Papers - YOKOTA Shinichi

Clonality investigation of clinical Escherichia coli isolates by polymerase chain reaction-based open-reading frame typing method.

Masachika Saeki, Toyotaka Sato, Daisuke Furuya, Yuki Yakuwa, Yuki Sato, Ryo Kobayashi, Mayumi Ono, Shinya Nirasawa, Makito Tanaka, Hirotaka Nakafuri, Mami Nakae, Masaaki Shinagawa, Kouichi Asanuma, Nozomi Yanagihara, Shin-Ichi Yokota, Satoshi Takahashi

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy   26 ( 1 ) 38 - 42  2020.01  [Refereed]  [International journal]

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Escherichia coli (E. coli) causes urinary tract infections, pneumonia, surgical site infections, and bloodstream infections and is the important pathogen for both community-acquired and healthcare-associated infections. To investigate the clonality of E. coli is important for infection control and prevention. We aimed to investigate the clonality of clinical E. coli isolates using Cica Geneus E. coli polymerase chain reaction (PCR)-based open-reading frame typing (POT) KIT and clarify the clinical usefulness of this kit. About 124 E. coli isolates obtained from inpatients at Sapporo Medical University Hospital were used. The POT method was used to classify 124 clinical isolates into 87 POT numbers. In addition to the clonality, it was possible to obtain additional information that 20 of the 124 isolates were extended-spectrum β-lactamase (ESBL) producing E. coli (5 isolates of CTX-M-1 group and 15 isolates of CTX-M-9 group) and 13 were sequence type (ST) 131 clone. Furthermore, when these ESBL-producing 20 isolates were compared with pulsed-field gel electrophoresis (PFGE) or multilocus sequence typing (MLST), Simpson's index of diversity was 0.968 in POT method, 0.979 in PFGE, and 0.584 in MLST. POT method had an analytical power similar to that of PFGE. In conclusion, attention should be paid to the difference in the interpretation of the results between the POT method and the PFGE, but POT method may be useful to timely monitor the spread of E. coli in medical facilities.

DOI PubMed

水平ゲノム転移を介したvanD5バンコマイシン耐性遺伝子を保有するEnterococcus faeciumの出現(Emergence of vanD5-type vancomycin-resistant Enterococcus faecium via horizontal genomic transfer)

佐藤 豊孝, 和田 崇之, 福島 由華里, 中島 千絵, 鈴木 定彦, 高橋 聡, 横田 伸一

日本細菌学雑誌 ( 日本細菌学会 )  75 ( 1 ) 100 - 100  2020.01

Campylobacter upsaliensisが検出された巨大肝嚢胞の1症例

大越 康雄, 佐藤 豊孝, 村林 広美, 酒井 昂平, 横田 伸一

日本臨床微生物学会雑誌 ( (一社)日本臨床微生物学会 )  30 ( Suppl.1 ) 308 - 308  2019.12

Structural analysis of the lipoteichoic acid anchor glycolipid: Comparison of methods for degradation of the glycerophosphate backbone polymer.

Tsukasa Shiraishi, Soh Yamamoto, Shin-Ichi Yokota

Journal of microbiological methods   166   105726 - 105726  2019.11  [International journal]

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Acetic acid treatment [98% (v/v), 100 °C, 3 h] was proposed as a new method for degrading the glycerophosphate polymer moiety of Gram-positive bacterial lipoteichoic acid. We demonstrated that this method resulted in partial O-acetylation on the carbohydrate residues of the anchor glycolipid. Hence, the acetic acid treatment is not suitable for the chemical structural analysis of lipoteichoic acid.

DOI PubMed

Comparison of measurements of anti-PLA2R antibodies in Japanese patients with membranous nephropathy using in-house and commercial ELISA.

