渡辺 哲

Invasive fungal infection (IFI) is a life-threating infectious disease in high-risk neonates. Strategies for the treatment and prevention of IFI in neonates in Japan remain unclear. We conducted a nationwide retrospective survey to determine IFI incidence between January 2014 and October 2015. Primary survey questionnaires were submitted to 309 medical facilities that regularly treat high-risk neonates. The questionnaire assessed IFI incidence during the study period, methods for preventing fungal infection in early delivery neonates, and methods for preventing mother-to-child fungal transmission. The secondary questionnaire was for facilities that had IFI cases and replied to the primary questionnaire. In total, 128 medical facilities (41.4%) completed the primary questionnaire, 17/128 facilities recorded 23 proven or probable IFI cases. Estimated annual IFI incidence was 0.33/1000 live births of hospitalized neonates. Patient data at IFI onset were available for all 23 patients. Birth weight was < 1000 g in 18 patients. Causative microorganisms were identified in 22 patients. Candida species (n = 21) were the most common pathogens, and one patient had mucormycosis. The mortality rate was 17.4%. Regarding neonatal fungal prophylaxis, 55/128 facilities (43.0%) reported administering therapy. The most frequently used prophylactic drugs were fluconazole, then micafungin. Fungal prophylaxis for mothers who showed fungal colonization was performed in 30/128 facilities (23.4%). Oxiconazole vaginal tablets were most commonly used as prophylaxis for high-risk mothers. In Japan, the diagnosis, treatment, and prevention of neonatal IFI varied. Continuous surveillance and treatment regimen for neonatal IFI are required to improve outcomes in high-risk neonates.

We elucidated a unique feature of sulfur metabolism in Cryptococcus neoformans. C. neoformans produces cysteine solely by the O-acetylserine pathway that consists of serine-O-acetyl transferase and cysteine synthase. We designated the gene encoding the former enzyme CYS2 (locus tag CNE02740) and the latter enzyme CYS1 (locus tag CNL05880). The cys1Δmutant strain was found to be avirulent in a murine infection model. Methionine practically does not support growth of the cys1Δ strain, and cysteine does not serve as a methionine source, indicating that the transsulfuration pathway does not contribute to sulfur amino acid synthesis in C. neoformans. Among the genes encoding enzymes catalyzing the reactions from homoserine to methionine, the gene corresponding to the Saccharomyces cerevisiae MET17 encoding O-acetylhomoserine sulfhydrylase (Met17p) had remained to be identified in C. neoformans. By genetic analysis of Met− mutants obtained by Agrobacterium tumefaciens-mediated mutagenesis, we concluded that Cnc01220, most similar to Str2p (36% identity), cystathionine-γ-synthase, in the Saccharomyces genome, is the C. neoformans version of O-acetylhomoserine sulfhydrylase. We designated CNC01220 as MET17. The C. neoformans met3Δ mutant defective in the first step of the sulfate assimilation pathway, sulfate adenylyltransferase, barely uses methionine as a sulfur source, whereas it uses cysteine efficiently. The poor utilization of methionine by the met3Δ mutant is most probably due to the absence of the transsulfuration pathway, causing an incapability of C. neoformans to produce cysteine and hydrogen sulfide from methionine. When cysteine is used as a sulfur source, methionine is likely produced de novo by using hydrogen sulfide derived from cysteine via an unidentified pathway. Altogether, the unique features of sulfur amino acid metabolism in C. neoformans will make this fungus a valuable experimental system to develop anti-fungal agents and to investigate physiology of hydrogen sulfide.

アスペルギルス症の主要な原因菌であるAspergillus fumigatusのゲノムが公開されてから15年が経とうとしている。ゲノム解読株(Af293株)を基準とした病原因子解析が世界中の研究者によって進められ、感染機構に関して多くの知見がもたらされたことは論を俟たない。一方で、単一のゲノム解読株に依拠した病原因子解析が、実際のヒト感染における複雑な臨床的側面を説明しうるかについては議論の余地がある。したがって、臨床的観点から病原菌の振る舞いを詳細に理解することが、今後の感染微生物学における課題だと考えられる。当グループは近年、多数の臨床分離株を対象として遺伝的、生理的、感染病理的知見を集積することにより、上記課題の解決を目指した研究を開始している。本稿では、次世代シークエンサーを活用した臨床分離株の大規模遺伝子解析について、特に病原性、感染形態、薬剤耐性に焦点を当てて紹介する。われわれのアプローチは、病原菌の株単位に存在する遺伝的差異と表現型との連関解析に基づいたものであり、今後、基準株の解析のみからは得られない病原性に関する新しい知見がもたらされると期待される。(著者抄録)

