Epidemiology of endemic systemic fungal infections in Latin America

Genotypic diversity, virulence, and molecular genetic tools in Histoplasma

SUMMARYHistoplasmosis is arguably the most common fungal respiratory infection worldwide, with hundreds of thousands of new infections occurring annually in the United States alone. The infection can progress in the lung or disseminate to visceral organs and can be difficult to treat with antifungal drugs. Histoplasma, the causative agent of the disease, is a pathogenic fungus that causes life-threatening lung infections and is globally distributed. The fungus has the ability to germinate from conidia into either hyphal (mold) or yeast form, depending on the environmental temperature. This transition also regulates virulence. Histoplasma and histoplasmosis have been classified as being of emergent importance, and in 2022, the World Health Organization included Histoplasma as 1 of the 19 most concerning human fungal pathogens. In this review, we synthesize the current understanding of the ecological niche, evolutionary history, and virulence strategies of Histoplasma. We also describe general patterns of the symptomatology and epidemiology of histoplasmosis. We underscore areas where research is sorely needed and highlight research avenues that have been productive.

Navigating the Complexities of Disseminated Histoplasmosis Diagnosis and Management in the Migrant Population: A Case Report

Histoplasma capsulatum is a dimorphic fungus that grows in nature as a mold or in culture but converts to a small yeast during cellular invasion. While most histoplasmosis infections are primarily asymptomatic or mildly symptomatic, disseminated histoplasmosis is a relentlessly progressive granulomatous disease that can mimic other granulomatous diseases, such as tuberculosis, sarcoidosis or coccidioidomycosis, more so in the proper context of immunosuppression. The current global migrant crisis, particularly the United States migrant crisis conversation is mostly socio-political; however, it also has a public health implication as exemplified by the case of a 35-year-old male who migrated from Haiti via Chile and Mexico to the United States. He presented with a four-day history of fever, generalized body aches, and cough. This case underscores the importance of entertaining a myriad of differentials and avoiding the tendency for anchoring, especially when initial therapy yields little clinical response.

Disseminated Histoplasmosis Infection Diagnosed by Metagenomic Next-Generation Sequencing: A Case Report

Histoplasmosis is an endemic disease caused by Histoplasma capsulatum. This systemic disease can affect various organs beyond the lungs, such as the liver, spleen, adrenal gland, and lymph nodes. The clinical symptoms can range from asymptomatic to severe, life-threatening conditions, depending on the state of the patient's immune system. This report describes a 40-year-old male who presented with reports of weight loss, low back pain, and progressively worsening movement disorder of the bilateral lower extremities for months. Computed tomography (CT) examination showed multiple lytic lesions of vertebral bodies, bilateral ribs, and pelvic bone, histopathological examination and tumor-related serum markers exclude tumors. mNGS was employed to identify H. capsulatum var. capsulatum as the etiological agent of the lesions in the bone biopsy. Through phylogenetic tree analysis, Histoplasma capsulatum var. Capsulatum (Hcc) was the main responsible pathogen, rarely reported in bone lesions. The patient underwent spinal surgery and was successfully treated with liposomal amphotericin B and itraconazole. Based on the diagnosis and treatment of this case, we discuss the epidemiologic status, clinical presentations, diagnostic criteria, and treatment guidelines of histoplasmosis to provide additional information about this disease. mNGS is utilized in this case, and it appears to be a reliable method for early and accurate diagnosis of this disease.

Identification and production of novel potential pathogen-specific biomarkers for diagnosis of histoplasmosis

IMPORTANCE

Histoplasmosis is considered one of the most important mycoses due to the increasing number of individuals susceptible to develop severe clinical forms, particularly those with HIV/AIDS or receiving immunosuppressive biological therapies, the high mortality rates reported when antifungal treatment is not initiated in a timely manner, and the limitations of conventional diagnostic methods. In this context, there is a clear need to improve the capacity of diagnostic tools to specifically detect the fungal pathogen, regardless of the patient's clinical condition or the presence of other co-infections. The proposed novel pathogen-specific biomarkers have the potential to be used in immunodiagnostic platforms and antifungal treatment monitoring in histoplasmosis. In addition, the bioinformatics strategy used in this study could be applied to identify potential diagnostic biomarkers in other models of fungal infection of public health importance.

Mycological diagnosis of paracoccidioidomycosis in a hospital from a nonendemic area: classical and molecular methods

Introduction

Paracoccidioidomycosis is a systemic mycosis endemic in Latin America. Climate change and host migration emphasize the need to optimize this infection diagnosis.

Objective

To evaluate the implementation of Paracoccidioides spp. DNA detection in the mycological diagnosis of patients with suspected paracoccidioidomycosis.

Materials and methods

It is a retrospective study with laboratory data from patients with clinical suspicion of paracoccidioidomycosis, who consulted a university hospital from a non-endemic area.

Results

We analyzed the laboratory results of samples from 19 patients with suspected paracoccidioidomycosis. Seventeen out of 19 patients were born in or had visited an endemic area in Latin America. Fourteen adult male patients were confirmed to have paracoccidioidomycosis by conventional diagnosis: the direct examination was positive in 12 samples while fungal growth was found only in 4. Anti-Paracoccidioides spp. antibodies were detected in 10 patients, 8 of them with proven paracoccidioidomycosis. Nested PCR for Paracoccidioides spp. detection was performed on clinical samples from 14 patients, and positive results were obtained for 9 out of 10 patients with the conventional diagnosis of paracoccidioidomycosis.

Conclusions

The incorporation of molecular techniques to detect Paracoccidioides spp. DNA complements the conventional diagnosis of paracoccidioidomycosis. This tool allows the prescription of antifungal treatment in those cases where the fungus is not observed in the clinical samples.

