Regional Differences in Antifungal Susceptibility of the Prevalent Dermatophyte Trichophyton rubrum.

In vitro susceptibility testing for Trichophyton rubrum has shown resistance to terbinafine, azoles and amorolfine, locally, but epidemiological cutoffs are not available. In order to assess the appropriateness of current first-line antifungal treatment for T. rubrum in China, we characterized antifungal susceptibility patterns of Chinese T. rubrum strains to nine antifungals and also described the upper limits of wild-type (WT) minimal inhibitory concentrations (MIC) (UL-WT) based on our study and another six studies published during the last decades. Sixty-two clinical isolates originating from seven provinces in China were identified as T. rubrum sensu stricto; all Chinese strains showed low MICs to eight out of nine antifungal drugs. Terbinafine (TBF) showed the lowest MICs of all antifungal classes tested in both the Chinese and global groups, with a 97.5% UL-WT MIC-value of 0.03 mg/L. No non-WT isolates were observed for TBF in China, but were reported in 18.5% of the global group. Our study indicated that TBF was still the most active drug for Chinese T. rubrum isolates, and all strains were within the WT-population. TBF therefore remains recommended for primary therapy to dermatophytosis caused by T. rubrum in China now, but regular surveillance of dermatophytes and antifungal susceptibility is recommended.

A new species concept for the clinically relevant Mucor circinelloides complex.

Mucor species are common soil fungi but also known as agents of human infections (mucormycosis) and used in food production and biotechnology. Mucor circinelloides is the Mucor species that is most frequently isolated from clinical sources. The taxonomy of Mucor circinelloides and its close relatives (Mucor circinelloides complex - MCC) is still based on morphology and mating behaviour. The aim of the present study was a revised taxonomy of the MCC using a polyphasic approach. Using a set of 100 strains molecular phylogenetic analysis of five markers (ITS, rpb1, tsr1, mcm7, and cfs, introduced here) were performed, combined with phenotypic studies, mating tests and the determination of the maximum growth temperatures. The multi-locus analyses revealed 16 phylogenetic species of which 14 showed distinct phenotypical traits and were recognised as discrete species. Five of these species are introduced as novel taxa: M. amethystinus sp. nov., M. atramentarius sp. nov., M. variicolumellatus sp. nov., M. pseudocircinelloides sp. nov., and M. pseudolusitanicus sp. nov. The former formae of M. circinelloides represent one or two separate species. In the MCC, the simple presence of well-shaped zygospores only indicates a close relation of both strains, but not necessarily conspecificity. Seven species of the MCC have been implemented in human infection: M. circinelloides, M. griseocyanus, M. janssenii, M. lusitanicus, M. ramosissimus, M. variicolumellatus, and M. velutinosus.

Intraspecific Diversity and Taxonomy of Emmonsia crescens.

Emmonsia crescens is known as an environmental pathogen causing adiaspiromycosis in small rodents. As the generic name Emmonsia is no longer available for this species, its taxonomic position is re-evaluated. The intraspecific variation of Emmonsia crescens was analyzed using molecular, morphological, and physiological data, and the relationship between frequency of adiaspiromycosis and body temperature of host animals was explored. A North American and a pan-global lineage could be discerned, each with subclusters at low genetic distance. European strains produced the classical type of very large adiaspores, while in the North American lineage adiaspores relatively small, resembling the broad-based budding cells of Blastomyces. Members of the closely related genus Emergomyces may exhibit large, broad-based in addition to small, narrow-based budding cells. We conclude that the morphology of the pathogenic phase in these fungi differs gradationally between species and even populations, and is therefore less suitable as a diagnostic criterion for generic delimitation. Two Emmonsia species are reclassified in Emergomyces.

Diagnostic implications of mycetoma derived from Madurella pseudomycetomatis isolates from Mexico.

