬現象のメカニズムの検証

大久保寅彦, 佐藤豊孝, 横田伸一, 中村眞二, 山口博之, 田中菜那

日本細菌学雑誌 ( 日本細菌学会 ) 77 ( 1 ) 64 - 64 2022.02

Colistin Susceptibility in Companion Animal-Derived Escherichia coli, Klebsiella spp., and Enterobacter spp. in Japan: Frequent Isolation of Colistin-Resistant Enterobacter cloacae Complex.

Toyotaka Sato, Kazuki Harada, Masaru Usui, Shin-Ichi Yokota, Motohiro Horiuchi

Frontiers in cellular and infection microbiology 12 946841 - 946841 2022 [International journal]

Transmission of colistin-resistant Enterobacterales from companion animals to humans poses a clinical risk as colistin is a last-line antimicrobial agent for treatment of multidrug-resistant Gram-negative bacteria including Enterobacterales. In this study, we investigated the colistin susceptibility of 285 Enterobacterales (including 140 Escherichia coli, 86 Klebsiella spp., and 59 Enterobacter spp.) isolated from companion animals in Japan. We further characterized colistin-resistant isolates by multilocus sequence typing (MLST), phylogenetic analysis of hsp60 sequences, and population analysis profiling, to evaluate the potential clinical risk of companion animal-derived colistin-resistant Enterobacterales to humans in line with the One Health approach. All E. coli isolates were susceptible to colistin, and only one Klebsiella spp. isolate (1.2%, 1/86 isolates) was colistin resistant. Enterobacter spp. isolates were frequently colistin resistant (20.3%, 12/59 isolates). In colistin-resistant Enterobacter spp., all except one isolate exhibited colistin heteroresistance by population analysis profiling. These colistin-heteroresistant isolates belonged to clusters I, II, IV, VIII, and XII based on hsp60 phylogeny. MLST analysis revealed that 12 colistin-resistant Enterobacter spp. belonged to the Enterobacter cloacae complex; five Enterobacter kobei (four ST591 and one ST1577), three Enterobacter asburiae (one ST562 and two ST1578), two Enterobacter roggenkampii (ST606 and ST1576), and Enterobacter hormaechei (ST1579) and E. cloacae (ST765) (each one strain). Forty-two percent of the colistin-resistant E. cloacae complex isolates (predominantly ST562 and ST591) belonged to lineages with human clinical isolates. Four E. kobei ST591 isolates were resistant to third-generation cephalosporines, aminoglycosides, and fluroquinolones but remained susceptible to carbapenems. In conclusion, our study is the first to our knowledge to report the frequent isolation of the colistin-resistant E. cloacae complex from companion animals. Furthermore, a subset of isolates belonged to human-associated lineages with resistance to multiple classes of antibiotics. These data warrant monitoring carriage of the colistin-resistant E. cloacae complex in companion animals as part of a domestic infection control procedure in line with the One Health approach.

DOI PubMed

Self-reported Smell and Taste Disorders in Patients With COVID-19: A Japanese Single-center Study.

Keisuke Yamamoto, Yoshihiro Fujiya, Koji Kuronuma, Noriko Ogasawara, Tsuyoshi Ohkuni, Shin-Ichi Yokota, Satoshi Takahashi, Kenichi Takano

In vivo (Athens, Greece) 36 ( 2 ) 918 - 924 2022 [International journal]

BACKGROUND/AIM: Smell and taste disorders are among the most common symptoms of COVID-19. However, the relationship between smell and taste disorders and systemic symptoms is not fully understood in Japan. PATIENTS AND METHODS: Questionnaires were mailed to 105 of 111 COVID-19 patients who were hospitalized at our hospital between March and July 2020 in Japan. RESULTS: A total of 74 patients (response rate: 70.5%) completed the survey. Of these, six patients (8.1%) presented with smell disorders only, 16 (21.6%) presented with taste disorders only, and 17 (23.0%) presented with both smell and taste disorders. The mean Visual Analog Scale for smell and taste was 0.5 and 20, respectively, at the time of the most severe symptoms. CONCLUSION: Among COVID-19 patients in Japan, smell and taste disorders are often followed by fever and may not be the first symptoms. Sense of smell is particularly impaired. These symptoms often improve, although they sometimes persist for a long time as sequelae.

DOI PubMed

Design, synthesis and biological evaluation of simplified analogues of MraY inhibitory natural product with rigid scaffold.

