Comparative genomic and phenotypic analyses of pathogenic fungi Neoscytalidium dimidiatum and Bipolaris papendorfii isolated from human skin scraping.

Neoscytalidium dimidiatum and Bipolaris species are fungal plant pathogens that have been reported to cause human diseases. Recently, we have isolated numerous N. dimidiatum and Bipolaris species from the skin scrapings and nails of different patients. In this work, we have sequenced the genome of one strain of N. dimidiatum. The sequenced genome was compared to that of a previously reported Bipolaris papendorfii genome for a better understanding of their complex lifestyle and broad host-range pathogenicity. Both N. dimidiatum UM 880 (~ 43 Mb) and B. papendorfii UM 226 (~ 33 Mb) genomes include 11,015-12,320 putative coding DNA sequences, of which 0.51-2.49% are predicted transposable elements. Analysis of secondary metabolism gene clusters revealed several genes involved in melanin biosynthesis and iron uptake. The arsenal of CAZymes related to plants pathogenicity is comparable between the species, including genes involved in hemicellulose and pectin decomposition. Several important gene encoding keratinolytic peptidases were identified in N. dimidiatum and B. papendorfii, reflecting their potential pathogenic role in causing skin and nail infections. In this study, additional information on the metabolic features of these two species, such as nutritional profiling, pH tolerance, and osmotolerant, are revealed. The genomic characterization of N. dimidiatum and B. papendorfii provides the basis for the future functional studies to gain further insights as to what makes these fungi persist in plants and why they are pathogenic to humans.

Onychomycosis caused by the environmental mold Neoscytalidium dimidiatum in Colombia, and in vitro antifungal susceptibility evaluation.

Neoscytalidium dimidiatum is a plant pathogen, but can also cause onychomycosis. We compared clinical and epidemiological data of cases of onychomycosis caused by N. dimidiatum and Trichophyton rubrum. We also evaluated the in vitro antifungal susceptibility of N. dimidiatum clinical isolates. It was not possible to establish any statistical differences between groups, except the place of residence and the number of affected nails. The results suggest that onychomycosis caused by N. dimidiatum is clinically similar to that caused by T. rubrum; besides, N. dimidiatum has been shown to have low sensitivity to itraconazole, but high to terbinafine. LAY SUMMARY: Cases of onychomycosis caused by Neoscytalidium dimidiatum were studied and compared to cases of onychomycosis caused by T. rubrum. The individuals affected were adults, and the clinical characteristics were not different between groups; accordingly, mycological diagnosis is mandatory.

Neoscytalidium dimidiatum un raro agente de onicomicosis no dermatofítica en Chile / Neoscytalidium dimidiatuma rare agent ofnon dermatophyticonychomycosisin Chile

El término de onicomicosis se emplea para describir las infecciones de las uñas causadas por diferentes grupos taxonómicos fúngicos ya sea filamentosos como levaduriformes. A pesar de que estas patologías son causadas en los vertebrados principalmente por integrantes de la Familia Artrodermatáceae (Onygenales), la micología médica aplicó para ellos la terminología más específica de dermatofitosis, por ser un grupo ecológico de mayor importancia y presencia clínica. Las dermatomicosis de piel y fanéreos, representan un conjunto de infecciones producidas por especies fúngicas distribuidas en ambientes diversos, capaces de crecer a temperaturas de 37° y que actúan usualmente como patógenos oportunistas cuando existe generalmente un factor predisponente en el huésped. Se destaca la colonización en una uña de los pies en un hombre de 49 años por Neoscytalidium dimidiatum(Penz.) Crous & Slippers, un reconocido fitopatógeno de rápido crecimiento, común en zonas tropicales y subtropicales, que presentó la capacidad de invadir tejidos queratinizados con un aspecto clínico indistinguible de los causadas por dermatofitos. Por la rara presencia de este hongo en nuestra zona geográfica (provincia de Valparaíso, Chile), se aportan los principales datos morfofisiológicos,taxonómicos y moleculares utilizados en su diagnóstico. (AU)