BACKGROUND: At the dermatology service of the General Hospital of Mexico City, Mexico, two patients, father and son, with black-grain mycetoma were seen. The grains were isolated, and the cultured fungi were identified as Madurella mycetomatis based on morphology. Using the M. mycetomatis specific PCR, amplicons of a different size than that of the M. mycetomatis type strain were obtained. OBJECTIVE: To determine the causative agent of the two black-grain mycetoma cases and develop non-culture-based diagnostic tools to identify them to the species level. METHODS: The M. mycetomatis specific, the internal transcribed spacer (ITS) region, ß-tubulin (BT) and ribosomal binding protein 2 (RBP2) PCRs were used to confirm the identity of the isolates. Genetic variation was established by amplification fragment length polymorphisms. To determine the antifungal susceptibility profile, the Sensititre™ YeastOne™ assay was used. To develop a species-specific PCR primers were designed on the sequenced PCR amplicon from the M. mycetomatis specific PCR. RESULTS: By analyzing the ITS, BT and RBP2 regions the isolates were identified as Madurella pseudomycetomatis. The isolates from father and son were similar but not identical to M. pseudomycetomatis from Venezuela and one from an unknown origin. Madurella pseudomycetomatis isolates were inhibited by itraconazole, posaconazole and voriconazole but showed increased MIC values for amphotericin B and fluconazole. They were not inhibited by the echinocandins and five flucytosine. The two patients were treated with itraconazole resulting in cure for the father while the son was lost to follow-up. The species-specific PCR developed for M. pseudomyceotmatis was discriminative and specific. CONCLUSION: Madurella pseudomycetomatis is genetically diverse with same susceptibility profile as M. mycetomatis and causes eumycetoma in Latin America. The M. pseudomycetomatis specific PCR can be used to identify this causative agent to the species level; however, this needs to be validated in an endemic setting.

Primary Central Nervous System Infection by Histoplasma in an Immunocompetent Adult.

Central nervous system (CNS) infection by Histoplasma capsulatum is a rare disease in immunocompromised individuals in endemic areas. About one quarter of cases result from hematogenous dissemination. A 23-year-old upholsterer with chronic occipital headache had developed intracranial hypertension and dizziness, incoordination with ataxic gait, and acute confusion 5 months prior to admission. Laboratory examinations and chest roentgenogram were normal. Postcontrast T1-weighted MRI of the brain revealed a multiple ring-enhancing cerebellar, brain stem and parietal lobe lesions, and meningeal contrast enhancement. Cerebrospinal fluid culture was positive for H. capsulatum species complex, which was confirmed by phylogenetic analysis. Thirteen years after the diagnosis and treatment, there was no H. capsulatum recurrence; sequels related to complications due to the ventriculoperitoneal shunt. This case shows a primary neurological presentation of cerebral histoplasmosis, without meningitis or disseminated disease in nonimmune-compromised patient. The authors propose a categorization of the diagnosis of CNS histoplasmosis. Routine diagnostics of sibling species within the H. capsulatum complex proved to be difficult.

Molecular Diagnosis of Emmonsia-Like Fungi Occurring in Wild Animals.

Using specific primers based on the ribosomal operon, positive DNA amplification was obtained from lungs of 11/215 tested small burrowing animals, both terrestrial and aquatic, and including frozen (n = 4) and formalin-fixed paraffin-embedded (n = 7) samples. The main species detected in Europe in mice, otters and river rats was Emmonsia crescens. Two strains from otters and weasels were Blastomyces parvus. Two Australian wombats revealed the presence of a hitherto unknown species of the geophilic genus Emmonsiellopsis.

Whole-genome resequencing of Trichophyton rubrum provides insights into population differentiation and drug resistance.

Trichophyton rubrum (T. rubrum) is anthropophilic fungus and thus a very common cause of dermatophyte infections around the world. Infection of T. rubrum could result in conditions such as tinea capitis, tinea corporis, tinea inguinalis, tinea manus, tinea unguium, or tinea pedis. Because of this, the resistance of T. rubrum to antifungal therapies has drawn extensive research interest. However, the pathogenic characteristics of T. rubrum, such as site of infections, geographic location and host groups, have yet to be explored. In this study, the whole genome of 48 strains from different regions is resequenced and the population structure and association of single nucleotide polymorphism with resistance to six widely used antifungal drugs are analyzed. A total of 23,394 genomic variations are detected, which cover 2165 genes with only 15.14% of the variations located in exons. The population structure of T. rubrum is monomorphic, and genetic diversity is very low. Population structure analysis shows that the 48 sampled strains can be divided into two sub-populations. The gene TERG_08771 harboring the highest SNPs density is found to be associated with resistance to voriconazole. Although many proteins have yet to be identified and explored, association studies could still be useful to identify drug resistance or drug-susceptible loci, which would warrant further insightful investigations.

Extensive tinea capitis and corporis in a child caused by Trichophyton verrucosum.