Hajime Kaga, Atsushi Komatsuda, Soh Yamamoto, Tadashi Kikuchi, Mika Kamata, Akiko Sato, Masafumi Odaka, Shin-Ichi Yokota, Naoto Takahashi, Hideki Wakui

Clinical and experimental nephrology   23 ( 4 ) 465 - 473  2019.04  [Domestic journal]

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BACKGROUND: The prevalence of antibodies against M-type anti-phospholipase A2 receptor (PLA2R) was reported to be ~ 70-80% in early studies on idiopathic membranous nephropathy (iMN) cohorts from Western countries, China, and Korea, and ~ 50% in recent studies on two Japanese iMN cohorts. METHODS: We developed an in-house enzyme-linked immunosorbent assay (ELISA) for the detection of anti-PLA2R antibodies, and examined sera from 217 patients with iMN, 22 patients with secondary MN (sMN), and 50 healthy individuals. All patients and healthy individuals were Japanese. The relationships between levels of anti-PLA2R antibodies and clinical parameters were analyzed. Serum samples were also tested using a standardized commercial ELISA (Euroimmun, Germany). RESULTS: In our ELISA, OD values greater than the mean + 3 standard deviation of healthy subjects were considered to be positive for anti-PLA2R antibodies. Of the patients with iMN, 33.6% (73/217) were positive, but all sMN patients were negative. Our ELISA and the Euroimmun ELISA had a high concordance (93.5%). The proportion of patients with nephrotic syndrome was significantly higher in anti-PLA2R antibody-positive patients than in antibody-negative patients (65.8 vs. 37.5%, P < 0.001). Levels of anti-PLA2R antibodies were significantly correlated with levels of urinary protein and serum albumin (P = 0.004 and P < 0.001, respectively). CONCLUSIONS: The prevalence of anti-PLA2R antibodies in our Japanese iMN cohort was lower than that in the previous studies from other countries and other Japanese institutes. The low prevalence of antibodies may be related with the characteristics of enrolled patients with mild proteinuria and undetectable antibody levels.

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Evaluation of Susceptibilities to Carbapenems and Faropenem Against Cephalosporin-Resistant Neisseria gonorrhoeae Clinical Isolates with penA Mosaic Alleles.

Yoshiki Hiyama, Satoshi Takahashi, Toyotaka Sato, Masaaki Shinagawa, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Naoya Masumori, Shin-Ichi Yokota

Microbial drug resistance (Larchmont, N.Y.)   25 ( 3 ) 427 - 433  2019.04  [Refereed]  [International journal]

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Neisseria gonorrhoeae is a principal pathogen for sexually transmitted infections, especially for male urethritis. Currently, the prevalence of multidrug resistance is increasing. Carbapenems are broad-spectrum antimicrobials that are widely used in the clinical setting, especially for multidrug-resistant Gram-negative bacteria. However, susceptibility to carbapenems has not been well evaluated for cephalosporin-resistant N. gonorrhoeae isolates. In this study, we determined the susceptibility to a series of carbapenems (meropenem, imipenem, doripenem, and biapenem) and faropenem against cephalosporin-resistant (resistant to cefixime, but susceptible to ceftriaxone) and cephalosporin-susceptible N. gonorrhoeae clinical isolates. The gene mutations associated with β-lactam resistance were evaluated. All cephalosporin-resistant N. gonorrhoeae isolates possessed mosaic mutation alleles in penA (NG-STAR penA-10.001, 27.001, or 108.001). They exhibited a low minimum inhibitory concentration (MIC) (≤0.125 mg/L) for meropenem and markedly high MICs (0.5-2 mg/L) for other carbapenems and faropenem. The strongest association was observed between the mosaic alleles in penA and decreased susceptibility to carbapenems and faropenem compared with mutations in mtrR, porB, and ponA. These results suggest that meropenem may serve as an alternative therapeutic agent for cephalosporin-resistant N. gonorrhoeae with a mosaic allele in penA, whereas other carbapenems and faropenem may be ineffective.

