Two cases of Emergomyces pasteurianus infection in immunocompromised patients in the Netherlands

Emergomycosis, an Emerging Thermally Dimorphic Fungal Infection: A Systematic Review

Emergomycosis is an endemic mycosis caused by the Emergomyces species. Infections due to this agent have been reported globally. Hence, the present systematic review on Emergomyces infections was conducted to study the disease epidemiology, underlying diseases and risk factors, causative agents, and treatment and outcome. The MEDLINE, Scopus, Embase, and Web of Science databases were searched systematically with appropriate keywords from January 1990 to October 2022. A total of 77 cases of emergomycosis were included in the analysis. Emergomycosis was most commonly seen in patients with human immunodeficiency virus (HIV) infection (n = 61, 79.2%) and HIV-uninfected patients with or without other comorbidities (n = 16, 20.8%). The underlying disease and risk factors significantly associated with emergomycosis in the HIV-infected patients were CD4+ T-cell counts less than 100 cells/mm3 (n = 55, 90.2%), anaemia (n = 30, 49.2%), and thrombocytopenia (n = 17, 27.9%), whereas in the HIV-uninfected patients, treatment with immunosuppressive drugs (n = 10, 62.5%), renal disease (n = 8, 50%), transplant recipients (n = 6, 37.5%), and diabetes mellitus (n = 4, 25%) were the significant risk factors associated with emergomycosis. Emergomyces africanus (n = 55, 71.4%) is the most common causative agent, followed by E. pasteurianus (n = 9, 11.7%) and E. canadensis (n = 5, 6.5%). E. africanus was most often isolated from HIV-infected patients (n = 54, 98.2%), whereas E. pasteurianus was most common in HIV-uninfected patients (n = 5, 55.6%). The all-cause mortality rate of the total cohort is 42.9%. No significant variation in the mortality rate is observed between the HIV-infected patients (n = 28, 36.4%) and the HIV-uninfected patients (n = 5, 6.5%). In conclusion, with an increase in the immunosuppressed population across the globe in addition to HIV infection, the case burden of emergomycosis may increase in the future. Hence, clinicians and mycologists should be vigilant and clinically suspicious of emergomycosis, which helps in early diagnosis and initiation of antifungal treatment to prevent disease mortality.

Emergomyces pasteurianus in Man Returning to the United States from Liberia and Review of the Literature

A 65-year-old man with HIV sought treatment for fever, weight loss, and productive cough after returning to the United States from Liberia. Fungal cultures grew Emergomyces pasteurianus, and the patient's health improved after beginning voriconazole. We describe the clinical case and review the literature, treatment, and susceptibilities for E. pasteurianus.

Review: Emergomycosis

Purpose of Review In this review, we provide an overview of emergomycosis from a clinical perspective and discuss the taxonomy and classification of the pathogens, epidemiology, pathophysiology of infection and mechanisms of pathogenesis, immunology, clinical manifestations, laboratory culture and diagnosis, molecular characterisation, therapy and prognosis. Recent Findings While Emergomyces pasteurianus is the most geographically-widespread species, Emergomyces africanus is endemic to Southern Africa and causes disseminated disease with cutaneous involvement primarily among patients with advanced human immunodeficiency virus (HIV) disease. Summary Emergomycosis, a disseminated clinical disease resulting from infection with dimorphic fungi in the genus Emergomyces, occurs primarily among immunocompromised patients. Further knowledge is needed on the pathophysiology, diagnosis and management of emergomycosis.

New Perspectives on Antimicrobial Agents: Isavuconazole

Isavuconazole is the newest of the clinically available advanced generation triazole antifungals and is active against a variety of yeasts, molds, and dimorphic fungi. Its current FDA-approved indications include the management of invasive aspergillosis as well as mucormycosis, though the latter indication is supported by limited clinical data. Isavuconazole did not achieve noninferiority to caspofungin for the treatment of invasive candidiasis and therefore lacks an FDA-approved indication for this invasive disease. Significant advantages of isavuconazole, primarily over voriconazole but in some circumstances posaconazole as well, make it an appealing option for the management of complex patients with invasive fungal infections. These potential advantages include lack of QTc interval prolongation, more predictable pharmacokinetics, a less complicated drug interaction profile, and improved tolerability, particularly when compared to voriconazole. This review discusses these topics in addition to addressing the in vitro activity of the compound against a variety of fungi and provides insight into other distinguishing factors among isavuconazole, voriconazole, and posaconazole. The review concludes with an opinion section in which the authors provide the reader with a framework for the current role of isavuconazole in the antifungal armamentarium and where further data are required.

Isolated Pulmonary Emergomycosis in an Immunocompetent Patient in Alberta, Canada

Emergomyces canadensis pulmonary infection was incidentally diagnosed in an asymptomatic patient suspected to have metastatic osteosarcoma. Molecular diagnosis was imperative to fungal identification given overlapping histopathological features with histoplasmosis. This report documents a case of isolated pulmonary emergomycosis in an otherwise immunocompetent patient while discussing diagnostic and management pitfalls of this emerging and underdiagnosed infection.