The term onychomycosis is used to describe nail infections caused by different fungal taxonomic groups, either filamentous or yeast. Despite the fact that these pathologies are caused in vertebrates mainly by members of the Artrodermatáceae Family (Onygenales), medical mycology applied the more specific terminology of dermatophytosis for them, as it is an ecological group of greater importance and clinical presence. Skin and pharynx dermatomycosis represent a set of infections produced by fungal species distributed in diverse environments, capable of growing at temperatures of 37° and that usually act as opportunistic pathogens when there is a predisposing factor in the host. The colonization on a toenail in a 49-year-old man by Nesoscytalidium dimidiatumis highlighted (Penz.) Crous & Slippers, a recognized fast-growing phytopathogen, common in tropical and subtropical areas, which presented the ability to invade keratinized tissues with a clinical appearance indistinguishable from those caused by dermatophytes. Due to the rare presence of this fungus in our geographical area (Valparaíso province, Chile), the main morphophysiological, taxonomic and molecular data used in its identificationare provided. (AU)

ITS rDNA Gene Analysis Versus MALDI-TOF MS For Identification of Neoscytalidium dimidiatum Isolated from Onychomycosis and Dermatomycosis Cases in Medellin (Colombia).

Within the Neoscytalidium genus, N. dimidiatum, N. oculus, N. orchidacearum, and N. novaehollandiae have been recognized. Although these species are frequently found in soil, N. dimidiatum has been identified as an etiologic agent of onychomycosis or dermatomycosis, and N. oculus has been identified as an etiologic agent of an ocular lesion. All these species can be cultured in vitro, but their morphological identification by macroscopic and microscopic traits is difficult and imprecise due to their similarity. In this study, 34 isolates of Neoscytalidium spp. from 32 onychomycosis and two dermatomycosis cases in Medellin (Colombia) were identified at the species level using sequencing of the ITS1+5.8S+ITS2 nuclear rDNA region and MALDI-TOF mass spectrometry (MS). Neoscytalidium dimidiatum strain MUM 17.21 was used to construct the reference spectrum in the in-house library to identify the clinical isolates by MALDI-TOF MS. Additionally, N. dimidiatum PPC-216 and PLAB-055 strains were used to validate the in-house constructed reference spectra. Although four groups were observed in the dendrogram obtained from the proteins of each isolate profile, MALDI-TOF MS and sequencing results are in accordance, since all isolates were identified as N. dimidiatum.

In vitro susceptibilities of Neoscytalidium spp. sequence types to antifungal agents and antimicrobial photodynamic treatment with phenothiazinium photosensitizers.

Neoscytalidium spp. are ascomycetous fungi consisting of pigmented and hyaline varieties both able to cause skin and nail infection. Their color-based identification is inaccurate and may compromise the outcome of the studies with these fungi. The aim of this study was to genotype 32 isolates morphologically identified as Neoscytalidiumdimidiatum or N. dimidiatum var. hyalinum by multilocus sequence typing (MLST), differentiate the two varieties by their sequence types, evaluate their susceptibility to seven commercial antifungal drugs [amphotericin B (AMB), voriconazole (VOR), terbinafine (TER), 5-flucytosine (5FC), ketoconazole (KET), fluconazole (FLU), and caspofungin (CAS)], and also to the antimicrobial photodynamic treatment (APDT) with the phenothiazinium photosensitizers (PS) methylene blue (MB), new methylene blue (NMBN), toluidine blue O (TBO) and the pentacyclic derivative S137. The efficacy of each PS was determined, initially, based on its minimal inhibitory concentration (MIC). Additionally, the APDT effects with each PS on the survival of ungerminated and germinated arthroconidia of both varieties were evaluated. Seven loci of Neoscytalidium spp. were sequenced on MLST revealing eight polymorphic sites and six sequence types (ST). All N. dimidiatum var. hyalinum isolates were clustered in a single ST. AMB, VOR and TER were the most effective antifungal agents against both varieties. The hyaline variety isolates were much less tolerant to the azoles than the isolates of the pigmented variety. APDT with S137 showed the lowest MIC for all the isolates of both varieties. APDT with all the PS killed both ungerminated and germinated arthroconidia of both varieties reducing the survival up to 5 logs. Isolates of the hyaline variety were also less tolerant to APDT. APDT with the four PS also increased the plasma membrane permeability of arthroconidia of both varieties but only NMBN and S137 caused peroxidation of the membrane lipids.

Laser treatment of onychomycosis due to Neoscytalidium dimidiatum: An open prospective study.

