Phaeoacremonium krajdenii, a cause of white grain eumycetoma

An updated list of eumycetoma causative agents and their differences in grain formation and treatment response

SUMMARYIn 2023, the World Health Organization designated eumycetoma causative agents as high-priority pathogens on its list of fungal priority pathogens. Despite this recognition, a comprehensive understanding of these causative agents is lacking, and potential variations in clinical manifestations or therapeutic responses remain unclear. In this review, 12,379 eumycetoma cases were reviewed. In total, 69 different fungal species were identified as causative agents. However, some were only identified once, and there was no supporting evidence that they were indeed present in the grain. Madurella mycetomatis was by far the most commonly reported fungal causative agent. In most studies, identification of the fungus at the species level was based on culture or histology, which was prone to misidentifications. The newly used molecular identification tools identified new causative agents. Clinically, no differences were reported in the appearance of the lesion, but variations in mycetoma grain formation and antifungal susceptibility were observed. Although attempts were made to explore the differences in clinical outcomes based on antifungal susceptibility, the lack of large clinical trials and the inclusion of surgery as standard treatment posed challenges in drawing definitive conclusions. Limited case series suggested that eumycetoma cases caused by Fusarium species were less responsive to treatment than those caused by Madurella mycetomatis. However, further research is imperative for a comprehensive understanding.

Mycetoma caused by Microascus gracilis: a novel agent of human eumycetoma in Sudan

Species of the genus Microascus are uncommon agents of human diseases despite their ubiquitous presence in the environment. In this communication, the first case of white grain eumycetoma caused by the fungus Microascus gracilis is reported. The patient was initially misdiagnosed as having actinomycetoma based on the grains morphological and cytological features and was treated with antimicrobial therapy with no clinical improvement. She underwent wide local surgical excision to improve the response to medical treatment and further grain cultural, molecular and taxonomy techniques were conducted and the diagnosis of mycetoma due to M. gracilis was established. The antifungal susceptibilities of this isolate to nine drugs were tested in vitro and they showed poor activity. Combination therapy with surgery and itraconazole led to complete recovery. A medical literature search revealed no previous report on M. gracilis as a causative agent of eumycetoma and hence we are reporting this new causative agent of human eumycetoma. Also, the difficulty in the management of this patient emphasizes the need for accurate and appropriate diagnostic tests for the identification of mycetoma-causative organisms and thus proper management.

A rare case of phaeohyphomycosis due to Phaeoacremonium krajdenii from Odisha

A 45-year-old healthy woodcutter presented with a cystic swelling on the sole of the left great toe. Other than barefoot walking, there was no history of trauma or significant illness in the past. Fine needle aspirate showed yeast and hyphae on microscopy and culture grew black mould which was identified as Phaeoacremonium krajdenii species and genus confirmed by internal transcribed spacer sequencing. Aspiration of the lesion resulted in cure. Phaeoacremonium is a genus of fungi which are rare human pathogens, and herein we report a rare case of phaeohyphomycosis due to Phaeoacremonium krajdenii from the state of Odisha, India.

Treatment of Madura foot: a systematic review

REVIEW QUESTION/OBJECTIVE

The objective of this review was to determine the best available evidence on the most effective treatment of Madura foot.

INTRODUCTION

Madura foot or mycetoma is a chronic granulomatous soft-tissue infection that is endemic to several regions of Africa and Asia. It may be of fungal (eumycetoma) or bacterial (actinomycetoma) origin, warranting therapy with either antifungal or antibacterial medication as well as surgery. Without timely intervention, it often results in lifelong disability. However, it is unclear what regimes are most effective for treatment.

INCLUSION CRITERIA

This review considered studies that included individuals of all ages with Madura foot (actinomycetoma or eumycetoma) as confirmed by microbiological or histological studies. Studies that evaluated antibiotic and antifungal regimens (any drug, dosage, frequency, duration) as well as surgical interventions (wound debridement, advanced excision or limb amputation) for Madura foot were included. Outcomes of interest were disease resolution (as determined by complete healing of mycetoma lesion after treatment), recurrence (return of mycetoma lesion after successful treatment) and mortality. Although this review considered both experimental and epidemiological study designs for inclusion, only case series and individual case reports were identified and were therefore included in the review.

