Sporothrix brunneoviolacea and Sporothrix dimorphospora, two new members of the Ophiostoma stenoceras-Sporothrix schenckii complex

Sporothrix inflata is a saprobic member of the Ophiostoma stenoceras-Sporothrix schenckii species complex, reported mainly from soil. Ophiostoma bragantinum, an ascomycete described from Brazil, has been proposed as its possible teleomorph. Previous studies revealed that Sporothrix inflata is phenotypically and genetically variable, suggesting the existence of cryptic species. During a continued survey on the biodiversity of microfungi from different countries, seven isolates morphologically similar to S. inflata were obtained from soil samples collected in Spain and USA. In this study their phenotypic features and phylogenetic relationships were assessed. DNA sequence data of two nuclear loci revealed that these isolates correspond to two unnamed clades in S. inflata s.l., one of which also included the type strain of Humicola dimorphospora, a species that traditionally has been considered a synonym of S. inflata. These two groups are proposed herein as Sporothrix brunneoviolacea sp. nov. and Sporothrix dimorphospora comb. nov. S. brunneoviolacea is characterized phenotypically by the production of a diffusible violet-brown pigment in culture and mostly globose, pigmented, lateral blastoconidia. On the other hand S. dimorphospora lacks diffusible pigments and shows mostly subglobose to obovoid pigmented lateral blastoconidia. In contrast to the type strain of S. inflata S. brunneoviolacea and S. dimorphospora assimilate raffinose. The phylogenetic analysis suggested that the proposed anamorph-teleomorph connection between S. inflata and O. bragantinum might not be correct.     

申克孢子丝菌感染诊治1例

通过1例16岁女孩由申克孢子丝菌导致的皮下孢子丝菌病,口服伊曲康唑治疗有效,回顾申克孢子丝菌的实验室检验方法 ,以此来提高孢子丝菌感染的诊断水平。     

申克孢子丝菌菌丝相至酵母相转化的实验研究

目的观察申克孢子丝菌菌丝相向酵母相转化的形态学变化并初步研究连续传代后菌株转化为酵母相的百分率。方法将95株申克孢子丝菌临床株于脑心浸液琼脂培养基上连续传代至酵母相,利用显微镜及血细胞计数板计数菌丝和孢子比例并记录显微镜下形态。结果 95株申克孢子丝菌中,经1次传代即成功转化有23株,经2次传代有14株,经3次传代有10株,经4次传代有6株,4次传代后总计55.8%实验菌株转化为酵母相。结论部分申克孢子丝菌由菌丝相向酵母相转化需经过连续多次传代,连续传代增加了菌丝相至酵母相的转化率。     

A Spotlight on Sporothrix and Sporotrichosis

Mycopathologia - Sporothrix (order Ophiostomatales) comprises a genus with 53 species, of which S. brasiliensis, S. schenckii, S. globosa, and S. luriei cause skin infections in humans and other...     

申克孢子丝菌毒力因子及宿主抗感染免疫的研究进展

申克孢子丝菌是一种重要的双相型真菌,其引起的孢子丝菌病是一种常见的侵袭性皮肤感染.研究该菌毒力因子及宿主对其抗感染免疫对于深入了解其致病性及防治该病具有重要意义.该文介绍了申克孢子丝菌毒力因子及宿主对其抗感染免疫方面的研究进展.     

Taxonomy and phylogeny of new wood- and soil-inhabiting Sporothrix species in the Ophiostoma stenoceras-Sporothrix schenckii complex

Sporothrix, one of the anamorph genera of Ophiostoma, includes the important human pathogen S. schenckii and various fungi associated with insects and sap stain of wood. A survey of fungi from wood utility poles in South Africa yielded two distinct groups of Sporothrix isolates from different geographical areas. DNA sequence and morphological data derived in this study showed that isolates in these groups represent two novel species in the S. schenckii-O. stenoceras species complex. A new species isolated from pine poles and rosebush wood and phylogenetically closely related to S. pallida is described here as Sporothrix stylites. Phylogenetic analyses also confirmed the synonymy of S. albicans and S. nivea with S. pallida. Sporothrix stylites and S. pallida also are related closely to the isolates from soil, previously treated as "environmental" isolates of S. schenckii. Soil isolates are clearly distinct from human isolates of S. schenckii. We describe the former here as Sporothrix humicola. The isolates from eucalypt poles group peripheral to most other species in the S. schenckii-O. stenoceras complex and are newly described as Sporothrix lignivora. Phylogenetic analyses of sequences of isolates from soil and wood together with those of clinical isolates showed that the human-pathogenic strains form an aggregate of several cryptic species.     

耐极端环境真菌对犬小孢子菌及孢子丝菌的拮抗研究

目的 检测极端环境分离出的真菌拮抗临床病原真菌的活性.方法 选用极端环境分离出的24株真菌菌株上清液及菌丝体的提取液,来进行临床病原真菌（孢子丝菌和犬小孢子菌）的拮抗试验,采用M38-A2产孢丝状真菌抗真菌药物敏感性试验方案和E-test纸片扩散法.结果 抑菌圈直径≥1.0 cm,具有较强拮抗孢子丝菌活性的极端环境真菌有8株;抑菌圈直径≥2.0 cm,具有极强拮抗犬小孢子菌的活性的极端环境真菌有1株.两种临床菌株的拮抗试验,90％的拮抗结果相一致.结论 70％极端环境真菌菌株上清液及菌丝体提取液具有拮抗临床病原真菌孢子丝菌和犬小孢子菌的活性.     

