Developments in hyalohyphomycosis and phaeohyphomycosis

Isolation and investigation of external reproduction tract mycoflora in healthy male cats

BACKGROUND

Various infectious agents can infect the male reproductive system.

OBJECTIVES

The aims of this study were to provide current data on fungal and yeast flora of the external organs of reproductive system of male short hair cats including penis and prepuce.

METHODS

In total 28 samples were taken from external genital system of male stray cats using sterilised cotton swabs. Samples were taken based on the absence of any reproductive complications using physical examinations. The samples were transferred to sterilised Stuart transport media and were then incubated in the Sabouraud dextrose agar with chloramphenicol at 32°C for 48 h. The identification of fungi and yeasts was confirmed by germ tube formation test, CHROM agar, urease testing and Corn meal agar medium with Tween 80.

RESULTS

Fungal agents were isolated from 7 (25%) out of 28 male stray cats. Fungal isolates were obtained from the penis and prepuce of 4 (36%) and 7 (100%) male cats, respectively. The most commonly recovered species samples were Candida krusei (3.75%) and Penicillum spp. (6.86%) from the penis and prepuce of the cats, respectively. The external organs of male reproduction of cats were infected with 2-4 different fungal agents. Only 5 (45%) cats were infected with one fungus; however, in 6 (55%) cats, mixed fungal infections were isolated. Cats 3-4 years old had the highest fungal contamination in the prepuce region (4/7), while the penis at this age had the least contamination (1/4).

CONCLUSIONS

It is concluded that the external reproduction organs of male cats could be infected by different fungal agents.

Molecular Pathway, Epidemiological Data and Treatment Strategies of Fungal Infection (Mycoses): A Comprehensive Review

The recent increase in fungal infections is a health crisis. This surge is directly tied to the increase in immunocompromised people caused by changes in medical practice, such as the use of harsh chemotherapy and immunosuppressive medicines. Immunosuppressive disorders such as HIV have exacerbated the situation dramatically. Subcutaneous or superficial fungal infections can harm the skin, keratinous tissues, and mucous membranes. This category includes some of the most common skin disorders that impact millions of people worldwide. Despite the fact that they are seldom fatal, they can have a catastrophic impact on a person's quality of life and, in rare situations, spread to other people or become obtrusive. The majority of fungal infections under the skin and on the surface are simply and quickly cured. An opportunistic organism that preys on a weak host or a natural intruder can both result in systemic fungal infections. Furthermore, it might be exceedingly lethal and dangerous to one's life. Dimorphic fungi may pose a hazard to healthy populations that are not exposed to endemic fungi. Increased surveillance, the availability of quick, noninvasive diagnostic tests, monitoring the emergence of antifungal medication resistance, and research on the pathophysiology, prevention, and management of fungal infections are just a few potential solutions to these new health problems. The goal of this review is to summarize the data available for fungal infections and the different therapies which are involved in their treatment. Additionally, it also summarizes the molecular and scientific data of the plants which contain anti-fungal activity. Data are acquired using Google, PubMed, Scholar, and other online sources.

Greater Mouse-Eared Bats (Myotis myotis) Hibernating in the Nietoperek Bat Reserve (Poland) as a Vector of Airborne Culturable Fungi

Bats can contribute to an increase of aeromycota in underground ecosystems and might be a vector/reservoir of microorganisms; however, there is no information about the number and species composition of fungi around hibernating bats. One of the most common species in Europe with direct human contact is the greater mouse-eared bat (Myotis myotis). The goal of our research was the first report of the airborne fungi present in the close vicinity of hibernating M. myotis in the Nietoperek bat reserve (Western Poland) by the use of culture-based techniques and genetic and phenotypic identifications. Aerobiological investigations of mycobiota under hibernating bats were performed on two culture media (PDA and YPG) and at two incubation temperatures (7 and 24 ± 0.5 °C). Overall, we detected 32 fungal species from three phyla (Ascomycota, Basidiomycota, and Zygomycota) and 12 genera. The application of YPG medium and the higher incubation temperature showed higher numbers of isolated fungal species and CFU. Penicillium spp. were dominant in the study, with spores found outside the underground hibernation site from 51.9% to 86.3% and from 56.7% to 100% inside the bat reserve. Penicillium chrysogenum was the most frequently isolated species, then Absidia glauca, Aspergillus fumigatus, A. tubingensis, Mortierella polycephala, Naganishia diffluens, and Rhodotorula mucilaginosa. Temperature, relative humidity, and the abundance of bats correlated positively with the concentration of airborne fungal propagules, between fungal species diversity, and the concentration of aeromycota, but the number of fungal species did not positively correlate with the number of bats. The air in the underground site was more contaminated by fungi than the air outside; however, the concentration of aeromycota does not pose a threat for human health. Nevertheless, hibernating bats contribute to an increase in the aeromycota and as a vector/reservoir of microscopic fungi, including those that may cause allergies and infections in mammals, and should be monitored.