Epidemiology of fungal diseases in Africa: A review of diagnostic drivers

Background and Purpose:

There has been a significant increase in the burden of fungal diseases in the last few decades which has imposed a global threat to the health of humans, animals, and plants. Epidemiology of fungal diseases is not completely understood in Africa. Most of these diseases are under-reported or not reported at all mainly due to the challenges related to the availability of and access to fungal diagnostics and the lack of human resources in clinical and diagnostic mycology across the continent. Therefore, it is imperative to highlight the epidemiology of the endemic and epidemic of emerging and re-emerging fungal diseases as well as their diagnostic challenges in Africa based on the available data. Moreover, it is important to underline the existing gaps in this regard as well.

Materials and Methods:

For the purposes of the study, Medline and Google Scholar were searched to retrieve articles on these prominent fungal diseases, as well as their etiologies and available diagnostics.

Results:

It was found that histoplasmosis and other AIDS-associated mycoses have been reported in Africa, including blastomycosis, coccidioidomycosis, and paracocci-dioidomycosis. Other reported infections were fungal neglected tropical diseases, especially sporotrichosis, dermatophytosis, mycetoma, and chromoblastomycosis as well as emerging fungal diseases, such as Emergomyces africanus, Candida auris, and Blastomyces emzantsi. In Africa, the major drivers of fungal diseases include human immunodeficiency infection, tuberculosis, and poverty.

Conclusion:

Serious fungal diseases are common in Africa; however, the true burden remains unknown.

Emergomycosis, an Emerging Systemic Mycosis in Immunocompromised Patients: Current Trends and Future Prospects

Recently, the global emergence of emergomycosis, a systemic fungal infection caused by a novel dimorphic fungus Emergomyces species has been observed among immunocompromised individuals. Though initially classified under the genus Emmonsia, a taxonomic revision in 2017 based on DNA sequence analyses placed five Emmonsia-like fungi under a separate genus Emergomyces. These include Emergomyces pasteurianus, Emergomyces africanus, Emergomyces canadensis, Emergomyces orientalis, and Emergomyces europaeus. Emmonsia parva was renamed as Blastomyces parvus, while Emmonsia crescens and Emmonsia sola remained within the genus Emmonsia until a taxonomic revision in 2020 placed both the species under the genus Emergomyces. However, unlike other members of the genus, Emergomyces crescens and Emergomyces sola do not cause disseminated disease. The former causes adiaspiromycosis, a granulomatous pulmonary disease, while the latter has not been associated with human disease. So far, emergomycosis has been mapped across four continents: Asia, Europe, Africa and North America. However, considering the increasing prevalence of HIV/AIDS, it is presumed that the disease must have a worldwide distribution with many cases going undetected. Diagnosis of emergomycosis remains challenging. It should be considered in the differential diagnosis of histoplasmosis as there is considerable clinical and histopathological overlap between the two entities. Sequencing the internal transcribed spacer region of ribosomal DNA is considered as the gold standard for identification, but its application is compromised in resource limited settings. Serological tests are non-specific and demonstrate cross-reactivity with Histoplasma galactomannan antigen. Therefore, an affordable, accessible, and reliable diagnostic test is the need of the hour to enable its diagnosis in endemic regions and also for epidemiological surveillance. Currently, there are no consensus guidelines for the treatment of emergomycosis. The recommended regimen consists of amphotericin B (deoxycholate or liposomal formulation) for 1–2 weeks, followed by oral itraconazole for at least 12 months. This review elaborates the taxonomic, clinical, diagnostic, and therapeutic aspects of emergomycosis. It also enumerates several novel antifungal drugs which might hold promise in the treatment of this condition and therefore, can be potential areas of future studies.

A global view on fungal infections in humans and animals: infections caused by dimorphic fungi and dermatophytoses

Fungal infections are still underappreciated and their prevalence is underestimated, which renders them a serious public health problem. Realistic discussions about their distribution, symptoms, and control can improve management and diagnosis and contribute to refinement of preventive actions using currently available tools. This article represents an overview of dermatophytes and endemic fungi that cause infections in humans and animals. In addition, the impact of climate change on the fungal spread is discussed. The endemic fungal infections characterized in this article include coccidioidomycosis, histoplasmosis, blastomycosis, lobomycosis, emergomycosis and sporotrichosis. Moreover the geographic distribution of these fungi, which are known to be climate sensitive and/or limited to endemic tropical and subtropical areas, is highlighted. In turn, dermatophytes cause superficial fungal infections of skin, hairs and nails, which are the most prevalent mycoses worldwide with a high economic burden. Therefore, the possibility of causing zoonoses and reverse zoonoses by dermatophytes is highly important. In conclusion, the article illustrates the current issues of the epidemiology and distribution of fungal diseases, emphasizing the lack of public programmes for prevention and control of these types of infection.

Revision and Update of the Consensus Definitions of Invasive Fungal Disease From the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium

BACKGROUND

Invasive fungal diseases (IFDs) remain important causes of morbidity and mortality. The consensus definitions of the Infectious Diseases Group of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group have been of immense value to researchers who conduct clinical trials of antifungals, assess diagnostic tests, and undertake epidemiologic studies. However, their utility has not extended beyond patients with cancer or recipients of stem cell or solid organ transplants. With newer diagnostic techniques available, it was clear that an update of these definitions was essential.

