Cerebral phaeohyphomycosis caused by Rhinocladiella mackenziei in a woman native to Afghanistan

Post covid cerebral phaeohyphomycosis by Rhinocladiella mackenziei: An unusual association

Cerebral phaeohyphomycosis (CP) is a rare but a highly morbid fungal infection of the central nervous system caused by the fungi belonging to the order Chaetothyriales, which includes Cladophialophora bantiana, Exophiala dermatitidis, Rhinocladiella mackenziei (RM) etc. This disease is associated with poor clinical outcomes, with reported mortality of over 80%. We present the case of a 65-year gentleman who developed CP secondary to RM infection following COVID-19 and the associated challenges in his medical and surgical management.

First case of Rhinocladiella mackenziei brain abscess in Turkey: Case report and review of the literature

Rhinocladiella mackenziei is a highly neurotropic fungus, mainly reported from the Middle East. However, in recent years, there have been some cases from outside this region. We described an additional fatal case of R. mackenziei cerebral infection for the first time from Turkey and made a literature review of all previously reported cases. During 34 years (1988-2022), there have been 42 R. mackenziei brain abscess cases. Most patients have been reported from Saudi Arabia (n = 14, 33.3%). It is noteworthy that 40.5% of patients, including our case, were immunocompetent at initial diagnosis and mostly presented with a single lesion (n = 10, 23.8%). The most frequent comorbidities were solid organ transplant (n = 9, 21.4%), diabetes mellitus (n = 6, 14.3%), malignancy (n = 6, 14.3%) and prior surgery (n = 3, 7.1%). The most commonly used initial antifungal regimen were amphotericin B together with itraconazole (n = 9, 21.4%), combinations of lipid preparations of amphotericin B, voriconazole and/or posaconazole (n = 9, 21.4%) and amphotericin B alone (n = 8, 19%). Although both surgical procedures and antifungal medication in the majority of patients were performed, mortality rates remained high (90.4%). The area at risk of R. mackenziei cerebral abscess cases extends to other countries. Clinicians should be aware of this emerging disease and take a detailed travel history in patients with atypical and undocumented brain abscesses. Our case confirms the hypothesis that this fungus might spread more widely than previously predicted regions.

Rhinocladiella mackenziei cerebral phaeohyphomycosis with a definitive outcome

A right-handed man in his early 60s with hypertension controlled by a single prescription medication presented with left-sided heaviness and intermittent right occipital headache. Initial diagnostic workup was unremarkable. CT revealed an enhancing lesion located in the right parietal lobe, with mild mass effect on the right occipital horn, indicative of a brain abscess. The patient was initially treated with a course of empirical antibiotics, including ceftriaxone, vancomycin, metronidazole and dexamethasone. The neurosurgery team aspirated the abscess the following day and extracted yellow pus that was sampled for bacterial and fungal cultures. These cultures returned positive for Rhinocladiella mackenziei, prompting a discontinuation of the empirical antibiotics and initiation of intravenous liposomal amphotericin B for 4 weeks. Intravenous posaconazole was added to the patient's existing therapy regimen, which was substituted with oral isavuconazole on discharge. The patient continues to take isavuconazole, and follow-up imaging has demonstrated regression of the abscess.

Molecular epidemiology of clinical filamentous fungi in Qatar beyond Aspergillus and Fusarium with notes on the rare species

Due to an increasing number of patients at risk (i.e., those with a highly compromised immune system and/or receiving aggressive chemotherapy treatment), invasive fungal infections (IFI) are increasingly being reported and associated with high mortality rates. Aspergillus spp., particularly A. fumigatus, is the major cause of IFI caused by filamentous fungi around the world followed by Fusarium spp., however, other fungi are emerging as human pathogens. The aim of this study was to explore the epidemiology and prevalence of the non-Aspergillus and non-Fusarium filamentous fungi in human clinical samples over an 11-year period in Qatar using molecular techniques. We recovered 53 filamentous fungal isolates from patients with various clinical conditions. Most patients were males (75.5%), 9.4% were immunocompromised, 20.7% had IFI, and 11.3% died within 30 days of diagnosis. The fungal isolates were recovered from a variety of clinical samples, including the nasal cavity, wounds, respiratory samples, body fluids, eye, ear, tissue, abscess, and blood specimens. Among the fungi isolated, 49% were dematiaceous fungi, followed by Mucorales (30%), with the latter group Mucorales being the major cause of IFI (5/11, 45.5%). The current study highlights the epidemiology and spectrum of filamentous fungal genera, other than Aspergillus and Fusarium, recovered from human clinical samples in Qatar, excluding superficial infections, which can aid in the surveillance of uncommon and emerging mycoses.