Dual fungal infection with Lomentospora prolificans and Aspergillus fumigatus: A pathogenetic diagnosis elucidated after two decades by sequential examinations

A 44-year-old male Japanese was admitted for further post-remission treatments for acute myeloid leukemia. He developed a right orbital abscess. An isolate of Lomentospora prolificans was obtained from the lesion, and orbital biopsy also revealed the presence of Aspergillus fumigatus. This fatal case involved a concurrent dual fungal infection.

Non-dermatophyte Mould Onychomycosis in Japan

The incidence of non-dermatophyte mould onychomycosis has been increasing worldwide for the past several decades, but it is not well recognized in Japan. Recent molecular techniques and phylogenetic analyses contributed to the identification of uncommon and emerging species. We came across 13 (0.5%) cases of non-dermatophyte onychomycosis among a total of 2,591 onychomycosis cases in 106,703 outpatients during the past 5 years (January 2015-December 2019). The cases included 5 patients with Aspergillus species, 4 patients with Fusarium species, and one patient each with Scopulariopsis brevicaulis and Botryosphaeria dothidea, respectively. Botryosphaeria dothidea is closely related phylogenetically to Neoscytalidium dimidiatum. In Japan, at the time of writing this report, there are 26 reported cases of ungual aspergillosis and 18 cases of hyalohyphomycosis caused by Fusarium species. We summarize these cases and report the symptoms and mycological features.

Unwanted Diagnosis of a Subcutaneous Swelling

Subcutaneous swelling is one of the common cases seen in surgical practice. The pathology of the subcutaneous swellings is varied ranging from epidermal inclusion cyst to malignant swelling. Fungal infections producing subcutaneous swelling are relatively rare. They occur in immunocompromised patients. We report a case of phaeohyphomycosis (PHM) which is characterized by the presence of pseudohyphae, hyphae, brown yeast-like cells, and melanin in their cell walls, presenting as subcutaneous swelling.

A 34-year-old male presented with a swelling over the anterior aspect of left knee joint for three months, which was initially painless. He gave a history of purulent discharge from the swelling 20 days back. He was a known case of myasthenia gravis on regular treatment with steroids. On examination, the swelling was firm, nontender, and mobile in subcutaneous plane. The skin over the swelling showed a healed puckered scar, fine needle aspiration cytology (FNAC) of the swelling showed slender, septate hyphae with variable branching bulbous ends, and few of the hyphae showed pigmentation morphologically suggestive of PHM. The swelling was excised with clear margin.

Subcutaneous mycosis is common in tropical and subtropical countries like India. Strong suspicion of this diagnosis is warranted especially in immunocompromised patients. Surgical excision is the treatment of choice to achieve early cure.

Causative fungi and treatment outcome of dematiaceous fungal keratitis in North India

Purpose

The aim of the study is to identify risk factors, clinical characteristics, causative fungi, and treatment outcome of dematiaceous fungal keratitis in North India.

Methods

Consecutive cases of culture-proven dematiaceous fungal keratitis between January 2012 and June 2017 were retrieved from the medical record department. Risk factors, clinical signs, and outcome were registered.

Results

Eighty-three patients were included. Identified dematiaceous fungal organism were Curvularia sp. (n = 55/83; 66.3%), Alternaria sp. (n = 12/83; 14.5%), Ulocladium sp. (n = 5/83; 6%), Bipolaris sp. (n = 5/83; 6.1%), Scedosporium sp. (n = 3/83; 3.6%), Acremonium sp. (n = 2/83; 2.4%), and Epicoccum sp. (n = 1/83; 1.2%). Male preponderance was reported. The most common predisposing factor was corneal trauma (67.4%). In cases associated with corneal trauma due to vegetative matter, sugarcane was the most common cause. In all, 89% of the patients were more than 30 years of age. The median infiltrate size was 8 mm². The median time of antifungal therapy was 4.2 weeks (interquartile range [IQR]: 1-25 weeks). Complications were seen in 14 (n = 14/65; 21.5%) patients. Complete resolution of dematiaceous fungal keratitis was present in 27 (n = 27/65; 41.5%) eyes.

Conclusion

Curvularia sp. and Alternaria sp. were the predominant pathogenic genera causing dematiaceous fungal keratitis. Among the causative fungi, infections due to Scedosporium sp. were associated with the worst outcomes. Ulocladium sp. and Epicoccum sp. were also identified. Both the species are not reported previously as a causal organism of dematiaceous fungal keratitis from North India.

