Cladophialophora saturnica sp. nov., a new opportunistic species of Chaetothyriales revealed using molecular data

Genome and transcriptome reveal lithophilic adaptation of Cladophialophora brunneola, a new rock-inhabiting fungus

Rock-inhabiting fungi (RIF) are slow-growing microorganisms that inhabit rocks and exhibit exceptional stress tolerance owing to their thick melanised cell walls. This study reports the identification of a novel rock-inhabiting fungus, Cladophialophora brunneola sp. nov. which was isolated from a karst landform in Guizhou, China, using a combination of morphological and phylogenetic analyses. The genome of C. brunneola was sequenced and assembled, with a total size of approximately 33.8 Mb, encoding 14,168 proteins and yielding an N50 length of 1.88 Mb. C. brunneola possessed a larger proportion of species-specific genes, and phylogenomic analysis positioned it in an early diverged lineage within Chaetothyriales. In comparison to non-RIF, C. brunneola displayed reduction in carbohydrate-active enzyme families (CAZymes) and secondary metabolite biosynthetic gene clusters (BGCs). Transcriptome analysis conducted under PEG-induced drought stress revealed elevated expression levels of genes associated with melanin synthesis pathways, cell wall biosynthesis, and lipid metabolism. This study contributes to our understanding of the genomic evolution and polyextremotolerance exhibited by rock-inhabiting fungi.

Evaluation of building washing machines as an extreme environment for potentially pathogenic fungi

Washing machines are commonly used in households and are considered indispensable appliances for maintaining cleanliness and hygiene. Environmental conditions within household washing machines are ideal for fungal colonization, which may pose risks to human health and contribute to sick building syndrome. This study aimed to investigate the fungal species contamination in the building washing machines. A total of 50 building washing machines were swab-sampled at three locations: the detergent drawer, the inner and outer parts of the rubber door seal. The housekeeping conditions of these appliances were assessed through a questionnaire. The isolated fungi were identified using standard mycological diagnostic procedures and molecular analysis based on the ITS1/ITS4 and β-tubulin gene regions. The possibility of fungal agents transferring from contaminated washing machines to autoclaved clothes during laundry cycles was investigated. Fungi were detected in 82% of the sampled appliances, with the inner rubber door seal being the most frequently colonized area. Using conventional and molecular techniques, we identified 122 fungal isolates, encompassing 17 diverse genera of molds, yeast-like, and yeast fungi. The mold fungi included 14 genera of hyaline and black genus. Among these, the most frequently identified genera of hyaline and black fungi were Aspergillus (27.7%), and Cladosporium (10.7%), respectively. This study demonstrates that building washing machines may serve as suitable ecological niches for fungal growth and transmission. Therefore, regular cleaning and disinfection of these devices are necessary.

First case of Rhinocladiella mackenziei brain abscess in Turkey: Case report and review of the literature

Rhinocladiella mackenziei is a highly neurotropic fungus, mainly reported from the Middle East. However, in recent years, there have been some cases from outside this region. We described an additional fatal case of R. mackenziei cerebral infection for the first time from Turkey and made a literature review of all previously reported cases. During 34 years (1988-2022), there have been 42 R. mackenziei brain abscess cases. Most patients have been reported from Saudi Arabia (n = 14, 33.3%). It is noteworthy that 40.5% of patients, including our case, were immunocompetent at initial diagnosis and mostly presented with a single lesion (n = 10, 23.8%). The most frequent comorbidities were solid organ transplant (n = 9, 21.4%), diabetes mellitus (n = 6, 14.3%), malignancy (n = 6, 14.3%) and prior surgery (n = 3, 7.1%). The most commonly used initial antifungal regimen were amphotericin B together with itraconazole (n = 9, 21.4%), combinations of lipid preparations of amphotericin B, voriconazole and/or posaconazole (n = 9, 21.4%) and amphotericin B alone (n = 8, 19%). Although both surgical procedures and antifungal medication in the majority of patients were performed, mortality rates remained high (90.4%). The area at risk of R. mackenziei cerebral abscess cases extends to other countries. Clinicians should be aware of this emerging disease and take a detailed travel history in patients with atypical and undocumented brain abscesses. Our case confirms the hypothesis that this fungus might spread more widely than previously predicted regions.