The relevance of clinical and epidemiological correlation in the early diagnosis of histoplasmosis: report of two clinical cases in Popayán, Colombia

Histoplasmosis is an endemic mycosis in Colombia. Here we present two cases in the Cauca department, to indicate the clinical impact of histoplasmosis delayed diagnosis and treatment when its epidemiology is unknown. Informed consent was requested to review patients’ medical records and case report publication. The first case was a patient diagnosed with human immunodeficiency virus and generalized presence of skin lesions. Initially, these lesions were diagnosed as herpes, but a postmortem diagnosis confirmed histoplasmosis through fungal cultures of tissues from the skin lesions. The second case is an immunocompetent patient with pulmonary symptoms diagnosed and treated for tuberculosis. However, given the lack of improvement and considering the bat cave entrance history, the patient was treated for possible pulmonary histoplasmosis with an adequate response. We made a review of laboratory tests and histoplasmosis epidemiological data relevant to health professionals. We concluded that health institutions must provide rapid tests, such as antigen ones, to adequately diagnose and treat this mycosis; and also take corrective measures to minimize exposure to Histoplasma.

Identification and immunogenic potential of glycosylphosphatidylinositol-anchored proteins in Paracoccidioides brasiliensis

In fungal pathogens the cell wall plays an important role in host-pathogen interactions because its molecular components (e.g., polysaccharides and proteins) may trigger immune responses during infection. GPI-anchored proteins represent the main protein class in the fungal cell wall where they can perform several functions, such as cell wall remodeling and adhesion to host tissues. Genomic analysis has identified the complement of GPI-anchored proteins in many fungal pathogens, but the function has remained unknown for most of them. Here, we conducted an RNA expression analysis of GPI-anchored proteins of Paracoccidioides brasiliensis which causes paracoccidioidomycosis (PCM), an important human systemic mycosis endemic in Latin America. The expression of the GPI-anchored proteins was analyzed by quantitative PCR in both the mycelium and yeast forms. qPCR analysis revealed that the transcript levels of 22 of them were increased in hyphae and 10 in yeasts, respectively, while 14 did not show any significant difference in either form. Furthermore, we cloned 46 open reading frames and purified their corresponding GPI-anchored proteins in the budding yeast. Immunoblot and ELISA analysis of four purified GPI-anchored proteins revealed immune reactivity of these proteins against sera obtained from PCM patients. The information obtained in this study provides valuable information about the expression of many GPI-anchored proteins of unknown function. In addition, based on our immune analysis, some GPI-anchored proteins are expressed during infection and therefore, they might serve as good candidates for the development of new diagnostic methods.

Hemophagocytic lymphohistiocytosis secondary to histoplasmosis: A case report in a patient with AIDS and recent SARS-CoV-2 infection and minireview

Here, we describe the case of a naïve HIV late presenter female African patient with progressive disseminated histoplasmosis and a severe life-threatening clinical picture in a non-endemic area. She had not visited Africa in the past decade. She developed a reactive hemophagocytic lymphohistiocytosis and an acute psychiatric disorder. Histoplasmosis was diagnosed after two bone marrow biopsies. Therapy with liposomal amphotericin B resulted in rapid and progressive improvements in blood examinations and clinical conditions, including the disappearance of psychiatric disorders. The characteristics of our case were compared with those of all other cases of hemophagocytic syndrome secondary to histoplasmosis in HIV-positive patients reported in PubMed. In conclusion, clinicians outside endemic areas should evaluate histoplasmosis as a cause of severe clinical picture, especially in a patient with a travel history to an endemic area, even after many years, considering the possible reactivation of latent infection.

The immunosuppressive activity of myeloid-derived suppressor cells in murine Paracoccidioidomycosis relies on Indoleamine 2,3-dioxygenase activity and Dectin-1 and TLRs signaling

Paracoccidioidomycosis (PCM) is a systemic mycosis with a high incidence in Latin America. Prior studies have demonstrated the significance of the enzyme Indoleamine 2,3-dioxygenase (IDO-1) in the immune regulation of PCM as well as the vital role of myeloid-derived suppressor cells (MDSCs) in moderating PCM severity. Additionally, Dectin-1 and Toll-Like Receptors (TLRs) signaling in cancer, infection, and autoimmune diseases have been shown to impact MDSC-IDO-1⁺ activity. To expand our understanding of MDSCs and the role of IDO-1 and pattern recognition receptors (PRRs) signaling in PCM, we generated MDSCs in vitro and administered an IDO-1 inhibitor before challenging the cells with Paracoccidioides brasiliensis yeasts. By co-culturing MDSCs with lymphocytes, we assessed T-cell proliferation to examine the influence of IDO-1 on MDSC activity. Moreover, we utilized specific antibodies and MDSCs from Dectin-1, TLR4, and TLR2 knockout mice to evaluate the effect of these PRRs on IDO-1 production by MDSCs. We confirmed the importance of these in vitro findings by assessing MDSC-IDO-1⁺ in the lungs of mice following the fungal infection. Taken together, our data show that IDO-1 expression by MDSCs is crucial for the control of T-cell proliferation, and the production of this enzyme is partially dependent on Dectin-1, TLR2, and TLR4 signaling during murine PCM.

Paracoccidioides lutzii Formamidase Contributes to Fungal Survival in Macrophages

Nitrogen is a crucial nutrient for microorganisms that compose essential biomolecules. However, hosts limit this nutrient as a strategy to counter infections, therefore, pathogens use adaptive mechanisms to uptake nitrogen from alternative sources. In fungi, nitrogen catabolite repression (NCR) activates transcription factors to acquire nitrogen from alternative sources when preferential sources are absent. Formamidase has been related to nitrogen depletion in Aspergillus nidulans through formamide degradation to use the released ammonia as a nitrogen source. In Paracoccidioides spp., formamidase is highly expressed in transcriptomic and proteomic analyses. Here, we aim to investigate the importance of formamidase to Paracoccidioides lutzii. Thereby, we developed a P. lutzii silenced strain of fmd gene (AsFmd) by antisense RNA technology using Agrobacterium tumefaciens-mediated transformation (ATMT). The AsFmd strain led to increased urease expression, an enzyme related to nitrogen assimilation in other fungi, suggesting that P. lutzii might explore urease as an alternative route for ammonia metabolism as a nitrogen source. Moreover, formamidase was important for fungal survival inside macrophages, as fungal recovery after macrophage infection was lower in AsFmd compared to wild-type (WT) strain. Our findings suggest potential alternatives of nitrogen acquisition regulation in P. lutzii, evidencing formamidase influence in fungal virulence.