A Mycoses Study Group International Prospective Study of Phaeohyphomycosis: An Analysis of 99 Proven/Probable Cases

Background

Phaeohyphomycosis is infection caused by dematiaceous, or darkly pigmented, fungi. The spectrum of disease is broad, and optimal therapy remains poorly defined. The Mycoses Study Group established an international case registry of patients with proven/probable phaeohyphomycosis with the goal of improving the recognition and management of these infections.

Methods

Patients from 18 sites in 3 countries were enrolled from 2009-2015. Cases were categorized as local superficial, local deep (pulmonary, sinus, osteoarticular infections), and disseminated infections. End points were clinical response (partial and complete) and all-cause mortality at 30 days and end of follow-up.

Results

Of 99 patients, 32 had local superficial infection, 41 had local deep infection, and 26 had disseminated infection. The most common risk factors were corticosteroids, solid organ transplantation, malignancy, and diabetes. Cultures were positive in 98% of cases. All-cause mortality was 16% at 30 days and 33% at end of follow-up, and 18 of 26 (69%) with dissemination died. Itraconazole was most commonly used for local infections, and voriconazole was used for more severe infections, often in combination with terbinafine or amphotericin B.

Conclusions

Phaeohyphomycosis is an increasingly recognized infection. Culture remains the most frequently used diagnostic method. Triazoles are currently the drugs of choice, often combined with other agents. Further studies are needed to develop optimal therapies for disseminated infections.

The first case of cutaneous phaeohyphomycosis caused by Bipolaris spicifera in Northern China: A case report

Phaeohyphomycosis (PHM) is a term used to describe any fungus presenting in tissues with pseudohyphae, hyphae, brown yeast-like cells or a combination of these forms. Sinusitis and skin infections are the most common presentation of subcutaneous PHM caused by the fungus Bipolaris spicifera. However, the majority of cases have so far been encountered in tropical climatic zones. The present study documents a case of subcutaneous PHM caused by infection with Bipolaris spicifera in a 56-year-old Chinese man, who presented with plaque papillomatosis on the left foot. The organism isolated from the lesion scar and tissue was identified as Bipolaris spicifera by its morphology, histopathology and DNA sequencing. The patient was successfully treated with itraconazole and terbinafine.

Ungual hyalohyphomycosis caused by Fusarium proliferatum in an immunocompetent patient

The patient was a 73-year-old healthy female farmer who had been treated with terbinafine for 25.5 months by a primary physician. She exhibited a discoloration and thickening of the right big toenail. She had no concomitant paronychia. Direct microscopy revealed chlamydoconidia and hyphae, and periodic acid-Schiff stained nail specimen showed septate hyphae. On the basis of these morphological features and gene analysis, the final diagnosis was ungual hyalohyphomycosis caused by Fusarium proliferatum. Topical application of 10% efinaconazole solution cured the disease in 10 months.

Phaeohyphomycosis in Transplant Patients

Phaeohyphomycosis is caused by a large, heterogenous group of darkly pigmented fungi. The presence of melanin in their cell walls is characteristic, and is likely an important virulence factor. These infections are being increasingly seen in a variety of clinical syndromes in both immunocompromised and normal individuals. Transplant patients are especially at risk due their prolonged immunosuppression. There are no specific diagnostic tests for these fungi, though the Fontana-Masson stain is relatively specific in tissue. They are generally seen in a worldwide distribution, though a few species are only found in specific geographic regions. Management of these infections is not standardized due to lack of clinical trials, though recommendations are available based on clinical experience from case reports and series and animal models. Superficial infections may be treated without systemic therapy. Central nervous system infections are unique in that they often affect otherwise normal individuals, and are difficult to treat. Disseminated infections carry a high mortality despite aggressive therapy, usually with multiple antifungal drugs. Considerable work is needed to determine optimal diagnostic and treatment strategies for these infections.

Isavuconazole, a broad-spectrum triazole for the treatment of systemic fungal diseases

The prodrug isavuconazonium sulfate (BAL8557) is an extended-spectrum water-soluble triazole, developed for the treatment of severe invasive and life-threatening fungal diseases. Its active moiety, BAL4815, is a potent inhibitor of ergosterol biosynthesis, resulting in the disruption of fungal membrane structure and function. The active compound shows broad-spectrum of activity and potency against all major opportunistic fungi, such as Aspergillus spp., Candida spp., Cryptococcus spp., Mucorales, Black yeasts and their filamentous relatives and the true pathogenic fungi, including Histoplasma capsulatum and Blastomyces dermatitidis. It is currently in Phase III clinical development for treatment of aspergillosis, candidiasis and mucormycosis, as well as other rare fungi infections. We reviewed the pharmacokinetic and pharmacodynamic characteristics of isavuconazole, and its microbiological and clinical investigation progress in advanced stages of development.