A 3-year-old boy presented with multiple lesions of tinea corporis with dermatophytids, and subsequent inflammatory lesions with alopecia on the scalp. At the beginning, topical clobetasone butyrate was prescribed. The infection was diagnosed as dermatophytosis on the basis of positive direct microscopy and fungal culture. The etiological agent was isolated from all sampled sites and identified as Trichophyton verrucosum. Clonal nature of the infection was confirmed by random amplified polymorphic DNA (RAPD) analysis. The child lived in close vicinity of cattle. He was successfully treated with itraconazole.

Fusarium volatile, a new potential pathogen from a human respiratory sample.

We describe the isolation and characterization of Fusarium volatile from a bronchoalveolar lavage (BAL) sample of a female patient living in French Guiana with underlying pulmonary infections. Phylogenetic analysis of fragments of the calmodulin (cmdA), translation elongation factor (tef1), RNA polymerase second largest subunit (rpb2), and ß-tubulin (tub) loci revealed that strain CBS 143874 was closely related to isolate NRRL 25615, a known but undescribed phylogenetic species belonging to the African clade of the Fusarium fujikuroi species complex. The fungus differed phylogenetically and morphologically from related known species, and is therefore described as the new taxon Fusarium volatile. Antifungal susceptibility testing suggested that the new species is resistant to echinocandins, fluconazole, itraconazole with lower MICs against amphotericin B, voriconazole and posaconazole.

Identification of chromoblastomycosis agents by PCR based reverse line blot (PCR-RLB) hybridization assay.

Chromoblastomycosis is one of the most prevalent implantation fungal infections caused by melanized fungi, affecting individuals with certain risk factors with high morbidity due to its recalcitrant nature. It is difficult to identify the etiological agents and thus a suitable reproductive molecular identification method applicable in developing countries has been investigated. We report the identification of four different fungal causative agents of chromoblastomycosis by reverse line blotting hybridization (RLB) based on biotin-labeled PCR products and amine labeled probes to hybridize. Sixty five reference strains, including type strains, i.e. Fonsecaea pedrosoi, F. monophora, F. nubica, and Phialophora verrucosa, obtained from the CBS-KNAW were included in this study. Internal transcribed spacer 1 (ITS1) regions of relevant species were aligned and adjusted using BIONUMERICS v. 4.61 in order to design four specific probes to identify informative nucleotide polymorphisms. The final identification of these species by RLB assay was concordant with ITS sequencing and showed 100% specificity with no cross hybridization, able to identify all tested strains. The time and cost were less compare to other routine identification methods such as sequencing. This assay allows sensitive and specific simultaneous detection and identification of a different fungal species.

Phylogeny of dermatophytes with genomic character evaluation of clinically distinct Trichophyton rubrum and T. violaceum.

Trichophyton rubrum and T. violaceum are prevalent agents of human dermatophyte infections, the former being found on glabrous skin and nail, while the latter is confined to the scalp. The two species are phenotypically different but are highly similar phylogenetically. The taxonomy of dermatophytes is currently being reconsidered on the basis of molecular phylogeny. Molecular species definitions do not always coincide with existing concepts which are guided by ecological and clinical principles. In this article, we aim to bring phylogenetic and ecological data together in an attempt to develop new species concepts for anthropophilic dermatophytes. Focus is on the T. rubrum complex with analysis of rDNA ITS supplemented with LSU, TUB2, TEF3 and ribosomal protein L10 gene sequences. In order to explore genomic differences between T. rubrum and T. violaceum, one representative for both species was whole genome sequenced. Draft sequences were compared with currently available dermatophyte genomes. Potential virulence factors of adhesins and secreted proteases were predicted and compared phylogenetically. General phylogeny showed clear gaps between geophilic species of Arthroderma, but multilocus distances between species were often very small in the derived anthropophilic and zoophilic genus Trichophyton. Significant genome conservation between T. rubrum and T. violaceum was observed, with a high similarity at the nucleic acid level of 99.38 % identity. Trichophyton violaceum contains more paralogs than T. rubrum. About 30 adhesion genes were predicted among dermatophytes. Seventeen adhesins were common between T. rubrum and T. violaceum, while four were specific for the former and eight for the latter. Phylogenetic analysis of secreted proteases reveals considerable expansion and conservation among the analyzed species. Multilocus phylogeny and genome comparison of T. rubrum and T. violaceum underlined their close affinity. The possibility that they represent a single species exhibiting different phenotypes due to different localizations on the human body is discussed.

Correction to: Rapid Identification of Seven Waterborne Exophiala Species by RCA DNA Padlock Probes.

