Onychomycosis of the toenails caused by Chaetomium globosum

Chaetomium and Chaetomium-like Species from European Indoor Environments Include Dichotomopilus finlandicus sp. nov

The genus Chaetomium is a frequently occurring fungal taxon world-wide. Chaetomium and Chaetomium-like species occur in indoor environments, where they can degrade cellulose-based building materials, thereby causing structural damage. Furthermore, several species of this genus may also cause adverse effects on human health. The aims of this research were to identify Chaetomium and Chaetomium-like strains isolated from indoor environments in Hungary and Finland, two geographically distant regions of Europe with drier and wetter continental climates, respectively, and to study their morphological and physiological properties, as well as their extracellular enzyme activities, thereby comparing the Chaetomium and Chaetomium-like species isolated from these two different regions of Europe and their properties. Chaetomium and Chaetomium-like strains were isolated from flats and offices in Hungary, as well as from schools, flats, and offices in Finland. Fragments of the translation elongation factor 1α (tef1α), the second largest subunit of RNA polymerase II (rpb2) and β-tubulin (tub2) genes, as well as the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster were sequenced, and phylogenetic analysis of the sequences performed. Morphological examinations were performed by stereomicroscopy and scanning electron microscopy. Thirty-one Chaetomium sp. strains (15 from Hungary and 16 from Finland) were examined during the study. The most abundant species was Ch. globosum in both countries. In Hungary, 13 strains were identified as Ch. globosum, 1 as Ch. cochliodes, and 1 as Ch. interruptum. In Finland, 10 strains were Ch. globosum, 2 strains were Ch. cochliodes, 2 were Ch. rectangulare, and 2 isolates (SZMC 26527, SZMC 26529) proved to be representatives of a yet undescribed phylogenetic species from the closely related genus Dichotomopilus, which we formally describe here as the new species Dichotomopilus finlandicus. Growth of the isolates was examined at different temperatures (4, 15, 20, 25, 30, 37, 35, 40, and 45 °C), while their extracellular enzyme production was determined spectrophotometrically.

Opportunistic phaeohyphomycoses in wild saffron cod Eleginus gracilis from waterways of Norton Sound and Toksook Bay, Alaska, USA

These case reports describe locally invasive black pigmented mycotic infections of the skin and gills of saffron cod Eleginus gracilis associated with 8 different opportunistic ascomycete fungi: Alternaria sp., Cladosporium herbarum, Chaetomium globosum, Cadophora luteo-olivacea, Penicillium sp., Phoma herbarum, Pseudophacidium ledi and Valsa sordida. These fungi were isolated on conventional media, identified according to morphological structures and confirmed by genetic sequencing. Several of these fungi are primary plant pathogens as well as opportunistic human pathogens in immunocompromised individuals. Several have also been described as causing opportunistic infections of fish. This case material represents the first report of C. luteo-olivacea, C. globosum, P. ledi and V. sordida as likely opportunistic fish pathogens in Alaskan watersheds of Norton Sound and south in Toksook Bay and possibly elsewhere.

Diversity of phenotypically non-dermatophyte, non-Aspergillus filamentous fungi causing nail infections: importance of accurate identification and antifungal susceptibility testing

Onychomycosis is most commonly caused by dermatophytes. In this study, we examined the spectrum of phenotypically non-dermatophyte and non-Aspergillus fungal isolates recovered over a 10-year period from nails of patients with onychomycosis in Hong Kong. A total of 24 non-duplicated isolates recovered from 24 patients were included. The median age of the patients was 51 years, and two-thirds of them were males. One-third and two-thirds had finger and toe nail infections respectively. Among these 24 nail isolates, 17 were confidently identified as 13 different known fungal species, using a polyphasic approach. These 13 species belonged to 11 genera and ≥9 families. For the remaining seven isolates, multilocus sequencing did not reveal their definite species identities. These seven potentially novel species belonged to four different known and three potentially novel genera of seven families. 33.3%, 41.7% and 95.8% of the 24 fungal isolates possessed minimum inhibitory concentrations of >1 µg/mL to terbinafine, itraconazole and fluconazole, respectively, the first line treatment of onychomycosis. A high diversity of moulds was associated with onychomycosis. A significant proportion of the isolates were potentially novel fungal species. To guide proper treatment, molecular identification and antifungal susceptibility testing should be performed for these uncommonly isolated fungal species.