Interaction of an opportunistic fungus Purpureocillium lilacinum with human macrophages and dendritic cells

INTRODUCTION

Purpureocillium lilacinum is emerging as a causal agent of hyalohyphomycosis that is refractory to antifungal drugs; however, the pathogenic mechanisms underlying P. lilacinum infection are not understood. In this study, we investigated the interaction of P. lilacinum conidia with human macrophages and dendritic cells in vitro.

METHODS

Spores of a P. lilacinum clinical isolate were obtained by chill-heat shock. Mononuclear cells were isolated from eight healthy individuals. Monocytes were separated by cold aggregation and differentiated into macrophages by incubation for 7 to 10 days at 37°C or into dendritic cells by the addition of the cytokines human granulocyte-macrophage colony stimulating factor and interleukin-4. Conidial suspension was added to the human cells at 1:1, 2:1, and 5:1 (conidia:cells) ratios for 1h, 6h, and 24h, and the infection was evaluated by Giemsa staining and light microscopy.

RESULTS

After 1h interaction, P. lilacinum conidia were internalized by human cells and after 6h contact, some conidia became inflated. After 24h interaction, the conidia produced germ tubes and hyphae, leading to the disruption of macrophage and dendritic cell membranes. The infection rate analyzed after 6h incubation of P. lilacinum conidia with cells at 2:1 and 1:1 ratios was 76.5% and 25.5%, respectively, for macrophages and 54.3% and 19.5%, respectively, for cultured dendritic cells.

CONCLUSIONS

P. lilacinum conidia are capable of infecting and destroying both macrophages and dendritic cells, clearly demonstrating the ability of this pathogenic fungus to invade human phagocytic cells.

Surgical management of subcutaneous Colletotrichum gloeosporioides

A 52-year-old male patient with a history of sarcoidosis and over 10 years of chronic low-dose glucocorticoid use, cirrhosis and type 2 diabetes mellitus presented with two painful, enlarging subcutaneous nodules ultimately identified as Colletotrichum gloeosporioides. Two attempts at needle aspiration of the larger nodule resulted in rapid reaccumulation. Complete surgical excision of both nodules resulted in complete resolution without the use of any concomitant antifungals. Patient had no recurrence at 2 years of follow-up.

Black yeasts and their filamentous relatives: principles of pathogenesis and host defense

Among the melanized fungi, the so-called "black yeasts" and their filamentous relatives are particularly significant as agents of severe phaeohyphomycosis, chromoblastomycosis, and mycetoma in humans and animals. The pathogenicity and virulence of these fungi may differ significantly between closely related species. The factors which probably are of significance for pathogenicity include the presence of melanin and carotene, formation of thick cell walls and meristematic growth, presence of yeast-like phases, thermo- and perhaps also osmotolerance, adhesion, hydrophobicity, assimilation of aromatic hydrocarbons, and production of siderophores. Host defense has been shown to rely mainly on the ingestion and elimination of fungal cells by cells of the innate immune system, especially neutrophils and macrophages. However, there is increasing evidence supporting a role of T-cell-mediated immune responses, with increased interleukin-10 (IL-10) and low levels of gamma interferon (IFN-γ) being deleterious during the infection. There are no standardized therapies for treatment. It is therefore important to obtain in vitro susceptibilities of individual patients' fungal isolates in order to provide useful information for selection of appropriate treatment protocols. This article discusses the pathogenesis and host defense factors for these fungi and their severity, chronicity, and subsequent impact on treatment and prevention of diseases in human or animal hosts.

Cerebral phaeohyphomycosis: a rare cause of brain abscess

Cerebral phaeohyphomycosis (CP) is a very rare but serious form of central nervous system fungal infection that is caused by dematiaceous fungi. It is commonly associated with poor prognosis irrespective of the immune status of the patient. In this study, the authors describe the first case of CP in Korea that occurred in a 75-year-old man without immunodeficiency and showed favorable outcome after surgical excision and antifungal therapy. In addition, the authors herein review the literature regarding characteristics of this rare clinical entity with previously reported cases.

Fungal rhinosinusitis: what every allergist should know

The interaction between fungi and the sinonasal tract results in a diverse range of diseases with an equally broad spectrum of clinical severity. The classification of these interactions has become complex, and this review seeks to rationalize and simplify the approach to fungal diseases of the nose and paranasal sinuses. These conditions may be discussed under two major headings: non-invasive disease (localized fungal colonization, fungal ball and allergic fungal rhinosinusitis) and invasive disease (acute invasive rhinosinusitis, chronic invasive rhinosinusitis and granulomatous invasive rhinosinusitis). A diagnosis of fungal rhinosinusitis is established by combining findings on history, clinical examination, laboratory testing, imaging and histopathology. The immunocompetence of the patient is of great importance, as invasive fungal rhinosinusitis is uncommon in immunocompetent patients. With the exception of localized fungal colonization, treatment of all forms of fungal rhinosinusitis relies heavily on surgery. Systemic antifungal agents are a fundamental component in the treatment of invasive forms, but are not indicated for the treatment of the non-invasive forms. Antifungal drugs may have a role as adjuvant therapy in allergic fungal rhinosinusitis, but evidence is poor to support recommendations. Randomized controlled trials need to be performed to confirm the benefit of immunotherapy in the treatment of allergic fungal rhinosinusitis. In this article, we will summarize the current literature, addressing the controversies regarding the diagnosis and management of fungal rhinosinusitis, and focussing on those aspects which are important for clinical immunologists and allergists.