Exploring diversity rock-inhabiting fungi from northern Thailand: a new genus and three new species belonged to the family Herpotrichiellaceae

Members of the family Herpotrichiellaceae are distributed worldwide and can be found in various habitats including on insects, plants, rocks, and in the soil. They are also known to be opportunistic human pathogens. In this study, 12 strains of rock-inhabiting fungi that belong to Herpotrichiellaceae were isolated from rock samples collected from forests located in Lamphun and Sukhothai provinces of northern Thailand during the period from 2021 to 2022. On the basis of the morphological characteristics, growth temperature, and multi-gene phylogenetic analyses of a combination of the internal transcribed spacer, the large subunit, and the small subunit of ribosomal RNA, beta tubulin and the translation elongation factor 1-a genes, the new genus, Petriomyces gen. nov., has been established to accommodate the single species, Pe. obovoidisporus sp. nov. In addition, three new species of Cladophialophora have also been introduced, namely, Cl. rupestricola, Cl. sribuabanensis, and Cl. thailandensis. Descriptions, illustrations, and a phylogenetic trees indicating the placement of these new taxa are provided. Here, we provide updates and discussions on the phylogenetic placement of other fungal genera within Herpotrichiellaceae.

Nine new species of black lichenicolous fungi from the genus Cladophialophora (Chaetothyriales) from two different climatic zones of China

Lichenicolous fungi are parasites of lichens. Many of these fungi are referred to as "black fungi". A diversity of these black fungi include species that are pathogenic to humans and plants. A majority of black fungi reside in the phylum Ascomycota within the sub-classes Chaetothyriomycetidae and Dothideomycetidae. To explore the diversity of lichenicolous "black fungi" associated with lichens in China, we conducted several field surveys in the Inner Mongolia Autonomous Region and Yunnan Province between 2019 and 2020. We recovered 1,587 fungal isolates from the lichens collected during these surveys. During the preliminary identification of these isolates using the complete internal transcribed spacer (ITS), partial large subunit of nuclear ribosomal RNA gene (LSU), and small subunit of nuclear ribosomal RNA gene (SSU), we identified 15 fungal isolates from the genus Cladophialophora. However, these isolates had low sequence similarities with all known species from the genus. Therefore, we amplified additional gene regions, such as, translation elongation factor (TEF) and partial β-tubulin gene (TUB), and constructed a multi-gene phylogeny using maximum likelihood, maximum parsimony, and Bayesian inference. In our datasets, we included type sequences where available for all Cladophialophora species. Phylogenetic analyses revealed that none of the 15 isolates belonged to any of the previously described species in the genus. Therefore, using both morphological and molecular data, we classified these 15 isolates as nine new species within the genus Cladophialophora: C. flavoparmeliae, C. guttulate, C. heterodermiae, C. holosericea, C. lichenis, C. moniliformis, C. mongoliae, C. olivacea, and C. yunnanensis. The outcome from this study shows that lichens are an important refugia for black lichenicolous fungi, such as those from Chaetothyriales.

Gram stain to the rescue: a case report of cerebral phaeohyphomycosis by Cladophialophora bantiana in an immunocompetent 24-year-old

BACKGROUND

Fungal brain abscesses in immunocompetent patients are exceedingly rare. Cladophialophora bantiana is the most common cause of cerebral phaeohyphomycosis, a dematiaceous mold. Radiological presentation can mimic other disease states, with diagnosis through surgical aspiration and growth of melanized fungi in culture. Exposure is often unknown, with delayed presentation and diagnosis.

CASE PRESENTATION

We present a case of cerebral phaeohyphomycosis in a 24-year-old with no underlying conditions or risk factors for disease. He developed upper respiratory symptoms, fevers, and headaches over the course of 2 months. On admission, he underwent brain MRI which demonstrated three parietotemporal rim-enhancing lesions. Stereotactic aspiration revealed a dematiaceous mold on staining and the patient was treated with liposomal amphotericin B, 5-flucytosine, and posaconazole prior to culture confirmation. He ultimately required surgical excision of the brain abscesses and prolonged course of antifungal therapy, with clinical improvement.

CONCLUSIONS

Culture remains the gold standard for diagnosis of infection. Distinct microbiologic findings can aid in identification and guide antimicrobial therapy. While little guidance exists on treatment, patients have had favorable outcomes with surgery and combination antifungal therapy. In improving awareness, clinicians may accurately diagnose disease and initiate appropriate therapy in a more timely manner.