Kazuhiro Okamoto, Aoi Ishikawa, Ryotaro Okawa, Kazuki Yamamoto, Toyotaka Sato, Shin-Ichi Yokota, Kazuhiro Chiba, Satoshi Ichikawa

Bioorganic & medicinal chemistry 55 116556 - 116556 2021.12 [Refereed] [International journal]

Muraymycins and caprazamycins are strong inhibitors of MraY, which is responsible for peptidoglycan biosynthesis. Although they are promising antibacterial agents with a novel mode of action, their chemical structures are rather complex. This study investigated the simplification of these natural products by structure-based drug design, synthesis, and biological evaluation. We developed a simplified rigid scaffold with an arylalkyne moiety, which shows sub-micromolar MraY inhibitory activity. The scaffold is suitable for further investigating the structure-activity relationship by virtue of our synthetic strategy, where the substituent of interest is installed in the last stage of synthesis. This scaffold shows the potential for further use in optimizing MraY inhibitory and antibacterial activities.

DOI PubMed

Isolation of Human Lineage, Fluoroquinolone-Resistant and Extended-β-Lactamase-Producing Escherichia coli Isolates from Companion Animals in Japan.

Toyotaka Sato, Shin-Ichi Yokota, Tooru Tachibana, Satoshi Tamai, Shigeki Maetani, Yutaka Tamura, Motohiro Horiuchi

Antibiotics (Basel, Switzerland) 10 ( 12 ) 2021.11 [International journal]

An increase in human and veterinary fluoroquinolone-resistant Escherichia coli is a global concern. In this study, we isolated fluoroquinolone-resistant E. coli isolates from companion animals and characterized them using molecular epidemiological analysis, multiplex polymerase chain reaction to detect E. coli ST131 and CTX-M type extended-spectrum β-lactamases (ESBL), and multi-locus sequence typing analysis. Using plain-CHROMagar ECC, 101 E. coli isolates were isolated from 34 rectal swabs of dogs and cats. The prevalence of resistance to fluoroquinolone and cefotaxime was 27.7% and 24.8%, respectively. The prevalence of fluoroquinolone-resistant isolates (89.3%) was higher when CHROMagar ECC with CHROMagar ESBL supplement was used for E. coli isolation. The prevalence of cefotaxime resistance was also higher (76.1%) when 1 mg/L of ciprofloxacin-containing CHROMagar ECC was used for isolation. The cefotaxime-resistant isolates possessed CTX-M type β-lactamase genes (CTX-M-14, CTX-M-15, or CTX-M-27). Seventy-five percent of fluoroquinolone-resistant isolates were sequence types ST131, ST10, ST1193, ST38, or ST648, which are associated with extensive spread in human clinical settings. In addition, we isolated three common fluoroquinolone-resistant E. coli lineages (ST131 clade C1-M-27, C1-nM27 and ST2380) from dogs and their respective owners. These observations suggest that companion animals can harbor fluoroquinolone-resistant and/or ESBL-producing E. coli, in their rectums, and that transmission of these isolates to their owners can occur.

DOI PubMed

Reduction of susceptibility to azoles and 5-fluorocytosine and growth acceleration in Candida albicans in glucosuria.

Yoshiki Hiyama, Toyotaka Sato, Satoshi Takahashi, Soh Yamamoto, Noriko Ogasawara, Naoya Masumori, Shin-Ichi Yokota

Diagnostic microbiology and infectious disease 102 ( 1 ) 115556 - 115556 2021.09 [International journal]

Diabetes mellitus is a chronic metabolic disease characterized by hyperglycemia and glucosuria, and is a risk factor for Candida infections. To reveal the potential effects of glucosuria on Candida spp., we investigated their growth and antifungal susceptibilities in normal human urine to which glucose was added. The viable cell numbers of Candida spp. were more than 10 fold higher in the urine added 3000 mg/dL glucose than in plain urine. In antifungal susceptibility, more than 80% of Candida albicans clinical isolates increased minimum inhibitory concentrations of azoles and 5-fluorocytosine with the addition of glucose, and exceeded their breakpoints. In most of the C. albicans clinical isolates, the mRNA expression of the azole resistance genes ERG11, CDR1, CDR2, and MDR1 in the presence of glucose in urine. These observations provide valuable information about the clinical course and therapeutic effects of azoles against C. albicans infections in patients with diabetes mellitus and hyperglucosuria.

