Feline cutaneous phaeohyphomycosis due to Cladophyalophora bantiana

Hyphae, pseudohyphae, yeasts, spherules, spores, and more: A review on the morphology and pathology of fungal and oomycete infections in the skin of domestic animals

Fungi are among the most common infectious agents affecting the skin of animals. The skin can serve as a port of entry for fungal infections, which can eventually become disseminated. In some regions of the world, oomycetes, such as Pythium and Lagenidium, are also responsible for a significant number of severe cutaneous infections. Histologic evaluation of fungal morphology, including size, shape, septation, branching, and budding characteristics, combined with the distribution of inflammatory infiltrates within different skin layers can potentially identify etiologic agents, guiding selection of antifungals and additional diagnostics. Fungal infections of the skin surface are typically caused by Malassezia and rarely Candida, with opportunistic fungi also capable of colonizing the skin surface, especially when the barrier is broken. Folliculocentric infections, caused by dermatophytes, result in mild to severe inflammation and can occasionally penetrate deep into the skin. A wide range of fungi, including agents of hyalohyphomycosis, phaeohyphomycosis, and dimorphic fungal infections, as well as oomycetes, result in nodular cutaneous and subcutaneous lesions. With the occasional exception of dimorphic fungi, fungal speciation often requires cultures performed on fresh tissues. However, molecular techniques such as pan-fungal polymerase chain reaction on paraffin blocks is becoming an increasingly useful tool to distinguish between cutaneous fungal pathogens. This review focuses on describing the clinical and histologic features of the most common fungal and oomycete infections affecting the skin of animals, divided according to distribution patterns of lesions and fungal or oomycete morphology.

Eumycetoma Caused by Madurella pseudomycetomatis in a Captive Tiger (Panthera tigris)

A captive-kept adult male tiger presented with a large cutaneous and subcutaneous mass on the thigh with a fistula. During sedation, multiple nodules were detected and samples for a histopathological exam were collected. Histologically, granulomatous panniculitis and dermatitis were seen around dense aggregates of pigmented fungal hyphae, and a diagnosis of phaeohyphomycosis was made; considering the clinical features, it was classified as a eumycotic mycetoma. This is a rarely reported subcutaneous fungal infection in humans and animals, caused by dematiaceous fungi. Clinically, it is characterized by tumefaction, fistulous sinus tracts, and the formation of macroscopically visible grains. In the literature, only a few infections in wild felids have been reported. In this case, Fontana-Masson staining better showed pigmentation and panfungal PCR and sequencing identified Madurella pseudomyectomatis (OP623507) as the causative agent. Systemic therapy with oral administration of itraconazole was planned, but the patient died during the first period of treatment. The animal was not submitted for post-mortem examination. Visceral dissemination of the agent cannot be excluded. To the authors' knowledge, this is the first report of eumycotic mycetoma by Madurella pseudomycetomatis in a captive tiger.

Chalastospora gossypii in a Maine Coon cat: case report and literature review

A 15-y-old castrated male Maine Coon cat was evaluated for an ulcerated soft tissue mass on the right hindlimb that had been observed for 4 mo and had grown rapidly. A 3 × 3 cm soft, raised, amorphous, and ulcerated subcutaneous mass was observed on the lateral right metatarsus. In-house cytology via fine-needle aspiration was nondiagnostic. Incisional biopsy of the mass and further staging was declined, and amputation was elected. The amputated limb was submitted for histopathology, which revealed severe chronic nodular granulomatous dermatitis and multifocal granulomatous popliteal lymphadenitis with large numbers of intralesional fungal hyphae. Fungal PCR and sequencing on formalin-fixed, paraffin-embedded tissue identified Chalastospora gossypii. No adjunctive therapy was elected at the time. The patient has done well clinically 1 y post-operatively. C. gossypii is a rare microfungus found worldwide and is considered a minor pathogen of several plants. To our knowledge, infection by this fungus has not been reported previously in veterinary species. Features in our case are comparable to other mycotic infections. Nodular granulomatous mycotic dermatitis and cellulitis, although uncommon, should be a differential for soft tissue masses in veterinary species; C. gossypii is a novel isolate.

Opportunistic Fungal Infections in Small Animals

Opportunistic fungal infections have long been recognized as rare causes of disease in immunocompetent dogs and cats. Recently, the escalating use of multiagent immunosuppression protocols (especially those that include cyclosporine) has resulted in an increased number of patients with opportunistic fungal infection encountered by small animal practitioners and has altered the typical case phenotype. Based on histologic and cytologic features such as pigmentation, hyphal diameter, and distribution in tissue, these opportunistic mycoses can be placed into categories such as phaeohyphomycosis, hyalohyphomycosis, and eumycotic mycetoma. This review aims to summarize the clinical presentations, methods for diagnosis, treatment recommendations, and prognosis for both immunocompetent and immunosuppressed patients with opportunistic fungal infections. An example case description is included to illustrate the most common current clinical presentation.

