研究者業績

渡辺 哲

ワタナベ アキラ  (Akira Watanabe)

基本情報

所属
千葉大学 真菌医学研究センター 准教授

J-GLOBAL ID
200901012250131603
researchmap会員ID
1000284726

論文

 463
  • 馬嶋 秀考, 大塚 雄一郎, 井上 祐三朗, 渡邉 哲, 亀井 克彦
    日本小児呼吸器学会雑誌 33(Suppl.) 118-118 2022年9月  
  • 渡辺 哲, 亀井 克彦
    日本医真菌学会雑誌 63(Suppl.1) 76-76 2022年9月  
  • 渡辺 哲, 亀井 克彦
    日本医真菌学会雑誌 63(Suppl.1) 86-86 2022年9月  
  • 新居 鉄平, 馬嶋 秀考, 亀井 克彦, 渡辺 哲
    日本医真菌学会雑誌 63(Suppl.1) 135-135 2022年9月  
  • 馬嶋 秀考, 新居 鉄平, 渡辺 哲, 亀井 克彦
    日本医真菌学会雑誌 63(Suppl.1) 97-97 2022年9月  
  • 馬嶋 秀考, 新居 鉄平, 渡辺 哲, 亀井 克彦
    日本医真菌学会雑誌 63(Suppl.1) 137-137 2022年9月  
  • 久保寺 愛, 栢森 健介, 濱田 千洋, 中島 彰宏, 加藤 怜, 桑名 由希子, 田中 一典, 西原 彩佳, 鎌田 百合, 李 千尋, 和泉 真太郎, 松井 愼一郎, 中尾 三四郎, 柴宮 明日香, 石井 改, 日野 裕太郎, 大島 渚, 武藤 朋也, 塚本 祥吉, 三川 紫緒, 竹田 勇輔, 三村 尚也, 堺田 惠美子, 渡辺 哲, 亀井 克彦
    千葉医学雑誌 98(4) 101-101 2022年8月  
  • 久保寺 愛, 栢森 健介, 濱田 千洋, 中島 彰宏, 加藤 怜, 桑名 由希子, 田中 一典, 西原 彩佳, 鎌田 百合, 李 千尋, 和泉 真太郎, 松井 愼一郎, 中尾 三四郎, 柴宮 明日香, 石井 改, 日野 裕太郎, 大島 渚, 武藤 朋也, 塚本 祥吉, 三川 紫緒, 竹田 勇輔, 三村 尚也, 堺田 惠美子, 渡辺 哲, 亀井 克彦
    千葉医学雑誌 98(4) 101-101 2022年8月  
  • Laís Pontes, Caio Augusto Gualtieri Beraquet, Teppei Arai, Akira Watanabe, Maria Luiza Moretti, Angelica Zaninelli Schreiber
    Medical mycology case reports 36 5-9 2022年6月  
    We present a case of a 55-year-old man with a heart transplant who acquired Invasive Aspergillosis by Aspergillus fumigatus with the focus in the kidney. During about two years of antifungal treatment, most of the time with voriconazole, it was possible to obtain nine isolates of A. fumigatus, with the same genotypic characteristics, but with an increase in MIC for several azoles. The two last isolates presented high MICs for Voriconazole (>8 μg/mL>). Sequencing of the CYP51A gene showed G448S amino acid substitution in the same two isolates. In long-term treatments with antifungals, it would be important to regularly evaluate the susceptibility of isolated strains, as resistance to azoles has been increasingly described around the world.
  • Eva Van Braeckel, Iain Page, Jesper Rømhild Davidsen, Christian B Laursen, Ritesh Agarwal, Ana Alastruey-Izquierdo, Aleksandra Barac, Jacques Cadranel, Arunaloke Chakrabarti, Oliver A Cornely, David W Denning, Holger Flick, Jean-Pierre Gangneux, Cendrine Godet, Yuta Hayashi, Christophe Hennequin, Martin Hoenigl, Muhammed Irfan, Koichi Izumikawa, Won-Jun Koh, Chris Kosmidis, Christoph Lange, Bernd Lamprecht, Francois Laurent, Oxana Munteanu, Rita Oladele, Thomas F Patterson, Akira Watanabe, Helmut J F Salzer
    The European respiratory journal 59(6) 2022年6月  
  • 馬嶋 秀考, 新居 鉄平, 渡邉 哲, 宮崎 泰成, 亀井 克彦
    日本呼吸器学会誌 11(増刊) 287-287 2022年4月  
  • 馬嶋 秀考, 新居 鉄平, 渡邉 哲, 宮崎 泰成, 亀井 克彦
    日本呼吸器学会誌 11(増刊) 287-287 2022年4月  
  • Akane Takamatsu, Takashi Yaguchi, Yasuaki Tagashira, Akira Watanabe, Hitoshi Honda
    Antimicrobial Agents and Chemotherapy 66(2) 2022年2月15日  
    <italic>Nocardia</italic> species cause a broad spectrum of infections, especially in immunocompromised patients. Given its relative rarity, data on the prognosis and distribution of nocardiosis from a large cohort are scarce.