Cerebral phaeohyphomycosis in liver transplant recipient: A case report

Cerebral phaeohyphomycosis is a fungal brain infection with a high fatality rate. It is caused by dematiaceous fungi and is increasingly recognized as a cause of serious illness in both immunocompetent and immunocompromised patients. We report cerebral phaeohyphomycosis in a liver transplant recipient. He was treated with multiple surgeries and antifungals and made a complete recovery. This report highlights that early and aggressive surgical intervention and extended antifungal coverage can have a positive outcome even in immunocompromised patients. The fungal infection in immunocompromised patients should be considered and treated aggressively.

Novel cases of cutaneous phaeohyphomycosis by Alternaria alstromeriae, Epicoccum tritici and Phialemonium obovatum from North India

BACKGROUND

A growing number of non-dermatophytic moulds and yeasts with the ability to act as human pathogens are reported every year. Dematiaceous fungi cause phaeohyphomycosis which encompasses a broad spectrum of diseases ranging from superficial (cutaneous and subcutaneous) to disseminated infections. Such fungal infections are responsible for causing significant morbidity and mortality, frequently in immunocompromised patients and rarely in immunocompetent patients.

OBJECTIVES

To investigate the prevalence of cutaneous mycosis in Jammu district (India) and to isolate and identify the recovered causal agents from the affected skin of the patients.

METHODS

For direct microscopy, 10% KOH was used. Skin samples were collected carefully from the affected areas of suspected patients, followed by the isolation and identification of the causal agents by cultural examination, morphological examination and ITS sequencing.

RESULTS

Herein, we report and describe three new cases of cutaneous phaeohyphomycosis from District Jammu of Union Territory Jammu and Kashmir, India. The age of the patients under study ranged from 17 to 42 years and the duration of infection from 1 to 2 years. The etiological agents that were recovered from the patients under study were Alternaria alstromeriae, Epicoccum tritici and Phialemonium obovatum. These dematiaceous fungal species were isolated from the skin specimen of immunocompetent hosts.

CONCLUSION

Among the three isolated etiological agents, two (Alternaria alstromeriae, Epicoccum tritici) represent new global records and one (Phialemonium obovatum) new record to India as causal agents of cutaneous phaeohyphomycosis. Careful microscopic and mycological examination form the basis of correct diagnosis of such fungal infections in the absence of simple and reliable laboratory tests (serologic or antigen tests).

Morocco as a possible source for acquisition of Rhinocladiella mackenziei

Rhinocladiella mackenziei cerebral phaeohyphomycosis is a rare severe disease that has been typically described in the Middle East. Here, we report 2 cases of R. mackenziei cerebral phaeohyphomycosis in patients from Morocco, diagnosed and treated in France, and raise a concern about the ever-going extension of the area at risk for this devastating invasive fungal infection.

Disseminated Rhinocladiella mackenziei infection in a kidney transplant recipient: A case report and literature review

Rhinocladiella mackenziei is a rare fungal pathogen which belongs to a large group of pigmented fungi causing phaeohyphomycosis. R. mackenziei primarily infects the brain and leads to high fatality rates among both immunocompetent and immunocompromised individuals. Among solid organ transplant recipients, the infection may disseminate to extra-neuronal sites, necessitating comprehensive radiologic imaging. Here we describe a new case of R. mackenziei infection in a renal transplant patient involving the brain and renal allograft. She received liposomal amphotericin B and voriconazole but no surgical intervention. Ultimately, the patient died after two months of hospital stay. A review of all reported cases of transplant patients infected with R. mackenziei is also presented.

Cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in an immunocompetent patient: A case report and review of literature

Background and Purpose

Rhinocladiella mackenziei is a neurotropic fungus, which can cause devastating intracerebral infections with up to 100% fatality rate. It is difficult to isolate this fungus in laboratory as it grows slowly and requires diagnostic skills.

Case report

A 42-year-old Pakistani man presented with headache, facial numbness, progressive upper limb weakness, and dysarthria. Magnetic resonance imaging of the brain showed a space-occupying lesion in the basal ganglia region. The patient underwent supratentorial craniotomy for biopsy and excision. Histopathology of the specimen revealed granulomatous inflammation with abscess formation. Periodic acid- Schiff special stains highlighted the presence of numerous septate fungal hyphae. The results revealed the growth of dematiaceous fungi, which were morphologically classified as R. mackenziei. The patient is currently stable and is being on amphotericin and posaconazole, along with neurorehabilitation therapy.

Conclusion

Rhinocladiella mackenziei brain abscess is a devastating infection with significant mortality. This condition should be suspected in patients with brain abscess from high endemic areas.

Case Report: Chronic Fungal Meningitis Masquerading as Tubercular Meningitis

Phaeohyphomycosis causes a wide spectrum of systemic manifestations and can affect even the immunocompetent hosts. Involvement of the central nervous system is rare. A 48-year-old farmer presented with chronic headache, fever, and impaired vision and hearing. Serial MRIs of the brain showed enhancing exudates in the basal cisterns, and lesions in the sella and perichiasmatic and cerebellopontine angle regions along with enhancement of the cranial nerves and leptomeninges. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis with elevated protein and decreased glucose on multiple occasions. Clinical, imaging, and CSF abnormalities persisted despite treatment with antitubercular drugs and steroids for 2 years. Biopsy of the dura mater at the cervicomedullary junction revealed necrotizing granulomatous lesions, neutrophilic abscesses, and giant cells containing slender, pauci-septate, pigmented fungal hyphae. Fungal culture showed growth of Fonsecaea pedrosoi, which is classically known to cause brain abscesses. Here, we report the diagnostic odyssey in a patient with chronic meningitis from a region endemic for tuberculosis and describe the challenges in establishing the accurate diagnosis. Lack of therapeutic response to an adequate trial of empirical antitubercular therapy warrants search for alternative causes, including fungal meningitis. We highlight the uncommon manifestation of F. pedrosoi with chronic meningitis as well as the protracted clinical course despite not receiving antifungal therapy.

Low Central Nervous System Posaconazole Concentrations during Cerebral Phaeohyphomycosis

Posaconazole diffusion has been documented in various organs, which contrasts with the scarce data available for the human central nervous system (CNS). We analyzed posaconazole concentrations in plasma and multiple CNS specimens taken from a patient who received posaconazole because of cerebral phaeohyphomycosis. Low posaconazole concentrations were obtained in CNS specimens, with sample-to-plasma ratios between 5% and 22%. This case highlights the role of neurosurgery during cerebral phaeohyphomycoses, even those caused by posaconazole-susceptible black fungi.

CNS Infections Caused by Brown-Black Fungi

Central nervous system (CNS) infections caused by brown-black or dematiaceous fungi are distinctly rare and represent a small proportion of infections termed phaeohyphomycoses. However, these are becoming more commonly reported. Though many fungi have been implicated in disease, most cases are caused by only a few species, Cladophialophora bantiana being the most common. Most of the fungi described are molds, and often cause infection in immunocompetent individuals, in contrast to infection with other more common molds such as Aspergillus, which is usually seen in highly immunocompromised patients. Diagnosis is challenging, as there are no specific tests for this group of fungi. In addition, these infections are often refractory to standard drug therapies, requiring an aggressive combined surgical and medical approach to improve outcomes, yet mortality remains high. There are no standardized treatments due to a lack of randomized clinical trials, though guidelines have been published based on available data and expert opinion.