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.

Doenças do sistema nervoso central em cães

RESUMO: São descritas doenças do sistema nervoso central (SNC) em cães diagnosticadas no sertão da Paraíba. Os registros de necropsia de 1.205 cães foram revisados. Em 354 casos (29,38%) foram registrados história clínica de alterações do sistema nervoso. Duzentos e noventa e seis casos tiveram diagnóstico definitivo e 58 foram inconclusivos. As doenças infecciosas foram observadas em 59,60% (211/354) de casos que representam a principal causa de distúrbios neurológicos; 53% dos casos (186/354) foram representadas por doenças virais; 3,11% (11/354) foram de etiologia parasitária, 2,54% (9/354) foram causadas por bactérias e 1,41% (5/354) por fungos. Os agentes físicos representaram a segunda causa mais importante de transtornos do SNC com 9,89% (35/354) e os tumores a terceira causa com 5,93% (21/354). Outras alterações pouco frequentes foram alterações metabólicas secundárias a insuficiência hepática ou renal, representando 2,54% (9/354). Casos raros de hidrocefalia congênita foram observados, 1,41% (5/354). Os casos de manifestações neurológicas associadas a alterações vasculares, degenerativas e inflamatórias não infecciosas, muitas das quais uma causa específica não foi estabelecida representaram 4,24% (15/354); Estavam dentro das seguintes categorias de doenças: Infartos isquêmicos e hemorrágicos (6/15), necrose vascular fibrinoide (5/15), doença do disco intervertebral (2/15), meningoencefalite granulomatosa (1/15) e granuloma de colesterol (1/15). Os distúrbios do sistema nervoso central representam uma importante causa de morte ou eutanásia em cães na região semiárida da Paraíba. Os sinais clínicos variaram de acordo com o agente envolvido, localização e distribuição das lesões. O conhecimento dos principais agentes que pode afetar o SNC canino é importante ao fazer uma lista de diagnóstico diferencial.

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.

Cerebral pyogranulomatous encephalitis caused by Cladophialophora bantiana in a 15-week-old domestic shorthair kitten

Case summary

A case of cerebral phaeohyphomycosis caused by Cladophialophora bantiana is described in a 15-week-old domestic shorthair kitten.

Relevance and novel information

Cerebral phaeohyphomycosis is a rare condition in cats caused by dematiaceous fungi. This report describes the clinical and histopathological findings in the youngest case documented in a feline, provides a brief review of aetiology, diagnosis, treatment and prognosis of cerebral phaeohyphomycosis and demonstrates the importance of molecular diagnostics in accurate mycotic species identification.

Fonsecaea pugnacius, a Novel Agent of Disseminated Chromoblastomycosis

We report a fatal case of a chromoblastomycosis-like infection caused by a novel species of Fonsecaea in a 52-year-old immunocompetent Caucasian male from an area of chromoblastomycosis endemicity in Brazil. The patient had a 30-year history of slowly evolving, verrucous lesions on the right upper arm which gradually affected the entire arm, the left hemifacial area, and the nose. Subsequent dissemination to the brain was observed, which led to death of the patient. The internal transcribed spacer (ITS) and partial large subunit (LSU), BT2, and CDC42 genes of the isolates recovered from skin and brain were sequenced, confirming the novelty of the species. The species is clinically unique in causing brain abscesses secondary to chromoblastomycosis lesions despite the apparent intact immunity of the patient. Histopathologic appearances were very different, showing muriform cells in skin and hyphae in brain.

Cladophialophora bantiana as an Emerging Pathogen in Animals: Case Report of Equine Endometritis and Review of the Literature

We present an unusual equine endometritis case associated with Cladophialophora bantiana in a 15-year-old mare. The mare displayed infertility and uterine fluid accumulation with numerous black, hairy granules. Microscopically, the fluid revealed numerous septate, dark fungal hyphae and conidia in chains. Culture yielded C. bantiana (CBS 138271); the species was confirmed by internal transcribed spacer (ITS) sequencing. Treatment was unsuccessful. C. bantiana causes cerebral phaeohyphomycosis in humans, while animal cases are rare. Animal cases are reviewed.

Rare opportunistic mycoses in cats: phaeohyphomycosis and hyalohyphomycosis: ABCD guidelines on prevention and management

OVERVIEW

Phaeohyphomycoses and hyalohyphomycoses are rare opportunistic infections acquired from the environment. More cases have been reported in recent years in humans and cats.