申克孢子丝菌酵母相和菌丝相cDNA消减文库的构建

目的 筛选与申克孢子丝菌酵母相与菌丝相双相转换相关的差异表达基因,为探讨其双相转换的分子的机制奠定基础.方法 应用抑制性消减杂交技术,构建高特异性的申克孢子丝菌菌丝相（mycelium,M）和酵母相（yeast,Y）的正反cDNA消减文库,并对其差异表达的基因进行生物信息学分析.结果 M＋Y文库获得751条表达序列标签,平均长度为690.98 bp,经拼接后获得101条非冗余序列.Y＋M文库获得875条表达序列标签,平均长度为575.9 bp,拼接获得249条非冗余序列.经BLASTN比对,这些差异表达基因中,某些结构基因和功能不明的细胞分子类基因可能与双相转换有关.结论 成功构建了高特异性的申克孢子丝菌菌丝相和酵母相的正反cDNA 消减文库,为进一步筛选申克孢子丝菌的双相转换基因奠定了基础.     

Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine

Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.     

球形孢子丝菌致婴儿固定型孢子丝菌病1例及相关实验研究

报道1例由球形孢子丝菌所致的婴儿固定型孢子丝菌病。患儿女,3个月,因左眼下内侧皮损2个月就诊,皮损脓液标本进行真菌培养,对培养获得菌株进行形态学、生理学和分子生物学鉴定,并进行药物敏感性检测。真菌培养阳性,镜下可见典型的套袖样菌丝。钙调蛋白基因序列分析鉴定为球形孢子丝菌。药敏试验显示特比萘芬和伊曲康唑对该菌株的菌丝相最低抑菌浓度（minimal inhibitorycon centration,MIC）分别为0．5μg／mL和0．5μg／mL;对该菌株的酵母相的MIC值分别为0．25μg／mL和0．5μg／mL。给予患者口服特比萘芬32．5mg／d治疗10周后皮损消退呈瘢痕化修复。依据临床及实验室检查确诊该病例为球形孢子丝菌所致固定型孢子丝菌病,特比萘芬治疗本病例显示较好疗效。     

Spore ultrastructure in Sporothrix schenckii

Pathogenic strains of Sporothrix schenkii may show triangular spores, whose angular shape is maintained by a tiebeam effect in the inner cell wall structure. This difference in wall structure lies adjacent to a folded and possibly more active part of the spore cytoplasm. The supposed generation of asci in old cultures was simulated by the death of hyphae which are reinvaded by intrahyphal growth with intrahyphal spore production, while true asci were not seen.     

伊曲康唑联合特比萘芬治疗孢子丝菌病疗效及其对病原真菌体外抗菌活性研究

目的 初步探讨伊曲康唑和特比萘芬联合治疗孢子丝菌病的疗效,评价两药体外联合对申克孢子丝菌菌丝相和酵母相的抗菌活性.方法 口服伊曲康唑200mg/d和特比萘芬250mg/d治疗孢子丝菌病;体外联合药敏试验采用棋盘微量稀释法,计算分数抑菌浓度(FIC)指数判定两药相互作用具有协同、拮抗或无关作用.结果 伊曲康唑和特比萘芬联...     

Ophiostoma gemellus and Sporothrix variecibatus from mites infesting Protea infructescences in South Africa

Ophiostoma (Ophiostomatales) represents a large genus of fungi mainly known from associations with bark beetles (Curculionidae: Scolytinae) infesting conifers in the northern hemisphere. Few southern hemisphere native species are known, and the five species that consistently occur in the infructescences of Protea spp. in South Africa are ecologically unusual. Little is known about the vectors of Ophiostoma spp. from Protea infructescences, however recent studies have considered the possible role of insects and mites in the distribution of these exceptional fungi. In this study we describe a new species of Ophiostoma and a new Sporothrix spp. with affinities to Ophiostoma, both initially isolated from mites associated with Protea spp. They are described as Ophiostoma gemellus sp. nov. and Sporothrix variecibatus sp. nov. based on their morphology and comparisons of DNA sequence data of the 28S ribosomal, beta-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. DNA sequences of S. variecibatus were identical to those of a Sporothrix isolate obtained from Eucalyptus leaf litter in the same area in which S. variecibatus occurs in Protea infructescences. Results of this study add evidence to the view that mites are the vectors of Ophiostoma spp. that colonize Protea infructescences. They also show that DNA sequence comparisons are likely to reveal additional cryptic species of Ophiostoma in this unusual niche.     