「輸入真菌症」として一般的に認識されている疾患:コクシジオイデス症、ヒストプラズマ症、マルネッフェイ型ペニシリウム症、パラコクシジオイデス症、ブラストミセス症について概説する。これらはすべて症状や一般臨床検査所見が非特異的であり、診察に当たり意識的に鑑別にあげることが診断への重要な手がかりとなる。また、5疾患すべての原因菌はバイオセーフティレベル3(BSL-3)に分類されており、一般医療機関での培養は避けるべきである。(著者抄録)

Aspergillus fumigatus is an important fungal pathogen of humans. Inhaled conidia of A. fumigatus adhere to pulmonary epithelial cells, causing opportunistic infection. However, little is known about the molecular mechanism of the adherence of resting conidia. Fungal molecules adhesive to host cells are presumed to be displayed on the conidial surface during conidial formation as a result of changes in gene expression. Therefore, we exhaustively searched for adhesion molecules by comparing the phenotypes and the gene expression profiles of A. fumigatus strains that have conidia showing either high or low adherence to human pulmonary A549 cells. Morphological observation suggested that strains that produce conidia of reduced size, hydrophobicity, or number show decreased adherence to A549 cells. K-means cluster analyses of gene expression revealed 31 genes that were differentially expressed in the high-adherence strains during conidial formation. We knocked out three of these genes and showed that the conidia of AFUA_4G01030 (encoding a hypothetical protein) and AFUA_4G08805 (encoding a haemolysin-like protein) knockout strains had significantly reduced adherence to host cells. Furthermore, the conidia of these knockout strains had lower hydrophobicity and fewer surface spikes compared to the control strain. We suggest that the selectively expressed gene products, including those we identified experimentally, have composite synergistic roles in the adhesion of conidia to pulmonary epithelial cells.

真菌症全体が大きな変革期を迎えているが、肺における糸状菌感染も例外ではない。菌種でみると、アスペルギルス以外に、真正担子菌(いわゆるキノコ類)、スケドスポリウムなどが増加しており、さらにアスペルギルスにおけるアゾール耐性も急増している点は大きな問題である。診断法開発ではMALDI-TOF MSを用いた迅速同定法が登場した。糸状菌に関してはまだ基礎となるデータベースが未完成だが、今後が期待される。また、上記の耐性菌増加を踏まえた耐性菌感染症の診断技術が注目される。治療ではposaconazoleとisavuconazoleの上市が我が国でも着々と近づいており、開発中の新薬を含めて今後を期待したい。(著者抄録)

&lt;p&gt;小児がん患者では，真菌感染症が疑われる場合でも，真菌の分離同定はしばしば困難であり臨床経過により診断治療が行われることが多い．2004年1月から2014年12月までに当科で治療を受けた小児血液がん患者6人より分離同定された糸状菌2株，酵母5株に関し，薬剤感受性試験を行い，分離同定することの意義について後方視的に検討した．糸状菌はいずれも耳漏より検出された．1例では好中球抑制期間に外耳炎を繰り返し，&lt;i&gt;Aspergillus terreus&lt;/i&gt;が同定された．薬剤感受性試験の結果よりミカファンギン（MCFG），ボリコナゾール（VRCZ）を併用し造血幹細胞移植を行った．酵母はすべてカンジダで，血液より分離同定された．&lt;i&gt;Candida tropicalis&lt;/i&gt;分離例は治療開始後にβ-Dグルカンの上昇，脾膿瘍の悪化を認めたが感受性試験にてMCFG感受性良好であることを確認し治療遂行できた．&lt;i&gt;C. parapsilosis&lt;/i&gt;，&lt;i&gt;C. glabrata&lt;/i&gt;分離例はいずれもMCFG投与下のブレイクスルー感染であった．MCFG感受性良好として知られている&lt;i&gt;C. glabrata&lt;/i&gt;に関しては薬剤感受性試験の結果，キャンディン系薬剤に対するMICの上昇が確認された．近年米国でもキャンディン系耐性カンジダが問題となっており，今後小児がん患者においても，治療効果が思わしくない際には薬剤感受試験を行うことが必要だろう．&lt;/p&gt;

