Papers - YOKOTA Shinichi

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

Emergence of the Novel Aminoglycoside Acetyltransferase Variant aac(6′)-Ib-D179Y and Acquisition of Colistin Heteroresistance in Carbapenem-Resistant Klebsiella pneumoniae Due to a Disrupting Mutation in the DNA Repair Enzyme MutS

Toyotaka Sato, Takayuki Wada, Suguru Nishijima, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Satoshi Takahashi, Shin-ichi Yokota

mBio ( American Society for Microbiology )  11 ( 6 )  2020.12

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The emergence of multidrug resistance in pathogens such as Klebsiella pneumoniae is of great clinical concern. Antimicrobial resistance sometimes arises during the course of an infection.

DOI

Sitafloxacin has a potent activity for eradication of extended spectrum β-lactamase-producing fluoroquinolone-resistant Escherichia coli forming intracellular bacterial communities in uroepithelial cells.

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

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy   26 ( 12 ) 1272 - 1277  2020.12  [International journal]

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INTRODUCTION: Eradication of asymptomatic bacteriuria (ASB) before urological procedures is important to reduce the risk for infectious complications after surgery. However, the appropriate regimen for antimicrobial treatment has not been fully determined. We experienced continuous (over 10 months) isolation of extended spectrum β-lactamase (ESBL)-producing fluoroquinolone-resistant Escherichia coli from urine of an asymptomatic patient. The four isolates obtained (SMESC1 to 4) were international high-risk clones of O25b:H4-ST131-H30R, and originated from one strain, as revealed by the whole genome sequences. Although the patient received meropenem (MEPM) and fosfomycin (FOM), to which the strains were susceptible before the urological procedures, they could not be eradicated. METHODS: To explore the reason for the continuous isolation even after MEPM and FOM administration, antimicrobial killing of adherent and/or intracellular bacterial communities (IBC) formed by coculture of the E. coli cells and T24 bladder epithelial cells were examined. RESULTS: FOM and levofloxacin did not decrease viable E. coli cells compared with gentamicin. MEPM partly decreased them, and sitafloxacin (STFX) decreased them most potently. These observations indicate that E. coli can survive in the urinary tract under antimicrobial administration, and some antimicrobials such as FOM and MEPM cannot eradicate E. coli in uroepithelial cells. Adhesion on urinary epithelial cells and/or IBC formation might result in continuous isolation from the urinary tract and recurrence of ASB and urinary tract infections. CONCLUSIONS: The present study suggests that STFX is a promising optional agent for the eradication of ESBL-producing fluoroquinolone-resistant E. coli in the urinary tract before urological procedures.

DOI PubMed

Whole-Genome Sequence of Fluoroquinolone-Resistant Escherichia coli HUE1, Isolated in Hokkaido, Japan.

Montgomery Munby, Jumpei Fujiki, Kotaro Aoki, Chika Kawaguchi, Keisuke Nakamura, Tomohiro Nakamura, Michihito Sasaki, Toyotaka Sato, Masaru Usui, Hirofumi Sawa, Shin-Ichi Yokota, Yutaka Tamura, Hidetomo Iwano

Microbiology resource announcements   9 ( 46 )  2020.11  [International journal]

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We report the complete genome sequence of Escherichia coli strain HUE1, isolated from the urinary catheter of a female patient, showing fluoroquinolone resistance without quinolone resistance-determining region mutations. To facilitate the exploration of the molecular characteristics of HUE1, the whole genome was sequenced using long- and short-read platforms.

DOI PubMed

Elucidating the Structural Requirement of Uridylpeptide Antibiotics for Antibacterial Activity.