Comparison of Immunodiagnostic Assays for the Rapid Diagnosis of Coccidioidomycosis in Dogs

Coccidioidomycosis is a disease caused by the dimorphic fungi Coccidioides spp., which affects humans and a variety of animal species, including domestic dogs. In dogs, accurate diagnosis could provide a substantial improvement on the quality of canine life, as well as an advancement in the mapping of regions endemic for coccidioidomycosis. The purpose of this study was to compare immunodiagnostic assays for anti-Coccidioides antibody (Ab) detection in dogs’ serum. Three commercially available immunodiagnostic assays (IMMY^®; Norman, OK, USA) were evaluated, including the sōna Coccidioides Ab Lateral Flow Assay (LFA), Coccidioides IDCF immunodiffusion assay (IDCF), and the Clarus Coccidioides Ab Enzyme Immunoassay (EIA). Assays were evaluated using 98 dog serum samples: 29 from dogs with coccidioidomycosis, 15 from dogs diagnosed with histoplasmosis, 10 from dogs diagnosed with blastomycosis, and 44 from dogs without a fungal disease. Using specimens from dogs with coccidioidomycosis, the IDCF had an accuracy of 92% (95% confidence interval [95% CI] = 85–96%), the EIA had an accuracy of 91% (95% CI = 83–96%), and the LFA displayed an accuracy of 82% (95% CI = 73–89%). Using Kappa analysis, the agreement between LFA and EIA was 0.59 (95% CI = 0.42–0.75), that between LFA and IDCF was 0.64 (95% CI = 0.48–0.79), and that between EIA and IDCF was 0.79 (95% CI = 0.64–0.90). Most cross-reactions were observed in dogs with histoplasmosis. Compared with EIA and IDCF, the LFA requires substantially less laboratory equipment and infrastructure and rapidly produces results, offering a substantial improvement for the initial screening of coccidioidomycosis in dogs.

Hemophagocytic Lymphohistiocytosis Secondary to Disseminated Histoplasmosis in HIV Seronegative Patients: A Case Report and Review of the Literature

Hemophagocytic lymphohistiocytosis (HLH) secondary to Histoplasma capsulatum infection is a rare disorder with poor outcome. Although cases of patients with human immunodeficiency virus (HIV) infection have been well documented, little study has reported in the setting of HIV seronegative. In this study, we report a case of HLH secondary to histoplasmosis in an immunocompetent patient in China and review all cases on this situation. The objective was to summary their epidemiology, clinical characteristics, diagnostic approaches, and therapeutic response. A 46-year-old male cooker presented fever, fatigue, anorexia, and weight loss. Bone marrow examination suggest fungus organism and hemophagocytosis, and further, bone marrow culture confirmed Histoplasma capsulatum, as the etiology of HLH. The patient was successfully treated. We reviewed a total of the 13 cases (including our patient) of HLH with histoplasmosis in intact immunology patients. Twelve of the 13 patients are from endemic areas, and nine of the 12 cases are from emerging endemic areas, India and China. Three patients had sojourn history may related to the disease onset. Twelve of the 13 cases fulfilled HLH-2004 criteria. The diagnosis of Histoplasma capsulatum infection was established by histological examination (13 of 13), culture (4 of 13), molecular method (2 of 13), and antigen or serological assays (2 of 13). Amphotericin B, posaconazole, and itraconazole show favorable activity against the fungus, seven patients used specific treatment for HLH. For analysis of outcomes, two of the 13 patients died. Our present case report and literature review show that disseminated Histoplasma capsulatum infection with HLH in the immunocompetent population becomes increasingly common in emerging endemic areas and have high mortality. It is necessary for clinicians to improve the awareness of disease diagnosis due to the atypical population and disease presentation. Timely diagnosis and early use of antifungal agents will lead to favorable prognosis.

Clinical and Eco-Epidemiological Aspects of a Novel Hyperendemic Area of Paracoccidioidomycosis in the Tocantins-Araguaia Basin (Northern Brazil), Caused by Paracoccidioides sp

Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Brazil. The disease is caused by dimorphic fungi nested within the Paracoccidioides genus. We described 106 PCM cases (47.1 cases/year) at the Tropical Diseases Public Hospital of Tocantins State. PCM was prevalent in males and rural workers over 50 years; the chronic pulmonary form predominated in 67% of cases. The male-to-female ratio was 2.65:1, with more women affected than other endemic regions of Brazil. Urban or indoor activities were reported in women and are ascribed to disease urbanization. qPCR-based assays confirmed the identification of Paracoccidioides DNA in 37 biological specimens. Paracoccidioides sp. DNA was found in 53% of the environmental samples, suggesting autochthonous infections. Therefore, the Tocantins-Araguaia basin must be considered a novel hyperendemic area of PCM in Brazil, reinforcing the importance of including PCM as a notifiable disease, requiring specific diagnosis and health measures.