Reviewing the Etiologic Agents, Microbe-Host Relationship, Immune Response, Diagnosis, and Treatment in Chromoblastomycosis

Chromoblastomycosis (CBM) is a neglected human disease, caused by different species of pigmented dematiaceous fungi that cause subcutaneous infections. This disease has been considered an occupational disease, occurring among people working in the field of agriculture, particularly in low-income countries. In 1914, the first case of CBM was described in Brazil, and although efforts have been made, few scientific and technological advances have been made in this area. In the field of fungi and host cell relationship, a very reduced number of antigens were characterized, but available data suggest that ectoantigens bind to the cell membrane of host cells and modulate the phagocytic, immunological, and microbicidal responses of immune cells. Furthermore, antigens cleave extracellular proteins in tissues, allowing fungi to spread. On the contrary, if phagocytic cells are able to present antigens in MHC molecules to T lymphocytes in the presence of costimulation and IL-12, a Th1 immune response will develop and a relative control of the disease will be observed. Despite knowledge of the resistance and susceptibility in CBM, up to now, no effective vaccines have been developed. In the field of chemotherapy, most patients are treated with conventional antifungal drugs, such as itraconazole and terbinafine, but these drugs exhibit limitations, considering that not all patients heal cutaneous lesions. Few advances in treatment have been made so far, but one of the most promising ones is based on the use of immunomodulators, such as imiquimod. Data about a standard treatment are missing in the medical literature; part of it is caused by the existence of a diversity of etiologic agents and clinical forms. The present review summarizes the advances made in the field of CBM related to the diversity of pathogenic species, fungi and host cell relationship, antigens, innate and acquired immunity, clinical forms of CBM, chemotherapy, and diagnosis.

Tinea nigra palmaris-associated peritonitis, caused by Hortaea werneckii: The first case report in a peritoneal dialysis patient

We report the first case of peritoneal dialysis (PD) patients with peritonitis from Hortaea werneckii, a halotolerant black yeast-like fungus. The pathogen was confirmed by nucleotide sequences of internal transcribed spacer regions of the ribosomal RNA gene. A potential cause of this infection was tinea nigra on the patient's palm. Therefore, gloving might be advised during PD bag exchange in patients or caregivers who have an obvious lesion of the palm.

Inhibition of growth and ochratoxin A production in Aspergillus species by fungi isolated from coffee beans

Ochratoxin A (OTA) is a mycotoxin found in several agricultural commodities. Produced by Aspergillus spp., it is nephrotoxic and hepatotoxic and can be carcinogenic. Preventive measures are preventing fungal growth and OTA production. In this study, fungal strains (Rhizopus oryzae, Lichtheimia ramosa, Aspergillus westerdijkiae, Aspergillus niger, Aspergillus tamarii, Aspergillus sp., and Aspergillus fumigatus) isolated from coffee beans were identified for their abilities to inhibit the growth of Aspergillus ochraceus, Aspergillus westerdijkiae, Aspergillus carbonarius, and Aspergillus niger, and OTA production. All fungi strains tested were able to inhibit growth of the four Aspergillus species and OTA production, where A. niger showed the best results in both tests. L. ramosa showed the lowest growth-reducing potential, while the other fungal strains had a growth-reducing potential higher than 70% against all Aspergillus species tested. Regarding OTA production, L. ramosa and Aspergillus sp. completely inhibited the mycotoxin production by A. ochraceus and non-toxigenic strain A. niger completely inhibited OTA production by A. niger. Our findings indicate that the strains tested can be used as an alternative means to control growth of OTA-producing fungi and production of the mycotoxin in coffee beans.

Fungal communities in oil contaminated mangrove sediments - Who is in the mud?

Mangroves are ecosystems located in tropical and subtropical regions of the world and are vital for coastal protection. Their unique characteristics make them hotspots for carbon cycling and biological diversity. Studies on isolated filamentous fungi and environmental and anthropogenic factors that influence sediments offer new understandings on how to preserve mangroves. Here we report on the filamentous fungi isolated from four mangroves. We correlated fungal community composition with sediment texture, polycyclic aromatic hydrocarbons concentration (oil pollution), pH, salinity, organic matter, total and thermotolerant coliforms (sewage pollution). In total we identified 34 genera and 97 species. The most polluted sites had highest species richness whereas the best preserved site showed the lowest species richness. Oil spill and sewage pollution were identified as the drivers of fungal community composition in the most polluted sites. We found very distinct fungal communities with no >5 species shared between any two mangrove sites.