Comparative genomic and transcriptomic analysis of wangiella dermatitidis, a major cause of phaeohyphomycosis and a model black yeast human pathogen

Black or dark brown (phaeoid) fungi cause cutaneous, subcutaneous, and systemic infections in humans. Black fungi thrive in stressful conditions such as intense light, high radiation, and very low pH. Wangiella (Exophiala) dermatitidis is arguably the most studied phaeoid fungal pathogen of humans. Here, we report our comparative analysis of the genome of W. dermatitidis and the transcriptional response to low pH stress. This revealed that W. dermatitidis has lost the ability to synthesize alpha-glucan, a cell wall compound many pathogenic fungi use to evade the host immune system. In contrast, W. dermatitidis contains a similar profile of chitin synthase genes as related fungi and strongly induces genes involved in cell wall synthesis in response to pH stress. The large portfolio of transporters may provide W. dermatitidis with an enhanced ability to remove harmful products as well as to survive on diverse nutrient sources. The genome encodes three independent pathways for producing melanin, an ability linked to pathogenesis; these are active during pH stress, potentially to produce a barrier to accumulated oxidative damage that might occur under stress conditions. In addition, a full set of fungal light-sensing genes is present, including as part of a carotenoid biosynthesis gene cluster. Finally, we identify a two-gene cluster involved in nucleotide sugar metabolism conserved with a subset of fungi and characterize a horizontal transfer event of this cluster between fungi and algal viruses. This work reveals how W. dermatitidis has adapted to stress and survives in diverse environments, including during human infections.

Therapy of infections caused by dematiaceous fungi

Dematiaceous fungi are responsible for a wide variety of clinical syndromes, from local infections due to trauma, to disseminated infection in immunocompromised patients. These fungi are unique owing to the presence of melanin in their cell walls, which imparts the characteristic dark color to their spores and hyphae. Melanin may also be a virulence factor in these fungi. Therapy depends upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Azoles such as itraconazole and voriconazole have the most consistent in vitro activity, although newer agents may also play a role in therapy in the future.

Subcutaneous phaeohyphomycosis caused by Exophiala equina, with susceptibility to eight antifungal drugs

A case of subcutaneous phaeohyphomycosis caused by Exophiala equina is reported in a 75-year-old female, who showed subcutaneous abscesses on both forearms for 8 months. A lesion was initiated by inoculation with a spine from a tree. Histopathologically, suppurative granulomatous inflammation was present and short hyphal elements were observed. Upon culture greyish–black, velvety colonies of a black yeast were obtained after 3 weeks. The strain grew well at 25 °C, but poorly at 37 °C. After sequencing the internal transcribed spacer domain and the partial β-tubulin gene, the fungus was identified as E. equina. The patient was successfully treated with fluconazole for 3 months.

An unusual infection, an unusual outcome--Fonsecaea pedrosoi cerebral granuloma

Phaeohyphomycosis is caused by pigmented fungi that are not normally pathogenic. Fonsecaea is a rare cause of cerebral infections, most of which are caused by F. monophora. Brain infections caused by F. pedrosoi are very rare, and there are only a few case reports describing this. Most infections take the form of abscesses (epidural or intracerebral). The authors report a rare case of a contained fungal granuloma caused by F. pedrosoi. The patient presented with epilepsy, which was treated as a case of extratemporal lesion-related epilepsy. The diagnosis was made after resection. The authors describe the clinical course of this patient.

Convergent strategies in biosynthesis

This review article focuses on how nature sometimes solves the same problem in the biosynthesis of small molecules but using very different approaches. Four examples, involving isopentenyl diphosphate, menaquinone, lysine, and aromatic polyketides, are highlighted that represent different strategies in convergent metabolism.

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.

Invasive mould infections of the naso-orbital region of cats: a case involving Aspergillus fumigatus and an aetiological review

CASE AND CONTEXT: This report describes a cat diagnosed with sinonasal-orbital Aspergillus fumigatus infection using advanced imaging, histopathology and culture. Aetiology, clinical aspects and treatment of this rare and devastating infection are discussed with reference to a literature review of invasive mould (ie, filamentous fungal) infections involving tissues of the naso-orbital region of cats.