Aspergillus fumigatus is the predominant fungal pathogen responsible for life-threatening systemic infections in humans. Recently developed high-throughput whole genome sequencing (WGS) and RNA-Seq technologies have proven to be powerful tools for systematically investigating pathogenic organisms. In this review, we present new virulence factors obtained through our "omics" researches on A. fumigatus. We first sequenced genomes of A. fumigatus stains isolated from one infected patient at different time points, and made an important finding that although the genome (microsatellites) type of the infected strain remained unchanged, the strain exhibited several genetic changes, including acquiring therapeutic drug resistance, during patient treatment for 1.5 years. Of the various presentations of aspergillosis, pulmonary aspergilloma (PA) is one of the most common forms of A. fumigatus infection, where fungus balls are composed of fungal hyphae, inflammatory cells, fibrin, mucus, and tissue debris. Chronic necrotizing pulmonary aspergillosis (CNPA), also known as semi-invasive or invasive aspergillosis, is locally invasive and predominantly seen in patients with mild immunodeficiency or with a chronic lung disease. We compared genomes of strains individually isolated from eight PA and eight CNPA patients in Japan, and found that the PA and CNPA strains show indiscernible genetic and ancestral backgrounds as far as genomic SNPs of the strains are concerned. The main route of infections caused by A. fumigatus is via inhalation of conidia. Inhaled conidia rapidly adhere to pulmonary epithelial cells. Nevertheless, little is known of the molecular mechanism of adherence in A. fumigatus resting conidia. We assumed corresponding adhesion molecules were highly expressed in high-adhesion conidia during conidia maturation, and exhaustively searched adhesion molecules by comparing gene expression levels in high- and low-adherence strains using the RNA-Seq technique. We found several factors involved in conidial adhesion and suggest that composite actions of these molecules have roles in conidial adhesion to human pulmonary epithelial cells.

近年の医療の高度化、診断法の発達などにより、いわゆる新興真菌症、再興真菌症が増加している。さらに国際交流の活発化などにより、輸入真菌症に遭遇する機会も増えてくると思われる。今回取り上げた肺真菌症はいずれも確立した診断法が存在せず、確定診断は培養検査、病理組織学的検査が中心となる。ただし輸入真菌症原因菌は感染力が極めて強いものが多いため、一般の検査室での検体培養は施行しないようにすべきである。(著者抄録)

We constructed deletion mutants of Cryptococcus neoformans var neoformans (serotype D) genes encoding late ergosterol biosynthetic pathway enzymes and found that the mutations enhanced susceptibility to various drugs including micafungin, one of the echinocandins, to which wild-type Cryptococcus strains show no susceptibility. Furthermore, through isolation of a mutant resistant to micafungin from a micafungin-sensitive erg mutant and genetic analysis of it, we found that the responsible mutation occurred in the hotspot 2 of FKS1 encoding beta-1, 3-glucan synthase, indicating that micafungin inhibited the growth of the erg mutant via inhibiting Fks1 activity. Addition of ergosterol to the culture of the erg mutants recovered the resistance to micafungin, suggesting that the presence of ergosterol in membrane inhibits the accession of micafungin to its target. We found that a loss of one of genes encoding subunits of v-ATPase, VPH1, made Cryptococcus cells sensitive to micafungin. Our observation that the erg2 vph1 double mutant was more sensitive to micafungin than either single mutant suggests that these two genes act differently in becoming resistant to micafungin. The erg mutants allowed us to study the physiological significance of beta-1, 3-glucan synthesis in C. neoformans; the inhibition of beta-1, 3-glucan synthesis induced cell death and changes in cellular morphology. By observing the erg mutant cells recovering from the growth inhibition imposed by micafungin, we recognized beta-1, 3-glucan synthesis would suppress filamentous growth in C. neoformans.