METHODS

A three-step search strategy, involving an initial search, a second more comprehensive search using identified keywords and a third search involving the reference lists of included articles, was utilized. Ten databases were searched. An additional 13 sources were searched for gray and/or unpublished literature. Included studies were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute. Disagreements were resolved through discussion or with a third reviewer. A data extraction tool was used to extract data on interventions, populations, study designs and outcomes of significance to the review question. Statistical pooling was not possible, therefore a narrative synthesis was performed.

RESULTS

Thirty-one studies were included in the review (27 case reports and four case series). A total of 47 patients with Madura foot were analyzed. Twenty-five had eumycetoma, 21 actinomycetoma and one had both. Therapy involved varying dosages of sulfa drugs (co-trimoxazole and dapsone), amikacin and tetracyclines administered for the therapy of actinomycetoma with resolution of disease in all affected patients. The azole derivatives (itraconazole, ketoconazole, voriconazole, fluconazole and miconazole) as well as co-trimoxazole were the most commonly employed drugs for eumycetoma, with resolution of disease in 88% of included patients. Surgery was performed in a total of 21 patients with resolution of disease in all cases. The overall resolution rate following therapy was 95.7%.

CONCLUSION

Therapy for Madura foot is informed by case series and case reports which provide low level evidence for practice. Antimicrobials in conjunction with surgery lead to resolution of disease.

Chaetomium atrobrunneum causing human eumycetoma: The first report

In this communication, a case of black grain eumycetoma produced by the fungus C. atrobrunneum is reported. The patient was initially misdiagnosed with M. mycetomatis eumycetoma based on the grains’ morphological and cytological features. However, further aerobic culture of the black grains generated a melanised fungus identified as C. atrobrunneum by conventional morphological methods and by internal transcribed spacer 2 (ITS2) ribosomal RNA gene sequencing. This is the first-ever report of C. atrobrunneum as a eumycetoma-causative organism of black grain eumycetoma. It is essential that the causative organism is identified to the species level, as this is important for proper patient management and to predict treatment outcome and prognosis.

Beta-tubulin and Actin gene phylogeny supports Phaeoacremoniumovale as a new species from freshwater habitats in China

A new species of Phaeoacremonium, P.ovale (Togniniaceae), was isolated during a diversity study of freshwater fungi from Yunnan Province in China. Morphological and cultural studies of the fungus were carried out and its sexual and asexual morphs (holomorph) are introduced herein. This species is characterised by peculiar long-necked, semi-immersed ascomata with oval to ellipsoid ascospores and ellipsoid to ovoid conidia. Phylogenetic analyses of a combined TUB and ACT gene dataset revealed that strains of P.ovale constitute a strongly supported independent lineage and are related to P.griseo-olivaceum and P.africanum. The number of nucleotide differences, across the genes analysed, also supports establishment of P.ovale as a new species.

In Vitro Susceptibility Profiles of Eight Antifungal Drugs against Clinical and Environmental Strains of Phaeoacremonium

In vitro susceptibilities of a worldwide collection of molecularly identified Phaeoacremonium strains (n = 43) belonging to seven species and originating from human and environmental sources were determined for eight antifungal drugs. Voriconazole had the lowest geometric mean MIC (0.35 μg/ml), followed by posaconazole (0.37 μg/ml), amphotericin B (0.4 μg/ml), and isavuconazole (1.16 μg/ml). Caspofungin, anidulafungin, fluconazole, and itraconazole had no activity.

Phaeoacremonium: from esca disease to phaeohyphomycosis

Phaeoacremonium spp. are commonly isolated from stems and branches of diseased woody hosts, and humans with phaeohyphomycosis. The genus Phaeoacremonium (Togniniaceae, Togniniales) has recently been monographed, and presently contains 46 species, while its sexual morph, Togninia, contains 26 epithets, of which 13 are insufficiently known. In this review we summarise information pertaining to the global distribution, pathology, ecology, and detection of these species, and present a case for retaining the genus Phaeoacremonium over that of Togninia. Furthermore, to obtain a single nomenclature, the following new combinations are also proposed: Phaeoacremonium africanum, P. aquaticum, P. fraxinopennsylvanicum, P. griseo-olivaceum, P. inconspicuum, P. leptorrhynchum, P. minimum, and P. vibratile.

