Correlation Between Cryptococcus Infection and the Nasal Mycobiota in a Population of Free-Ranging Koalas (Phascolarctos cinereus) in New South Wales, Australia

Cryptococcosis is a fungal disease in humans and animals, caused by the Cryptococcus neoformans and Cryptococcus gattii species complexes. Clinical cryptococcosis primarily manifests as upper respiratory tract disease; however, dissemination to other organs, particularly the brain, can occur. Nasal colonisation and subclinical cryptococcosis are common in koalas (Phascolarctos cinereus) due to their shared environmental niche with Cryptococcus: Eucalyptus trees. However, for reasons that remain unclear, the prevalence of clinical disease is low in koalas. Interactions between respiratory pathogens and the nasal mycobiome are thought to play a role in the development and progression of numerous respiratory diseases. As such, this study aimed to characterise the mycobiome of the nasal vestibule in koalas with and without evidence of cryptococcal colonisation and subclinical disease via the next-generation sequencing (NGS) of the ITS1 region of the fungal internal transcribed spacer (ITS) gene. Samples were collected from 47 koalas from a population of free-ranging koalas in the Liverpool Plains, NSW, Australia, with a known history of Cryptococcus exposure and nasal colonisation. Of the 47 animals tested, 6.4% were culture-positive only, 4.3% were seropositive only, and 2.1% were culture- and seropositive. C. gattii was detected in four samples via NGS. C. neoformans was not detected via NGS. There were no significant differences in the nasal mycobiomes of Cryptococcus-positive and -negative animals; thus, we could not establish a definitive association between the mycobiome and infection outcomes. We identified a number of fungal genera that were significantly more abundant in samples from Cryptococcus-positive animals, but there was no apparent relationship between these genera and the development of cryptococcosis. This study represents the first investigation of the nasal mycobiota of wild koalas. Further studies involving koalas with clinical disease are necessary to determine the role of the nasal mycobiota in the development of cryptococcosis.

Recurrent Subcutaneous Phaeohyphomycosis Due to Medicopsis romeroi: A Case Report in a Dermatomyositis Patient and Review of the Literature

Medicopsis romeroi phaeohyphomycosis is increasingly reported in immunocompromised patients living in or originating from tropical and subtropical areas. We report a case of subcutaneous phaeohyphomycosis caused by M. romeroi in a 56-year-old Malian woman residing in France for 20 years. She developed a small nodule on her dominant hand's ring finger 15 months after starting immunosuppressive medications for paraneoplastic dermatomyositis. A first surgical debridement was followed by a local recurrence. Despite a second surgical excision combined with posaconazole treatment, the infection recurred one year after antifungal therapy discontinuation. A wide excision was performed again, and antifungal therapy was resumed and maintained for six months, resulting in the absence of relapse during the 18 months following the surgery. This case highlighted the high risk of relapse in immunocompromised patients, suggesting the need for long-term follow-up and prolonged antifungal treatment following surgical excision in cases with sustained immunosuppression. The literature review was performed according to PRISMA guidelines and included 51 scientific publications. A noteworthy predominance of the subcutaneous phaeohyphomycosis presentation was found in immunocompromised patients, whereas eumycetoma had been reported in apparently healthy individuals. A combination of complete excision with antifungal treatment seemed to confer the best outcome.

Disseminated Medicopsis Romeroi Infection in a Kidney Transplant Recipient

Medicopsis romeroi is a rare, dematiaceous fungus that is difficult to identify using conventional fungal tests. Although uncommon, immunocompromised patients are particularly susceptible to this opportunistic fungus. Here, we report the case of a renal transplant recipient who presented with painful disseminated subcutaneous and soft tissue lesions. Sequencing of the Internal transcribed spacer (ITS) region of the ribosomal DNA identified the fungus as Medicopsis romeroi. Additionally, tissue samples from a non-healing wound on the left forearm grew Rhizopus spp. on Sabouraud dextrose agar, indicating a Mucormycosis superinfection. The patient's condition improved with surgical intervention and antifungal therapy with Posaconazole and Terbinafine. This case demonstrates the need for a high index of suspicion in order to facilitate early diagnosis and treatment and thus reduce the risk of dissemination.