It is well known that 5-fluoroorotic acid (5-FOA)-resistant mutants isolated from wild-type Cryptococcus neoformans are exclusively either ura3 or ura5 mutants. Unexpectedly, many of the 5-FOA-resistant mutants isolated in our selective regime were Ura(+). We identified CNM00460 as the gene responsible for these mutations. Cnm00460 belongs to the nucleobase cation symporter 1/purine-related transporter (NCS1/PRT) super family of fungal transporters, representative members of which are uracil transporter, uridine transporter and allantoin transporter of Saccharomyces cerevisiae. Since the CNM00460 gene turned out to be involved in utilization of orotic acid, most probably as transporter, we designated this gene Orotic Acid Transporter 1 (OAT1). This is the first report of orotic acid transporter in this family. C. neoformans has four members of the NCS1/PRT family, including Cnm00460, Cnm02550, Cnj00690, and Cnn02280. Since the cnm02550a Delta strain showed resistance to 5-fluorouridine, we concluded that CNM02550 encodes uridine permease and designated it URidine Permease 1 (URP1). We found that oat1 mutants were sensitive to 5-FOA in the medium containing proline as nitrogen source. A mutation in the GAT1 gene, a positive transcriptional regulator of genes under the control of nitrogen metabolite repression, in the genetic background of oat1 conferred the phenotype of weak resistance to 5-FOA even in the medium using proline as nitrogen source. Thus, we proposed the existence of another orotic acid utilization system (tentatively designated OAT2) whose expression is under the control of nitrogen metabolite repression at least in part. We found that the OAT1 gene is necessary for full pathogenic activity of C. neoformans var. neoformans.

Recently, azole-resistant Aspergillus fumigatus containing a 34-bp or 46-bp tandem repeat in the promoter region of cyp51A combined with amino acid substitution(s) has appeared in the environment worldwide, including several Asian countries. In this study, we isolated the 34-bp tandem repeat-containing azole-resistant A. fumigatus strain OKH50 from a patient in Japan in May 2016. The patient had not been treated with medical azoles before the strain isolation, suggesting that the resistant property was acquired before infection. In addition, the patient had not traveled overseas. Our analysis of short tandem repeats of the strain indicates that the strain is strongly related to the 34-bp tandem repeat-containing isolates from European countries and Asia-Oceania countries but not to susceptible isolates from Japan, suggesting that the strain was introduced from overseas and might spread in Japan. (C) 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Aspergillus niger and its related species, known as Aspergillus section Nigri, are ubiquitously distributed across the globe and are often isolated from clinical specimens. In Japan, Aspergillus section Nigri is second most often isolated from clinical specimens following Aspergillus fumigatus. We determined the species of Aspergillus section Nigri isolated in Japan by DNA sequencing of partial beta-tubulin genes and investigated drug susceptibility by the CLSI M38-A2 method. The collection contained 20 Aspergillus niger, 59 Aspergillus welwitschiae, and 39 Aspergillus tubingensis strains. Drug susceptibility testing revealed 30 to 55% of A. niger, 6.8 to 18.6% of A. welwitschiae, and 79.5 to 89.7% of A. tubingensis isolates to be less susceptible (so-called resistant) to itraconazole (ITC) and/or voriconazole (VRC) according to the epidemiologic cutoff values (ECVs) proposed for A. niger previously. MIC distributions of ITC or VRC showed no remarkable differences between clinical and environmental isolates. When the cyp51A sequences were compared between susceptible and resistant strains, 18 amino acid mutations were specific for resistant isolates of A. niger and A. tubingensis; however, none of them were confirmed to be associated with azole resistance. Three nonrelated A. welwitschiae isolates possessed a partial deletion in cyp51A, likely attributable to being more susceptible to azoles than other isolates. One of five ITC-resistant A. tubingensis isolates showed higher expression of cyp51A than did susceptible strains. Our results show that cyp51A point mutations may have no association with azole resistance but that in some cases the overexpression of cyp51A may lead to the azole resistance in these species.

深在性真菌症は近年、死亡数が再び増加を始めており、大きな転機を迎えつつある。接合菌や、あるいは近縁種のような自然耐性菌種の増加といった菌種の多様化に加え、アゾール系やキャンディン系に対する耐性株増加の本格化など、我が国ではこれまで遭遇してこなかった問題が、真菌症治療における深刻なテーマとして立ちはだかっている。アムホテリシンB、特に副作用を減じたリポソーム製剤の意義は大きく、スペクトラムの広さや抗菌力の強さなどに加え、獲得耐性の少ない点でも真菌症治療の大きな核となりつつある。(著者抄録)