DOI PubMed

Clonal/subclonal changes and accumulation of CTX-M-type β-lactamase genes in fluoroquinolone-resistant Escherichia coli ST131 and ST1193 strains isolated during the past 12 years, Japan.

Yukari Fukushima, Toyotaka Sato, Naoyuki Tsukamoto, Chie Nakajima, Yasuhiko Suzuki, Satoshi Takahashi, Shin-Ichi Yokota

Journal of global antimicrobial resistance 27 150 - 155 2021.09 [International journal]

OBJECTIVES: Fluoroquinolone (FQ)- and third-generation cephalosporin-resistant Escherichia coli are increasing in Japan. In the early 2000s, the FQ-resistant E. coli clone ST131 increased in clinical settings worldwide. It frequently produces extended-spectrum β-lactamases (ESBLs) such as CTX-M. This study aimed to explore the characteristics of FQ-resistant E. coli isolated in Japan during 2008-2009 and 2020. METHODS: We compared FQ-resistant E. coli clinical isolates from urine samples collected in 2020 (151 isolates) with a FQ-resistant E. coli collection isolated in 2008-2009 (42 isolates). Identification of E. coli ST131 clades and blaCTX-M were determined by multiplex PCR. Sequence types of non-ST131 isolates were determined by whole-genome sequencing. RESULTS: Although the prevalence of ST131 was comparable in 2020 (74.2%) and 2008-2009 (78.6%), the subclades differed during the two time periods (C1-nM27: 40.2% in 2008-2009 vs. 78.8% in 2020; C1-M27: 32.1% in 2008-2009 vs. 9.1% in 2020). The incidence of blaCTX-M among ST131 isolates increased from 27.3% in 2008-2009 to 64.3% in 2020. blaCTX-M was found in 80.6% and 93.8% of C1-M27 and C2 in 2020, respectively, and blaCTX-M possession in C1-nM27 increased from 19.2% in 2008-2009 to 40% in 2020. FQ-resistant ST1193 was detected only in 2020 (17.9% of 151 isolates, of which 14.8% possessed blaCTX-M). CONCLUSION: Increased resistance of E. coli to FQs and third-generation cephalosporins in Japan can be attributed to the accumulation of blaCTX-M in C1-nM27 and the increase of C1-M27 and C2 clades with high blaCTX-M possession, alongside the spread of ST1193.

DOI PubMed

Complete Genome Sequence of an mcr-10-Possessing Enterobacter roggenkampii Strain Isolated from a Dog in Japan.

Toyotaka Sato, Masaru Usui, Kazuki Harada, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota

Microbiology resource announcements 10 ( 30 ) e0042621 2021.07 [International journal]

DOI PubMed

Oligosaccharide Metabolism and Lipoteichoic Acid Production in Lactobacillus gasseri and Lactobacillus paragasseri

Tsukasa Shiraishi, Shintaro Maeno, Sayoko Kishi, Tadashi Fujii, Hiroki Tanno, Katsuaki Hirano, Takumi Tochio, Yasuhiro Tanizawa, Masanori Arita, Shin-ichi Yokota, Akihito Endo

Microorganisms ( MDPI AG ) 9 ( 8 ) 1590 - 1590 2021.07

Lactobacillus gasseri and Lactobacillus paragasseri are human commensal lactobacilli that are candidates for probiotic application. Knowledge of their oligosaccharide metabolic properties is valuable for synbiotic application. The present study characterized oligosaccharide metabolic systems and their impact on lipoteichoic acid (LTA) production in the two organisms, i.e., L. gasseri JCM 1131T and L. paragasseri JCM 11657. The two strains grew well in medium with glucose but poorly in medium with raffinose, and growth rates in medium with kestose differed between the strains. Oligosaccharide metabolism markedly influenced their LTA production, and apparent molecular size of LTA in electrophoresis recovered from cells cultured with glucose and kestose differed from that from cells cultured with raffinose in the strains. On the other hand, more than 15-fold more LTA was observed in the L. gasseri cells cultured with raffinose when compared with glucose or kestose after incubation for 15 h. Transcriptome analysis identified glycoside hydrolase family 32 enzyme as a potential kestose hydrolysis enzyme in the two strains. Transcriptomic levels of multiple genes in the dlt operon, involved in D-alanine substitution of LTA, were lower in cells cultured with raffinose than in those cultured with kestose or glucose. This suggested that the different sizes of LTA observed among the carbohydrates tested were partly due to different levels of alanylation of LTA. The present study indicates that available oligosaccharide has the impact on the LTA production of the industrially important lactobacilli, which might influence their probiotic properties.