METHODS

To achieve this, 10 working groups looked closely at imaging, laboratory diagnosis, and special populations at risk of IFD. A final version of the manuscript was agreed upon after the groups' findings were presented at a scientific symposium and after a 3-month period for public comment. There were several rounds of discussion before a final version of the manuscript was approved.

RESULTS

There is no change in the classifications of "proven," "probable," and "possible" IFD, although the definition of "probable" has been expanded and the scope of the category "possible" has been diminished. The category of proven IFD can apply to any patient, regardless of whether the patient is immunocompromised. The probable and possible categories are proposed for immunocompromised patients only, except for endemic mycoses.

CONCLUSIONS

These updated definitions of IFDs should prove applicable in clinical, diagnostic, and epidemiologic research of a broader range of patients at high-risk.

Re-drawing the Maps for Endemic Mycoses

Endemic mycoses such as histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, and talaromycosis are well-known causes of focal and systemic disease within specific geographic areas of known endemicity. However, over the past few decades, there have been increasingly frequent reports of infections due to endemic fungi in areas previously thought to be “non-endemic.” There are numerous potential reasons for this shift such as increased use of immune suppressive medications, improved diagnostic tests, increased disease recognition, and global factors such as migration, increased travel, and climate change. Regardless of the causes, it has become evident that our previous understanding of endemic regions for these fungal diseases needs to evolve. The epidemiology of the newly described Emergomyces is incomplete; our understanding of it continues to evolve. This review will focus on the evidence underlying the established areas of endemicity for these mycoses as well as new data and reports from medical literature that support the re-thinking these geographic boundaries. Updating the endemic fungi maps would inform clinical practice and global surveillance of these diseases.

Disseminated Emergomyces pasteurianus Infection in India: A Case Report and a Review

We report here a case of disseminated Emergomyces pasteurianus infection from India in a patient with AIDS. The patient presented with weight loss, dyspnoea and multiple non-tender skin lesions over face, neck and chest over 3 months. The case was diagnosed by microscopy, histopathology of sample and isolation of fungus from skin lesion, breast nodule, bone marrow and sputum. The identification of the isolates was confirmed by sequencing internal transcribed spacer region of rDNA, beta-tubulin, actin and intein PRP8. The patient responded well to intravenous amphotericin B deoxycholate followed by itraconazole therapy.

Molecular characterisation of emerging pathogens of unexplained infectious disease syndromes

Introduction: The discoveries of HIV and Helicobacter pylori in the 1980s were landmarks in identification of novel pathogens causing unexplained infectious syndromes using conventional microbiological technologies. In the last few decades, advancement of molecular technologies has provided us with more robust tools to expand our armamentarium in this microbial hunting process. Areas covered: In this article, we give a brief overview of the most important molecular technologies we use for identification of emerging microbes associated with unexplained infectious syndromes, including 16S rRNA and other conserved targets sequencing for bacteria, internal transcribed spacer (ITS) and other target gene sequencing for fungi, polymerase and other gene sequencing for viruses, as well as deep sequencing. Then, we use several representative examples to illustrate how these techniques have been used for the discoveries of a few notable bacterial, fungal and viral pathogens associated with unexplained infectious syndromes in the last 20-30 years. Expert opinion: In the past and present, characterization of emerging pathogens of unexplained infectious disease syndromes has relied on a combination of conventional culture- and phenotype-based technologies and nucleic acid amplification and sequencing. In the next era, we envisage more widespread adoption of next generation technologies that can detect both known and previously undescribed pathogens.

Emerging Fungal Infections: New Patients, New Patterns, and New Pathogens

The landscape of clinical mycology is constantly changing. New therapies for malignant and autoimmune diseases have led to new risk factors for unusual mycoses. Invasive candidiasis is increasingly caused by non-albicans Candida spp., including C. auris, a multidrug-resistant yeast with the potential for nosocomial transmission that has rapidly spread globally. The use of mould-active antifungal prophylaxis in patients with cancer or transplantation has decreased the incidence of invasive fungal disease, but shifted the balance of mould disease in these patients to those from non-fumigatus Aspergillus species, Mucorales, and Scedosporium/Lomentospora spp. The agricultural application of triazole pesticides has driven an emergence of azole-resistant A. fumigatus in environmental and clinical isolates. The widespread use of topical antifungals with corticosteroids in India has resulted in Trichophyton mentagrophytes causing recalcitrant dermatophytosis. New dimorphic fungal pathogens have emerged, including Emergomyces, which cause disseminated mycoses globally, primarily in HIV infected patients, and Blastomyceshelicus and B. percursus, causes of atypical blastomycosis in western parts of North America and in Africa, respectively. In North America, regions of geographic risk for coccidioidomycosis, histoplasmosis, and blastomycosis have expanded, possibly related to climate change. In Brazil, zoonotic sporotrichosis caused by Sporothrix brasiliensis has emerged as an important disease of felines and people.