Asexual spores (conidia) are reproductive structures that play a crucial role in fungal distribution and survival. As fungal conidia are, in most cases, etiological agents of plant diseases and fungal lung disease, their stress resistance and interaction with their hosts have drawn increasing attention. In the present study, we investigated whether environmental temperature during conidiation affects the stress tolerance of the conidia of the human pathogenic fungus Aspergillus fumigatus. Conidia from a 25 degrees C culture showed a lower tolerance to heat (60 degrees C) and oxidative (H2O2) stresses and a marked resistance to ultraviolet radiation exposure, compared with those produced at 37 and 45 degrees C. The accumulation of trehalose was lower in the conidia from the 25 degrees C culture. Furthermore, the conidia from the 25 degrees C culture showed darker pigmentation and increased transcripts of dihydroxynaphthalene (DHN)melanin biosynthesis-related genes (i.e., pksP, arp1, and arp2). An RNA-sequencing analysis revealed that the transcription level of the trypacidin (tpc) gene cluster, which contains 13 genes, was sharply and coordinately activated in the conidia from the 25 degrees C culture. Accordingly, trypacidin was abundant in the conidia from the 25 degrees C culture, whereas there was little trypacidin in the conidia from the 37 degrees C culture. Taken together, these data show that the environmental temperature during conidiation affects conidial properties such as stress tolerance, pigmentation, and mycotoxin accumulation. To enhance our knowledge, we further explored the temperature-dependent production of DHN-melanin and trypacidin in clinical A. fumigatus isolates. Some of the isolates showed temperature-independent production of DHN-melanin and/or trypacidin, indicating that the conidia-associated secondary metabolisms differed among the isolates.

QuantiFERON-TB gold in-tube has been used for screening latent tuberculosis infection in newly employed health care workers in Japan. There have been a few studies concerning quality control. We retrospectively analysed QuantiFERON-TB gold in-tube results in a hospital in Japan. Interferon-gamma values in three blood collection tubes for QuantiFERON-TB gold in-tube were analysed in association with the positivity rate. The data set consisted of health care workers aged 20-29 years during the 7 years between 2010 and 2016. The yearly QuantiFERON-TB gold in-tube positivity rate was 0.9%, 16.4%, 3.0%, 39.3%, 2.8%, 0.9% and 1.5%, and was extremely high in 2011 and 2013. The interferon-gamma values in the tuberculosis antigen tube were elevated in these two years, as indicated by higher median and wider interquartile range. The interferon-gamma value in the negative control tube was also higher in 2011. The higher interferon-gamma values in collection tubes (tuberculosis antigen tube and/or negative control tube) resulted in higher QuantiFERON-TB gold in-tube positivity rate. The distribution of interferon-gamma in tuberculosis antigen tube and negative control tube, as evaluated by median and interquartile range, proved to be an effective index for the quality control of QuantiFERON-TB gold in-tube. (C) 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Background: Fungi can cause a variety of infectious diseases, including invasive mycosis and non-invasive mycosis, as well as allergic diseases. The different forms of mycosis usually have been described as mutually exclusive, independent entities, with few descriptions of overlapping cases. Here, we describe the first reported case of a patient with the complication of pulmonary eosinophilia in the course of invasive mucormycosis. Case presentation: A 74-year-old Japanese man with asthma-COPD overlap underwent emergency surgery for a ruptured abdominal aortic aneurysm. The surgery was successful, but fever and worsening dyspnea appeared and continued from postoperative day (POD) 10. A complete blood count showed leukocytosis with neutrophilia and eosinophilia, and the chest X-ray showed consolidation of the left upper lung at POD 15. We suspected nosocomial pneumonia together with an exacerbation of the asthma-COPD overlap, and both antibiotics and bronchodilator therapy were initiated. However, the symptoms, eosinophilia and imaging findings deteriorated. We then performed a bronchoscopy, and bronchoalveolar lavage (BAL) fluid analysis revealed an increased percentage of eosinophils (82% of whole cells) as well as filamentous fungi. We first suspected that this was a case of allergic bronchopulmonary mycosis (ABPM) caused by Aspergillus infection and began corticosteroid therapy with an intravenous administration of voriconazole at POD 27. However, the fungal culture examination of the BAL fluid revealed mucormycetes, which were later identified as Cunninghamella bertholletiae by PCR and DNA sequencing. We then switched the antifungal agent to liposomal amphotericin B for the treatment of the pulmonary mucormycosis at POD 29. Despite replacing voriconazole with liposomal amphotericin B, the patient developed septic shock and died at POD 39. The autopsy revealed that filamentous fungi had invaded the lung, heart, thyroid glands, kidneys, and spleen, suggesting that disseminated mucormycosis had occurred. Conclusions: We describe the first reported case of pulmonary mucormycosis with pulmonary eosinophilia caused by Cunninghamella bertholletiae, which resulted in disseminated mucormycosis. Although it is a rather rare case, two important conclusions can be drawn: i) mycosis can simultaneously cause both invasive infection and a host allergic reaction, and ii) Cunninghamella bertholletiae rarely infects immunocompetent patients.