Spatial Variation of Cladophora Epiphytes in the Nan River, Thailand

Cladophora is an algal genus known to be ecologically important. It provides habitats for microorganisms known to provide ecological services such as biosynthesis of cobalamin (vitamin B12) and nutrient cycling. Most knowledge of microbiomes was obtained from studies of lacustrine Cladophora species. However, whether lotic freshwater Cladophora microbiomes are as complex as the lentic ones or provide similar ecological services is not known. To illuminate these issues, we used amplicons of 16S rDNA, 18S rDNA, and ITS to investigate the taxonomy and diversity of the microorganisms associated with replicate Cladophora samples from three sites along the Nan River, Thailand. Results showed that the diversity of prokaryotic and eukaryotic members of Cladophora microbiomes collected from different sampling sites was statistically different. Fifty percent of the identifiable taxa were shared across sampling sites: these included organisms belonging to different trophic levels, decomposers, and heterotrophic bacteria. These heterogeneous assemblages of bacteria, by functional inference, have the potential to perform various ecological functions, i.e., cellulose degradation, cobalamin biosynthesis, fermentative hydrogen production, ammonium oxidation, amino acid fermentation, dissimilatory reduction of nitrate to ammonium, nitrite reduction, nitrate reduction, sulfur reduction, polyphosphate accumulation, denitrifying phosphorus-accumulation, and degradation of aromatic compounds. Results suggested that river populations of Cladophora provide ecologically important habitat for microorganisms that are key to nutrient cycling in lotic ecosystems.

Medicopsis romeroi nodular subcutaneous infection in a kidney transplant recipient

Phaeohyphomycosis is a set of fungal infections caused by various dematiaceous fungi such as coelomycetes. These infections can occur either in immunocompetent or immunocompromised patients like solid organ transplants. Here we describe a nodular lesion of the right hallux that occurred in a kidney transplant patient. Microscopic examination of the biopsy revealed fungal hyphae and culture was positive to a grey to black mould that lacked characteristic elements to be identified. Nucleic acid sequencing targeting the internal transcribed spacer of the ribosomal DNA identified this mould as Medicopsis romeroi. The patient benefited of an antifungal therapy with voriconazole associated with surgical excision of the lesion. No relapse of the lesion was observed during a six-month follow-up. In solid organ transplants, phaeohyphomycosis caused by Medicopsis romeroi are very rare with only 12 cases reported. The clinical history should be well assessed since the lesion can appear several years after a cutaneous trauma that happened in a tropical region. Therapy generally combines antifungals with surgical excision of the lesion in order to avoid any relapse or dissemination of the infection.

Subcutaneous phaeohyphomycosis from Medicopsis romeroi in a diabetic patient

Dematiaceous fungi can cause subcutaneous phaeohyphomycosis, an uncommon fungal infection of the dermis and subcutaneous tissues. Medicopsis romeroi is an emerging organism that can infect patients with subcutaneous phaeohyphomycosis, especially immunocompromised patients. The present case involved subcutaneous phaeohyphomycosis caused by Medicopsis romeroi in an 80-year-old Thai male with poorly controlled diabetes, for whom the lesion underwent spontaneous remission after his glycemic control was improved. Furthermore, cases of subcutaneous phaeohyphomycosis for the last 10 years were reviewed.