An updated comprehensive systematic review of Cladophialophora bantiana and analysis of epidemiology, clinical characteristics, and outcome of cerebral cases

Cladophialophora bantiana is a phaeoid fungus that only rarely has been isolated from sources other than the human brain. It has a particular tropism for the central nervous system (CNS). We have integrated and updated large-scale data related to several aspects of C. Bantiana and reviewed all the available reports on its cerebral infections, focusing on their geographical distribution, infection routes, immune status of infected individuals, type and location of infections, clinical manifestations and treatment and outcome, briefly looking over the spectrum of other disease entities associated with C. bantiana, that is, extra-cerebral and animal infections and on the environmental sources of this fungus. Among the agents of phaeohyphomycosis, a term used to describe an infection caused by a dark pigmented fungus, C. bantiana has some significant specific features. A total of 120 case reports were identified with a significantly higher percentage of healthy subjects than immune-debilitated patients (58.3% vs. 41.7%). Infections due to C. bantiana occur worldwide. The main clinical manifestations are brain abscess (97.5%), coinfection of brain tissue and meninges (14.2%) and meningitis alone (2.5%). Among immunocompetent patients, cerebral infection occurred in the absence of pulmonary lesions. The mortality rate is 65.0% regardless of the patient's immune status. The therapeutic options used include surgery or antifungals alone, and the combination of both, in most cases the fatal outcome being rapid after admission. Since the fungus is a true pathogen, laboratory workers should be made aware that BioSafety Level-3 precautions might be necessary.

Cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Persian Gulf region: A case and review

Cerebral phaeohyphomycosis is frequently a fatal disease caused by truly neurotropic dematiaceous fungi. Although rare, this infection occurs especially among immunocompetent patients, and the clinical symptoms are often misdiagnosed as a cerebral tumour or bacterial brain abscess. The appropriate diagnosis and therapy of cerebral infections by melanized fungi are very challenging if they are caused by mysterious fungi with unknown ecological niche. We reported the second case of cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Iran and the first culture-confirmed case. In this report, the differential diagnosis and histopathological findings are discussed and a review of the literature is provided.

Novel treatment using topical malachite green for nasal phaeohyphomycosis caused by a new Cladophialophora species in a cat

CASE SUMMARY

A 1.5-year-old castrated male domestic shorthair cat presented with a 2 month history of progressive nasal swelling and hyporexia. Minimal improvement prior to referral was achieved with a course of antibiotics and glucocorticoids. Cytology of an ulcerative lesion on the dorsal aspect of the nose was consistent with a diagnosis of phaeohyphomycosis. The cat achieved static disease for 6 weeks following initiation of itraconazole but developed epistaxis at 9 weeks. CT of the head demonstrated nasal and frontal sinus involvement. Nasal biopsy and culture identified infection with a Cladophialophora species not previously reported to cause disease. Initial response to a combination of itraconazole and terbinafine was noted, but owing to severe thrombocytopenia this combination was discontinued. Voriconazole was used but discontinued because of adverse side effects. Posaconazole treatment was offered throughout the clinical course but rejected owing to financial constraints and an uncertain response to medical therapy. Rhinotomy with debulking of diseased tissue and topical malachite green treatment was performed. Following the procedure itraconazole was continued and the cat has had no recurrence for over 1 year.

RELEVANCE AND NOVEL INFORMATION

Infections by Cladophialophora species have been reported in veterinary species, including cats. The specific fungal organism isolated from this cat has not been previously reported to cause disease in humans or animals and has only been described in the mangroves of Brazil. Furthermore, this is the first report to describe the use of topical malachite green as a treatment for refractory phaeohyphomycosis.