Challenges in Serologic Diagnostics of Neglected Human Systemic Mycoses: An Overview on Characterization of New Targets

Systemic mycoses have been viewed as neglected diseases and they are responsible for deaths and disabilities around the world. Rapid, low-cost, simple, highly-specific and sensitive diagnostic tests are critical components of patient care, disease control and active surveillance. However, the diagnosis of fungal infections represents a great challenge because of the decline in the expertise needed for identifying fungi, and a reduced number of instruments and assays specific to fungal identification. Unfortunately, time of diagnosis is one of the most important risk factors for mortality rates from many of the systemic mycoses. In addition, phenotypic and biochemical identification methods are often time-consuming, which has created an increasing demand for new methods of fungal identification. In this review, we discuss the current context of the diagnosis of the main systemic mycoses and propose alternative approaches for the identification of new targets for fungal pathogens, which can help in the development of new diagnostic tests.

Invasive and Subcutaneous Infections Caused by Filamentous Fungi: Report from a Portuguese Multicentric Surveillance Program

Invasive fungal infections (IFI) have significantly increased over the past years due to advances in medical care for the at-risk immunocompromised population. IFI are often difficult to diagnose and manage, and can be associated with substantial morbidity and mortality. This study aims to contribute to understanding the etiology of invasive and subcutaneous fungal infections, their associated risk factors, and to perceive the outcome of patients who developed invasive disease, raising awareness of these infections at a local level but also in a global context. A laboratory surveillance approach was conducted over a seven-year period and included: (i) cases of invasive and subcutaneous fungal infections caused by filamentous/dimorphic fungi, confirmed by either microscopy or positive culture from sterile samples, (ii) cases diagnosed as probable IFI according to the criteria established by EORTC/MSG when duly substantiated. Fourteen Portuguese laboratories were enrolled. Cases included in this study were classified according to the new consensus definitions of invasive fungal diseases (IFD) published in 2020 as follows: proven IFI (N = 31), subcutaneous fungal infection (N = 23). Those proven deep fungal infections (N = 54) totalized 71.1% of the total cases, whereas 28.9% were classified as probable IFI (N = 22). It was possible to identify the etiological fungal agent in 73 cases (96%). Aspergillus was the most frequent genera detected, but endemic dimorphic fungi represented 14.47% (N = 11) of the total cases. Despite the small number of cases, a high diversity of species were involved in deep fungal infections. This fact has implications for clinical and laboratory diagnosis, and on the therapeutic management of these infections, since different species, even within the same genus, can present diverse patterns of susceptibility to antifungals.

Diagnosis of Histoplasmosis Using the MVista Histoplasma Galactomannan Antigen Qualitative Lateral Flow-Based Immunoassay: A Multicenter Study

Background

Accurate and timely methods for the diagnosis of histoplasmosis in resource-limited countries are lacking. Histoplasma antigen detection by enzyme immunoassay (EIA) is widely used in the United States (US) but not in resource-limited countries, leading to missed or delayed diagnoses and poor outcomes. Lateral flow assays (LFAs) can be used in this setting.

Methods

Frozen urine specimens were submitted to MiraVista diagnostics for antigen testing from 3 medical centers in endemic areas of the US. They were blinded and tested for the MVista Histoplasma LFA. Patients were classified as controls or cases of histoplasmosis. Cases were divided into proven or probable; pulmonary or disseminated; immunocompetent or immunosuppressed; and mild, moderate, or severe.

Results

Three hundred fifty-two subjects were enrolled, including 66 cases (44 proven, 22 probable) and 286 controls. Most of the cases were immunocompromised (71%), and 46 had disseminated and 20 had pulmonary histoplasmosis. Four cases were mild, 42 moderate, and 20 severe. LFA and EIA were highly concordant (κ = 0.84). Sensitivity and specificity of the LFA were 78.8% and 99.3%, respectively. LFA sensitivity was higher in proven cases (93.2%), patients with disseminated (91.3%), moderate (78.6%), and severe disease (80%), and those with galactomannan levels >1.8 ng/mL (97.8%). Specificity was 99.3% in proven cases, 99.3% in patients with moderate or severe disease, and 96.8% in those with galactomannan levels >1.8 ng/mL. Cross-reactivity was noted with other endemic mycoses.

Conclusions

The MVista Histoplasma LFA meets the need for accurate rapid diagnosis of histoplasmosis in resource-limited countries, especially in patients with high disease burden, potentially reducing morbidity and mortality.

Histoplasmosis Related to Immunosuppression in a Patient with Crohn's Disease: A Diagnostic Challenge

BACKGROUND Infliximab, a monoclonal antibody against tumor necrosis factor (TNF) alpha with proven efficacy and known safety profile, is currently widely used in the treatment of inflammatory bowel diseases. Increased risk for serious infections and malignant neoplasms secondary to immunosuppression is a major concern during therapy with this medication. Histoplasmosis is a granulomatous disease caused by the fungus Histoplasma capsulatum. Disseminated forms of the disease have immunodepression as a major risk factor. CASE REPORT A 39-years-old man had been followed with refractory fistulizing ileocolonic Crohn's disease using combination therapy (infliximab plus azathioprine) and also receiving short courses of steroids. After 2 years of this immunosuppressive therapy, the patient presented with high fever (39.5ºC) for 5 days, associated with profuse sweating, and moderate pain in the left hypochondrium. The patient was hospitalized. Diagnoses of tuberculosis, malignancy, autoimmune diseases, and bacterial and viral infections were rapidly discarded after investigation. Clinical, laboratory, and image signs of liver involvement prompted a guided percutaneous biopsy, which revealed granulomatous hepatitis, with the presence of fungal structures suggestive of Histoplasma capsulatum. Upon treatment with liposomal amphotericin followed by itraconazole, the patient showed an impressively positive clinical response. CONCLUSIONS TNF blockers, particularly when associated with other immunosuppressors, are a serious risk factor for opportunistic infections. This unusual case of disseminated histoplasmosis in a patient with Crohn's disease using infliximab in combination with azathioprine and steroids emphasizes the need for surveillance of this uncommon but potentially lethal complication before starting TNF blockers therapy.