Neuroinfections caused by fungi

BACKGROUND

Fungal infections of the central nervous system (FIs-CNS) have become significantly more common over the past 2 decades. Invasion of the CNS largely depends on the immune status of the host and the virulence of the fungal strain. Infections with fungi cause a significant morbidity in immunocompromised hosts, and the involvement of the CNS may lead to fatal consequences.

METHODS

One hundred and thirty-five articles on fungal neuroinfection in PubMed, Google Scholar, and Cochrane databases were selected for review using the following search words: "fungi and CNS mycoses", CNS fungal infections", "fungal brain infections", " fungal cerebritis", fungal meningitis", "diagnostics of fungal infections", and "treatment of CNS fungal infections". All were published in English with the majority in the period 2000-2018. This review focuses on the current knowledge of the epidemiology, clinical presentations, diagnosis, and treatment of selected FIs-CNS.

RESULTS

The FIs-CNS can have various clinical presentations, mainly meningitis, encephalitis, hydrocephalus, cerebral abscesses, and stroke syndromes. The etiologic factors of neuroinfections are yeasts (Cryptococcus neoformans, Candida spp., Trichosporon spp.), moniliaceous moulds (Aspergillus spp., Fusarium spp.), Mucoromycetes (Mucor spp., Rhizopus spp.), dimorphic fungi (Blastomyces dermatitidis, Coccidioides spp., Histoplasma capsulatum), and dematiaceous fungi (Cladophialophora bantiana, Exophiala dermatitidis). Their common route of transmission is inhalation or inoculation from trauma or surgery, with subsequent hematogenous or contiguous spread. As the manifestations of FIs-CNS are often non-specific, their diagnosis is very difficult. A fast identification of the etiological factor of neuroinfection and the application of appropriate therapy are crucial in preventing an often fatal outcome. The choice of effective drug depends on its extent of CNS penetration and spectrum of activity. Pharmaceutical formulations of amphotericin B (AmB) (among others, deoxycholate-AmBd and liposomal L-AmB) have relatively limited distribution in the cerebrospinal fluid (CSF); however, their detectable therapeutic concentrations in the CNS makes them recommended drugs for the treatment of cryptococcal meningoencephalitis (AmBd with flucytosine) and CNS candidiasis (L-AmB) and mucormycosis (L-AmB). Voriconazole, a moderately lipophilic molecule with good CNS penetration, is recommended in the first-line therapy of CNS aspergillosis. Other triazoles, such as posaconazole and itraconazole, with negligible concentrations in the CSF are not considered effective drugs for therapy of CNS fungal neuroinfections. In contrast, clinical data have shown that a novel triazole, isavuconazole, achieved considerable efficacy for the treatment of some fungal neuroinfections. Echinocandins with relatively low or undetectable concentrations in the CSF do not play meaningful role in the treatment of FIs-CNS.

CONCLUSION

Although the number of fungal species causing CNS mycosis is increasing, only some possess well-defined treatment standards (e.g., cryptococcal meningitis and CNS aspergillosis). The early diagnosis of fungal infection, accompanied by identification of the etiological factor, is needed to allow the selection of effective therapy in patients with FIs-CNS and limit their high mortality.

Genomic Understanding of an Infectious Brain Disease from the Desert

Rhinocladiella mackenziei accounts for the majority of fungal brain infections in the Middle East, and is restricted to the arid climate zone between Saudi Arabia and Pakistan. Neurotropic dissemination caused by this fungus has been reported in immunocompromised, but also immunocompetent individuals. If untreated, the infection is fatal. Outside of humans, the environmental niche of R. mackenziei is unknown, and the fungus has been only cultured from brain biopsies. In this paper, we describe the whole-genome resequencing of two R. mackenziei strains from patients in Saudi Arabia and Qatar. We assessed intraspecies variation and genetic signatures to uncover the genomic basis of the pathogenesis, and potential niche adaptations. We found that the duplicated genes (paralogs) are more susceptible to accumulating significant mutations. Comparative genomics with other filamentous ascomycetes revealed a diverse arsenal of genes likely engaged in pathogenicity, such as the degradation of aromatic compounds and iron acquisition. In addition, intracellular accumulation of trehalose and choline suggests possible adaptations to the conditions of an arid climate region. Specifically, protein family contractions were found, including short-chain dehydrogenase/reductase SDR, the cytochrome P450 (CYP) (E-class), and the G-protein β WD-40 repeat. Gene composition and metabolic potential indicate extremotolerance and hydrocarbon assimilation, suggesting a possible environmental habitat of oil-polluted desert soil.

Cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Persian Gulf region: A case and review

Cerebral phaeohyphomycosis is frequently a fatal disease caused by truly neurotropic dematiaceous fungi. Although rare, this infection occurs especially among immunocompetent patients, and the clinical symptoms are often misdiagnosed as a cerebral tumour or bacterial brain abscess. The appropriate diagnosis and therapy of cerebral infections by melanized fungi are very challenging if they are caused by mysterious fungi with unknown ecological niche. We reported the second case of cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Iran and the first culture-confirmed case. In this report, the differential diagnosis and histopathological findings are discussed and a review of the literature is provided.

Multiple brain abscesses caused by Rhinocladiella mackenziei in an immunocompetent patient: a case report and literature review

Primary cerebral phaeohyphomycosis due to Rhinocladiella mackenziei is an extremely rare infection carrying more than 80% mortality, with most cases reported from the Middle East region. This darkly pigmented black yeast is highly neurotropic, aggressive and refractory to most antifungal agents. Here we present an immunocompetent elderly male, presenting with multiple brain abscesses, with R. mackenziei confirmed by nuclear ribosomal repeat region sequencing, who was successfully treated by surgical debridement and intravenous voriconazole. To our knowledge this is the first case reported from the United Kingdom. We also present a review of all such cases so far reported in the English literature world-wide, which we believe is a step further to understanding the pathogenesis and establishing effective treatment of this rare, yet often fatal disease.

First fatal cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Iran, based on ITS rDNA

Black yeast-like fungi and relatives as agents of cerebral phaeohyphomycosis are often encountered in human fatal brain abscesses and lead to almost 100% mortality despite the application of antifungal and surgical therapy. We report to our knowledge the first case of brain infection due to Rhinocladiella mackenziei in a 54-year-old immunocompetent male in Iran where R. mackenziei has not been reported previously. The initial diagnosis was brain fungal infection because of pigmented, irregular, branched, septated hyphae based on histopathological staining. The patient was treated with intravenous amphotericin B deoxycholate (0.5mg/kg/day) combined with oral itraconazole (200mg twice daily), nevertheless, his neurological function deteriorated rapidly and ultimately the patient died due to respiratory failure later two weeks. R. mackenziei was identified based on the sequencing of internal transcribed spacer (ITS rDNA region) (KJ140287). Therefore, considerable attention for this life-threatening infection is highly recommended.

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 infections of the central nervous system in the immunocompetent host]

The majority of mycoses which lead to mycotic tumors in patients without any predisposing underlying disease are either caused by Cryptococcus gattii and C. neoformans or by dematiaceous fungi which include Cladophialophora bantiana, Ramichloridium mackenziei, Exophiala and Fonsecaea species. The detection of hyphae in granuloma in the brain should lead to screening for pigmented fungi, which are recognized best in hematoxylin eosin (HE) or sometimes also in periodic acid-Schiff (PAS) stained sections. In patients who survive a near drowning accident and those who develop brain abscesses, scedosporiosis should always be considered as a possible infection.

Rhinocladiella mackenziei as an emerging cause of cerebral phaeohyphomycosis in Pakistan: a case series

Six cases of Rhinocladiella mackenziei cerebral phaeohyphomycosis are being reported for the first time in Pakistan. Identification was confirmed by DNA sequencing (isolates and fixed tissue). Diabetes, head trauma, immunosuppressive treatment, and postpartum state were present in 4 cases. Two survivals and 3 fatalities occurred, with 1 patient lost to follow-up.