The Editorial Office of Mycopathologia reports that several paragraphs of Najafzadeh et al. were transcribed with only minor edits from previously published material by Najafzadeh M.J.

Rapid Identification of Seven Waterborne Exophiala Species by RCA DNA Padlock Probes.

The black yeast genus Exophiala includes numerous potential opportunistic species that potentially cause systematic and disseminated infections in immunocompetent individuals. Species causing systemic disease have ability to grow at 37-40 °C, while others consistently lack thermotolerance and are involved in diseases of cold-blooded, waterborne vertebrates and occasionally invertebrates. We explain a fast and sensitive assay for recognition and identification of waterborne Exophiala species without sequencing. The ITS rDNA region of seven Exophiala species (E. equina, E. salmonis, E. opportunistica, E. pisciphila, E. aquamarina, E. angulospora and E. castellanii) along with the close relative Veronaea botryosa was sequenced and aligned for the design of specific padlock probes for the detection of characteristic single-nucleotide polymorphisms. The assay demonstrated to successfully amplify DNA of target fungi, allowing detection at the species level. Amplification products were visualized on 1% agarose gels to confirm specificity of probe-template binding. Amounts of reagents were reduced to prevent the generation of false positive results. The simplicity, tenderness, robustness and low expenses provide padlock probe assay (RCA) a definite place as a very practical method among isothermal approaches for DNA diagnostics.

Combination of Amphotericin B and Terbinafine against Melanized Fungi Associated with Chromoblastomycosis.

Our in vitro studies showed that a combination of amphotericin B and terbinafine had synergistic effects against the majority of melanized fungi associated with chromoblastomycosis (CBM) and similar infections, including those with Cladophialophora carrionii, Cladophialophora arxii, Exophialadermatitidis, Exophialaspinifera, Fonsecaea monophora, Fonsecaea nubica, Fonsecaea pedrosoi, and Phialophora verrucosa. This drug combination could provide an option for the treatment of severe or unresponsive cases of CBM, particularly in cases due to species of Fonsecaea and Cladophialophora.

Direct detection of Exophiala and Scedosporium species in sputa of patients with cystic fibrosis.

Detection of species of Exophiala and Scedosporium in the respiratory tracts of cystic fibrosis (CF) patients remains controversial because of highly variable results. The results of our study suggested a significantly higher prevalence and more complex colonization than previously estimated. Approximately 17% (27/162) of clinical sputum samples were found to be positive for Exophiala dermatitidis and 30% (49/162) were positive for Scedosporium apiospermum / S. boydii species complex determined by reverse line blot (RLB) hybridization. In contrast, only 14.2% (23/162) and 1.2% (2/162) of clinical sputa were positive for E. dermatitidis and S. apiospermum / S. boydii species complex when tested by culture, respectively. Molecular detection methods, such as loop-mediated isothermal amplification (LAMP) or reverse line blot (RLB) hybridization, have the potential to become powerful alternatives to selective culture, providing a more realistic understanding on the prevalence of E. dermatitidis and S. apiospermum / S. boydii species complex in the respiratory tract of CF patients.

Biodiversity and human-pathogenicity of Phialophora verrucosa and relatives in Chaetothyriales.

Phialophora as defined by its type species P. verrucosa is a genus of Chaetothyriales, and a member of the group known as 'black yeasts and relatives'. Phialophora verrucosa has been reported from mutilating human infections such as chromoblastomycosis, disseminated phaeohyphomycosis and mycetoma, while morphologically similar fungi are rather commonly isolated from the environment. Phenotypes are insufficient for correct species identification, and molecular data have revealed significant genetic variation within the complex of species currently identified as P. verrucosa or P. americana. Multilocus analysis of 118 strains revealed the existence of five reproductively isolated species apparently having different infectious potentials. Strains of the sexual morph Capronia semiimmersa cluster within P. americana. The newly defined taxa differ markedly in their predilection for the human host.

Consistent high prevalence of Exophiala dermatitidis, a neurotropic opportunist, on railway sleepers.