PRESENTATIONS

Invasive fungal infections can present with different localisations (nasal passages, sinuses, orbits, subcutaneous space, palate, etc) depending on the species involved and its means of introduction into the tissues. Localised subcutaneous lesions (swellings, ulcerations, masses, nodules, etc), without concomitant signs of nasal/orbital disease, generally result from traumatic injuries and subsequent inoculation of fungal spores into the subcutaneous space. In contrast, naso-ocular involvement and concurrent signs of nasal disease (nasal discharge, sneezing, masses protruding from the nostrils) generally result from inhalation of spores, with subsequent spread of infection into the nasal planum or penetration of overlying bone and invasion of the subcutaneous space. Aspergillus species typically show such an invasion mechanism and frequently affect orbital tissues. Dematiaceous fungi (ie, filamentous fungi with brown/black hyphae) are reported to cause solitary, less invasive, slowly developing lesions, probably as a result of traumatic injuries with inoculation of fungal propagules. Accordingly, the subcutaneous space is more frequently primarily involved.

TREATMENT AND OUTCOME

Whatever the mould species, reported treatment options include surgery and a series of antifungal drugs. The outcome is frequently poor, especially for Aspergillus infections, although various measures can be taken to maximise the chances of success, as discussed in this report.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

Roles of the pH signaling transcription factor PacC in Wangiella (Exophiala) dermatitidis

To study the function of the PacC transcription factor in Wangiella dermatitidis, a black, polymorphic fungal pathogen of humans with yeast-phase predominance, the PACC gene was cloned, sequenced, disrupted and expressed. Three zinc finger DNA-binding motifs were found at the N-terminus, and a signaling protease cleavage site at the C-terminus. PACC was more expressed at neutral-alkaline pH than at acidic pH. Truncation at about 40 residues of the coding sequence upstream of the conserved protease processing cleavage site of PacC affected growth on a nutrient-rich medium, increased sensitivity to Na(+) stress, decreased yeast growth at neutral-alkaline pH, and repressed hyphal growth on a nutrient-poor medium at 25 degrees C. Truncation at the coding sequence for the conserved signaling protease box of PacC impaired growth and reduced RNA expression of the class II chitin synthase gene at acidic pH. The results suggested that PacC is important not only for the adaptation of W. dermatitidis to different ambient pH conditions and Na(+) stress conditions, but also for influencing yeast-hyphal transitions in this agent of phaeohyphomycosis.

Disseminated Phaeohyphomycosis in Weedy Seadragons (Phyllopteryx Taeniolatus) and Leafy Seadragons (Phycodurus Eques) Caused by Species of Exophiala, Including a Novel Species

During the period from January 2002 to March 2007, infections by melanized fungi were identified with greater frequency in aquarium-maintained leafy seadragons ( Phycodurus eques)and weedy seadragons ( Phyllopteryx taeniolatus), pivotal species to the educational and environmental concerns of the aquarium industry and conservation groups. The objective of this study was to characterize the pathology and identify fungi associated with phaeohyphomycotic lesions in these species. Samples from 14 weedy and 6 leafy seadragons were received from 2 institutions and included fresh, frozen, and formalin-fixed tissues from necropsy and biopsy specimens. Fresh and frozen tissues were cultured for fungi on Sabouraud dextrose agar only or both Sabouraud dextrose agar and inhibitory mold agar with gentamicin and chloramphenicol at 30°C. Isolates were processed for morphologic identification and molecular sequence analysis of the internal transcribed spacer region and D1/D2 domains of the large subunit ribosomal RNA gene. Lesions were extensive and consisted of parenchymal and vascular necrosis with fungal invasion of gill (11/20), kidney (14/20), and other coelomic viscera with or without cutaneous ulceration (13/20). Exophiala sp. isolates were obtained from 4 weedy and 3 leafy seadragons and were identified to species level in 6 of 7 instances, namely Exophiala angulospora (1) and a novel species of Exophiala (5), based on nucleotide sequence comparisons and phylogenetic analyses. Disseminated phaeohyphomycosis represents an important pathologic condition of both weedy and leafy seadragons for which 2 species of Exophiala,1a novel species, have been isolated.

Molecular cloning and characterization of WdTUP1, a gene that encodes a potential transcriptional repressor important for yeast-hyphal transitions in Wangiella (Exophiala) dermatitidis

The general transcriptional repressor Tup1p is known to influence cell development in many fungi. To determine whether the Tup1p ortholog (WdTup1p) of Wangiella dermatitidis also influences cellular development in this melanized, polymorphic human pathogen, the gene (WdTUP1) that encodes this transcription factor was isolated, sequenced and disrupted. Phylogenetic analysis showed that the WdTup1p sequence was closely related to homologues in other polymorphic, conidiogenous fungi. Disruption of WdTUP1 produced mutants (wdtup1Delta) with pronounced growth and cellular abnormalities, including slow growth on various agar media and exclusively as a filamentous morphotype in liquid media. We concluded that WdTup1p represents an important switch regulator that controls the yeast-to-filamentous growth transition. However, detailed observations of the filamentous growth of the disruption mutant showed that the hyphae produced by the wdtup1Delta mutants, unlike those of the wild-type, were arrested at a stage prior to the formation of true hyphae and subsequent conidia production.