DOI

Next-generation sequencing of 16S rRNA for identification of invasive bacterial pathogens in a formalin-fixed paraffin-embedded placental specimen: a case report of perinatal fulminant Streptococcus pyogenes infection.

Tasuku Mariya, Toyotaka Sato, Yuya Fujibe, Manami Ishido, Hiroshi Shimada, Terufumi Kubo, Yoko Nagai, Wataru Arai, Suguru E Tanaka, Kyota Ashikawa, Yoshiyuki Sakuraba, Shinichi Ishioka, Shin-Ichi Yokota, Tsuyoshi Saito

Medical molecular morphology 2021.07 [Domestic journal]

Intrauterine infection is one of the most important causes of maternal death. In perinatal emergency, we often miss an opportunity to obtain culture specimens. In this study, we tried to examine whether we investigated whether bacteria causing infection can be detected from a formalin-fixed paraffin-embedded (FFPE) placental specimen. We examined the placenta from a maternal invasive infection that resulted in infectious abortion at 18 weeks of gestation. The case was diagnosed by acute fever and abdominal pain, and the patient was cured after 3 weeks of intensive antimicrobial treatment. Four Streptococcus pyogenes strains were isolated from vaginal fluid and blood cultures of the patient. All of the strain types were emm1/ST28. We amplified the V1-V2 region of 16S rRNA from an FFPE placental specimen and sequencing was performed using a next-generation sequencer (NGS). Taxonomic analysis was then performed for sequenced data. We succeeded in detecting causative pathogens from the FFPE placenta: 69.1% of the predominantly identified bacteria were S. pyogenes and other small populations of bacteria were detected. Our results revealed the utility of NGS for 16S rRNA analysis of an FFPE placenta. This method may reveal previous perinatal invasive infections of unknown origin retrospectively.

DOI PubMed

Complete Genome Sequence of an mcr-9-Possessing Enterobacter asburiae Strain Isolated from a Cat in Japan.

Toyotaka Sato, Masaru Usui, Kazuki Harada, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota

Microbiology resource announcements 10 ( 26 ) e0028121 2021.07 [International journal]

DOI PubMed

RSウイルスが結合する核内タンパク質の機能解明

小笠原徳子, 山本圭佑, 工由佳, 高野賢一, 横田伸一

日本耳鼻咽喉科免疫アレルギー感染症学会抄録集 ( 日本耳鼻咽喉科免疫アレルギー感染症学会 ) 1回 138 - 138 2021.05

プラークアッセイ法を用いたRSウイルス感染力価定量

工由佳, 小笠原徳子, 山本圭佑, 高野賢一, 横田伸一

日本耳鼻咽喉科免疫アレルギー感染症学会抄録集 ( 日本耳鼻咽喉科免疫アレルギー感染症学会 ) 1回 182 - 182 2021.05

Possible clinical outcomes using early enteral nutrition in individuals with allogeneic hematopoietic stem cell transplantation: A single-center retrospective study

Satoshi Iyama, Hiroomi Tatsumi, Tsukasa Shiraishi, Masahiro Yoshida, Ayumi Tatekoshi, Akihito Endo, Taichiro Ishige, Yuh Shiwa, Soushi Ibata, Akari Goto, Kana Nagashima, Hiroto Horiguchi, Chisa Fujita, Hiroshi Ikeda, Kohichi Takada, Takayuki Nobuoka, Yusuke Kamihara, Shohei Kikuchi, Tsutomu Sato, Hirofumi Ohnishi, Shin-ichi Yokota, Masayoshi Kobune

Nutrition ( Elsevier BV ) 83 111093 - 111093 2021.03

DOI

Na+/H+アンチポーター(NhaA)は大腸菌の乾燥抵抗性を規定する

榎枝秀朗, 田中菜那, 大久保寅彦, 佐藤豊孝, 横田伸一, タパ・ジーワン, 山口博之

日本細菌学雑誌 ( 日本細菌学会 ) 76 ( 1 ) 71 - 71 2021.02

共生細菌依存的にアメーバに起こる細菌運搬現象には運ばれる細菌のNa+/H+アンチポーターNhaAが関与する

田中菜那, 大久保寅彦, 佐藤豊孝, 横田伸一, タパ・ジーワン, 山口博之

日本細菌学雑誌 ( 日本細菌学会 ) 76 ( 1 ) 68 - 68 2021.02

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Papers - YOKOTA Shinichi