  • Keita Takeda, Junko Suzuki, Akira Watanabe, Osamu Narumoto, Masahiro Kawashima, Yuka Sasaki, Hideaki Nagai, Katsuhiko Kamei, Hirotoshi Matsui
    Journal of clinical microbiology 60(2) JCM0201821 2021年12月8日  
    Aspergillus antibody testing is key for the clinical diagnosis of chronic pulmonary aspergillosis (CPA) with high sensitivity. However, false-negative results in patients with CPA might be obtained, depending on the Aspergillus species. The aim of this study was to investigate which factors are associated with false-negative results in Aspergillus precipitin tests and whether the sensitivity of precipitin tests in CPA is influenced by Aspergillus fumigatus and non-fumigatus Aspergillus species. Between February 2012 and December 2020, 116 consecutive antifungal treatment-naïve patients with CPA were identified and included in this retrospective chart review. Aspergillus species isolated from the respiratory tract of patients were identified by DNA sequencing. Characteristics of patients with positive and negative results for Aspergillus precipitin tests were compared. The sensitivity of the Aspergillus precipitin tests was compared between patients with A. fumigatus-associated CPA and non-fumigatus Aspergillus-associated CPA. A non-fumigatus Aspergillus species was the only factor significantly associated with negative Aspergillus precipitin test results in patients with CPA in the multivariate analysis (hazard ratio: 8.3, 95% confidence interval: 3.2-22.1, p < 0.0001). The positivity of the Aspergillus precipitin test in patients with non-fumigatus Aspergillus-associated CPA was lower than that in patients with A. fumigatus-associated CPA (84.8% vs. 37.9%; p < 0.0001). These results revealed that the presence of non-fumigatus Aspergillus-associated CPA should be considered with a negative Aspergillus precipitin test; this finding may prevent diagnostic delay or misdiagnosis for CPA.
  • Hazim O Khalifa, Vit Hubka, Akira Watanabe, Minoru Nagi, Yoshitsugu Miyazaki, Takashi Yaguchi, Katsuhiko Kamei
    Antimicrobial agents and chemotherapy 66(2) AAC0185621 2021年12月6日  
    This study was designed to evaluate the prevalence of antifungal resistance, genetic mechanisms associated with in vitro induction of azole and echinocandin resistance and genotyping of Candida krusei, which is intrinsically resistant to fluconazole and is recovered from clinical and non-clinical sources from different countries. Our results indicated that all the isolates were susceptible or had the wild phenotype (WT) to azoles, amphotericin B, and only 1.27% showed non-WT for flucytosine. Although 70.88% of the isolates were resistant to caspofungin, none of them were categorized as echinocandin-resistant as all were susceptible to micafungin and no FKS1 hotspot 1 (HS1) or HS2 mutations were detected. In vitro induction of azole and echinocandin resistance confirmed the rapid development of resistance at low concentrations of fluconazole (4 μg/ml), voriconazole (0.06 μg/ml) and micafungin (0.03 μg/ml), with no difference between clinical and non-clinical isolates in the resistance development. Overexpression of ABC1 gene and FKS1 HS1 mutations were the major mechanisms responsible for azole and echinocandin resistance, respectively. Genotyping of our 79 isolates coupled with 217 other isolates from different sources and geography confirmed that the isolates belong to two main subpopulations, with isolates from human clinical material and Asia being more predominant in cluster 1, and environmental and animals isolates and those from Europe in cluster 2. Our results are of critical concern, since realizing that the C. krusei resistance mechanisms and their genotyping are crucial for guiding specific therapy and for exploring the potential infection source.
  • 山下 晃司, 伴 さやか, 新居 鉄平, 宮部 安規子, 村田 正太, 川崎 健治, 矢口 貴志, 渡辺 哲, 松下 一之
    日本臨床微生物学会雑誌 32(Suppl.1) 252-252 2021年12月  
  • 山下 晃司, 伴 さやか, 新居 鉄平, 宮部 安規子, 村田 正太, 川崎 健治, 矢口 貴志, 渡辺 哲, 松下 一之
    日本臨床微生物学会雑誌 32(Suppl.1) 252-252 2021年12月  
  • Keita Takeda, Junko Suzuki, Akira Watanabe, Ryo Sekiguchi, Tomoya Sano, Masato Watanabe, Osamu Narumoto, Masahiro Kawashima, Takeshi Fukami, Yuka Sasaki, Atsuhisa Tamura, Hideaki Nagai, Hirotoshi Matsui, Katsuhiko Kamei
    Mycoses 65(2) 164-170 2021年11月16日  
    BACKGROUND: Aspergillus spp. is identified morphologically without antifungal susceptibility tests (ASTs) in most clinical laboratories. The aim of this study was to examine the clinical impact of the morphological identification of Aspergillus spp. to ensure the adequate clinical management of Aspergillus infections. PATIENTS/METHODS: Aspergillus isolates (n=126) from distinct antifungal treatment-naïve patients with aspergillosis were first identified morphologically, followed by species-level identification via DNA sequencing. An AST for itraconazole (ITC) and voriconazole (VRC) was performed on each Aspergillus isolate. RESULTS: Based on the genetic test results, morphology-based identification was accurate for > 95% of the isolates at the species sensu lato level although the test concordance of Aspergillus spp. with low detection rates was low. The rates of cryptic species were found to be 1.2% among the isolates of A. fumigatus complex and 96.8% in the A. niger complex. Cryptic species with lower susceptibilities to antifungal drugs than sensu stricto species among the same Aspergillus section were as follows: The A. lentulus (n=1) isolates had low susceptibilities to azoles among the A. fumigatus complex species (n=86), and A. tubingensis isolates (n=18) exhibited lower susceptibility to azoles among the A. niger complex species (n=31). CONCLUSION: Diagnostic accuracy was high at the A. fumigatus and A. niger complex level. However, in the presence of cryptic species, a solely morphological identification was insufficient. Particularly, ITC and VRC might be inappropriate for aspergillosis treatment when the A. niger complex is identified morphologically because it is possible that the Aspergillus isolate is A. tubingensis.