Closing gaps in histoplasmosis: clinical characteristics and factors associated with probable/histoplasmosis in HIV/AIDS hospitalized patients, a retrospective cross-sectional study in two tertiary centers in Pereira, Colombia

BACKGROUND

The HIV pandemic continues to cause a high burden of morbidity and mortality due to delayed diagnosis. Histoplasmosis is prevalent in Latin America and Colombia, is difficult to diagnose and has a high mortality. Here we determined the clinical characteristics and risk factors of histoplasmosis in people living with HIV (PLWH) in Pereira, Colombia.

MATERIALS AND METHODS

This was a retrospective cross-sectional study (2014-2019) involving two tertiary medical centers in Pereira, Colombia. People hospitalized with HIV were included. Histoplasma antigen detection was performed in urine samples. Probable histoplasmosis was defined according to European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group/National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria.

RESULTS

172 HIV-infected patients were analyzed. Histoplasmosis was confirmed in 29% (n = 50/172) of patients. The logistic regression analysis showed that the risk factors for histoplasmosis were pancytopenia (OR 4.1, 95% CI 1.6-10.3, P = 0.002), < 50 CD4 + cells/μL (OR 3.1, 95% CI 1.3-7.3, P = 0.006) and Aspartate transaminase (AST) levels > 46 IU/L (OR 3.2, 95% CI 1.3-8, P = 0.010).

CONCLUSIONS

Histoplasmosis is highly prevalent in hospitalized patients with HIV in Pereira, Colombia. The clinical findings are nonspecific, but there are some clinical abnormalities that can lead to suspicion of the disease, early diagnosis and prompt treatment. Urine antigen detection is useful for diagnosis, but is not widely available. An algorithmic approach is proposed for low-resource clinical settings.

Hemophagocytic lymphohistiocytosis secondary to progressive disseminated histoplasmosis presenting as cellulitis

Histoplasmosis-associated hemophagocytic lymphohistiocytosis is a rate but lethal disease in immunocompromised hosts. Unusual clinical presentations make diagnosing invasive fungal infection even more challenging. Here we present a case of hemophagocytic lymphohistiocytosis secondary to progressive disseminated histoplasmosis presenting as cellulitis in a patient with systemic lupus erythematous. A high index of suspicion combined with histopathology and molecular diagnostic techniques are important to establish an accurate and timely diagnosis of opportunistic infections in immunocompromised patients.

Reintroduction of immunosuppressive medications in pediatric rheumatology patients with histoplasmosis: a case series

BACKGROUND

Children with rheumatic diseases (cRD) receiving immunosuppressive medications (IM) are at a higher risk for acquiring potentially lethal pathogens, including Histoplasma capsulatum (histoplasmosis), a fungal infection that can lead to prolonged hospitalization, organ damage, and death. Withholding IM during serious infections is recommended yet poses risk of rheumatic disease flares. Conversely, reinitiating IM increases risk for infection recurrence. Tumor necrosis factor alpha inhibitor (TNFai) biologic therapy carries the highest risk for histoplasmosis infection after epidemiological exposure, so other IM are preferred during active histoplasmosis infection. There is limited guidance as to when and how IM can be reinitiated in cRD with histoplasmosis. This case series chronicles resumption of IM, including non-TNFai biologics, disease-modifying anti-rheumatic drugs (DMARDs), and corticosteroids, following histoplasmosis among cRD.

CASE PRESENTATION

We examine clinical characteristics and outcomes of 9 patients with disseminated or pulmonary histoplasmosis and underlying rheumatic disease [juvenile idiopathic arthritis (JIA), childhood-onset systemic lupus erythematosus (cSLE), and mixed connective tissue disease (MCTD)] after reintroduction of IM. All DMARDs and biologics were halted at histoplasmosis diagnosis, except hydroxychloroquine (HCQ), and patients began antifungals. Following IM discontinuation, all patients required systemic or intra-articular steroids during histoplasmosis treatment, with 4/9 showing Cushingoid features. Four patients began new IM regimens [2 abatacept (ABA), 1 HCQ, and 1 methotrexate (MTX)] while still positive for histoplasmosis, with 3/4 (ABA, MTX, HCQ) later clearing their histoplasmosis and 1 (ABA) showing decreasing antigenemia. Collectively, 8/9 patients initiated or continued DMARDs and/or non-TNFai biologic use (5 ABA, 1 tocilizumab, 1 ustekinumab, 3 MTX, 4 HCQ, 1 leflunomide). No fatalities, exacerbations, or recurrences of histoplasmosis occurred during follow-up (median 33 months).

CONCLUSIONS

In our cohort of cRD, histoplasmosis course following reintroduction of non-TNFai IM was favorable, but additional studies are needed to evaluate optimal IM management during acute histoplasmosis and recovery. In this case series, non-TNFai biologic, DMARD, and steroid treatments did not appear to cause histoplasmosis recurrence. Adverse events from corticosteroid use were common. Further research is needed to implement guidelines for optimal use of non-TNFai (like ABA), DMARDs, and corticosteroids in cRD following histoplasmosis presentation.

Progressive disseminated histoplasmosis in children living with HIV: a case series study

