Alternaria infections: laboratory diagnosis and relevant clinical features

Clinical characteristics of alternaria keratitis

Purpose. Alternaria spp. are an uncommon cause of mycotic keratitis. Previous studies on Alternaria keratitis have generally been limited to case reports. We examined the clinical characteristics of Alternaria keratitis in this study. Methods. The characteristics and outcomes of 7 patients with culture-proven Alternaria keratitis treated in our hospital were compared with 25 previously reported cases. Results. The risk factors for Alternaria keratitis were trauma in 5 patients and soft contact lenses in 1 patient. Six patients with early diagnosis (<2 weeks) were cured with medical antimicrobial treatment; a patch graft was required in 1 patient with perforation. When incorporated with previous reports on Alternaria keratitis (n = 32), 14 (44%) infections followed trauma, 10 (31%) were associated with preexisting corneal disease or previous ocular surgery, and 5 (16%) occurred in soft contact lens wearers. Successful medical treatment was achieved in 23 (72%) patients, including 10 out of 21 eyes (48%) treated with natamycin and/or amphotericin B. Therapeutic penetrating keratoplasty was performed in 9 (28%) cases. Conclusions. Alternaria keratitis is generally associated with specific risk factors and responds to medical treatment when early diagnosis is performed and prompt antifungal treatment is initiated.

Cutaneous infection with Alternaria triticina in a Bilateral lung transplant recipient

We report the case of a 60-year-old man who was receiving immunosuppressive therapy for a bilateral lung transplant and presented with a crusted, violaceous plaque on the left hand. Based on histopathology and microbiological culture the patient was diagnosed with infection by Alternaria species. Treatment with itraconazole led to complete resolution of the skin lesion. Forty months later he developed four reddish, nodular, skin lesions on the left leg. Analysis of a biopsy from one of these lesions using histopathologic and molecular techniques identified a mold that shared 98% homology with a strain of Alternaria triticina. Alternaria species belong to a group of dematiaceous fungi that cause opportunistic infections in humans. The incidence of these infections is increasing, mainly in transplant centers. To the best of our knowledge, this is the first reported case of a human infection caused by A. triticina.

Cutaneous Alternariosis Caused by Alternaria infectoria: Three Cases in Kidney Transplant Patients

The genus Alternaria has more than 80 species. Alternaria alternata and Alternaria infectoria are the most frequent species associated with infections in humans. Their clinical importance lies in the growing number of cases reported in immunocompromised patients. Herein, we report three cases of kidney-transplanted patients with different clinical presentations of cutaneous alternariosis and we discuss the treatment options.

Immunodetection of fungal and oomycete pathogens: established and emerging threats to human health, animal welfare and global food security

Filamentous fungi (moulds), yeast-like fungi, and oomycetes cause life-threatening infections of humans and animals and are a major constraint to global food security, constituting a significant economic burden to both agriculture and medicine. As well as causing localized or systemic infections, certain species are potent producers of allergens and toxins that exacerbate respiratory diseases or cause cancer and organ damage. We review the pathogenic and toxigenic organisms that are etiologic agents of both animal and plant diseases or that have recently emerged as serious pathogens of immunocompromised individuals. The use of hybridoma and phage display technologies and their success in generating monoclonal antibodies for the detection and control of fungal and oomycete pathogens are explored. Monoclonal antibodies hold enormous potential for the development of rapid and specific tests for the diagnosis of human mycoses, however, unlike plant pathology, their use in medical mycology remains to be fully exploited.

Alternaria scalp infection in a patient with alopecia areata. Coexistence or causative relationship?

BACKGROUND

Alopecia areata is an autoimmune disease that is affecting anagen hair follicles. The triggers of autoimmunity in patients with alopecia areata remain unknown.

MAIN OBSERVATION

A 13-year-old boy developed multiple hairless patches of focal hair loss with typical clinical and trichoscopy features of alopecia areata. Mycology examination of the scalp hair and epidermal scrapings reveled massive growth of Alternaria chlamydospora.

CONCLUSION

We hypothesize that fungal antigens (e.g. antigens involved in fungal melanin synthesis) may be possible triggers, contributing to autoimmune reactions in patients with alopecia areata. We discuss research data, which may indirectly support this hypothesis, however the concept has yet to be verified.

First case of disseminated phaeohyphomycosis in an immunocompetent individual due to Alternaria malorum

A 27-year-old Iranian, previously healthy male presented with sub-cutaneous necrotic lesions with a localized dermatosis affecting the anterior chest, neck and face. These lesions consisted of singular, well-defined verrucous plaques which gradually developed and disseminated over time. The dermatosis was followed by the development of necrotic swollen lesions localized on the hard palate. The patient did not recall any history of trauma or puncture at any of the sites of infection. While histopathological examination of periodic acid-Schiff (PAS) stained material revealed irregular, unbranched, septate hyphae, direct examination (KOH 10%) of lesion samples demonstrated the presence of septate indistinct brownish hyphae. Alternaria malorum was isolated (CBS 126589) and its identity was confirmed by sequencing of the internal transcribed spacer (ITS rDNA). Since the palate lesion reoccurred after 10 years and the patient's condition did not improve with amphotericin B combination therapy, the lesion was surgical excised and he underwent antifungal therapy with amphotericin B and itraconazole. There was no dehiscence or fistula formation or any evidence of relapse of fungal infection during a one year follow-up and the patient was successfully cured. In vitro antifungal susceptibility tests revealed that the MIC values for those antifungals employed in this case were amphotericin B (0.125 μg/ml), fluconazole (32 μg/ml), itraconazole (0.125 μg/ml), voriconazole (1 μg/ml), and posaconazole (0.063 μg/ml). The MECs for caspofungin and anidulafungin were 0.25 μg/ml and 0.016 μg/ml, respectively. However, treatment of A. malorum infections with the latter agents remains to be evaluated.