  • Akio Toh-E, Misako Ohkusu, Naruhiko Ishiwada, Akira Watanabe, Katsuhiko Kamei
    Current genetics 2021年11月10日  
    Cryptococcus neoformans, basidiomycetous pathogenic yeast, is basically an environmental fungus and, therefore, challenged by ever changing environments. In this study, we focused on how C. neoformans responds to stress caused by cadmium that is one of high-risk pollutants. By tracking phenotypes of the resistance or sensitivity to cadmium, we undertook forward and reverse genetic studies to identify genes involved in cadmium metabolism in C. neoformans. We found that the main route of Cd2+ influx is through Mn2+ ion transporter, Smf1, which is an ortholog of Nramp (natural resistance-associated macrophage protein 1) of mouse. We found that serotype A strains are generally more resistant to cadmium than serotype D strains and that cadmium resistance of H99, a representative of serotype A strains, was found to be due to a partial defect in SMF1. We found that calcium channel has a subsidiary role for cadmium uptake. We also showed that Pca1 (P-type-ATPase) functions as an extrusion pump for cadmium. We examined the effects of some metals on cadmium toxicity and suggested (i) that Ca2+ and Zn2+ could exert their protective function against Cd2+ via restoring cadmium-inhibited cellular processes and (ii) that Mg2+ and Mn2+ could have antagonistic roles in an unknown Smf1-independent Cd2+ uptake system. We proposed a model for Cd2+-response of C. neoformans, which will serve as a platform for understanding how this organism copes with the toxic metal.
  • Chie Watanabe, Yoshifumi Kimizuka, Yuji Fujikura, Takaaki Hamamoto, Akira Watanabe, Takashi Yaguchi, Tomoya Sano, Ryohei Suematsu, Yoshiki Kato, Jun Miyata, Susumu Matsukuma, Akihiko Kawana
    Internal medicine (Tokyo, Japan) 2021年10月26日  
    A 69-year-old woman who had undergone renal transplantation and was receiving sulfamethoxazole/trimethoprim (ST) developed pulmonary nocardiosis. To our knowledge, this is the first report of the identification of Nocardia elegans using nanopore sequencing, supported by 16S rDNA capillary sequencing findings. Chest computed tomography performed after ST initiation revealed significant improvement of the pulmonary shadows compared to previous findings. We herein report the value of nanopore sequencing for rapid identification of rare pathogens, such as Nocardia elegans. Furthermore, our findings suggest that Nocardia may infect even patients receiving ST, which is currently the most effective prophylactic drug.
  • Hazim O Khalifa, Akira Watanabe, Katsuhiko Kamei
    Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases 2021年10月20日  
    OBJECTIVES: We aimed to assess the prevalence and genetic basis of antifungal mechanisms as well as the genotyping of Candida tropicalis from clinical and non-clinical sources in Japan. METHODS: Eighty C. trpoicalis isolates, including 32 clinical isolates recovered from 29 patients and 48 non-clinical isolates recovered from 24 different sources (animals and the environment) were evaluated. All isolates were tested phenotypically for resistance to a wide range of antifungals and genotypically for resistance mechanisms to azole and echinocandin resistance. Furthermore, all the isolates were genotyped by multilocus sequence typing (MLST). RESULTS: Phenotypically, 30.2% (16/53) of the isolates were azole-resistant, with high levels of azole resistance among clinical isolates (51.7% [15/29]) and low levels (4.3% [1/24]) among non-clinical isolates. None of the isolates were reported as echinocandin resistant, with 60.4% (32/53) of the isolates were intermediate to caspofungin. Azole resistance was basically attributed to high expression levels of drug efflux transporter genes (CDR2 and CDR3), transcription factors (TAC1 and UPC2), and ergosterol biosynthesis pathway HMG gene. No FKS1 hot spot 1 (HS1) or HS2 missense mutations were detected in any of the isolates. MLST analysis revealed 35 different sequence types (STs), with the first identification of 23 new STs. Phylogenetic analysis confirmed the close relationship between the clinical and non-clinical isolates, with identifications of ST232 and ST933 among patients and marine mammals. CONCLUSION: Our results confirmed the emergence of azole resistance in C. tropicalis in Japan. Furthermore, phylogenetic analysis confirmed the transboundary dissemination and cross-transmission of C. tropicalis between humans and animals.