DOI PubMed

人臨床検体から分離された腸内細菌科細菌のコリスチン感受性および分子遺伝学的解析

佐藤 豊孝, 品川 雅明, 高橋 聡, 横田 伸一

日本化学療法学会雑誌 ( (公社)日本化学療法学会 )  67 ( Suppl.A ) 248 - 248  2019.03

伴侶動物由来Klebsiella pneumoniae complexにおけるチゲサイクリン非感受性(Tigecycline-Nonsusceptible Klebsiella pneumoniae Complex Isolated from Companion Animals)

佐藤 豊孝, 原田 和記, 横田 伸一

日本細菌学雑誌 ( 日本細菌学会 )  74 ( 1 ) 102 - 102  2019.03

Synthesis and biological evaluation of MraY selective analogue of tunicamycins

Kazuki Yamamoto, Toyotaka Sato, Yuta Hikiji, Akira Katsuyama, Takanori Matsumaru, Fumika Yakushiji, Shin-ichi Yokota, Satoshi Ichikawa

Nucleosides, Nucleotides & Nucleic Acids    2019  [Refereed]

侵襲性肺炎球菌感染症患者から分離された多剤耐性肺炎球菌の全ゲノム解析

大越 康雄, 佐藤 豊孝, 村林 広美, 横田 伸一

日本臨床微生物学会雑誌 ( (一社)日本臨床微生物学会 )  29 ( Suppl.1 ) 417 - 417  2018.12

Lactobacillus gasseriに共通する種特異的なリポテイコ酸の化学構造

白石 宗, 久富 亮佑, 佐藤 耶舞羽, 森田 直樹, 吹谷 智, 佐藤 豊孝, 横田 篤, 横田 伸一

エンドトキシン・自然免疫研究 ( 日本エンドトキシン・自然免疫研究会 )  21   35 - 37  2018.11

緑膿菌はリポ多糖の菌体外放出量が多く、高菌量下でコリスチンの抗菌活性が減弱する

横田 伸一, 袴田 浩, 山本 聡, 佐藤 豊孝, 白石 宗

緑膿菌感染症研究会講演記録 ( 緑膿菌感染症研究会 )  52回   52 - 54  2018.10

淋菌に対するpiperacillinとtazobactam/piperacillinの薬剤感受性の検討

桧山 佳樹, 高橋 聡, 佐藤 豊孝, 山本 聡, 品川 雅明, 横田 伸一, 舛森 直哉

日本性感染症学会誌 ( (一社)日本性感染症学会 )  29 ( 2 ) 236 - 236  2018.10

Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x.

Toyotaka Sato, Tsukasa Shiraishi, Yoshiki Hiyama, Hiroyuki Honda, Masaaki Shinagawa, Masaru Usui, Koji Kuronuma, Naoya Masumori, Satoshi Takahashi, Yutaka Tamura, Shin-Ichi Yokota

Antimicrobial agents and chemotherapy   62 ( 9 ) e00864-18  2018.09  [Refereed]  [International journal]

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Colistin is a last-line drug for multidrug-resistant Gram-negative bacteria. We previously reported four plasmid-mediated colistin resistance (mcr) gene-negative colistin-resistant Escherichia coli clinical isolates, including the major pathogenic and fluoroquinolone-resistant strains O25b:H4-ST131-H30Rx (isolates SRE34 and SRE44; MIC for colistin = 16 mg/liter), non-x (SME296; MIC = 8 mg/liter), and O18-ST416 (SME222; MIC = 4 mg/liter). In this study, we investigated the colistin resistance mechanism and identified novel amino acid substitutions or deletions in the PmrAB two-component system that activates eptA (encoding a phosphoethanolamine transferase) and arnT (encoding an undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase) in all colistin-resistant isolates. SRE34 possessed deletion Δ27-45 (LISVFWLWHESTEQIQLFE) in PmrB, SRE44 possessed substitution L105P in PmrA, and both SME222 and SME296 included substitution G206D in PmrB. Matrix-assisted laser desorption ionization-time of flight mass spectrometry revealed that lipid A is modified with phosphoethanolamine in all four isolates. Deletion of pmrAB decreased colistin MICs to 0.5 mg/liter and lowered eptA and arnT expression. Chromosomal replacement of mutated pmrA or pmrB in colistin-susceptible O25b:H4-ST131 strain SME98 (colistin MIC = 0.5 mg/liter) increased the colistin MIC to that of the respective parent colistin-resistant isolate. In addition, SME98 mutants in which pmrAB was replaced with mutated pmrAB showed no significant differences in bacterial growth and competition culture from the parent strain, except for the mutant with L105P in PmrA, whose growth was significantly suppressed in the presence of the parent strain. In conclusion, some O25b:H4-ST131 strains appear to acquire colistin resistance via phosphoethanolamine modification of lipid A through amino acid changes in PmrAB, and the amino acid changes in PmrB do not influence bacterial growth.