Diversity and taxonomy of Chaetomium and chaetomium-like fungi from indoor environments

During a study of indoor fungi, 145 isolates belonging to Chaetomiaceae were cultured from air, swab and dust samples from 19 countries. Based on the phylogenetic analyses of DNA-directed RNA polymerase II second largest subunit (rpb2), β-tubulin (tub2), ITS and 28S large subunit (LSU) nrDNA sequences, together with morphological comparisons with related genera and species, 30 indoor taxa are recognised, of which 22 represent known species, seven are described as new, and one remains to be identified to species level. In our collection, 69 % of the indoor isolates with six species cluster with members of the Chaetomium globosum species complex, representing Chaetomium sensu stricto. The other indoor species fall into nine lineages that are separated from each other with several known chaetomiaceous genera occurring among them. No generic names are available for five of those lineages, and the following new genera are introduced here: Amesia with three indoor species, Arcopilus with one indoor species, Collariella with four indoor species, Dichotomopilus with seven indoor species and Ovatospora with two indoor species. The generic concept of Botryotrichum is expanded to include Emilmuelleria and the chaetomium-like species B. muromum (= Ch. murorum) in which two indoor species are included. The generic concept of Subramaniula is expanded to include several chaetomium-like taxa as well as one indoor species. Humicola is recognised as a distinct genus including two indoor taxa. According to this study, Ch. globosum is the most abundant Chaetomiaceae indoor species (74/145), followed by Ch. cochliodes (17/145), Ch. elatum (6/145) and B. piluliferum (5/145). The morphological diversity of indoor Chaetomiaceae as well as the morphological characteristics of the new genera are described and illustrated. This taxonomic study redefines the generic concept of Chaetomium and provides new insight into the phylogenetic relationships among different genera within Chaetomiaceae.

Onychomycosis due to Chaetomium globosum with yellowish black discoloration and periungual inflammation

Onychomycosis is usually caused by dermatophytes, although also other filamentous and yeast-like fungi are associated with nail invasion. Chaetomium is an environmental genus of ascomycetes exhibiting a certain degree of extremotolerance. We report the first case of onychomycosis in a 46-year-old woman in China caused by Chaetomium globosum. The patient showed yellowish black discoloration with periungual inflammation on the left first toenail. We confirmed the causative agent, C. globosum, by KOH mount, culture, micromorphology and DNA sequence analysis

Chaetomium atrobrunneum and Aspergillus fumigatus in multiple tracheal aspirates: Copathogens or symbiosis

Chaetomium atrobrunneum has never been reported to be associated with pneumonia. We report the isolation of C. atrobrunneum and Aspergillus fumigatus from a Chinese elderly patient with fatal pneumonia. Branched, long, and septate hyphae were observed in potassium hydroxide preparations and Gram-stained smears, and confluent C. atrobrunneum growth and a few A. fumigatus colonies were found in tracheal aspirates (nine separate occasions). These isolates were identified by conventional morphological methods and by sequencing the internal transcribed spacer and the D1/D2 domain of the 26S rRNA gene. The patient responded poorly to the combination therapy of amphotericin B and caspofungin. This report adds C. atrobrunneum to the list of fungal pneumonia in immunocompromised hosts. This case report also illustrated the presence of a growth symbiosis between Chaetomium species and A. fumigatus.

Invasive pulmonary mycosis due to Chaetomium globosum with false-positive galactomannan test: a case report and literature review

In this case, the authors report Chaetomium globosum as a cause of invasive pulmonary infection in a patient with Wegener's granulomatosis. Fungal hyphae (KOH and Calcofluor) were seen on direct microscopy of lung biopsy sample and bronchoalveolar lavage (BAL) sample. C. globosum isolated on culture clinched the diagnosis of invasive pulmonary infection by Chaetomium spp. A positive galactomannan of serum and BAL was repeatedly seen and was utilised for follow-up and as prognostic marker in patient management. The patient was successfully treated with liposomal amphotericin B followed by voriconazole. All the Chaetomium infections reported till date since 1980 are reviewed. Chaetomium spp. with its unique ecology has a hidden clinical potential to cause invasive mould infections.