Potential of endophytic fungi as biocontrol agents of Duponchelia fovealis (Zeller) (Lepidoptera:Crambidae)

Abstract This study reports the first assessment of endophytic fungi isolated from strawberry leaves and selection of isolates for the control of Duponchelia fovealis, a new pest of strawberries. A total of 400 strawberry leaves of the cultivar ‘Albion’ were collected in four commercial farms. Leaves were disinfected, cut in fragments, and placed on Petri dishes containing potato dextrose agar media with tetracycline and incubated for 30 days. Following this time, 517 fungal colonies were isolated, and thirteen genera were identified: Cladosporium, Aspergillus, Nigrospora, Fusarium, Trichoderma, Chaetomium, Alternaria, Paecilomyces, Penicillium, Ulocladium, Bipolaris, Diaporthe, and Phoma. Eight isolates belonging to the genera Aspergillus, Diaporthe, Paecilomyces, and Cladosporium were selected for pathogenicity bioassays against third instar larvae of D. fovealis. Isolates of Paecilomyces induced the highest mortality rates.

Effect of environmental parameters on biodiversity of the fungal component in lithic Antarctic communities

A wide sampling of rocks, colonized by microbial epi-endolithic communities, was performed along an altitudinal gradient from sea level to 3600 m asl and sea distance from the coast to 100 km inland along the Victoria Land Coast, Antarctica. Seventy-two rock samples of different typology, representative of the entire survey, were selected and studied using denaturing gradient gel electrophoresis to compare variation in fungal diversity according to environmental conditions along this altitudinal and sea distance transect. Lichenized fungi were largely predominant in all the samples studied and the biodiversity was heavily influenced even by minimal local variations. The n-MDS analysis showed that altitude and sea distance affect fungal biodiversity, while sandstone allows the communities to maintain high biodiversity indices. The Pareto-Lorenz curves indicate that all the communities analyzed are highly adapted to extreme conditions but scarcely resilient, so any external perturbation may have irreversible effects on these fragile ecosystems.

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.

Potential for biocontrol of melanized fungi by actinobacteria isolated from intertidal region of Ilha Do Mel, Paraná, Brazil

Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.

First fatal cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Iran, based on ITS rDNA

Black yeast-like fungi and relatives as agents of cerebral phaeohyphomycosis are often encountered in human fatal brain abscesses and lead to almost 100% mortality despite the application of antifungal and surgical therapy. We report to our knowledge the first case of brain infection due to Rhinocladiella mackenziei in a 54-year-old immunocompetent male in Iran where R. mackenziei has not been reported previously. The initial diagnosis was brain fungal infection because of pigmented, irregular, branched, septated hyphae based on histopathological staining. The patient was treated with intravenous amphotericin B deoxycholate (0.5mg/kg/day) combined with oral itraconazole (200mg twice daily), nevertheless, his neurological function deteriorated rapidly and ultimately the patient died due to respiratory failure later two weeks. R. mackenziei was identified based on the sequencing of internal transcribed spacer (ITS rDNA region) (KJ140287). Therefore, considerable attention for this life-threatening infection is highly recommended.

Use of rolling circle amplification to rapidly identify species of Cladophialophora potentially causing human infection

The genus Cladophialophora comprises etiologic agents of disease in immunocompetent patients, ranging from mild cutaneous colonization to cerebral encephalitis, in addition to saprobic species. Due to the high degree of phenotypic similarity between closely related species of the genus, identification problems are imminent. In the present study, we described rapid and sensitive rolling circle amplification (RCA) method based on species-specific padlock probes targeted for the internal transcribed spacer regions of rDNA. ITS regions of 12 Cladophialophora species were sequenced, and subsequently, 10 specific padlock probes were designed for the detection of single nucleotide polymorphisms. The majority of circularizable padlock probes were designed based on single nucleotide polymorphisms (SNPs), while for C. bantiana, C. immunda and C. devriesii were characterized by two or more nucleotides. Individual species-specific probes correctly identified in all ten Cladophialophora species correctly by visualization on 1.2 % agarose gels used to verify specificity of probe-template binding; no cross-reactivity was observed. Simplicity, sensitivity, robustness and low costs provide RCA a distinct place among isothermal techniques for DNA diagnostics. However, restriction and specificity and sensitivity should be lowered and increased, respectively, to be useful for a wide variety of clinical applications.