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Multiclonal Expansion and High Prevalence of β-Lactamase-Negative Haemophilus influenzae with High-Level Ampicillin Resistance in Japan and Susceptibility to Quinolones.

Hiroyuki Honda, Toyotaka Sato, Masaaki Shinagawa, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Tsukasa Shiraishi, Koji Kuronuma, Satoshi Takahashi, Hiroki Takahashi, Shin-Ichi Yokota

Antimicrobial agents and chemotherapy   62 ( 9 ) e00851-18  2018.09  [Refereed]  [International journal]

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β-Lactam-resistant Haemophilus influenzae is a clinical concern. A high prevalence (>40%) of β-lactamase-negative high-level ampicillin-resistant H. influenzae (high-BLNAR) isolates in Japan has been reported. However, the reasons for the expansion are unknown. High-BLNAR strains possess an amino acid substitution, either Asn526Lys (group III) or Arg517His (group III-like) in addition to Ser385Thr, in penicillin-binding protein 3 (PBP3). To determine the current prevalence of high-BLNAR strains and the mechanisms behind their expansion in Japan, their prevalence, PBP3 types, multilocus sequence types, and susceptibilities to quinolones approved in Japan as alternatives were determined. Sixty percent of H. influenzae clinical isolates (62/104 isolates) were β-lactamase-negative ampicillin-resistant H. influenzae (BLNAR) strains. Among BLNAR isolates, 92% (57/62 isolates) were high-BLNAR strains. Most isolates were classified as belonging to group III, which contained many genotypes (11 PBP3 types and 25 sequence types). These results indicated that the expansion of high-BLNAR isolates was multiclonal and such strains are still predominant in Japanese clinical settings. One high-BLNAR isolate harbored the novel amino acid substitution Asn526Met in addition to Ser385Thr in PBP3, suggesting a new group (group IV). No quinolone-resistant H. influenzae isolates were identified. The MICs for the quinolones (moxifloxacin, garenoxacin, and tosufloxacin) were similar to that for levofloxacin, whereas sitafloxacin exhibited a lower MIC. However, we obtained 4 H. influenzae isolates with decreased quinolone susceptibility with the amino acid substitution Ser84Leu in GyrA, and 3 of those isolates were high-BLNAR isolates. In summary, this study shows that multiclonal high-BLNAR strains predominate in a Japanese university hospital. Isolates remain sensitive to quinolones, but vigilance is required to prevent the development of fluoroquinolone resistance in high-BLNAR strains.

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Response to pneumococcal vaccine in interstitial lung disease patients: Influence of systemic immunosuppressive treatment.

Koji Kuronuma, Hiroyuki Honda, Tessei Mikami, Atsushi Saito, Kimiyuki Ikeda, Mitsuo Otsuka, Hirofumi Chiba, Gen Yamada, Toyotaka Sato, Shin-Ichi Yokota, Hiroki Takahashi

Vaccine   36 ( 33 ) 4968 - 4972  2018.08  [Refereed]  [International journal]

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BACKGROUND: Interstitial lung diseases (ILD) are severe respiratory diseases, and ILD patients are treated with corticosteroid and immunosuppressive agents. However, it is unclear whether these medications influence the response of pneumococcal vaccine. OBJECTIVES: We examined the immunogenicity of pneumococcal vaccines (PPSV23 and PCV13) in ILD patients undergoing immunosuppressive treatment. METHODS: ILD patients who were regularly followed at the outpatient clinic were enrolled. Sera were collected before and 4-8 weeks after vaccination. Serotype-specific immunoglobulin G (IgG) concentrations against pneumococcal serotype 19F were measured by ELISA. RESULTS: IgG concentrations to serotype 19F were increased in all groups in response to the vaccine. Both PCV13 and PPSV23 induced IgG concentrations in patients immunized for the first time. Response rates for the ILD group were comparable with those for the ILD group undergoing corticosteroid therapy. Only idiopathic pulmonary fibrosis patients undergoing immunosuppressive therapy had a significantly lower response.