Progressive disseminated histoplasmosis (PDH) is thought to be on the top of the list of AIDS-defining illnesses in South America. Reported experience in children is very scarce. The aim of this study was to describe the clinical characteristics, management, and outcomes of children living with HIV presenting with PDH in Ecuador. We did a retrospective study using collected data on medical records of children living with HIV attended in Francisco Icaza Bustamante Children's Hospital (Guayaquil) between 1997 and 2019. The inclusion criteria consisted of patients under 18 years of age at admission with documented HIV infection and laboratory-confirmed diagnosis of PDH. Twenty-four children living with HIV were attended due to laboratory-confirmed PDH. Median CD4 cell count was 39 cells/mm³ (p25-p75 21-155) between 1 and 5 years and 22 cells/mm³ (p25-p75 10-57) for those aged 6 years and over. Fever (96%) was the most common clinical manifestation, followed by hepatomegaly (75%), cough (67%), weight loss (63%), diarrhea (63%), and abdominal distension (58%). Most significant laboratory findings were hypoalbuminemia (90%), hypertransaminasemia (78%), and pancytopenia (46%). Intravenous treatment with amphotericin B deoxycholate was started in all but one case in which diagnosis was postmortem. All these 23 patients were discharged after being hospitalized for a median of 68 days (p25-p75 48-90). Two children showed relapse during follow-up, one of whom died during the hospitalization of this second episode of PDH.Conclusion: Clinical manifestations and laboratory findings of PDH in children living with HIV seem similar to those seen in adults, and low CD4 cell count appears to be the most important risk factor. What is Known: • Since 1987, progressive disseminated histoplasmosis has been considered an AIDS-defining illness and, although underdiagnosis is frequent, is thought to be on the top of the list of AIDS-defining illnesses in South America. • Reported experience in children is very scarce. What is New: • Clinical manifestations and laboratory findings of progressive disseminated histoplasmosis in children living with HIV seem similar to those seen in adults. • Low CD4 cell count to be the most important risk factor.

Deep fungal infections diagnosed by histology in Uganda: a 70-year retrospective study

Fungal infections cause substantial morbidity and mortality. However, the burden of deep fungal infections is not well described in Uganda. We aimed to estimate the burden and etiology of histologically diagnosed deep fungal infections in Uganda. We retrospectively reviewed histology reports at the Pathology Reference Laboratory, Department of Pathology, Makerere University, Kampala, Uganda from January 1950 to September 2019 to identify any reports that had a fungal infection as the diagnosis. Over the study period, 697 cases of deep fungal infections were identified with an average incidence of 0.73/100,000 persons per decade. There was a general decline in the number of cases detected. Median age of the cases was 28 years (IQR: 11-40) and majority (59%) were male. The age group of 0-10 years were the most affected. The foot was the most affected part of the body (26%). Deep mycoses identified include eumycetoma (32%), subcutaneous phycomycosis (26%), histoplasmosis (9.2%), chromoblastomycosis (4.6%), aspergillosis (3.3%), cryptococcosis (3.3%), blastomycosis (1.6%), subcutaneous mycosis (1.4%), dermatomycosis (1.3%), coccidioidomycosis (0.6%), mucormycosis (0.6%), and sporotrichosis (0.1%). Histoplasma was the commonest causative agent (9.2%) followed by Aspergillus (3.4%) and Cryptococcus (3.3%), while 81% of the fungal pathogens were not identified to genus/species level. Only 31% of the cases were diagnosed clinically as deep fungal infections. There is a substantial burden of deep fungal infections caused by multiple fungal pathogens in Uganda. There is need to build local capacity for mycology so as to improve on the index of clinical suspicion and diagnostic capabilities.

Circulating Nestin-GFP+ Cells Participate in the Pathogenesis of Paracoccidioides brasiliensis in the Lungs

Multiple infectious diseases lead to impaired lung function. Revealing the cellular mechanisms involved in this impairment is crucial for the understanding of how the lungs shift from a physiologic to a pathologic state in each specific condition. In this context, we explored the pathogenesis of Paracoccidioidomycosis, which affects pulmonary functioning. The presence of cells expressing Nestin-GFP has been reported in different tissues, and their roles as tissue-specific progenitors have been stablished in particular organs. Here, we explored how Nestin-GFP⁺ cells are affected after lung infection by Paracoccidioides brasiliensis, a model of lung granulomatous inflammation with fibrotic outcome. We used Nestin-GFP transgenic mice, parabiosis surgery, confocal microscopy and flow cytometry to investigate the participation of Nestin-GFP⁺ cells in Paracoccidioides brasiliensis pathogenesis. We revealed that these cells increase in the lungs post-Paracoccidioides brasiliensis infection, accumulating around granulomas. This increase was due mainly to Nestin-GPF⁺ cells derived from the blood circulation, not associated to blood vessels, that co-express markers suggestive of hematopoietic cells (Sca-1, CD45 and CXCR4). Therefore, our findings suggest that circulating Nestin-GFP⁺ cells participate in the Paracoccidioides brasiliensis pathogenesis in the lungs.

Nanoparticles as a Tool for Broadening Antifungal Activities

Fungal infections are diseases that are considered neglected although their infection rates have increased worldwide in the last decades. Thus, since the antifungal arsenal is restricted and many strains have shown resistance, new therapeutic alternatives are necessary. Nanoparticles are considered important alternatives to promote drug delivery. In this sense, the objective of the present study was to evaluate the contributions of newly developed nanoparticles to the treatment of fungal infections. Studies have shown that nanoparticles generally improve the biopharmaceutical and pharmacokinetic characteristics of antifungals, which is reflected in a greater pharmacodynamic potential and lower toxicity, as well as the possibility of prolonged action. It also offers the proposition of new routes of administration. Nanotechnology is known to contribute to a new drug delivery system, not only for the control of infectious diseases but for various other diseases as well. In recent years, several studies have emphasized its application in infectious diseases, presenting better alternatives for the treatment of fungal infections.

Screening for acute disseminated histoplasmosis in HIV disease using urinary antigen detection enzyme immunoassay: A pilot study in Cameroon

Acute disseminated histoplasmosis (ADH) is an AIDS-defining illness and reported in Cameroon, but there are few data about its incidence. Between June and August 2019, we conducted a descriptive cross-sectional study to screen for histoplasmosis in a population of adults with HIV infection, irrespective of their CD4 T-cell counts, using Histoplasma urine antigen detection enzyme immunoassay (EIA) and histoplasmin skin test. Of the 138 participants screened, 36 (26%) had detectable antigen in urine, using an OD cut off of 0.045. Skin lesions were present in two (6%) cases. Of 39 patients tested for histoplasmin skin test positivity, one was positive. Histoplasma antigenuria was associated with a positive history of chest infection (Odds ratio: 3.632, 95% confidence interval: 1.635-8.071, p= 0.001). As 30 (21.7%) of titres were between 0.045 (the current cut off) and 0.25, the cut off may need adjustment in Cameroon, using disease confirmation with alternative, highly sensitive diagnostic approaches such as PCR and bone marrow examination. H. capsulatum infection appears to be common among HIV-infected patients attending outpatient clinics at the Buea Regional Hospital. There is an acute need to improve awareness and management of HIV patients with respect to H. capsulatum infection.