Potential of Fourier transform infrared spectroscopy (FT-IR) to differentiate environmental Aspergillus fungi species A. niger, A. ochraceus, and A. westerdijkiae using two different methodologies

We assessed the ability of Fourier transform infrared spectroscopy (FT-IR) to differentiate three important and morphologically similar Aspergillus species: A. ochraceus and A. westerdijkiae, and A. niger. Fungi were processed by two methods, powdered mycelia and conidiospore-saline solution, and then recorded in a spectrometer. Second derivatives with nine points of smoothing were applied as spectra data pretreatment. Partial least squares regression was used for the species comparison models and a prediction test was used to evaluate the models. The powdered-mycelia methodology correctly identified 100% of the prediction test set to discriminate A. niger from A. ochraceus and A. westerdijkiae; in addition, it had a 86.6% success rate in discriminating A. ochraceus and A. westerdijkiae. This is the first time a study assessed the ability of FT-IR to differentiate A. niger, A. ochraceus, and A. westerdijkiae, and we believe this technique is very promising for classifying and distinguish fungi isolates.

[Taxonomy and biology of fungi causing human infection]

The advent of molecular techniques, mainly DNA sequencing, has led to important changes in the taxonomy of pathogenic fungi and a better understanding of the phylogenetic relationships among them. The number of fungal species potentially pathogenic for humans has increased dramatically. Most of them are cryptic species belonging to complex species that have replaced traditional single morphospecies. This has occurred in several genera of mucorales and particularly in different ascomycetous genera, such as Aspergillus, Fusarium, Sporothrix and Scedosporium, among others. The correct identification of these species is crucial for a better management of patients, since on many occasions those species show different virulence and different antifungal responses. This review summarises some of the most striking recent taxonomic changes produced in pathogenic fungi.

Multiple subcutaneous cysts due to Exophiala spinifera in an immunocompetent patient

Here we report a case of a 55-year-old Indian male presenting with multiple subcutaneous cysts, which developed from painful nodules at the dorsal right wrist joint. Subsequently a painful nodule appeared on the left knee joint. Cytological examination of the knee swelling revealed a suppurative inflammatory lesion consisting of neutrophils, lymphocytes, multinucleated giant cells and few fungal elements, without involvement of the overlying skin. Exophiala spinifera was cultured (CBS 125607) and its identity was confirmed by sequencing of the internal transcribed spacer (ITS rDNA). The cysts were excised surgically, without need of additional antifungal therapy. There was no relapse during one-year follow-up and the patient was cured successfully. In vitro antifungal susceptibility testing showed that posaconazole (0.063 μg/ml) and itraconazole (0.125 μg/ml) had the highest and caspofungin (4 μg/ml) and anidulafungin (2 μg/ml) the lowest activity against this isolate. However, their clinical effectiveness in the treatment of E. spinifera infections remains to be evaluated. In this case report, we have also compiled cases of human E. spinifera mycoses which have been reported so far.

Coniosporium epidermidis sp. nov., a new species from human skin

Coniosporium epidermidis sp. nov. is described from a superficial skin lesion with blackish discolouration in an 80-yr-old Chinese patient. The species produces dark, thick-walled, inflated, reluctantly liberating arthroconidia without longitudinal septa. Sequences of the ribosomal operon, as well as of the translation elongation factor 1-α support its novelty. The species is found in a lineage basal to the order Chaetothyriales, amidst relatives from rock, but also species repeatedly isolated from human skin and nails and eventually causing mild cutaneous infections. Coniosporium epidermidis is consistently found on humans, either asymptomatic or symptomatic. The species indicates a change of life style towards human pathogenicity, which is a recurrent type of ecology in derived Chaetothyriales. Superficial and cutaneous infection by melanized fungi is a new category in dermatology.

Tinea nigra by Hortaea werneckii, a report of 22 cases from Mexico

Tinea nigra is a superficial mycosis caused by Hortaea werneckii. It is an infrequent asymptomatic infection that affects human palms and soles, and is mostly observed in tropical countries. We evaluate retrospectively twenty-two confirmed cases of tinea nigra from a total of eleven yr (1997–2007) and discuss the epidemiology, clinical features and treatment of this disease. In twelve cases, adults were involved, in 10, children. In nineteen cases the disorder was located on palms of hands and in three on soles of feet. In all cases, the obtained isolates were morphologically identified as Hortaea werneckii and the identification of ten isolates was retrospectively confirmed with the help of sequences of the internal transcribed spacer regions of the ribosomal DNA. The patients received topical treatment with Whitfield ointment, ketoconazole, bifonazole, or terbinafine. Treatment with keratolytic agents and topical antifungals was effective.