  • 馬嶋 秀考, 新居 鉄平, 楠屋 陽子, 高橋 弘喜, 渡邉 哲, 矢口 貴志, 宮崎 泰成, 亀井 克彦
    日本医真菌学会雑誌 62(Suppl.1) 100-100 2021年10月  
  • 馬嶋 秀考, 新居 鉄平, 楠屋 陽子, 高橋 弘喜, 渡邉 哲, 矢口 貴志, 宮崎 泰成, 亀井 克彦
    日本医真菌学会雑誌 62(Suppl.1) 100-100 2021年10月  
  • Yutaro Hino, Akira Watanabe, Rio Seki, Shokichi Tsukamoto, Yusuke Takeda, Emiko Sakaida, Katsuhiko Kamei
    Journal of Fungi 7(10) 2021年9月27日  
    Invasive fungal disease (IFD) in patients with haematological disorders is a fatal disease, making rapid identification and treatment crucial. However, the identification of the causative fungus is often difficult, sometimes even impossible. There have been few reports concerning the causative species of IFD. This study aimed to investigate the epidemiology and causative organism of IFD in patients with haematological diseases in Japan. We analyzed the IFD cases among the patients with haematological malignancies identified at the Medical Mycological Research Center, Chiba University, between 2013 and 2019. The most common underlying disease was acute myeloid leukaemia (34.3%). Forty-six point one percent of IFD patients received haematopoietic stem cell transplantation (HSCT). The major pathogens were Aspergillus, Candida, and Fusarium. Aspergillus fumigatus was the most common Aspergillus species, and Candida fermentati and Fusarium petroliphilum were the most common Candida and Fusarium species, respectively, in this analysis. Furthermore, various cryptic species and non-albicans Candida were identified. The drug susceptibility of such relatively rare strains suggests that analysis of the causative fungi should provide valuable information for therapeutic options. Therefore, our study indicated that it is clinically significant to identify the organism in as much detail as possible.
  • Hidetaka Majima, Teppei Arai, Yoko Kusuya, Hiroki Takahashi, Akira Watanabe, Yasunari Miyazaki, Katsuhiko Kamei
    Mycoses 64(11) 1354-1365 2021年9月24日  
    BACKGROUND: Mutations in cyp51A gene are known as main mechanisms of azole resistance in Aspergillus fumigatus, whereas azole-susceptible strains also carry cyp51A mutations (polymorphisms). The polymorphisms found in Europe mainly consist of two combinations of mutations, i.e., combinations of five single nucleotide polymorphisms (SNPs) of cyp51A, referred to as cyp51A-5SNPs, and combinations of three SNPs of cyp51A, referred to as cyp51A-3SNPs. Few studies have compared the distributions of cyp51A polymorphisms between different regions. OBJECTIVES: The aim of this study was to investigate the regional differences of cyp51A polymorphisms. METHODS: We compared the proportions of cyp51A polymorphisms in clinical and environmental strains isolated in various countries, and analysed the strains phylogenetically using short tandem repeats (STRs) and whole genome sequence (WGS). RESULTS: Among the Japanese strains, 15 out of 98 (15.3%) clinical strains and 8 out of 95 (8.4%) environmental strains had cyp51A polymorphisms. A mutation of cyp51AN248K was the most prevalent polymorphism in both clinical (n=14, 14.3%) and environmental strains (n=3, 3.2%). Only one environmental strain harboured cyp51A-5SNPs, which was reported to be the most prevalent in Europe. For phylogenetic analyses using STRs and WGS, 183 and 134 strains, respectively, were employed. They showed that most of the strains with cyp51AN248K clustered in the clades different from those of the strains with cyp51A-5SNPs and cyp51A-3SNPs as well as from those with TR34 /L98H mutations. CONCLUSIONS: This study suggests that there are genetic differences between cyp51A polymorphisms of A. fumigatus in Japan and Europe.
  • Plinio Trabasso, Tetsuhiro Matsuzawa, Teppei Arai, Daisuke Hagiwara, Yuzuru Mikami, Maria Luiza Moretti, Akira Watanabe
    Scientific reports 11(1) 17087-17087 2021年8月24日  
    Infections due to triazole-resistant Aspergillus fumigatus are increasingly reported worldwide and are associated with treatment failure and mortality. The principal class of azole-resistant isolates is characterized by tandem repeats of 34 bp or 46 bp within the promoter region of the cyp51A gene. Loop-mediated isothermal amplification (LAMP) is a widely used nucleic acid amplification system that is fast and specific. Here we describe a LAMP assay method to detect the 46 bp tandem repeat insertion in the cyp51A gene promoter region based on novel LAMP primer sets. It also differentiated strains with TR46 tandem repeats from those with TR34 tandem repeats. These results showed this TR46-LAMP method is specific, rapid, and provides crucial insights to develop novel antifungal therapeutic strategies against severe fungal infections due to A. fumigatus with TR46 tandem repeats.