Phylogenetic reassessment of the Chaetomium globosum species complex

Chaetomium globosum, the type species of the genus, is ubiquitous, occurring on a wide variety of substrates, in air and in marine environments. This species is recognised as a cellulolytic and/or endophytic fungus. It is also known as a source of secondary metabolites with various biological activities, having great potential in the agricultural, medicinal and industrial fields. On the negative side, C. globosum has been reported as an air contaminant causing adverse health effects and as causal agent of human fungal infections. However, the taxonomic status of C. globosum is still poorly understood. The contemporary species concept for this fungus includes a broadly defined morphological diversity as well as a large number of synonymies with limited phylogenetic evidence. The aim of this study is, therefore, to resolve the phylogenetic limits of C. globosum s.str. and related species. Screening of isolates in the collections of the CBS-KNAW Fungal Biodiversity Centre (The Netherlands) and the China General Microbiological Culture Collection Centre (China) resulted in recognising 80 representative isolates of the C. globosum species complex. Thirty-six species are identified based on phylogenetic inference of six loci, supported by typical morphological characters, mainly ascospore shape. Of these, 12 species are newly described here. Additionally, C. cruentum, C. mollipilium, C. rectum, C. subterraneum and two varieties of C. globosum are synonymised under C. globosum s.str., and six species are resurrected, i.e. C. angustispirale, C. coarctatum, C. cochliodes, C. olivaceum, C. spiculipilium and C. subglobosum. Chaetomium ascotrichoides is segregated from C. madrasense and the genus name Chaetomidium is rejected. Five species, including C. globosum s.str., are typified here to stabilise their taxonomic status. A further evaluation of the six loci used in this study as potential barcodes indicated that the 28S large subunit (LSU) nrDNA and the internal transcribed spacer regions and intervening 5.8S nrRNA (ITS) gene regions were unreliable to resolve species, whereas β-tubulin (tub2) and RNA polymerase II second largest subunit (rpb2) showed the greatest promise as DNA barcodes for differentiating Chaetomium species. This study provides a starting point to establish a more robust classification system for Chaetomium and for the Chaetomiaceae.

Black Molds and Melanized Yeasts Pathogenic to Humans

A review is given of melanized fungi involved in human infection, including species forming budding cells and strictly filamentous representatives. Classically, they are known as "phaeoid" or "dematiaceous" fungi, and, today, agents are recognized to belong to seven orders of fungi, of which the Chaetothyriales and Pleosporales are the most important. Infections range from cutaneous or pulmonary colonization to systemic or disseminated invasion. Subcutaneous involvement, either primary or after dissemination, may lead to host tissue proliferation of dermis or epidermis. Particularly in the Chaetothyriales, subcutaneous and systemic infections may occur in otherwise apparently healthy individuals. Infections are mostly chronic and require extended antifungal therapy and/or surgery.

Onychomycosis Caused by Chaetomium globosum

Onychomycosis is usually caused by dermatophytes, but some nondermatophytic molds and yeasts are also associated with invasion of nails. The genus Chaetomium is a dematiaceous nondermatophytic mold found in soil and plant debris as a saprophytic fungus. We report the first Korean case of onychomycosis caused by Chaetomium globosum in a 35-year-old male. The patient showed brownish-yellow discoloration and subungual hyperkeratosis on the right toenails (1st and 5th) and left toenails (1st and 4th). Direct microscopic examination of scraping on the potassium hydroxide preparation revealed septate hyphae and repeated cultures on Sabouraud's dextrose agar (SDA) without cycloheximide slants showed the same fast-growing colonies, which were initially velvety white then turned to dark gray to brown. However, there was no growth of colony on SDA with cycloheximide slants. Brown-colored septated hyphae, perithecia and ascospores were shown in the slide culture. The DNA sequence of internal transcribed spacer region of the clinical sample was a 100% match to that of C. globosum strain ATCC 6205 (GenBank accession number EF524036.1). We confirmed C. globosum by KOH mount, colony, and light microscopic morphology and DNA sequence analysis. The patient was treated with 250 mg oral terbinafine daily and topical amorolfine 5% nail lacquer for 3 months.