Selective factors involved in oil flotation isolation of black yeasts from the environment

The oil flotation isolation technique has been successfully applied to recover chaetothyrialean black yeasts and relatives from the environment. The selective mechanisms playing a role in isolation are unknown. The fungi concerned are supposed to occupy specialized microniches in nature, taking advantage of (1) oligotrophism. Mineral oil as a main selective agent may be based on (2) hydrophobicity or on (3) assimilation. All three hypotheses are tested in this paper. Results show that cell wall hydrophobicity is unlikely to be a selective factor. Incubation under poor nutrient conditions provides competitive advantage for black yeasts, especially for Exophiala strains, which are subsequently enriched by mineral oil which enhances growth in this group of fungi. Incubation under mineral media and mineral oil can be used as selective factor.

Black yeast-like fungi in skin and nail: it probably matters

Black yeast-like fungi are rarely reported from superficial infections. We noticed a consistent prevalence of these organisms as single isolations from mycological routine specimens. To investigate the prevalence of black yeast-like fungi in skin, hair and nail specimens and to discuss the probability of these species to be involved in disease. Slow-growing black yeast-like fungi in routine specimens were prospectively collected and identified. A questionnaire regarding patient information was sent to physicians regarding black yeast-like fungus positive patients. A total of 20,746 dermatological specimens were examined by culture. Black yeast-like fungi accounted for 2.2% (n=108) of the positive cultures. Only 31.0% of the samples, culture positive for black yeast-like fungi were direct microscopy positive when compared with overall 68.8% of the culture positive specimens. The most prevalent species were Phialophora europaea (n=29), Coniosporium epidermidis (n=12), Ochroconis cf. humicola (n=6) and Cladophialophora boppii (n=4). These are not common saprobes and thus less likely to be coincidental colonizers. In 10/30 cases, discolouration of nail/skin had been noticed. A limited number of black yeast-like fungi were repeatedly isolated from routine specimens suggesting that they may play a role in superficial infections or as colonizers.

Cladophialophora psammophila, a novel species of Chaetothyriales with a potential use in the bioremediation of volatile aromatic hydrocarbons

Cladophialophora is a genus of asexual black yeast-like fungi with one-celled, hydrophobic conidia which is predicted to have teleomorphs in the ascomycete genus Capronia, a member of the order Chaetothyriales. Cladophialophora species are relatively frequently involved in human disease ranging from mild cutaneous lesions to cerebral abscesses. Although the natural niche outside humans is unknown for most opportunistic Cladophialophora species, the fungi concerned are rarely isolated from environmental samples such as dead plant material, rotten wood, or soil. The objective of the present paper is to describe a novel species of Cladophialophora which was isolated from soil polluted with benzene, toluene, ethylbenzene, and xylene (BTEX). It proved to be able to grow with toluene and other related alkylbenzenes as its sole carbon and energy source. This strain is of interest for the biodegradation of toluene and other related xenobiotics under growth limiting conditions, particularly in air biofilters, dry and/or acidic soil. A preliminary genetic analysis using multilocus sequencing typing (MLST) and amplified fragments length polymorphism (AFLP) showed that this fungus was closely related to the pathogenic species Cladophialophora bantiana, sharing a C. bantiana-specific intron in SSU rDNA. However, it was unable to grow at 40°C and proved to be non-virulent in mice. The clear phylogenetic and ecophysiological delimitation of the species is fundamental to prevent biohazard in engineered bioremediation applications.

Melanized fungi in human disease

Melanized or dematiaceous fungi are associated with a wide variety of infectious syndromes, including chromoblastomycosis, mycetoma, and phaeohyphomycosis. [corrected]. Many are soil organisms and are generally distributed worldwide, though certain species appear to have restricted geographic ranges. Though they are uncommon causes of disease, melanized fungi have been increasingly recognized as important pathogens, with most reports occurring in the past 20 years. The spectrum of diseases with which they are associated has also broadened and includes allergic disease, superficial and deep local infections, pneumonia, brain abscess, and disseminated infection. For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common etiologic fungi. Melanin is a likely virulence factor for these fungi. Diagnosis relies on careful microscopic and pathological examination, as well as clinical assessment of the patient, as these fungi are often considered contaminants. Therapy varies depending upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Triazoles such as voriconazole, posaconazole, and itraconazole have the most consistent in vitro activity. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.