  • Takahito Toyotome, Kenji Onishi, Mio Sato, Yoko Kusuya, Daisuke Hagiwara, Akira Watanabe, Hiroki Takahashi
    Antimicrobial agents and chemotherapy 65(9) e0265720 2021年8月17日  
    Azole resistance of Aspergillus fumigatus is a global problem. The major resistance mechanism is through cytochrome P450 14-α sterol demethylase Cyp51A alterations such as a mutation(s) in the gene and the acquisition of a tandem repeat in the promoter. Although other azole tolerance and resistance mechanisms, such as the hmg1 (a 3-hydroxy-3-methylglutaryl coenzyme-A reductase gene) mutation, are known, few reports have described studies elucidating non-Cyp51A resistance mechanisms. This study explored genes contributing to azole tolerance in A. fumigatus by in vitro mutant selection with tebuconazole, an azole fungicide. After three rounds of selection, we obtained four isolates with low susceptibility to tebuconazole. These isolates also showed low susceptibility to itraconazole and voriconazole. Comparison of the genome sequences of the isolates obtained and the parental strain revealed a nonsynonymous mutation in MfsD, a major facilitator superfamily protein (Afu1g11820; R337L mutation [a change of R to L at position 337]), in all isolates. Furthermore, nonsynonymous mutations in AgcA, a mitochondrial inner membrane aspartate/glutamate transporter (Afu7g05220; E535Stop mutation), UbcD, a ubiquitin-conjugating enzyme E2 (Afu3g06030; T98K mutation), AbcJ, an ABC transporter (Afu3g12220; G297E mutation), and RttA, a putative protein responsible for tebuconazole tolerance (Afu7g04740; A83T mutation), were found in at least one isolate. Disruption of the agcA gene led to decreased susceptibility to azoles. Reconstruction of the A83T point mutation in RttA led to decreased susceptibility to azoles. Reversion of the T98K mutation in UbcD to the wild type led to decreased susceptibility to azoles. These results suggest that these mutations contribute to lowered susceptibility to medical azoles and agricultural azole fungicides.
  • Antonio Camargo Martins, Eliane Molina Psaltikidis, Tiago Cristiano de Lima, Renata Fagnani, Angelica Zaninelli Schreiber, Lucieni de Oliveira Conterno, Katsuhiko Kamei, Akira Watanabe, Plinio Trabasso, Mariângela Ribeiro Resende, Maria Luiza Moretti
    Journal de mycologie medicale 31(4) 101175-101175 2021年7月14日  
    BACKGROUND: COVID-19 co-infections have been described with different pathogens, including filamentous and yeast fungi. METHODOLOGY: A retrospective case series study conducted from February to December 2020, at a Brazilian university hospital. Data were collected from two hospital surveillance systems: Invasive fungal infection (IFI) surveillance (Mycosis Resistance Program - MIRE) and COVID-19 surveillance. Data from both surveillance systems were cross-checked to identify individuals diagnosed with SARS-CoV-2 (by positive polymerase chain reaction (PCR)) and IFI during hospital stays within the study period. RESULTS: During the study period, 716 inpatients with COVID-19 and 55 cases of IFI were identified. Fungal co-infection with SARS-CoV-2 was observed in eight (1%) patients: three cases of aspergillosis; four candidemia and one cryptococcosis. The median age of patients was 66 years (IQR 58-71 years; range of 28-77 years) and 62.5% were men. Diagnosis of IFI occurred a median of 11.5 days (IQR 4.5-23 days) after admission and 11 days (IQR 6.5-16 days) after a positive PCR result for SARS-CoV-2. In 75% of cases, IFI was diagnosed in the intensive care unit (ICU). Cases of aspergillosis emerged earlier than those of candidemia: an average of 8.6 and 28.6 days after a positive PCR for SARS-CoV-2, respectively. All the patients with both infections ultimately died. CONCLUSION: A low rate of COVID-19 co-infection with IFI was observed, with high mortality. Most cases were diagnosed in ICU patients. Aspergillosis diagnosis is highly complex in this context and requires different criteria.