Environmental isolation of black yeasts potentially causing human disorders is essential for understanding ecology and routes of infection. Several Exophiala species show prevalence for man-made environments rich in monoaromatic compounds, such as creosote-treated or petroleum-stained railway sleepers. Ambient climatic conditions play a role in species composition in suitable habitats. Therefore, the aim of the present study was to establish the composition of Exophiala species in railway stations as a potential source of human infections in a subtropical region with evaluation of their antifungal susceptibility profiles. We examined 150 railway samples using cotton swabs moistened with sterile physiological saline. Black yeasts and relatives were selected on theirs colony morphology and identified based on ITS rDNA sequencing. Overall, 36 (24%) of samples were positive for black yeast-like fungi, i.e., Exophiala dermatitidis (n=20, 55.6%) was predominant, followed by E. phaeomuriformis (n=9, 25%), E. heteromorpha (n=5, 13.9%), and E. xenobiotica (n=2, 5.6%). Massive contaminations of E. dermatitidis were seen on railway sleepers on creosoted oak wood at the region close to the sea level, while in cold climates were primarily contaminated with clinically insignificant or rare human opportunists (E. crusticola). It seems that, high temperature and humidity are significant effect on species diversity. Moreover, the MIC results for all E. dermatitidis and E. phaeomuriformis strains revealed the widest range and the highest MICs to caspofungin (range 1-16mg/L, Geometric mean 4.912mg/L), and the lowest MIC for posaconazole (0.016-0.031mg/L, G mean 0.061mg/L). However, their clinical effectiveness in the treatment of Exophiala infections remains to be determined.

Tintelnotia, a new genus in Phaeosphaeriaceae harbouring agents of cornea and nail infections in humans.

Phaeosphaeriaceae is a family in the order Pleosporales containing numerous plant pathogens, endophytes, lichenised fungi, and environmental saprobes. A novel genus, Tintelnotia is introduced containing two species, one of which caused an eye infection and several nail infections in humans. All species of Tintelnotia produce conidia in soft pycnidia with a wide ostiole. The generic type species is T. opuntiae causing necrotic spots on cactus plants. The isolates of the human opportunist T. destructans showed variable susceptibility pattern to a panel of common antifungal agents. The MICs of amphotericin B, voriconazole, posaconazole and itraconazole were 1 µg/mL, complemented by an in vitro MEC of 16 µg/mL against caspofungin; the MIC of terbinafine was 0.125 µg/mL. The latter compound contributed to the successful therapy in the ocular mycosis refractory to standard antifungal therapy, the benefit of terbinafine should be highlighted as a therapeutic option especially in difficult-to-treat fungal keratitis.

Molecular Epidemiology of Agents of Human Chromoblastomycosis in Brazil with the Description of Two Novel Species.

The human mutilating disease chromoblastomycosis is caused by melanized members of the order Chaetothyriales. To assess population diversity among 123 clinical strains of agents of the disease in Brazil we applied sequencing of the rDNA internal transcribed spacer region, and partial cell division cycle and ß-tubulin genes. Strains studied were limited to three clusters divided over the single family Herpotrichiellaceae known to comprise agents of the disease. A Fonsecaea cluster contained the most important agents, among which F. pedrosoi was prevalent with 80% of the total set of strains, followed by 13% for F. monophora, 3% for F. nubica, and a single isolate of F. pugnacius. Additional agents, among which two novel species, were located among members of the genus Rhinocladiella and Cyphellophora, with frequencies of 3% and 1%, respectively.

Redefining Microascus, Scopulariopsis and allied genera.

The genera Microascus and Scopulariopsis comprise species commonly isolated from soil, decaying plant material and indoor environments. A few species are also recognised as opportunistic pathogens of insects and animals, including humans. In the past, the taxonomy of these fungi has been based on morphology only. With the aim to clarify the taxonomy and phylogeny of these fungi, we studied a large set of clinical and environmental isolates, including the available ex-type strains of numerous species, by means of morphological, physiological and molecular analyses. Species delineation was assessed under the Genealogical Phylogenetic Species Recognition (GCPSR) criterion using DNA sequence data of four loci (ITS region, and fragments of rDNA LSU, translation elongation factor 1-α and ß-tubulin). The genera Microascus and Scopulariopsis were found to be separated in two distinct lineages. The genus Pithoascus is reinstated and the new genus Pseudoscopulariopsis is erected, typified by P. schumacheri. Seven new species of Microascus and one of Scopulariopsis are described, namely M. alveolaris, M. brunneosporus, M. campaniformis, M. expansus, M. intricatus, M. restrictus, M. verrucosus and Scopulariopsis cordiae. Microascus trigonosporus var. macrosporus is accepted as a species distinct from M. trigonosporus. Nine new combinations are introduced. Microascus cinereus, M. longirostris, P. schumacheri and S. flava are neotypified. A table summarising the morphological features of the species treated and identification keys for each genus are provided.