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Whole genome analysis of a multidrug-resistant Streptococcus pneumoniae isolate from a patient with invasive pneumococcal infection developing disseminated intravascular coagulation.

Yasuo Ohkoshi, Toyotaka Sato, Takayuki Wada, Yukari Fukushima, Hiromi Murabayashi, Yasunari Takakuwa, Kaoru Nishiyama, Hiroyuki Honda, Tsukasa Shiraishi, Koji Kuronuma, Hiroki Takahashi, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy   24 ( 8 ) 674 - 681  2018.08  [Refereed]  [International journal]

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Multidrug-resistant Streptococcus pneumoniae strains were isolated from blood and sputum of a patient with disseminated intravascular coagulation in Sapporo city, Japan. These antibiograms were only susceptible to vancomycin, linezolid, daptomycin, some carbapenems, and some fluoroquinolones. Identical antibiograms, serotypes (19F), and sequence types (ST10017) suggested a shared origin of these isolates. Only one ST10017 strain has been isolated in the same city in Japan previously (2014), and the 2014 isolate is still susceptible to macrolides. The whole genome of the blood-derived isolate was sequenced. The strain harbored resistance mutations in parC, gyrA, pbp1a, pbp2a, pbp2b, and pbp2x, and harbored the resistance genes, ermB and tetM. The nucleotide sequences of parC and pbp2x genes of strain MDRSPN001 were clearly different from those of other S. pneumoniae strains and were similar to those of oral streptococci strains. These findings suggest that strain MDRSPN001 has been rapidly and drastically evolving multidrug resistance by gene replacement and accumulation of genes originating from other strains, such as oral streptococci, Streptococcus mitis.

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乳酸桿菌の対数期に膜小胞上に局在するリポテイコ酸

白石 宗, 横田 伸一, 佐藤 耶舞羽, 伊藤 利章, 吹谷 智, 山本 聡, 佐藤 豊孝, 横田 篤

日本乳酸菌学会誌 ( 日本乳酸菌学会 )  29 ( 2 ) 116 - 116  2018.07

Isolation of a mcr-1-harbouring Escherichia coli isolate from a human clinical setting in Sapporo, Japan.

Toyotaka Sato, Akira Fukuda, Masaru Usui, Masaaki Shinagawa, Tsukasa Shiraishi, Yutaka Tamura, Satoshi Takahashi, Shin-Ichi Yokota

Journal of global antimicrobial resistance   13   20 - 21  2018.06  [Refereed]  [International journal]

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Release of large amounts of lipopolysaccharides from Pseudomonas aeruginosa cells reduces their susceptibility to colistin.

Shin-Ichi Yokota, Hiroshi Hakamada, Soh Yamamoto, Toyotaka Sato, Tsukasa Shiraishi, Masaaki Shinagawa, Satoshi Takahashi

International journal of antimicrobial agents   51 ( 6 ) 888 - 896  2018.06  [Refereed]  [International journal]

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Pseudomonas aeruginosa is an important etiological agent of opportunistic infections. Injectable colistin is available as a last-line treatment option for multidrug-resistant P. aeruginosa infections. When cells were inoculated at a high number, colistin-susceptible P. aeruginosa grew on agar medium containing colistin at a concentration 10-fold higher than the minimum inhibitory concentration without acquiring colistin resistance. This study examined the responsible mechanism for growth in the presence of a high concentration of colistin. Cell wash fluid derived from P. aeruginosa efficiently reduced colistin antimicrobial activity. This reduction was mediated by lipopolysaccharide (LPS) in the wash fluid. Extracellular LPS inhibited colistin activity more effectively than cell-bound LPS in fixed cells. Cell wash fluids from Escherichia coli and Acinetobacter baumannii also reduced colistin activity; however, they were less potent than those from P. aeruginosa. The amount of LPS in cell wash fluid from P. aeruginosa was approximately 10-fold higher than that in fluid from E. coli or A. baumannii. In conclusion, cell-free LPS derived from bacterial cells inhibited the antimicrobial activity of colistin, and this effect was greatest for P. aeruginosa. Thus, large amounts of broken and dead cells of P. aeruginosa at infection foci will reduce the effectiveness of colistin, even against cells that have not yet acquired resistance.

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