Yuma Terasawa, Chisato Sataka, Toyotaka Sato, Kazuki Yamamoto, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Akira Katsuyama, Takanori Matsumaru, Fumika Yakushiji, Shin-Ichi Yokota, Satoshi Ichikawa

Journal of medicinal chemistry   63 ( 17 ) 9803 - 9827  2020.09  [International journal]

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The synthesis and biological evaluation of analogues of uridylpeptide antibiotics were described, and the molecular interaction between the 3'-hydroxy analogue of mureidomycin A (3'-hydroxymureidomycin A) and its target enzyme, phospho-MurNAc-pentapeptide transferase (MraY), was analyzed in detail. The structure-activity relationship (SAR) involving MraY inhibition suggests that the side chain at the urea-dipeptide moiety does not affect the MraY inhibition. However, the anti-Pseudomonas aeruginosa activity is in great contrast and the urea-dipeptide motif is a key contributor. It is also suggested that the nucleoside peptide permease NppA1A2BCD is responsible for the transport of 3'-hydroxymureidomycin A into the cytoplasm. A systematic SAR analysis of the urea-dipeptide moiety of 3'-hydroxymureidomycin A was further conducted and the antibacterial activity was determined. This study provides a guide for the rational design of analogues based on uridylpeptide antibiotics.

DOI PubMed

Emergence of vancomycin- and teicoplanin-resistant Enterococcus faecium via vanD5-harbouring large genomic island.

Toyotaka Sato, Takayuki Wada, Masaaki Shinagawa, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Satoshi Takahashi, Shin-Ichi Yokota

The Journal of antimicrobial chemotherapy    2020.06  [Refereed]  [International journal]

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BACKGROUND: Treatment of VRE is of clinical concern. While certain numbers of vanD-type VRE have been isolated, only two vanD5-harbouring Enterococcus faecium isolates have been reported in Canada and Japan. METHODS: We report the isolation of vanD5-type E. faecium and the first ever determination of the whole-genome sequence to investigate the possible mechanisms of the acquisition of the vanD5 gene cluster in E. faecium. RESULTS: Two vanD5-harbouring vancomycin-resistant E. faecium were isolated from the skin (SMVRE19) and faeces (SMVRE20) of a patient with a skin ulcer in Japan. The isolates exhibited vancomycin and teicoplanin MIC values of 128 mg/L, whilst the previous isolates of vanD5-harbouring E. faecium were only resistant to vancomycin. SMVRE19 and SMVRE20 were clones related to ST18, which is also seen in vanA- and vanB-type VRE. These isolates harboured an insertion element, ISEfm1, in the ddl gene, similar to a previously described teicoplanin-resistant vanD3-type E. faecium. The vanD5 gene cluster was integrated into the SMVRE20 chromosome as a part of a large genomic island (approximately 127 kb), similar to other recently spreading vanD variants in the Netherlands. The genomic island shared the greatest similarity with a part of the Blautia coccoides genome sequence, except for the region surrounding the vanD gene cluster. CONCLUSIONS: This study reports that emergence of vancomycin- and teicoplanin-resistant vanD5-type E. faecium occurred via acquisition of the vanD5 cluster and ISEfm1 insertion into ddl. Considering the genetic similarity between the various VRE strains, the current study should serve as a warning against the spread of vanD5-type VRE.

DOI PubMed

Campylobacter upsaliensis isolated from a giant hepatic cyst.

Yasuo Ohkoshi, Toyotaka Sato, Hiromi Murabayashi, Kohei Sakai, Yasunari Takakuwa, Yukari Fukushima, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy    2020.03  [Refereed]  [International journal]

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Campylobacter upsaliensis is an enteropathogenic bacterium in animals, and is also rarely isolated from humans, where it can cause enteritis and bacteremia. This report describes the first case of isolation of C. upsaliensis from an infected giant hepatic cyst. This bacterium could not be cultured from abscess punctuate in a usual Campylobacter-selection medium (charcoal cefoperazone deoxycholate agar medium), because of high concentration of cefoperazone as a selection agent. It could not identified by matrix-assisted laser desorption ionization-time of flight mass spectrum. Rather, it was identified as C. upsaliensis by whole genome sequencing, including by multilocus sequence typing.