Conventional systemic and topical treatments have proven ineffective for the treatment of onychomycosis caused by Neoscytalidium dimidiatum. Our aim was to evaluate the effectiveness and safety of laser monotherapy for the treatment of onychomycosis caused by this pathogen. Patients with clinical onychomycosis of the toenails and positive results both on direct mycological examination and N. dimidiatum culture underwent four 1064 nm Nd:YAG laser sessions with 6-week intervals between sessions. Participants were monitored by clinical examination supported by dermoscopy, measurement of diseased nail and the onychomycosis severity index (OSI), and by mycological examination for 12 months after completion of treatment. Treatment outcome was based on clinical and laboratory criteria and was divided in complete or partial cure, clinical improvement, treatment failure and relapse. No patient had complete or partial cure at any time during the study. Clinical improvement was observed in 40.6% of the patients at the end of the laser sessions; however, it did not persist during the follow-up. Treatment failure was observed in 64.7% of the patients at the end of 12 month follow-up period. Direct microscopy and culture results remained positive in most patients. Adverse events, in addition to treatment-related pain, were observed and considered severe in one case. The 1064 nm Nd:YAG laser was not able to cure onychomycosis caused by N. dimidiatum but temporarily improved the clinical appearance of the nail; however, adverse events may occur.

Cutaneous murine model of infection caused by Neoscytalidium dimidiatum: a preliminary study of an emerging human pathogen.

Neoscytalidium dimidiatum is an emerging fungus that causes a skin infection similar to dermatophytosis; it affects both immunocompetent and immunosuppressed individuals, and it may invade deeper tissues and organs and cause systemic disease. Little is known about the etiopathogenesis of the infection caused by this fungus, and no standard effective treatment is available. The aim of the present experimental study was to develop an animal model of skin infection with N. dimidiatum. BALB/c mice were inoculated with two fungal strains, and different routes of infection were tested. When challenged intradermally, N. dimidiatum strain HUPE164165 caused skin infection in 67% of the animals whereas strain HUPE115669 did it in 49%. Neoscytalidium dimidiatum was isolated from the skin of 25% of the animals inoculated via epidermal scarification and from 100% of the animals challenged via subcutaneous injection. Mice inoculated intradermally were followed-up during four weeks, and clinical samples were collected on days 3, 8, 15, and 29 after inoculation, corresponding to different stages of infection. The cutaneous infection rate, as measured by the recovery of N. dimidiatum strain HUPE164165 from skin biopsies of animals inoculated intradermally, revealed the presence of infection in 90% of the animals sacrificed at 3 days post-inoculation, 71% at 8, 85% at 15, and 33% at 29. Conidia and hyphae were observed in PAS-stained sections as well as a mild to moderate inflammatory infiltrate in haematoxylin-eosin, although it did not differ from animals inoculated either with T. quinckeanum or PBS. The intradermal route of inoculation was considered to be suitable for the study of skin infection with N. dimidiatum The animal model developed in this preliminary study is the first to allow the study of cutaneous infection with N. dimidiatum and may contribute to further investigations of the aetiology, immunology, pathogenesis and treatment targeting this emerging mycosis.

Non-dermatophyte mould onychomycosis: a clinical and epidemiological study at a dermatology referral centre in Bogota, Colombia.

Worldwide prevalence of non-dermatophyte mould onychomycosis has increased in recent years; however, available information on the topic is confusing and oftentimes contradictory, probably due to the small number of reported cases. The aim of this study was to determine and describe the aetiological agents, as well as the epidemiological and clinical characteristics of non-dermatophyte mould onychomycosis in a dermatology referral centre in Bogota, Colombia. A cross-sectional descriptive study was conducted between January 2001 and December 2011 among patients who attend the National Institute of Dermatology with a confirmed diagnosis of onychomycosis by non-dermatophytes moulds. There were 317 confirmed cases of non-dermatophyte mould onychomycosis in 196 women and 121 men whose average age was 43 years. Twenty-seven per cent of them had a history of systemic disease. The habit of walking and showering barefoot was the major infection-related factor. Distal and lateral subungual presentation was the most common pattern of clinical presentation. The most frequent non-dermatophyte mould was Neoscytalidium dimidiatum followed by Fusarium spp. No relationship was observed with predisposing factors previously reported in the literature. Clinical features found in this population are indistinguishable from onychomycosis caused by dermatophytes. High prevalence of N. dimidiatum found here was in contrast to a large number of studies where other types of moulds predominate.