A case report of a mixed Chaetomium globosum/Trichophyton mentagrophytes onychomycosis

Recently, an increasing prevalence of nondermatophyte mold onychomycosis was observed, in which Chaetomium globosum was rarely involved as primary pathogenic agent. Besides this, reports of mixed infection associating a dermatophyte and a nondermatophyte mold have become more frequent. Here, we present a clinical case of a mixed onychomycosis infection of a toenail caused by Chaetomium globosum and Trichophyton mentagrophytes. To our knowledge, this specific association is reported for the first time in Canada.

Phaeohyphomycosis and onychomycosis due to Chaetomium spp., including the first report of Chaetomium brasiliense infection

Chaetomium species have been rarely described as aetiological agents of invasive and dermatomycotic infections in humans. The majority of cases have been reported within the last two decades. Treatment failed in most of these cases. In this paper we present two cases in which Chaetomium spp. can be clearly identified as an aetiological agent in pathological conditions. In the first report, we describe a new aetiological agent, Chaetomium brasiliense, which was implicated in a case of otitis externa in a patient with spinocellular carcinoma basis cranii. The patient had been repeatedly treated for relapsing otitis externa and had previously undergone surgery several times for otitis media. The fungal aetiology was confirmed by repeated positive culture and histologic studies. The second case involved onychomycosis with strikingly brown nail discoloration due to Chaetomium globosum in an otherwise healthy patient. The nail lesion was successfully cured by oral terbinafine. The determination of both species was supported by sequencing of rDNA regions. The morphological aspect of Chaetomium spp. identification is also discussed. In vitro antifungal susceptibility tests demonstrated that both isolates were susceptible to terbinafine and azole derivates except fluconazole. Amphotericin B was effective only against the C. brasiliense strain. We review the literature to summarize clinical presentations, histologic findings, and treatment strategies.

Three isolations of Chaetomium globosum from erythematous epilation of canine skin

Chaetomium globosum is commonly found in natural environments worldwide and is known to be a causative agent for emerging fungal infections. The present study describes a case of erythematous epilation of a dog caused by C. globosum. A mixed-breed young dog, a 4-months-old male, weighing 7.25 kg, showed depilation, scales, and dermatitis with slightly itchiness on his skin. The main symptom was an erythematous epilation on the left subocular skin 7.5 cm in diameter, accompanied by elephantiasis-like hyperplasia and scales. Similar lesions were observed on the skin on both sides of the ear lobes, the heels, tail, and left angulus oris. The scales from the crusted lesion were cultured on chrolamphenicole-added potato dextrose agar plates at the first visit, as well as followed by ambulatory practices. The isolates at the first visit, 1 and 3 weeks after treatment, were identified as C. globosum by mycological study and the D1/D2 domain of the large subunit rRNA gene sequence. The patient dog was treated by ketoconzole both orally and externally. The lesions were cured, showing new hair growth 9 weeks later. In addition, the susceptibilities to antifungal agents for the present C. globosum isolate were as follows: amphotericin B, 4.0 microg/ml; 5-FC 64.0 microg/ml; itraconazole, 0.5 microg/ml; miconazole, 1.0 microg/ml; fulconazole, 16.0 microg/ml; ketoconazole, 0.25 microg/ml; and micafungin, 16.0 microg/ml.

First Spanish case of onychomycosis caused byChaetomium globosum

Members of the fungal genus Chaetomium usually colonize cellulose-containing plant remains but on rare occasions may cause opportunistic mycoses and cutaneous infection in otherwise healthy individuals. To our knowledge, there have been only five credible descriptions of onychomycosis caused by members of this genus and only two of these contained information on therapy. We describe the first case of Chaetomium globosum onychomycosis recorded in Spain. The etiologic significance of the fungus was confirmed by its repeated isolation at different times, to the exclusion of dermatophytes. Clinically, the affected nails showed an excellent response to terbinafine and complete cure appeared to have been attained.