DOI PubMed

Contribution of β-lactamase and efflux pump overproduction to tazobactam-piperacillin resistance in clinical isolates of Escherichia coli.

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

International journal of antimicrobial agents     105919 - 105919  2020.02  [Refereed]  [International journal]

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INTRODUCTION: Tazobactam-piperacillin (TZP) is a mixture of a broad-spectrum penicillin and an irreversible β-lactamase inhibitor. TZP is effective against Gram-negative bacteria that produce extended-spectrum β-lactamases, and it is used as a first-line or second-line drug to treat serious infections. METHODS: This study identified three TZP-resistant and two TZP-intermediate strains among 514 clinical isolates of Escherichia coli. RESULTS: These five isolates possessed one or more β-lactamase genes, blaTEM-1, blaCTX-M-2, blaCTX-M-14, and/or blaCMY-8. The expression levels of β-lactamase genes and acrAB genes in the strains were examined by using real-time reverse transcription PCR. The total enzymatic piperacillin-degrading activity in cells was determined. Two TZP-resistance mechanisms were identified: hyperproduction of TEM-1 in the two resistant strains; and simultaneous high production of β-lactamase and efflux pump AcrAB in the two TZP-intermediate isolates. The latter are an international high-risk clone O25b:H4-ST131-H30R. CONCLUSION: TZP resistance is still rare in clinical isolates of E. coli. However, resistance can develop on high production and/or combinations of known antimicrobial resistance mechanisms in different ways.

DOI PubMed

In Vitro Derivation of Fluoroquinolone-Resistant Mutants from Multiple Lineages of Haemophilus influenzae and Identification of Mutations Associated with Fluoroquinolone Resistance.

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

Antimicrobial agents and chemotherapy   64 ( 2 )  2020.01  [Refereed]  [International journal]

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Haemophilus influenzae is a pathogenic bacterium that causes respiratory and otolaryngological infections. The increasing prevalence of β-lactamase-negative high-level ampicillin-resistant H. influenzae (high-BLNAR) is a clinical concern. Fluoroquinolones are alternative agents to β-lactams. However, the emergence and increasing prevalence of fluoroquinolone-resistant H. influenzae have been reported. The current risk of fluoroquinolone resistance in H. influenzae (especially in high-BLNAR) has not yet been evaluated. Here, we examined the development of fluoroquinolone resistance in fluoroquinolone-susceptible clinical H. influenzae isolates in vitro during passaging in the presence of moxifloxacin (from 0.03 to 128 mg/liter). Twenty-nine isolates were examined. Seventeen isolates (58.6%) showed reduced moxifloxacin susceptibility, and 10 of these 17 isolates (34.5% of all isolates) exceeded the Clinical and Laboratory Standards Institute breakpoint for moxifloxacin (MIC of >1 mg/liter) after repeat cultivation on moxifloxacin-containing agar. Seven of these ten isolates were high-BLNAR and represented multiple lineages. We identified 56 novel mutations in 45 genes induced during the development of fluoroquinolone resistance, except the defined quinolone resistance-determining regions (Ser84Leu and Asp88Tyr/Gly/Asn in GyrA and Gly82Asp, Ser84Arg, and Glu88Lys in ParC). Glu153Leu and ΔGlu606 in GyrA, Ser467Tyr and Glu469Asp in GyrB, and ompP2 mutations were novel mutations contributing to fluoroquinolone resistance in H. influenzae In conclusion, H. influenzae clinical isolates from multiple lineages can acquire fluoroquinolone resistance by multiple novel mutations. The higher rate of derivation of fluoroquinolone-resistant H. influenzae from high-BLNAR than β-lactamase-negative ampicillin-susceptible isolates (P = 0.01) raises the possibility of the emergence and spread of fluoroquinolone-resistant high-BLNAR in the clinical setting.

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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

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.

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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

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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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]

A unique species-specific structure of lipoteichoic acid common to Lactobacillus gasseri

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

J-GLOBAL

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

J-GLOBAL

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.

DOI PubMed

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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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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