Rapid and Robust Identification of the Agents of Black-Grain Mycetoma by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

Eumycetoma, a chronic fungal infection endemic in India, Indonesia, and parts of Africa and South and Central America, follows traumatic implantation of saprophytic fungi and frequently requires radical surgery or amputation in the absence of appropriate treatment. Fungal species that can cause black-grain mycetomas include Madurella spp., Falciformispora spp., Trematosphaeria grisea, Nigrograna mackinnonii, Pseudochaetosphaeronema larense, Medicopsis romeroi, and Emarellia spp. Rhytidhysteron rufulum and Parathyridaria percutanea cause similar subcutaneous infections, but these infections lack the draining sinuses and fungal grains characteristic of eumycetoma. Accurate identification of the agents of subcutaneous fungal infection is essential to guide appropriate antifungal therapy. Since phenotypic identification of the causative fungi is often difficult, time-consuming molecular approaches are currently required. In the study described here we evaluated whether matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry might allow the accurate identification of eumycetoma agents and related fungi. A panel of 57 organisms corresponding to 10 different species from confirmed cases of eumycetoma and subcutaneous pedal masses, previously formally identified by PCR amplification and sequencing of internal transcribed spacer 1 (ITS1), was employed. Representative isolates of each species were used to create reference MALDI-TOF spectra, which were then used for the identification of the remaining isolates in a user-blinded manner. Here, we demonstrate that MALDI-TOF mass spectrometry accurately identified all of the test isolates, with 100%, 90.4%, and 67.3% of isolates achieving log scores greater than 1.8, 1.9, and 2.0, respectively.

Genome Anatomy of Pyrenochaeta unguis-hominis UM 256, a Multidrug Resistant Strain Isolated from Skin Scraping

Pyrenochaeta unguis-hominis is a rare human pathogen that causes infection in human skin and nail. P. unguis-hominis has received little attention, and thus, the basic biology and pathogenicity of this fungus is not fully understood. In this study, we performed in-depth analysis of the P. unguis-hominis UM 256 genome that was isolated from the skin scraping of a dermatitis patient. The isolate was identified to species level using a comprehensive multilocus phylogenetic analysis of the genus Pyrenochaeta. The assembled UM 256 genome has a size of 35.5 Mb and encodes 12,545 putative genes, and 0.34% of the assembled genome is predicted transposable elements. Its genomic features propose that the fungus is a heterothallic fungus that encodes a wide array of plant cell wall degrading enzymes, peptidases, and secondary metabolite biosynthetic enzymes. Antifungal drug resistance genes including MDR, CDR, and ERG11/CYP51 were identified in P. unguis-hominis UM 256, which may confer resistance to this fungus. The genome analysis of P. unguis-hominis provides an insight into molecular and genetic basis of the fungal lifestyles, understanding the unrevealed biology of antifungal resistance in this fungus.

Subcutaneous Phaeohyphomycosis Due to Pyrenochaeta romeroi Mimicking a Synovial Cyst

Opportunistic subcutaneous fungal infections are increasing nowadays due to the growing number of medical conditions causing immunosuppression, especially organ transplant. The incidence rate of subcutaneous phaeohyphomycosis is very low. Most studies found are case reports. They showed a wide variation of clinical presentations. Pyrenochaeta romeroi, a fungus from the Dematiaceae group is a saprophyte found in soil and plants and a possible causative agent of phaeohyphomycosis. We present a rare case of subcutaneous phaeohyphomycosis caused by P. romeroi mimicking a synovial cyst in a diabetic patient.

Subcutaneous Phaeohyphomycosis Cyst Associated with Medicopsis romeroi in an Immunocompromised Host

An 88-year-old man, receiving prednisolone for sarcoidosis, presented with a discrete keratotic lesion on the dorsum of his right hand following the placement of an intravenous cannula a month prior to its appearance. Medicopsis romeroi was isolated from the tissue and identified by sequencing the internal transcribed spacer region ITS-1 and the D1-2 fragment of the 28S rDNA gene. Histopathological examination showed fungal hyphae in the internal inflammatory cells layer and within the histocyte-macrophage layer, highly suggestive of deep mycosis. The patient was successfully treated with surgical excision of the cyst. M. romeroi exhibited high MIC values for echinocandin drugs in vitro, but appeared susceptible to newer triazole agents, amphotericin B and terbinafine. This is the first report of a subcutaneous phaeohyphomycotic cyst occurring following the placement of an intravenous cannula. This report highlights the potential role of M. romeroi as an emerging cause of deep, non-mycetomatous infection in immunocompromised patients.