High prevalence and mortality due to Histoplasma capsulatum in the Brazilian Amazon: An autopsy study

BACKGROUND

Histoplasmosis is acquired by inhalation of spores of the dimorphic fungus Histoplasma spp. Although this pathogen is distributed worldwide, it is more prevalent in the Americas. However, the real burden of histoplasmosis remains undefined in many endemic regions.

METHODOLOGY

We conducted a series of 61 autopsies to individuals who died in a hospital in the Brazilian Amazon focused on infectious diseases. We performed a detailed histological and microbiological evaluation with genetic characterization of Histoplasma strains with the aim to evaluate the contribution of histoplasmosis to morbidity and mortality. Additionally, we assessed the clinicopathological correlation.

PRINCIPAL FINDINGS

Evidence of Histoplasma infection was detected in 21 patients (34%). Eight cases were disseminated infections, all of them occurred in HIV-positive patients. Six cases were localized histoplasmosis, limited to the lungs. In seven patients Histoplasma DNA was detected by PCR in patients with no histological lesions. Histoplasma infection was detected in 38% of HIV-positive patients and was a major contributor to death in 22% of them. Lungs, liver and spleen were affected in all cases of disseminated histoplasmosis. Phylogenetic analysis of the strains suggested a high diversity of Histoplasma species circulating in the Brazilian Amazon. Histoplasmosis was clinically missed in 75% of the disseminated infections.

CONCLUSIONS

The high incidence of histoplasmosis, the low index of clinical suspicion, and the severity of the disseminated disease highlight the need of proactively implementing sensitive routine screening methods for this pathogen in endemic areas. Antifungal prophylaxis against Histoplasma should be encouraged in the severely immunocompromised HIV patients in these areas. In conclusion, substantial mortality is associated with disseminated histoplasmosis among HIV-positive patients in the Brazilian Amazon.

Neutrophil and Eosinophil DNA Extracellular Trap Formation: Lessons From Pathogenic Fungi

Fungal infections represent a worldwide health problem. Fungal pathogens are responsible for a variety of conditions, including superficial diseases, allergic pathologies and potentially lethal invasive infections. Neutrophils and eosinophils have been implicated as effector cells in several pathologies. Neutrophils are major effector cells involved in the control of fungal infections and exhibit a plethora of antifungal mechanisms, such as phagocytosis, reactive oxygen species production, degranulation, extracellular vesicle formation, and DNA extracellular trap (ET) release. Eosinophils are polymorphonuclear cells classically implicated as effector cells in the pathogenesis of allergic diseases and helminthic infections, although their roles as immunomodulatory players in both innate and adaptive immunity are currently recognized. Eosinophils are also endowed with antifungal activities and are abundantly found in allergic conditions associated with fungal colonization and sensitization. Neutrophils and eosinophils have been demonstrated to release their nuclear and mitochondrial DNA in response to many pathogens and pro-inflammatory stimuli. ETs have been implicated in the killing and control of many pathogens, as well as in promoting inflammation and tissue damage. The formation of ETs by neutrophils and eosinophils has been described in response to pathogenic fungi. Here, we provide an overview of the mechanisms involved in the release of neutrophil and eosinophil ETs in response to fungal pathogens. General implications for understanding the formation of ETs and the roles of ETs in fungal infections are discussed.

Endemic and Other Dimorphic Mycoses in The Americas

Endemic fungi are thermally dimorphic fungi that have a limited geographic range and can cause both primary disease and opportunistic infections. The Americas are home to more genera of endemic fungi than anywhere else on earth. These include Coccidioides, Histoplasma, Blastomyces, Paracoccidioides, and Sporothrix. Endemic fungi are found across the Americas and the Caribbean, from Blastomyces gilchristi, which extends into the northeast corners of North America, to Histoplasma capsulatum, which occurs all the way down in the southern regions of South America and into the Caribbean Islands. Symptoms of endemic fungal infection, when present, mimic those of many other diseases and are often diagnosed only after initial treatment for a bacterial or viral disease has failed. Endemic fungi place a significant medical burden on the populations they affect, especially in immunocompromised individuals and in resource-limited settings. This review summarizes the ecology, geographical range, epidemiology, and disease forms of the endemic fungi found in the Americas. An emphasis is placed on new and proposed taxonomic changes, including the assignment of new species names in Histoplasma, Blastomyces, and Paracoccidioides.

Paracoccidioides brasiliensis Releases a DNase-Like Protein That Degrades NETs and Allows for Fungal Escape