Dual Invasive Infection with Phaeoacremonium parasiticum and Paraconiothyrium cyclothyrioides in a Renal Transplant Recipient: Case Report and Comprehensive Review of the Literature of Phaeoacremonium Phaeohyphomycosis

Despite increasing reports of human infection, data about the optimal care of Phaeoacremonium infections are missing. We report a case of an infection due to Phaeoacremonium parasiticum and Paraconiothyrium cyclothyrioides, initially localized to skin and soft tissue, in a kidney transplant patient. Despite surgical drainage and excision of the lesion and combination antifungal therapy with voriconazole and liposomal amphotericin B, a disseminated infection involving the lungs and brain developed and led to death. We performed a systematic literature review to assess the general features and outcome of human infections due to Phaeoacremonium species. Thirty-six articles were selected, and 42 patients, including ours, were reviewed. Thirty-one patients (74%) were immunocompromised because of organ or bone marrow transplantation (n = 17), diabetes or glucose intolerance (n = 10), rheumatoid arthritis or Still's disease (n = 4), chronic hematological diseases (n = 3), or chronic granulomatous disease (n = 3). Ten patients (24%) reported initial cutaneous trauma. Skin and soft tissue infections represented 57% of infections (n = 24), and disseminated infections, all occurring in immunocompromised patients, represented 14% of infections (n = 6). The main antifungal drugs used were azoles (n = 41) and amphotericin B (n = 16). Surgical excision or drainage was performed in 64% of cases (n = 27). The cure rate was 67% (n = 28). There were 10% cases of treatment failure or partial response (n = 4), 19% relapses (n = 8), and 7% losses to follow-up (n = 3). The death rate was 19% (n = 8). Management of Phaeoacremonium infections is complex because of slow laboratory identification and limited clinical data, and treatment relies on a combination of surgery and systemic antifungal therapy.

Pulmonary phaeohyphomycosis caused by phaeoacremonium in a kidney transplant recipient: successful treatment with posaconazole

We report a rare case of pulmonary phaeohyphomycosis in a 49-year-old woman 6 years after kidney transplantation. She presented with dyspnea, cough, and fatigue. Her chest CT scan revealed nodular opacities in the right upper lung. A fine needle aspirate biopsy culture yielded Phaeoacremonium and surgical pathology of the biopsy showed chronic inflammation. We successfully treated her with posaconazole and managed drug interactions between posaconazole and tacrolimus. This is the second reported case of biopsy-proven pulmonary infection by Phaeoacremonium in a kidney transplant recipient and successfully treated with posaconazole.

Cervical spondylitis due to Phaeoacremonium venezuelense in an immunocompetent patient. A first case report

In this paper, we present a case of cervical spondylitis due to Phaeoacremonium venezuelense, in a fifty-two-year-old male who complained about neck pain and tingles in his right arm. Fungal cervical spondylitis is extremely rare in immunocompetent patients. This case is the first case of spondylitis due to P. venezuelense.

Novel Phaeoacremonium species associated with necrotic wood of Prunus trees

The genus Phaeoacremonium is associated with opportunistic human infections, as well as stunted growth and die-back of various woody hosts, especially grapevines. In this study, Phaeoacremonium species were isolated from necrotic woody tissue of Prunus spp. (plum, peach, nectarine and apricot) from different stone fruit growing areas in South Africa. Morphological and cultural characteristics as well as DNA sequence data (5.8S rDNA, ITS1, ITS2, beta-tubulin, actin and 18S rDNA) were used to identify known, and describe novel species. From the total number of wood samples collected (257), 42 Phaeoacremonium isolates were obtained, from which 14 species were identified. Phaeoacremonium scolyti was most frequently isolated, and present on all Prunus species sampled, followed by Togninia minima (anamorph: Pm. aleophilum) and Pm. australiense. Almost all taxa isolated represent new records on Prunus. Furthermore, Pm. australiense,Pm. iranianum, T. fraxinopennsylvanica and Pm. griseorubrum represent new records for South Africa, while Pm. griseorubrum, hitherto only known from humans, is newly reported from a plant host. Five species are newly described, two of which produce a Togninia sexual state. Togninia africana, T. griseo-olivacea and Pm. pallidum are newly described from Prunus armeniaca, while Pm. prunicolum and Pm. fuscum are described from Prunus salicina.