Novel Taxa Associated with Human Fungal Black-Grain Mycetomas: Emarellia grisea gen. nov., sp. nov., and Emarellia paragrisea sp. nov

Eumycetoma is a debilitating, chronic, fungal infection that is endemic in India, Indonesia, and parts of Africa and South and Central America. It remains a neglected tropical disease in need of international recognition. Infections follow traumatic implantation of saprophytic fungi and frequently require radical surgery or amputation in the absence of appropriate treatment. Several fungal species can cause black-grain mycetomas, including Madurella spp. (Sordariales), Falciformispora spp., Trematosphaeria grisea, Biatriospora mackinnonii, Pseudochaetosphaeronema larense, and Medicopsis romeroi (all Pleosporales). We performed phylogenetic analyses based on five loci on 31 isolates from two international culture collections to establish the taxonomic affiliations of fungi that had been isolated from cases of black-grain mycetoma and historically classified as Madurella grisea Although most strains were well resolved to species level and corresponded to known agents of eumycetoma, six independent isolates, which failed to produce conidia under any conditions tested, were only distantly related to existing members of the Pleosporales Five of the six isolates shared >99% identity with each other and are described as Emarellia grisea gen. nov. and sp. nov; the sixth isolate represents a sister species in this novel genus and is described as Emarellia paragrisea. Several E. grisea isolates were present in both United Kingdom and French culture collections and had been isolated independently over 6 decades from cases of imported eumycetoma. Four of the six isolates involved patients that had originated on the Indian subcontinent. All isolates were all susceptible in vitro to the azole antifungals, but had elevated MICs with caspofungin.

Subcutaneous Phaeohyphomycosis Caused By Pyrenochaeta Romeroi in a Kidney Transplant Recipient: A Case Report

Infections are Achilles heel of kidney transplant recipients. Opportunistic fungal infections are increasingly recognized in these patients. We report a case of kidney transplant recipient with skin and soft tissue infection caused by Pyrenochaeta romeroi, a dematiaceous fungi. Infection by this organism is rare.

Subcutaneous abscess due to Pyrenochaeta romeroi in a renal transplant recipient

An infective aetiology, including fungal infection, should be considered in the differential diagnosis of immunocompromised patients presenting with skin lesions. Dematiaceous fungi are recognised as pathogens in organ transplant recipients. Herein, we describe a rare case of a chronic necrotising granulomatous skin lesion caused by Pyrenochaeta romeroi in a renal transplant recipient, and review the existing literature on the topic. To the best of our knowledge, this is the first report of such a case in Singapore. Recognition of infections caused by dematiaceous fungi is important because some strains are difficult to identify and require special molecular diagnostic techniques. Treatment involves surgical excision and long-term antifungal therapy. Data on the optimal antifungal regimen in such a diagnosis is limited.

Pyrenochaeta romeroi causing subcutaneous phaeohyphomycotic cyst in a diabetic female

Opportunistic subcutaneous fungal infections are increasing in present times due to increasing incidence of many medical conditions causing immunosupression like diabetes, AIDS, organ transplant recipients and anticancer therapy. Pyrenochaeta romeroi, a fungus from the dematiaceae group, first described by Borelli in 1959, is saprophyte to soil and plants.We present a rare case of subcutaneous phaeohyphomycotic cyst in a diabetic female caused by P. romeroi.