DISEASE SIGNS

Single or multiple nodules or ulcerated plaques (which may be pigmented) in the skin are the typical lesions. In some cases the infection disseminates or involves the central nervous system (CNS).

DIAGNOSIS

Diagnosis is based on fungal detection by cytology and/or histology. Culture provides definitive diagnosis and species identification.

TREATMENT

Treatment involves surgical excision in cases of localised skin disease followed by systemic antifungal therapy, with itraconazole as the agent of first choice. Relapses after treatment are common. Itraconazole and other systemic antifungal agents have been used to treat systemic or neurological cases, but the response is unpredictable. The prognosis is guarded to poor in cats with multiple lesions and systemic or neurological involvement. ZOONOTIC RISK: There is no zoonotic risk associated with contact with infected cats.

Phaeohyphomycoses, emerging opportunistic diseases in animals

Emerging fungal diseases due to black yeasts and relatives in domestic or wild animals and in invertebrates or cold- and warm-blooded vertebrates are continually being reported, either as novel pathogens or as familiar pathogens affecting new species of hosts. Different epidemiological situations can be distinguished, i.e., occurrence as single infections or as zoonoses, and infection may occur sporadically in otherwise healthy hosts. Such infections are found mostly in mammals but also in cold-blooded animals, are frequently subcutaneous or cerebral, and bear much similarity to human primary disorders. Infections of the nervous system are mostly fatal, and the source and route of infection are currently unknown. A third epidemiological situation corresponds to pseudoepidemics, i.e., infection of a large host population due to a common source. It is often observed and generally hypothesized that the susceptible animals are under stress, e.g., due to poor housing conditions of mammals or to a change of basins in the case of fishes. The descriptions in this article represent an overview of the more commonly reported and recurring black fungi and the corresponding diseases in different types of animals.

Focal pulmonary granuloma caused by Cladophialophora bantiana in a domestic short haired cat

Following a 4-week history of coughing, a 12-year-old cat with a history of insulin-dependent diabetes mellitus was diagnosed with a pulmonary granuloma caused by Cladophialophora bantiana. Thoracic radiographs revealed consolidation of the right caudal lung lobe and cytology confirmed the presence of mycotic pneumonia. Results of clinical investigations showed no evidence of extra-pulmonary infection. A thoracotomy and lung lobe resection was performed. Histological examination of the mass revealed black pigmented fungal hyphae and pyogranulomatous inflammation. Cultures inoculated with portions of these tissues yielded a dark walled fungus consistent with an etiologic agent of phaeohyphomycosis and DNA sequencing confirmed the presence of Cladophialophora bantiana. The cat was treated with itraconazole for 4 weeks post-operatively and then with posaconazole for 7 months but was euthanized 13 months after initial diagnosis due to a hepatocellular carcinoma. On post-mortem examination there was no evidence of recurrent fungal infection. This is the first report of localized pulmonary C. bantiana infection in a cat.

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.

Nodular granulomatous fungal skin diseases of cats in the United Kingdom: a retrospective review

IDEXX Laboratories database of cases submitted from the UK between March 2005 and February 2008 (36 months) was investigated for feline nodular granulomatous skin disease associated with fungal infection. Cytological and/or histological slides were reviewed and the diagnosis was based on the microscopic pattern of the inflammatory response and morphology of the causative organism. Aetiological diagnoses were hyalohyphomycosis (64 of 77 cases), phaeohyphomycosis (five of 77 cases) and dermatophytic pseudomycetoma (eight of 77 cases). All cases of hyalohyphomycosis were suspected to be alternariosis based on common features including anatomical distribution of lesions (48 of 64 cases involved the nostril and bridge of nose, face and ears), pattern of histological changes, morphology of the causative organism and results of fungal culture (Alternaria three of 16 and 'saprophyte' nine of 16 cases). Cases of phaeohyphomycosis were demographically and histologically similar to those of alternariosis, except the causative organisms were deeply pigmented brown and had a variety of morphologies that were different from Alternaria. Dermatophytic pseudomycetomas had a characteristic histological pattern including the presence of fungal microcolonies or grains within the tissue. These occurred most often on the trunk (five of eight cases) and four of eight cases were in Persian cats. These findings indicate that alternariosis is by far the most common nodular fungal skin disease of cats in the UK.

Successful treatment of disseminated cutaneous phaeohyphomycosis in a dog

A 7-year-old castrated male Whippet developed deep ulcerative skin lesions whilst receiving immunosuppressive doses of prednisolone and cyclosporine for the treatment of immune-mediated haemolytic anaemia. The lesions were determined to be a phaeohyphomycosis, caused by Curvularia lunata. The dog was treated with a combination of systemic antifungals and weaning off immunosuppressants and made a complete recovery. To the authors' knowledge, this is the first case report of the successful treatment of disseminated cutaneous phaeohyphomycosis in a dog.