Subcutaneous phaeohyphomycosis due to Alternaria infectoria in a renal transplant patient: surgical treatment with no long-term relapse

BACKGROUND

Phaeohyphomycosis can be caused by a number of different species, being the most common Alternaria alternata and Alternaria infectoria. The biggest risk factor for the development of the infection is immunosuppression.

AIMS

We present the case of a 64-year-old male renal transplant patient who came to hospital for presenting a tumour in the Achilles region which had been gradually growing in size.

METHODS

A skin biopsy was taken for histological study and culture of fungi and mycobacteria. Blood tests and imaging studies were performed.

RESULTS

Histopathology study and cultures identified A. infectoria as the causal agent. Imaging studies ruled out internal foci of infection. The lesion was surgically removed with no signs of recurrence after 24 months of follow-up.

CONCLUSIONS

There are no treatment guidelines at present for cutaneous and subcutaneous Alternaria spp. infections. Various systemic antifungals have been used, either in combination with surgical removal or alone, with varying results. Surgery alone could be useful in the treatment of solitary, localised lesions in transplant patients in whom there are difficulties in controlling immunosuppression.

Phaeohyphomycosis due to Alternaria infectoria: a single-center experience with utility of PCR for diagnosis and species identification

The term phaeohyphomycosis refers to a rare group of fungal infections characterized by the presence of dark-walled hyphae or yeast-like cells in affected tissues. Herein, we report on the clinical and epidemiological characteristics of six cases of phaeohyphomycosis due to Alternaria spp. that occurred in our hospital over a 30-month period (from January 2008 to June 2010). Interestingly, whereas histopathological examinations were positive and fungal cultures yielded molds in all cases, mycological identification using conventional phenotypic methods was never possible despite prolonged incubation of the isolates. Identification of Alternaria infectoria species complex was obtained for each isolate by amplification and sequencing of the internal transcribed spacer of the ribosomal DNA (ITS rDNA). All patients had favourable outcomes following the introduction of azole-based antifungal therapy. This case series describes the clinical course of these six patients and highlights the utility of molecular identification to help in the identification of the etiologic agent when classical mycological methods have failed.

Antifungal susceptibility profile of clinical Alternaria spp. identified by molecular methods

OBJECTIVES

To analyse the susceptibility pattern of a collection of Alternaria spp. clinical isolates.

METHODS

The antifungal susceptibilities of 35 isolates identified by means of sequencing the internal transcribed spacer region of rDNA were analysed by European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology.

RESULTS AND CONCLUSIONS

No clear differences among the activity of antifungals against Alternaria alternata and Alternaria infectoria were detected, except for echinocandins.

Cutaneous alternariosis microscopically mimicking blastomycosis

A 57-year-old man status post several myocardial infarcts and heart transplantation presented with a slowly growing violaceous plaque on his lateral left knee at the site of prior minor trauma. A biopsy revealed a suppurative dermatitis with associated pseudocarcinomatous epithelial hyperplasia. There were multiple non-pigmented eosinophilic organisms with clear cytoplasmic halos within the infiltrate. A methenamine silver stain showed round to ovoid organisms of slightly variable size. Rare uni-polar budding, some of which was broad based, was apparent. A few short hyphae with indeterminate septa were also noted. Fontana-Masson, mucicarmine, Alcian blue and Fite stains were all negative. These findings suggested a diagnosis of blastomycosis. However, a fungal culture grew colonies of Alternaria species. Alternariosis has been previously shown to possess morphologic characteristics that can simulate other fungal infections. To our knowledge, a striking similarity to blastomycosis, as seen in our case, has not been previously reported. Dermatopathologists should be aware that alternariosis may mimic blastomycosis, especially when hyphal forms are rare or absent in tissue specimens. Culture is necessary for definitive classification.

Cutaneous fungal granulomas due to Alternaria spp. infection in a horse in New Zealand

Equine cutaneous fungal granulomas have been previously referred to in New Zealand (Fairley 1998), and are described in the veterinary literature from around the world, including North America and Australia (Pascoe and Summers 1981; Genovese et al. 2001; Valentine et al. 2006), but no peer-reviewed reports appear published in the literature in New Zealand. Described here is a case of multiple cutaneous fungal granulomas caused by Alternaria spp. in a horse in New Zealand.

Primary subcutaneous Alternaria alternata infection of the hand in an immunocompromised host

We describe a case of a progressive subcutaneous Alternaria alternata infection in the hand of a patient with chronic lymphocytic leukemia (CLL). The diagnosis was based upon the examination of tissue biopsy and isolation of the etiologic agent in culture. The identity of the isolate was determined by phenotypic characteristics and by sequencing the ITS and D1/D2 regions of the rDNA. Despite combination therapy with voriconazole and micafungin, the lesion continued to progress. Posaconazole therapy, along with surgical excision of the infected tissue, resulted in the eradication of infection. The limitations of the clinical management of invasive Alternaria infections are discussed.

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.

Molecular identification of phaeohyphomycosis due to Alternaria infectoria in a patient with acute myeloid leukemia--a case report

We report the case of a 15-year old with acute myeloid leukemia who developed breakthrough invasive fungal rhinitis. The fungus was identified as Alternaria infectoria by polymerase chain reaction (PCR) and successfully treated by surgical excision and combination antifungal therapy, emphasizing the utility of fungal PCR in timely diagnosis of invasive fungal infections.