In vitro antifungal susceptibility of coelomycete agents of black grain eumycetoma to eight antifungals

Fungal mycetoma (eumycetoma) represents one of the most difficult infections to appropriately manage. The current recommended treatment is based on extensive surgical debridement combined with prolonged antifungal therapy with ketoconazole or itraconazole. Despite the different phylogenetic positions of black-grain eumycetoma species, they are all treated with the same antifungal agents. The in vitro antifungal susceptibility of coelomycetous eumycetoma agents in the order of Pleosporales presently is largely unknown. Here we determined the in vitro activity of eight antifungal agents against seven species causing human eumycetoma using the Sensititre YeastOne method. High minimum inhibitory concentrations (MICs) were found with fluconazole, caspofungin, flucytosine, and amphotericin B. Voriconazole and posaconazole were found to be active against all species tested. Of the species included in the investigation, MICs of Medicopsis romeroi differed from the rest of the mycetoma causative agents belonging to the order of the Pleosporales. We found significantly lower MICs for amphotericin B and significantly higher MICs for fluconazole, ketoconazole, and itraconazole against this species. Our results emphasised that identification of black grain mycetoma agent is important as well as performing susceptibility testing before starting of antifungal treatment.

Molecular identification of melanised non-sporulating moulds: a useful tool for studying the epidemiology of phaeohyphomycosis

Subcutaneous infections caused by melanised fungi have been increasingly reported among transplant patients, and these infections have the potential for blood and visceral dissemination. Some moulds, such as Mycelia sterilia, cannot grow and sporulate on different media, making their identification impossible by conventional methods. The fast and accurate identification of melanised fungi at the species level is important because species may have tropism to different organs and different susceptibilities to antifungal agents. Molecular tools have been reported to be helpful for the species identification of non-sporulating moulds. Our goal was to identify the species of M. sterilia isolates obtained from clinical samples of transplant patients using sequences of ITS and the D1/D2 regions of rDNA. Clinical samples were obtained from eight kidney transplant recipients who developed subcutaneous fungal infections. The diagnosis was confirmed by histopathology and conventional culture. Histopathology showed septated, melanised hyphae, and the cultures identified non-sporulating fungi. Therefore, the DNA from the M. sterilia isolates was subjected to PCR amplification and sequencing of the ITS and D1/D2 regions. Genus/species identification was obtained by comparison with gene banks. We obtained the following identifications: Alternaria sp. (2), Cochliobolus lunatus/Curvularia lunata (2), Cochliobolus hawaiiensis/Bipolaris hawaiiensis (1), Ochroconis sp. (1), Medicocopsis romeroi/Pyrenochaeta romeroi (1) and Nigrograna mackinnonii/Pyrenochaeta mackinnonii (1).

A nodulo-cystic eumycetoma caused by Pyrenochaeta romeroi in a renal transplant recipient: A case report

Introduction

Pyrenochaeta romeroi (P. romeroi) is a saprophytic fungus found in soil and plants. The fungal spores can be introduced into deeper tissues by trauma. It causes eumycetoma, which affects skin and subcutaneous tissues.

Case presentation

A 57-year-old South Asian man presented with a painless, nodular lesion (1 cm × 0.5 cm) on the left knee. He had had a renal transplant eight months earlier for end-stage renal failure. The patient was on tacrolimus, mycophenolate mofetil and prednisolone for immunosuppression. The lesion had progressed dramatically (to 5 cm × 5 cm) despite antibiotic treatment. The size and location of the lesion was severely affecting his quality of life, so an excision biopsy was performed. Nuclear ribosomal repeat-region sequencing confirmed the causative organism as P. romeroi. An in vitro antifungal susceptibility test demonstrated that P. romeroi was sensitive to voriconazole. Following a successful surgical removal, voriconazole was continued orally for two months.

Conclusion

To the best of our knowledge, we are reporting the first case of Eumycetoma caused by P. romeroi in a renal transplant recipient. Physicians should be aware of this rare fungal disease in transplant recipients. We recommend a combination of medical and surgical management in these immunosuppressed patients.