Phaeohyphomycosis in a snow leopard (Uncia uncia) due to Cladophialophora bantiana

Phaeohyphomycosis caused by Cladophialophora bantiana was diagnosed in a 5-month-old snow leopard with spastic paralysis of the hind legs and inability to defaecate or urinate. At post-mortem examination, a greenish soft mass resembling an abscess was found on one side of the epidural space at the fourth lumbar vertebral body. Histological examination revealed a purulent meningitis with myelomalacia. Dematiaceous fungal hyphae, present within the inflammatory infiltrate, were identified as C. bantiana by culture and sequence analysis of the 18S ribosomal RNA gene. This neurotropic fungus rarely affects organs other than the brain in human beings and cats, and has been reported only occasionally in Europe. The case described suggests that phaeohyphomycosis due to C. bantiana infection may be recognized more frequently in the future and the possible involvement of organs other than the brain should be borne in mind.

Concomitat late soft tissue infections byCladophialophora bantianaandMycobacterium abscessusfollowing tsunami injuries

A Swedish man and woman sustained severe soft tissue injuries during the tsunami catastrophe in Thailand in December 2004, and subsequently received partial thickness skin grafts after multiple surgical revisions. Four to six weeks post trauma they displayed signs of purulent infections in the non-traumatized, virtually intact skin outside the resection margins. Skin biopsies revealed granulomatous reactions and pigmented fungal hyphae were observed in specimens from the male patient. Cladophialophora bantiana and Mycobacterium abscessus were recovered concomitantly from samples obtained from both patients. Antifungal treatment was given with voriconazole for one month, after which no fungal growth was detected on biopsies. Antimycobacterial treatment was given with clarithromycin and amikacin. The symptoms gradually subsided in the male patient, but recurrent abscesses were noted with the female patient, from which M. abscessus was recovered despite prolonged antibiotic therapy.

Feline cutaneous toxoplasmosis: a case report

A 9-year-old female, domestic short hair cat was presented with sudden onset of polyuria/polydipsia, and hundreds of cutaneous nodules. Prior to referral, the cat had had four skin nodules that were treated with steroids. The four skin nodules then multiplied to form more than 100 ulcerated and nonulcerated nodules located all over the trunk. Clinical evaluation revealed hypothermia and respiratory distress. Cytology from both skin nodules and bronchoalveolar lavage showed macrophages and small organisms whose shape and size were indicative of Toxoplasma spp., or similar organisms. Feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) serology results were negative. The cat was seropositive for Toxoplasma (IgG 1 : 640) and Neospora (1 : 80) infections. The cat died soon after referral. Necropsy revealed pyothorax, necrotic/purulent pneumonia, haemorrhagic spots on kidneys and mesentery. Histopathology from skin nodules showed diffuse, deep necrotic dermatitis/panniculitis, vasculitis and disseminated free and grouped protozoa. The parasites were found in lungs, spleen, kidneys and liver. Immunohistochemistry on skin tissue with anti-Toxoplasma gondii and Neospora caninum antibodies gave positive results with both. Electron microscopy showed single and grouped tachyzoites with morphological features of T. gondii, often within macrophages. Samples of cutaneous nodules and bronchoalveolar fluid were examined by a polymerase chain reaction (PCR) assay for detecting apicomplexa coccidia. PCR results were consistent only with T. gondii infection. Therefore, immunohistochemistry positivity for N. caninum was considered a cross-reaction and a diagnosis of cutaneous and visceral toxoplasmosis was made.

Eumycetoma caused by Cladophialophora bantiana in a dog

We report a case of eumycetoma due to Cladophialophora bantiana in a 3-year-old male Siberian Husky living in France. The dog presented a tumefaction on the thorax and deformity of the second and third subjacent ribs, which were surgically removed. Macroscopic black granules were visible on the ribs, and direct microscopic examination revealed their fungal origin. Cultures yielded pure colonies of C. bantiana. The identification of the causative agent was confirmed after amplification and sequence analysis of fungal internal transcribed spacers 1 and 2 and 5.8S ribosomal DNA regions. Surgery and antifungal treatment with oral itraconazole associated with flucytosine allowed apparent cure after a 10-month follow-up. Envenomation with pine processionary caterpillars (Thaumetopoea pityocampa) and subsequently intensive corticotherapy were considered as possible predisposing factors. This is, to the best of our knowledge, the first case in which C. bantiana is identified as the causative agent of eumycetoma.