＜Point＞主な病型として,侵襲性肺アスペルギルス症,慢性肺アスペルギルス症,アレルギー性気管支肺アスペルギルス症がある.画像検査や血液検査は感度・特異度ともに十分ではなく,治療開始は総合的判断によることが多い.治療期間は数ヵ月以上に及ぶことがしばしばである.侵襲性肺アスペルギルス症,慢性肺アスペルギルス症では外科的切除術の併用も検討することが望ましい.(著者抄録)

Successful treatment of aspergillosis caused by Aspergillus fumigatus is threatened by an increasing incidence of drug resistance. This situation is further complicated by the finding that strains resistant to azoles, the major antifungal drugs for aspergillosis, have been widely disseminated across the globe. To elucidate mechanisms underlying azole resistance, we identified a novel transcription factor that is required for normal azole resistance in Aspergill-us fungi including A. fumigatus, Aspergillus oryzae, and Aspergillus nidulans. This fungal-specific Zn-2-Cys(6) type transcription factor AtrR was found to regulate expression of the genes related to ergosterol biosynthesis, including cyp51A that encodes a target protein of azoles. The atrR deletion mutant showed impaired growth under hypoxic conditions and attenuation of virulence in murine infection model for aspergillosis. These results were simi-lar to the phenotypes for a mutant strain lacking SrbA that is also a direct regulator for the cyp51A gene. Notably, AtrR was responsible for the expression of cdr1B that encodes an ABC transporter related to azole resistance, whereas SrbA was not involved in the regula-tion. Chromatin immunoprecipitation assays indicated that AtrR directly bound both the cyp51A and cdr1B promoters. In the clinically isolated itraconazole resistant strain that har-bors a mutant Cyp51A (G54E), deletion of the atrR gene resulted in a hypersensitivity to the azole drugs. Together, our results revealed that AtrR plays a pivotal role in a novel azole resistance mechanism by co-regulating the drug target (Cyp51A) and putative drug efflux pump (Cdr1B).

In Japan, Fusarium species are known etiological agents of human fungal infection however, there has been no report of a large-scale epidemiological study on the etiological agents of fusariosis. A total of 73 Fusarium isolates from patients with invasive fusariosis (IF, n = 36) or superficial fusariosis (SF, n = 37), which were obtained at hospitals located in 28 prefectures in Japan between 1998 and 2015, were used for this study. Fusarium isolates were identified using Fusarium- and Fusarium solani species complex (FSSC)-specific real-time PCR and partial DNA sequences of the elongation factor-1 alpha (EF-1α) gene and the nuclear ribosomal internal transcribed spacer (ITS)region. FSSC was predominately isolated from both patients with IF and SF (IF, 77.8% and SF, 67.6%). Distribution of the phylogenetic species of FSSC isolates from patients with IF and SF exhibited different spectra specifically, F. keratoplasticum (FSSC 2) (25.0%)was the most frequent isolate from patients with IF, whereas F. falciforme (FSSC 3+ 4) (32.4%)was the most frequent isolate from patients with SF. Fusarium sp. (FSSC 5)was the second most frequent isolate from both patients with IF and SF (IF, 22.2% and SF, 24.3%). Notably, F. petroliphilum (FSSC 1)was isolated only from patients with IF. Each species was isolated from a broad geographic area, and an epidemic was not observed. This is the first epidemiological study of Fusarium species causing IF and SF in Japan.