Pheohyphomycotic soft tissue disease caused by Alternaria alternata in a kidney transplant patient: a case report and literature review

A 61-year-old Italian man, who underwent a renal transplantation 8 years ago, receiving azathioprine, prednisone, and cyclosporine for immunosuppressive therapy, presented with a large reddish indurated plaque with a central ulcer, which was slowly enlarged, on the right knee. From the diseased tissue biopsy, a dematiaceous fungus matching Alternaria alternata in all essential characters was isolated in pure culture. This is an uncommon fungal complication in a kidney transplant patient. A detailed morphological description of the isolate is provided as well as review of the literature.

WdStuAp, an APSES transcription factor, is a regulator of yeast-hyphal transitions in Wangiella (Exophiala) dermatitidis

APSES transcription factors are well-known regulators of fungal cellular development and differentiation. To study the function of an APSES protein in the fungus Wangiella dermatitidis, a conidiogenous and polymorphic agent of human phaeohyphomycosis with yeast predominance, the APSES transcription factor gene WdSTUA was cloned, sequenced, disrupted, and overexpressed. Analysis showed that its derived protein was most similar to the APSES proteins of other conidiogenous molds and had its APSES DNA-binding domain located in the amino-terminal half. Deletion of WdSTUA in W. dermatitidis induced convoluted instead of normal smooth colony surface growth on the rich yeast maintenance agar medium yeast extract-peptone-dextrose agar (YPDA) at 37 degrees C. Additionally, deletion of WdSTUA repressed aerial hyphal growth, conidiation, and invasive hyphal growth on the nitrogen-poor, hypha-inducing agar medium potato dextrose agar (PDA) at 25 degrees C. Ectopic overexpression of WdSTUA repressed the convoluted colony surface growth on YPDA at 37 degrees C, and also strongly repressed hyphal growth on PDA at 25 degrees C and 37 degrees C. These new results provide additional insights into the diverse roles played by APSES factors in fungi. They also suggest that the transcription factor encoded by WdSTUA is both a positive and negative morphotype regulator in W. dermatitidis and possibly other of the numerous human pathogenic, conidiogenous fungi capable of yeast growth.

[Subcutaneous phaeomycotic cyst of the ankle]

Phaeohyphomycosis is a rare mycotic opportunist disease witch usually affects immunodepressed patients. Infection follows a traumatic inoculation of fungi into the skin with formation of a subcutaneous cyst. We report the case of a 20-year-old woman presenting with a subcutaneous, painless, and recurrent cystic lesion on the right ankle for 9 years. A surgical excision was performed. Histopathologic examination showed a granuloma with central abscess surrounded by a thick fibrous tissue. After staining with PAS, septate hyphae and spores were found in the granuloma, consistent with a phaeomycotic cyst.

Dematiaceous fungi

Dematiaceous fungi are responsible for a wide variety of infectious syndromes. They are often found in soil and generally distributed worldwide. This suggests that most if not all individuals are exposed to them, presumably from inhalation or trauma. In recent years, these fungi have been increasingly recognised as important pathogens. The spectrum of diseases they are associated with has also broadened and includes superficial and deep local infections, allergic disease, 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 aetiological agents. These fungi may have unique pathogenic mechanisms owing to the presence of melanin in their cell walls, which imparts the characteristic dark colour to their spores and hyphae. Diagnosis rests on careful microscopical and pathological examination, as there are no simple laboratory tests to reliably identify these fungi. Therapy depends upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Azoles such as itraconazole and voriconazole have the most consistent in vitro activity, though there is more clinical experience with itraconazole. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.

Fungal infections

Tropical mycoses vary from the commonplace to the rare and exotic but they are seen regularly even as imported conditions and it is important to consider the diagnosis, where possible, in individuals who have visited remote areas. Patients may present many years after they have left an endemic area with subcutaneous or endemic systemic mycoses. In establishing a diagnosis, it is always important to take an accurate travel history so that the movements of the individual can be correlated with the potential risk for exposure to infection.