Two new Ophiostoma species with Sporothrix anamorphs from Austria and Azerbaijan

The genus Ophiostoma includes numerous species of primarily insect-vectored, wood-staining fungi. Several anamorph genera that differ in their micronematous or macronematous conidiogenous cells have been associated with Ophiostoma species. Among the former group, Sporothrix is associated with many species and is characterized by conidiogenous cells that arise laterally or terminally from any place on the hyphae and produce nonseptate conidia on sympodially developing denticles. The purpose of this study was to characterize ophiostomatoid isolates with Sporothrix anamorphs recently collected in Austria and Azerbaijan. The isolates were characterized based on comparisons of rDNA and β-tubulin sequence data. Morphology, growth in culture, and sexual reproductive mode were also considered. Phylogenetic analyses of the combined sequence data showed that the isolates formed two distinct groups, one including isolates from Austria and the other isolates from Austria and Azerbaijan. Growth at 25 C and morphology revealed some differences between the two groups, and supported the view that they represent two new species, which we describe here as Ophiostoma fusiforme sp. nov. and Ophiostoma lunatum sp. nov. Both these groups phylogenetically were related to, but distinct from, Ophiostoma stenoceras.     

Interference of melanin in the susceptibility profile of Sporothrix species to amphotericin B

BackgroundThe presence of melanin in the fungal cell is a major virulence factor of the genus Sporothrix since it protects the fungal cells against the defense systems.AimsThe present study aimed to investigate the interference of melanin in the susceptibility of Sporothrix brasiliensis and Sporothrix schenckii sensu stricto to amphotericin B and itraconazole, drugs recommended as therapy for disseminated and subcutaneous sporotrichosis, respectively.MethodsYeast cells were cultivated in minimal medium with or without l-DOPA in order to induce the production of melanin. Microdilution and killing assay methods were used to determine the antifungal activity against yeast cells with different amounts of melanin.ResultsThe killing assay showed that melanization protected isolates within the S. schenckii complex from amphotericin B, particularly in the lower concentrations tested.ConclusionsStudies combining amphotericin B and inhibitors of melanin are required in order to avoid this effect.     

Sporothrix globosa,a pathogenic fungus with widespread geographical distribution

Sporothrix globosa, reported from the USA, Europe, and Asia, is a recently described pathogenic species morphologically similar to Sporothrix schenckii. In this study, the phylogenetic affinities of 32 clinical and environmental isolates morphologically identified as S. schenckii, from Mexico, Guatemala, and Colombia, were assessed by cladistic analysis of partial sequences of the calmodulin gene using the maximum parsimony and neighbor-joining methods. The study revealed that one out of 25 isolates from Mexico (4%), one out of three isolates from Guatemala (33.3%), and two out of four isolates from Colombia (50%) belonged to S. globosa, while the other isolates belonged to S. schenckii sensu stricto. This is the first record of S. globosa from Mexico, and Central and South America.     

来自中国北方部分地区33株孢子丝菌菌株的表型和基因型鉴定

孢子丝菌病是一种临床常见的真菌感染疾病,近期有研究认为其致病菌是由多个同形种构成的复合体。为明确我国孢子丝菌病致病菌的生理学以及分子生物学方面的特点,对33株分离自我国孢子丝菌病患者组织的病原菌进行了研究,首先检测其在37℃是否生长以及PDA培养基上生长21d的菌落直径,其次检测其糖同化特点,最后对其钙调蛋白(Calmodulin,CAL)基因进行PCR扩增、序列测定以及系统进化分析。结果显示,这些菌株全部为球形孢子丝菌Sporothrix globosa,说明我国孢子丝菌病的病原菌可能以球形孢子丝菌为主。     

Sporothrix eucalypti (sp. nov.), a shoot and leaf pathogen ofEucalyptus in South Africa

A species ofSporothrix was consistently isolated from leaf spots and serious shoot infections on a clone ofEucalyptus grandis in Northern Natal, South Africa. The fungus was morphologically distinct from other species in the genus and is consequently described as a new taxon,S. eucalypti. Sporothrix eucalypti was shown to be highly virulent in pathogenicity tests on a number ofE. grandis clones. Significant differences amongst susceptibility of clones were also detected in these tests.Sporothrix eucalypti represents a new pathogen ofEucalyptus that has the potential to cause substantial damage to this host in South Africa and probably elsewhere in the world.     

Molecular and cellular events during the germination of conidia of Sporothrix schenckii

Hyaline, non pigmented microconidia of Sporothrix schenckii were harvested and allowed to form germ tubes in a basal medium with glucose at pH 4.0 and 25 °C. These conditions supported only the development of the mycelial form of Sporothrix schenckii in a reproducible, synchronized manner which allowed further analysis of the early cellular events ocurring during the germination of the conidia. The relationship between macromolecular synthesis (DNA, RNA and protein synthesis) and nuclear division, hyphal growth and septum formation were established. Following inoculation, protein synthesis was observed after 10 minutes followed by RNA synthesis, after 1 h and DNA synthesis after 2 h. The first nuclear division was observed during the 9 to 12 h interval after inoculation. Germ tube formation slightly preceeded nuclear division and was first evidenced 9 h after the induction of germination but was not completed until 12 h after inoculation. Septation was first observed in the germ tubes 0.25 m from the mother cell-germ tube function 9 h after induction of germination.