A case of subcutaneous phaeohyphomycosis caused byChaetomium globosumand the sequences analysis ofC. globosum

A 14-year-old boy developed painful erythema and necrosis on his face with petechia on his upper extremities. Microscopically, necrotic tissue treated with potassium hydroxide showed branched, dematiaceous, septate hyphae. Chaetomium globosum was isolated repeatedly from the necrotic tissues. Morphology and thermotolerance test of the pathogen were also studied. The internal transcribed spacer region in rRNA gene was amplified and sequenced. The sequence of this patient matched well with that of C. globosum in GenBank and from other patients and environment.

Magnetic resonance imaging findings in fatal primary cerebral infection due to Chaetomium strumarium

This report describes MRI findings of a rare case of biopsy-proven fatal cerebral infection with Chaetomium strumarium in a 28-year-old man with a history of i.v. drug abuse. Magnetic resonance imaging revealed rapidly progressing lesions with irregular peripheral enhancement, possible central haemorrhage and significant mass effect. Only six cases of cerebral infection with Chaetomium have been reported in the English literature. This is the first report in the radiology literature describing the imaging findings. The previously reported cases of cerebral infection by the Chaetomium species are also reviewed.

Invasive mycotic infections caused by Chaetomium perlucidum, a new agent of cerebral phaeohyphomycosis

We report the first two cases of invasive human mycoses caused by the phaeoid ascomycete, Chaetomium perlucidum, and review the English literature regarding invasive Chaetomium infections. Fatal disseminated disease involving the brain, heart, lungs, and spleen is described in an acute myelogenous leukemia patient. A second patient with a history of asthma and chronic bronchiectasis experiencing right-middle-lobe syndrome grew C. perlucidum from lung tissue. This study adds C. perlucidum to the list of other known neurotropic Chaetomium species, C. atrobrunneum and C. strumarium, and also documents this organism's ability to disseminate beyond the central nervous system.

Case report. Onychomycosis due to Chaetomium globosum successfully treated with itraconazole

We have experienced a case of toenail infection caused by Chaetomium globosum which we treated with itraconazole 100 mg day-1 for 6 months, after which time the nail lesions were almost cured. Our case is the first reported case of onychomycosis caused by Ch. globosum in Japan, and the seventh in the world.

[Aspergillus fumigatus and Chaetomium homopilatum in a leukemic patient. Pathogenic significance of Chaetomium species]

From the tracheal secretion of a leukaemic patient Aspergillus fumigatus and Chaetomium homopilatum was isolated. Radiographically (HR-CT) an invasive pulmonary mycosis was diagnosed from which the patient died. As an autopsy was not performed, the role of the isolated fungi could not be clarified safely. Aspergillus fumigatus is supposed to have been responsible for the invasive mycosis. The etiopathological significance of Ch. homopilatum remained unclear. The isolation of Ch. homopilatum was a reason for reviewing the genus Chaetomium. In the literature 18 reported cases of infections by Chaetomium sp. were found. Ch. globosum was the most prevalent species and caused mostly onychomycosis. Ch. strumarium and Ch. atrobrunneum caused brain infections. The predisposing factor in case of onychomycosis and cutaneous lesions was a trauma, and the systemic mycoses were a consequence of leukaemia, renal transplantation, intravenous drug use or renal failure. The reported cases show, that Chaetomium sp. may cause infections, if predisposing factors are present. Therefore the isolation of Chaetomium sp. in clinical specimen should not regarded as a contamination, and the possible etiopathological significance should be clarified.

Onychomycosis in Rome, Italy

This report presents the results of a study conducted between 1985 and 1994 on onychomycosis observed in the city of Rome. Six thousand six hundred and eighty eight patients were examined during this period. Among them 1,762 (26.3%) were affected by fungal nail infections. Because the etiologic agents could not be isolated in 105 cases (6%), the results refer to 1,657 subjects (24.8% of the total), presenting with positive microscopic and cultural examinations. Thirty eight patients (2.3%) had onychomycosis of both their hands and feet. From an etiological point of view, 59.1% of the nail infections were caused by yeasts, 23.2% were infected with dermatophytes and 17.6% by non-dermatophytic fungi. The etiology of onychomycosis of the hands differed from that of the feet. Yeasts were primarily responsible for onychomycosis of the hands (86.2%), while dermatophytes caused tinea unguium peduum (48%). Fungal fingernail infections by Candida spp. were the most common (50.3%), followed by those of the feet by dermatophytes (20%). Candida albicans was responsible for 70.6% of the hand infections but for only 15.9% of those of the feet. Trichophyton rubrum and T mentagrophytes were the most common dermatophytes, mainly causing toenail infections (23.4% and 21%, respectively), while Aspergillus spp., Scopulariopsis brevicaulis, Acremonium spp. and Aspergillus niger were the most common non-dermatophytes observed. With regard to sex, the fungal nail infections were more widespread in women (72.1%) and in subjects of both sexes over the age of 50.