  • 渡辺 哲, 亀井 克彦
    感染と抗菌薬 24(2) 98-102 2021年6月  
    <文献概要>COVID-19に合併する肺アスペルギルス症の報告が増加している。本症に関する知見は極めて限られており,今後の詳細な病態解析が必要であるが,臨床像としてインフルエンザ関連肺アスペルギルス症と類似している部分も多く,診断や治療法の参考となる。
  • 亀井 克彦, 渡辺 哲
    日本医師会雑誌 150(特別1) S301-S303 2021年6月  
  • Takuya Matsuzaki, Hajime Kasai, Hideki Ikeda, Yuki Tajiri, Kenichi Suzuki, Akira Watanabe, Katsuhiko Kamei, Takashi Urushibara
    Respirology case reports 9(6) e00763 2021年6月  
    Chrysosporium zonatum is a soil-dwelling fungus that rarely causes pulmonary infections, and a small number of cases have been reported to date. A 74-year-old man, who had previously been treated for tuberculosis, presented with symptoms of low-grade fever, anorexia, cough, and bloody sputum. Chest computed tomography (CT) showed a thick-walled cavitary lesion in the right upper lobe, in which there was a suspected mycotic mass. Initially, the patient was suspected to have chronic aspergillosis due to positive serum anti-Aspergillus antibodies. However, bronchoscopic culture revealed the growth of C. zonatum. Symptoms and imaging findings improved with administration of voriconazole for 18 months. Infection by C. zonatum is very rare and is difficult to differentiate from aspergillosis by clinical features. Clinicians should be aware of the possibility of coinfection with C. zonatum and Aspergillus sp. Voriconazole may be an effective treatment option.
  • Hazim O Khalifa, Teppei Arai, Hidetaka Majima, Akira Watanabe, Katsuhiko Kamei
    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy 27(6) 834-839 2021年6月  
    INTRODUCTION: Infections with Candida glabrata have recently gained worldwide attention owing to its association with long hospitalizations and high mortality rates. This problem is highlighted when the infection is associated with echinocandin resistance, which is used for first-line therapy. Echinocandin resistance is exclusively attributed to functional mutations in FKS genes, and especially in hot spot (HS) regions. Unfortunately, few studies have focused on the rapid identification of FKS mutations associated with echinocandin resistance in C. glabrata. This study was intended to evaluate and validate the use of Surveyor nuclease assay (SN) for detection of FKS gene mutations. METHODS: SN was evaluated against three segments of FKS1 and FKS2 genes including whole gene, regions including all HSs, and the region including only HS1. RESULTS: Our results showed that SN results are basically dependent on the type of gene as well as the segment type. Interestingly, SN can detect mutations in the region containing HS1 in both FKS1 and FKS2 genes. Furthermore, SN can detect mutations in the segment containing all HS regions for FKS1 but not FKS2. SN was unable to detect mutations in the whole FKS1 and FKS2 genes. CONCLUSIONS: As far as we know, this is the first study to validate SN for rapid identification of FKS gene mutations. This assay could be used as a sample for rapid identification of mutations associated with HS1 region in FKS genes, which have a predominant role for echinocandin resistance induction in C. glabrata.
  • Teppei Arai, Takashi Umeyama, Hidetaka Majima, Tatsuya Inukai, Akira Watanabe, Yoshitsugu Miyazaki, Katsuhiko Kamei
    Medical mycology 59(10) 980-984 2021年5月21日  
    Triazole-resistant Aspergillus fumigatus is a global health concern. In general, each triazole resistance pattern caused by the specified amino acid substitution of Cyp51A has a typical pattern depending on the mutation site. We evaluated the contribution of both Cyp51A and Hmg1 mutations to atypical triazole resistance in A. fumigatus. We used clinical triazole-resistant A. fumigatus strains collected in Japan and investigated the sequences of cyp51A and hmg1 genes. To delineate the association between the hmg1 mutation and atypical triazole resistance, the mutant hmg1 alleles in clinical multi-azole resistant strains were replaced with the wild-type hmg1 allele by CRISPR/Cas9 system. In our study, the combination of Cyp51A mutation and Hmg1 mutation was shown to additively contribute to triazole resistance. We also demonstrated that the triazole resistance conferred by the Hmg1 mutation showed a different pattern depending on the mutation site, similar to the Cyp51A mutation. Our results indicate that focusing on the phenotypes of multiple genes is essential to clarify the overall picture of the triazole resistance mechanism of A. fumigatus. LAY SUMMARY: The number of triazole-resistant Aspergillus fumigatus is increasing. We confirmed thatmutation in a hydroxymethylglutaryl-CoA reductase (Hmg1) in the fungus contributesto the resistance separately from Cyp51A mutation, and that susceptibility patterns aredifferent based on mutation site.