Indoor wet cells harbour melanized agents of cutaneous infection

The biota of black fungi in humid indoor environments was established using a protocol that consisted of non-selective and selective isolation procedures. In total, 113 samples were taken from bathrooms of residences in The Netherlands, Germany and Austria. Samples were processed either (i) directly by culturing on agar media, or (ii) by pre-incubating samples for enrichment in mineral solutions with perlite granules under constant toluene atmosphere for three months. Dilutions from the latter were then cultured and incubated as were those directly plated to agar media. Black colonies were selected and identified by sequencing the rDNA Internal Transcribed Spacer (ITS) region. Twenty-eight strains of black fungi were found in 26 positive samples without enrichment, and 42 strains were isolated from 38 positive samples after enrichment in toluene. The great majority of black fungal species were members of the order Chaetothyriales, which is the main order of melanized human opportunistic pathogens. Cladosporium species (Capnodiales) were the most frequent isolates when no enrichment was applied, as opposed to Exophiala species (Chaetothyriales) with enrichment. The enrichment method provides insight into a fungal biota commonly occurring in homes which has previously been overlooked. Several species have been previously known only from cutaneous infections and could suggest that bathrooms are a likely reservoir of these fungi.

Use of amplified fragment length polymorphism to identify 42 Cladophialophora strains related to cerebral phaeohyphomycosis with in vitro antifungal susceptibility

The amplified fragment length polymorphism technique has been applied to identify neurotropic chaetothyrialean black yeasts and relatives from clinical sources. Cladophialophora bantiana, C. emmonsii, C. arxii, C. devriesii, and C. modesta, previously identified on the basis of sequencing and phenotypic and physiological criteria, were confirmed by cluster analysis, demonstrating the clear separation of C. bantiana as a rather homogeneous group from the other species. C. bantiana is a neurotropic fungus causing cerebral abscesses with a mortality of up to 70%. Successful therapy consists of neurosurgical intervention and optimal antifungal therapy. Since the latter is not clearly defined in a large series, we tested the in vitro activities of eight antifungal drugs against clinical isolates of C. bantiana (n = 37), C. modesta (n = 2), C. arxii (n = 1), C. emmonsii (n = 1), and C. devriesii (n = 1), all of which had caused invasive infections. The resulting MIC(90)s for all neurotropic C. bantiana strains were as follows, in increasing order: posaconazole, 0.125 microg/ml; itraconazole, 0.125 microg/ml; isavuconazole, 0.5 microg/ml; amphotericin B, 1 microg/ml; voriconazole, 2 microg/ml; anidulafungin, 2 microg/ml; caspofungin, 4 microg/ml; and fluconazole, 64 microg/ml. On the basis of these in vitro results and the findings of previous clinical and animal studies, posaconazole seems to be a good alternative to the standard treatment, amphotericin B, for C. bantiana cerebral infections. The new agent isavuconazole, which is also available as an intravenous preparation, has adequate activity against C. bantiana.

First autochthonous case of Rhinocladiella mackenziei cerebral abscess outside the Middle East

Cerebral phaeohyphomycosis due to Rhinocladiella mackenziei is a severe infection in the middle east, resulting in nearly 100% mortality despite the application of combined surgical and antifungal therapy and occurring occasionally in otherwise healthy patients. We report the first case of brain infection in a middle-aged male in India, where R. mackenziei is not endemic.

Biodiversity of the genus Cladophialophora

Cladophialophora is a genus of black yeast-like fungi comprising a number of clinically highly significant species in addition to environmental taxa. The genus has previously been characterized by branched chains of ellipsoidal to fusiform conidia. However, this character was shown to have evolved several times independently in the order Chaetothyriales. On the basis of a multigene phylogeny (nucLSU, nucSSU, RPB1), most of the species of Cladophialophora (including its generic type C. carrionii) belong to a monophyletic group comprising two main clades (carrionii- and bantiana-clades). The genus includes species causing chromoblastomycosis and other skin infections, as well as disseminated and cerebral infections, often in immunocompetent individuals. In the present study, multilocus phylogenetic analyses were combined to a morphological study to characterize phenetically similar Cladophialophora strains. Sequences of the ITS region, partial Translation Elongation Factor 1-alpha and beta-Tubulin genes were analysed for a set of 48 strains. Four novel species were discovered, originating from soft drinks, alkylbenzene-polluted soil, and infected patients. Membership of the both carrionii and bantiana clades might be indicative of potential virulence to humans.