Phaeohyphomycosis

Phaeohyphomycosis is an uncommon infection, but has become increasingly recognized in a wide variety of clinical syndromes. Many species are associated with human infection, though a few are responsible for most cases. Because these are typically soil organisms and common laboratory contaminants, they are often disregarded from clinical specimens as non-pathogenic. The clinical setting in which they are isolated, however, should always be carefully considered before making decisions regarding therapy. Bipolaris and Curvularia are often associated ith allergic disease. Diagnosis depends on a high degree of clinical suspicion and appropriate pathologic and mycologic examination of clinical specimens. Therapy is evolving for many of the clinical syndromes described, and randomized clinical trials are unlikely given the sporadic nature of cases. Case reporting of successful and unsuccessful clinical experiences is important in attempting to better define optimal therapy for the more refractory infections. Itraconazole and voriconazole demonstrate the most consistent in vitro activity against this group of fungi. Itraconazole should be considered the drug of choice for most situations, given the greater clinical experience associated with its use for these infections. Given the lack of comparative clinical data, however, decisions over which azole to use in particular setting are largely empiric. Much additional work is needed to better understand the pathogenic mechanisms underlying phaeohyphomycosis and optimize therapy for these often refractory infections.

WdChs1p, a class II chitin synthase, is more responsible than WdChs2p (Class I) for normal yeast reproductive growth in the polymorphic, pathogenic fungus Wangiella (Exophiala) dermatitidis

The chitin synthase gene WdCHS1 was isolated from a partial genomic DNA library of the pathogenic polymorphic fungus Wangiella dermatitidis. Sequencing showed that WdCHS1 encoded a class II chitin synthase composed of 988 amino acids. Disruption of WdCHS1 produced strains that were hyperpigmented in rich media, grew as yeast at wild-type rates at both 25 and 37 degrees C and were as virulent as the wild type in a mouse model. However, detailed morphological and cytological studies of the wdchs1Delta mutants showed that yeast cells often failed to separate, tended to be enriched with chitin in septal regions and, sometimes, were enlarged with multiple nuclei, had broader mother cell-daughter bud regions and had other cell wall defects seen considerably less often than in the wild type or wdchs2 Delta strains. Disruption of WdCHS1 and WdCHS2 in the same background revealed that WdChs1p had functions synergistic to those of WdChs2p, because mutants devoid of both isozymes produced growth that was very abnormal at 25 degrees C and was not viable at 37 degrees C unless osmotically stabilized. These results suggested that WdChs1p was more responsible than WdChs2p for normal yeast cell reproductive growth because strains with defects in the latter exhibited no morphological abnormalities, whereas those with defects in WdChs1p were frequently impaired in one or more yeast developmental processes.

Subcutaneous fungal infections

Subcutaneous mycoses are caused by a variety of mostly tropical organisms, usually when they are implanted into the dermis or the subcutaneous tissue. They rarely disseminate or become systemic. Sporotrichosis, mycetoma, and chromoblastomycosis are more common subcutaneous mycoses than are rhinosporidiosis, zygomycosis, pheohyphomycosis, and lobomycosis.

Wangiella (Exophiala) dermatitidis WdChs5p, a class V chitin synthase, is essential for sustained cell growth at temperature of infection

The chitin synthase structural gene WdCHS5 was isolated from the black fungal pathogen of humans Wangiella dermatitidis. Sequence analysis revealed that the gene has a myosin motor-like-encoding region at its 5' end and a chitin synthase (class V)-encoding region at its 3' end. Northern blotting showed that WdCHS5 is expressed at high levels under conditions of stress. Analysis of the 5' upstream region of WdCHS5 fused to a reporter gene indicated that one or more of the potential regulatory elements present may have contributed to the high expression levels. Disruption of WdCHS5 produced mutants that grow normally at 25 degrees C but have severe growth and cellular abnormalities at 37 degrees C. Osmotic stabilizers, such as sorbitol and sucrose, rescued the wild-type phenotype, which indicated that the loss of WdChs5p causes cell wall integrity defects. Animal survival tests with a mouse model of acute infection showed that all wdchs5Delta mutants are less virulent than the parental strain. Reintroduction of the WdCHS5 gene into the wdchs5Delta mutants abolished the temperature-sensitive phenotype and reestablished their virulence. We conclude that the product of WdCHS5 is required for the sustained growth of W. dermatitidis at 37 degrees C and is of critical importance to its virulence.

Onychomycosis caused by Fusarium solani and Fusarium oxysporum in São Paulo, Brazil

Fusarium species are common soil saprophytes and plant pathogens that have been frequently reported as etiologic agents of opportunistic infections in humans. We report eight cases of onychomycosis caused by Fusarium solani (4) and Fusarium oxysporum (4) in São Paulo, Brazil. These species were isolated from toenails in all cases. The infections were initially considered to be caused by dermatophytes. The clinical appearance of the affected toenails was leukonychia or distal subungual hyperkeratosis with yellowish brown coloration. The eight cases reported here suggest that Fusarium spp. should be taken into consideration in the differential diagnosis of tinea unguium.