Fatal cerebral mycoses caused by the ascomycete Chaetomium strumarium

Three cases of fatal cerebral mycosis in males with prior histories of intravenous drug use from the United States and Australia are reported. Infection in each case was limited to brain abscess; no other sites of infection were observed. The fungus seen by histopathology and isolated from the brain tissue in each case was identified as Chaetomium strumarium. This is the first report of human infection by this species, and C. strumarium is the second species of Chaetomium known to cause primary brain infection. Chaetomium strumarium is unusual among members of the genus Chaetomium in forming ascocarps covered with pale, thin-walled, flexuous hairs, a feature leading to its original placement in the genus Achaetomium. Presence of pinkish exudate droplets and/or crystals associated with hyphae or ascocarps, sometimes accompanied by a pinkish diffusible pigment; good growth at 42 degrees C; and production of small conidia further distinguish this species. The brain abscess isolates were compared with isolates from prior cases of cerebral infection which had been identified as either Chaetomium atrobrunneum or Chaetomium globosum. With reidentification of one isolate originally identified as C. globosum to C. atrobrunneum, only C. strumarium and C. atrobrunneum have been confirmed to cause infection involving the brain.

Pathogenicity and antifungal susceptibility of Chaetomium species

Several reports have been published implicating Chaetomium spp. as opportunistic pathogens. A critical review of these cases was made, and the majority of the responsible strains were studied. Chaetomium globosum was the most common species, being isolated in at least nine clinical cases of infection. Some of these clinical isolates and others from environmental sources were tested against six antifungal agents (5-fluorocytosine, fluconazole, amphotericin B, itraconazole, ketoconazole and miconazole). The 23 strains tested were totally resistant to the first two drugs, and none of the other antifungal agents demonstrated fungicidal activity. There were no significant differences between the susceptibility of the clinical strains and the other strains.

The dermatophytes

The etiologic agents of the dermatophytoses (ringworm) are classified in three anamorphic (asexual or imperfect) genera, Epidermophyton, Microsporum, and Trichophyton. Species capable of reproducing sexually belong in the teleomorphic genus, Arthroderma, of the Ascomycota. On the basis of primary habitat association, they may be grouped as geophilic (soil associated), zoophilic, and anthropophilic. Adaptation to growth on humans by most geophilic species resulted in diminished loss of sporulation, sexuality, and other soil-associated characteristics. The dermatophytes have the ability to invade keratinized tissue (skin, hair, and nails) but are usually restricted to the nonliving cornified layer of the epidermis because of their inability to penetrate viable tissue of an immunocompetent host. However, invasion does elicit a host response ranging from mild to severe. Acid proteinases, elastase, keratinases, and other proteinases reportedly act as virulence factors. The development of cell-mediated immunity correlated with delayed hypersensitivity and an inflammatory response is associated with clinical cure, whereas the lack of or a defective cell-mediated immunity predisposes the host to chronic or recurrent dermatophyte infection. Chronic dermatophytosis is mostly caused by Trichophyton rubrum, and there is some evidence that mannan produced by this fungus suppresses or diminishes the inflammatory response. Since dermatophytes cause a communicable disease, modes of transmission and control are discussed as well as a survey of recent trends in therapy. Collection of specimens, culture media, and tests for identification are also presented. Genetic studies have led to an understanding of incompatibility mechanisms, pleomorphism and variation, resistance to griseofulvin, and virulence. Molecular biology has contributed to our knowledge of the taxonomy and phylogenetic relationships of dermatophytes.