  • Hiroki Takahashi, Maiko Umemura, Akihiro Ninomiya, Yoko Kusuya, Masaaki Shimizu, Syun-ichi Urayama, Akira Watanabe, Katsuhiko Kamei, Takashi Yaguchi, Daisuke Hagiwara
    Frontiers in Fungal Biology 2 2021年4月16日  
    Filamentous fungi produce various bioactive compounds that are biosynthesized by sets of proteins encoded in biosynthesis gene clusters (BGCs). For an unknown reason, many BGCs are transcriptionally silent in laboratory conditions, which has hampered the discovery of novel fungal compounds. The transcriptional reactiveness of fungal secondary metabolism is not fully understood. To gain the comprehensive view, we conducted comparative genomic and transcriptomic analyses of nine closely-related species of <italic>Aspergillus</italic> section <italic>Fumigati</italic> (<italic>A. fumigatus, A. fumigatiaffinis, A. novofumigatus, A. thermomutatus, A. viridinutans, A. pseudoviridinutans, A. lentulus, A. udagawae</italic>, and <italic>Neosartorya fischeri</italic>). For expanding our knowledge, we newly sequenced genomes of <italic>A. viridinutans</italic> and <italic>A. pseudoviridinutans</italic>, and reassembled and reannotated the previously released genomes of <italic>A. lentulus</italic> and <italic>A. udagawae</italic>. Between 34 and 84 secondary metabolite (SM) backbone genes were identified in the genomes of these nine respective species, with 8.7–51.2% being unique to the species. A total of 247 SM backbone gene types were identified in the nine fungi. Ten BGCs are shared by all nine species. Transcriptomic analysis using <italic>A. fumigatus, A. lentulus, A. udagawae, A. viridinutans</italic>, and <italic>N. fischeri</italic> was conducted to compare expression levels of all SM backbone genes in four different culture conditions; 32–83% of SM backbone genes in these species were not expressed in the tested conditions, which reconfirmed that large part of fungal SM genes are hard to be expressed. The species-unique SM genes of the five species were expressed with lower frequency (18.8% in total) than the SM genes that are conserved in all five species (56%). These results suggest that the expression tendency of BGCs is correlated with their interspecies distribution pattern. Our findings increase understanding of the evolutionary processes associated with the regulation of fungal secondary metabolism.
  • 馬嶋 秀考, 新居 鉄平, 渡辺 哲, 亀井 克彦
    感染症学雑誌 95(臨増) 246-246 2021年4月  
  • 渡辺 哲, 新居 鉄平, 亀井 克彦
    日本化学療法学会雑誌 69(Suppl.A) 125-125 2021年4月  
  • 馬嶋 秀考, 新居 鉄平, 渡辺 哲, 亀井 克彦
    感染症学雑誌 95(臨増) 246-246 2021年4月  
  • Hazim O. Khalifa, Hidetaka Majima, Akira Watanabe, Katsuhiko Kamei
    Journal of Fungi 7(2) 108-108 2021年2月2日  
    This study was designed to analyze the interaction of 21 antifungal combinations consisting of seven major antifungal agents against 11 echinocandin- susceptible and six-resistant C. glabrata isolates. The combinations were divided into five major groups and were evaluated by checkerboard, disc diffusion, and time-killing assays. Synergy based on the fractional inhibitory concentration index of ≤0.50 was observed in 17.65-29.41% of the cases for caspofungin combinations with azoles or amphotericin B. Amphotericin B combination with azoles induced synergistic interaction in a range of 11.76-29.41%. Azole combinations and 5-flucytosine combinations with azoles or amphotericin B did not show synergistic interactions. None of the 21 combinations showed antagonistic interactions. Interestingly, 90% of the detected synergism was among the echinocandin-resistant isolates. Disk diffusion assays showed that the inhibition zones produced by antifungal combinations were equal to or greater than those produced by single drugs. The time-killing assay showed the synergistic action of caspofungin combination with fluconazole, voriconazole, and posaconazole, and the amphotericin B-5-flucytosine combination. Furthermore, for the first time, this assay confirmed the fungicidal activity of caspofungin-voriconazole and amphotericin B-5-flucytosine combinations. The combination interactions ranged from synergism to indifference and, most importantly, no antagonism was reported and most of the synergistic action was among echinocandin-resistant isolates.
  • 亀井 克彦, 渡辺 哲
    検査と技術 49(2) 120-125 2021年2月  
    <文献概要>Point ●輸入真菌症の起因菌は一歩間違えば自分だけでなく,病院全体を巻き込んだ感染事故に発展します."これは怪しいかも"と疑いをもつ慎重さこそが大切です.●疑いをもつためには,海外渡航/滞在歴(ヒストプラスマ症を除く)と菌の関係を理解していること,そして特徴には乏しいものの,これらの菌種のコロニーの概観(一部は特徴的)を知っておく必要があります.●疑ったら遠慮なく専門家と相談しましょう.培養同定による診断は最後の手段です.主治医と連携をとって一歩一歩慎重に検査を進めることが大切です.