Azole-resistant strains of Aspergillus fumigatus containing a tandem repeat in the cyp51A promoter and amino acid substitution(s) have been isolated in the environment worldwide; however, this type of resistant strain had never been isolated from the environment in Japan. Our previous study indicated that an azole-resistant A. fumigatus strain OKH50 containing a 34-bp tandem repeat in cyp51A promoter with L98H substitution in Cyp51A was isolated from a patient in Obihiro of Hokkaido, Japan. In this study, we collected azole-resistant Aspergillus spp. by air sampling from the environment in Japan. One Aspergillus-like colony was isolated from one of 10 sampling sites surveyed. The strain Env1 was confirmed as A. fumigatus by nucleotide sequencing and possessed a 34-bp tandem repeat in the promoter region of cyp51A with L98H substitution in Cyp51A. A. fumigatus Env1 has the identical short tandem repeat pattern with the OKH50 strain, indicating that these strains are closely related with each other. Additionally, the short tandem repeat pattern is closely related to Danish and Iranian environmental isolates, suggesting that azole-resistant strains have crossed transnational boundaries and are now present in Japan, and therefore, further analysis throughout Japan is required to determine the distribution of this type of azole-resistant A. fumigatus.

Azoles are widely used for controlling fungal growth in both agricultural and medical settings. The target protein of azoles is CYP51, a lanosterol 14-alpha-demethylase involved in the biosynthesis of ergosterol. Recently, a novel azole resistance mechanism has arisen in pathogenic fungal species Aspergillus fumigatus. Resistant strains contain a 34-bp or 46-bp tandem repeat (TR) in the promoter of cyp51A, and have disseminated globally in a short period of time. In this study, we investigated whether an azole-resistant strain with a 46-bp TR (TR46/Y121F/T289A) could be sensitised to azoles by deletion of srbA, encoding a direct regulator of cyp51A. The loss of SrbA did not affect colony growth or conidia production, but decreased expression of cyp51A. The srbA deletion strain showed hypersusceptibility to medical azoles as well as azole fungicides, while its sensitivity to non-azole fungicides was unchanged. This is the first demonstration that deletion of a regulator of cyp51A can sensitise an azole-resistant A. fumigatus strain. This finding may assist in the development of new drugs to help combat life-threatening azole-resistant fungal pathogens.

現在上市されている抗真菌薬はその種類,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臨床上大きな問題となる。近年,アゾール耐性アスペルギルスやキャンディン耐性カンジダが世界的に大きな問題となっている。いずれも海外・国内の治療ガイドラインでfirst lineの治療薬であり,今後の動向が注目される。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してゆく必要がある。(著者抄録)

Pulmonary nocardiosis is a rare but potentially serious infection typically in immunosuppressed patients (ISPs). It is also known to occur in immunocompetent patients (ICPs). However, little is currently known regarding the clinical characteristics and radiographic findings of pulmonary nocardiosis specifically in ICPs. In this study, 30 patients with pulmonary nocardiosis were identified and 10 were considered to be colonized. Of all patients with pulmonary nocardiosis, 12 patients were ICPs and 18 were ISPs. Although half of ISPs were infected by Nocardia nova, ICPs were affected by various Nocardia species. Compared with ISPs, chest CT findings of ICPs showed a higher prevalence of bronchiectasis (67% vs 6%, p &lt;.01) and centrilobular nodular opacities (67% vs 11%, p &lt;.01), both of which are often seen in pulmonary nontuberculous mycobacterial disease. Additionally, nontuberculous mycobacterium was isolated from 6 of 21 ICPs with positive Nocardia species culture. Therefore, we recommend that physicians carefully differentiate pulmonary nocardiosis from pulmonary nontuberculous mycobacterial disease in ICPs. (C) 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

＜要点早わかり!key point!＞病院感染対策において対象となることが多い真菌感染症としては、カンジダ症、トリコスポロン症、クリプトコックス症、アスペルギルス症、ムーコル症などがある。カンジダ属、トリコスポロン属は、ヒトの皮膚、腸管、尿路などに常在しているため、接触予防策が有効である。クリプトコックス属は、ハトなどの鳥類の排泄物中で増殖するため、感染対策として防鳥ネットの設置が有効である。アスペルギルス症、ムーコル症などは、空調のメンテナンス不備、病院建築工事に伴うアウトブレイク事例が多数報告されている。(著者抄録)

(1→3)-β-D-グルカン検査は深在性真菌症の診断に有用である。現在,わが国では2種類の測定キットが販売されている。それぞれ測定法が異なり性能にも特徴があるが,いずれのキットを用いた場合でも,偽陽性例,偽陰性例は少なからず存在する。本検査単独での診断を行うのではなく,臨床経過や基礎疾患,その他の検査所見などと組み合わせながら診断に役立てていくことが望ましい。(著者抄録)