  • Phuong-Thao Nguyen, Akio Toh-E, Ngoc-Hung Nguyen, Yumi Imanishi-Shimizu, Akira Watanabe, Katsuhiko Kamei, Kiminori Shimizu
    Current genetics 67(1) 115-128 2021年2月  
    The amino acid biosynthetic pathway of invasive pathogenic fungi has been studied as a potential antifungal drug target. Studies of the disruption of genes involved in amino acid biosynthesis have demonstrated the importance of this pathway in the virulence of Cryptococcus neoformans. Here, we identified the MET5 (CNL05500) and MET10 (CNG03990) genes in this pathway, both encoding sulfite reductase, which catalyzes the reduction of sulfite to sulfide. The MET14 (CNE03880) gene was also identified, which is responsible for the conversion of sulfate to sulfite. The use of cysteine as a sulfur source led to the production of methionine via hydrogen sulfide synthesis mediated by CYS4 (CNA06170), CYS3 (CNN01730), and MST1 (CND03690). MST1 exhibited high homology with the TUM1 gene of Saccharomyces cerevisiae, which has functional similarity with the 3-mercaptopyruvate sulfurtransferase (3-MST) gene in humans. Although the hypothesis that hydrogen sulfide is produced from cysteine via CYS4, CYS3, and MST1 warrants further study, the new insight into the metabolic pathway of sulfur-containing amino acids in C. neoformans provided here indicates the usefulness of this system in the development of screening tools for antifungal drug agents.
  • 渡邉 哲, 亀井 克彦
    日本化学療法学会雑誌 69(1) 54-55 2021年1月  
  • 渡邉 哲, 亀井 克彦
    日本化学療法学会雑誌 69(1) 61-61 2021年1月  
  • 渡辺 哲, 亀井 克彦
    日本医事新報 (5039) 33-38 2020年11月  
    <Point>▼現在上市されている抗真菌薬は種類、数ともに少ないため、特定の薬剤に耐性を有する真菌の出現は治療戦略上大きな問題となりうる▼近年、アゾール耐性アスペルギルスが世界的に大きな問題となっている。わが国においてもそれらの耐性株の検出が確認されているため、全国的な疫学調査を継続する必要がある(著者抄録)
  • 馬嶋 秀考, 新居 鉄平, 渡辺 哲, 宮崎 泰成, 亀井 克彦
    日本医真菌学会雑誌 61(Suppl.) 83-83 2020年9月  
  • 新居 鉄平, 梅山 隆, 犬飼 達也, 渡辺 哲, 宮崎 義継, 亀井 克彦
    日本医真菌学会雑誌 61(Suppl.) 90-90 2020年9月  
  • 新居 鉄平, 高橋 弘喜, 楠屋 陽子, 渡辺 哲, 亀井 克彦
    日本医真菌学会雑誌 61(Suppl.) 90-90 2020年9月  
  • 馬嶋 秀考, 新居 鉄平, 渡辺 哲, 宮崎 泰成, 亀井 克彦
    日本医真菌学会雑誌 61(Suppl.) 90-90 2020年9月  
  • Hazim Khalifa, 渡辺 哲, 亀井 克彦, 新居 鉄平, 馬嶋 秀考
    日本化学療法学会雑誌 68(Suppl.A) 323-323 2020年9月  
  • 渡辺 哲, 亀井 克彦
    Medical Technology 48(8) 845-851 2020年8月  
    いわゆる輸入真菌症は、一般旅行者でも罹患しうるきわめて感染性が高い疾患である。一般医療機関における通常の微生物検査室では、培養を行わず専門機関に相談・依頼するべきである。症状は非特異的であるため、確定診断に至るためにはまず主治医が詳細な渡航歴を聴取したうえでこれらの疾患を疑うことが重要である。(著者抄録)
  • Hirokazu Takatsuka, Shingo Yamazaki, Akira Watanabe, Iichiro Yokoyama, Takaaki Suzuki, Katsuhiko Kamei, Itsuko Ishii
    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy 26(8) 847-850 2020年8月  査読有り
    Aspergillus empyema is treated with either systemic administration of antifungal drugs or surgery, but the mortality rate is very high. Here, we report a case of Aspergillus empyema successfully treated using combined intrathoracic and intravenous administration of voriconazole (VRCZ). Treatment success was achieved by monitoring VRCZ plasma trough concentration. The patient was a 71-year-old Japanese woman diagnosed with Aspergillus empyema whom we started on intravenous administration of VRCZ. Although penetration of VRCZ into the pleural effusion was confirmed, the level was below 1 μg/mL, which is the minimum inhibitory concentration for Aspergillus fumigatus determined by antifungal susceptibility testing in pleural effusion culture. Therefore, we initiated combination therapy with intrathoracic and intravenous administration of VRCZ. VRCZ 200 mg was first dissolved in 50-100 mL of saline and administered into the thoracic cavity via a chest tube. The chest tube was clamped for 5-6 h, and then VRCZ solution was excreted though the chest tube. When a single dose of the VRCZ was administered into the intrathoracic space, the plasma concentration before intravenous administration increased from 1.45 μg/mL on day 27 to 1.53 μg/mL on day 28. Although intravenous administration was continued, the VRCZ plasma trough concentration decreased to 1.36 μg/mL on day 29. We therefore decided on an intrathoracic administration schedule of 2-3 times a week. Intrathoracic administration was performed 14 times in total until fenestration surgery on day 64. Our case suggests that combined intrathoracic and intravenous administration of VRCZ may be a valid treatment option for Aspergillus empyema.

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