Paracoccidioidomycosis is a systemic fungal disease, considered endemic in Latin America. Its etiological agents, fungi of the Paracoccidioides complex, have restricted geographic habitat, conidia as infecting form, and thermo-dimorphic characteristics. Polymorphonuclear neutrophils (PMNs) are responsible for an important defense response against fungus, releasing Neutrophil Extracellular Traps (NETs), which can wrap and destroy the yeasts. However, it has been described that some pathogens are able to evade from these DNA structures by releasing DNase as an escape mechanism. As different NETs patterns have been identified in PMNs cultures challenged with different isolates of Paracoccidioides brasiliensis, the general objective of this study was to identify if different patterns of NETs released by human PMNs challenged with Pb18 (virulent) and Pb265 (avirulent) isolates would be correlated with fungal ability to produce a DNase-like protein. To this end, PMNs from healthy subjects were isolated and challenged in vitro with both fungal isolates. The production, release, and conformation of NETs in response to the fungi were evaluated by Confocal Microscopy, Scanning Microscopy, and NETs Quantification. The identification of fungal DNase production was assessed by DNase TEST Agar, and the relative gene expression for hypothetical proteins was investigated by RT-qPCR, whose genes had been identified in the fungal genome in the GenBank (PADG_11161 and PADG_08285). It was possible to verify the NETs release by PMNs, showing different NETs formation when in contact with different isolates of the fungus. The Pb18 isolate induced the release of looser, larger, and more looking like degraded NETs compared to the Pb265 isolate, which induced the release of denser and more compact NETs. DNase TEST Agar identified the production of a DNase-like protein, showing that only Pb18 showed the capacity to degrade DNA in these plates. Besides that, we were able to identify that both PADG_08528 and PADG_11161 genes were more expressed during interaction with neutrophil by the virulent isolate, being PADG_08528 highly expressed in these cultures, demonstrating that this gene could have a greater contribution to the production of the protein. Thus, we identified that the virulent isolate is inducing more scattered and loose NETs, probably by releasing a DNase-like protein. This factor could be an important escape mechanism used by the fungus to escape the NETs action.

Paracoccidioimycosis and white individuals: Susceptibility and biogeographic aspects in an important endemic area in Brazil

Paracoccidioidomycosis (PCM) is a neglected mycosis most commonly occurring in Latin America. The etiologic agents are thermo dimorphic fungi of the genus Paracoccidioides, and cause an important granulomatous response in affected tissues. The Botucatu Medical School, from São Paulo State University (UNESP), is a PCM study pole, located in São Paulo State Midwest region, which is classified as a hyperendemic area in the Southeast region in Brazil. This study aimed to perform a retrospective epidemiological, geographical, and clinical analysis by the information available in medical records. It was listed as socio-demographic data along with clinical characteristics from patients diagnosed and treated during a 10-year period in Botucatu, totaling 177 patients with Paracoccidioidomycosis confirmed by the histopathological test. It was observed that the main clinical presentation was the chronic type (76,3%), most commonly identified in white male individuals over the age of 29 years old, smokers, and alcoholics, providing evidences for the first time that white individuals were more affected by the disease, in comparison to non-white individuals that may be more resistant to infection. This data opens new avenues for study within ancestry, resistance and susceptibility in paracoccidioidomycosis.

Immunoproteomic Analysis Reveals Novel Candidate Antigens for the Diagnosis of Paracoccidioidomycosis Due to Paracoccidioides lutzii

Paracoccidioidomycosis (PCM) is a life-threatening systemic infection caused by the fungal pathogen Paracoccidioides brasiliensis and related species. Whole-genome sequencing and stage-specific proteomic analysis of Paracoccidioides offer the opportunity to profile humoral immune responses against P. lutzii and P. brasiliensis s. str. infection using innovative screening approaches. Here, an immunoproteomic approach was used to identify PCM-associated antigens that elicit immune responses by combining 2-D electrophoresis of P. lutzii and P. brasiliensis proteomes, immunological detection using a gold-standard serum, and mass spectrometry analysis. A total of 16 and 25 highly immunoreactive proteins were identified in P. lutzii and P. brasiliensis, respectively, and 29 were shown to be the novel antigens for Paracoccidioides species, including seven uncharacterized proteins. Among the panel of proteins identified, most are involved in metabolic pathways, carbon metabolism, and biosynthesis of secondary metabolites in both immunoproteomes. Remarkably, six isoforms of the surface-associated enolase in the range of 54 kDa were identified as the major antigens in human PCM due to P. lutzii. These novel immunoproteomes of Paracoccidioides will be employed to develop a sensitive and affordable point-of-care diagnostic assay and an effective vaccine to identify infected hosts and prevent infection and development of human PCM. These findings provide a unique opportunity for the refinement of diagnostic tools of this important neglected systemic mycosis, which is usually associated with poverty.

Detection of Histoplasma DNA from Tissue Blocks by a Specific and a Broad-Range Real-Time PCR: Tools to Elucidate the Epidemiology of Histoplasmosis

Lack of sensitive diagnostic tests impairs the understanding of the epidemiology of histoplasmosis, a disease whose burden is estimated to be largely underrated. Broad-range PCRs have been applied to identify fungal agents from pathology blocks, but sensitivity is variable. In this study, we compared the results of a specific Histoplasma qPCR (H. qPCR) with the results of a broad-range qPCR (28S qPCR) on formalin-fixed, paraffin-embedded (FFPE) tissue specimens from patients with proven fungal infections (n = 67), histologically suggestive of histoplasmosis (n = 36) and other mycoses (n = 31). The clinical sensitivity for histoplasmosis of the H. qPCR and the 28S qPCR was 94% and 48.5%, respectively. Samples suggestive for other fungal infections were negative with the H. qPCR. The 28S qPCR did not amplify DNA of Histoplasma in FFPE in these samples, but could amplify DNA of Emergomyces (n = 1) and Paracoccidioides (n = 2) in three samples suggestive for histoplasmosis but negative in the H. qPCR. In conclusion, amplification of Histoplasma DNA from FFPE samples is more sensitive with the H. qPCR than with the 28S qPCR. However, the 28S qPCR identified DNA of other fungi in H. qPCR-negative samples presenting like histoplasmosis, suggesting that the combination of both assays may improve the diagnosis.

The Therapy of Pulmonary Fibrosis in Paracoccidioidomycosis: What Are the New Experimental Approaches?

Pulmonary fibrosis (PF) is considered the most important sequela developed in patients suffering from the chronic form of paracoccidioidomycosis (PCM), which leads to the loss of respiratory function in 50% of cases; this residual pulmonary abnormality is present even after antifungal treatment. To date, there is no effective treatment for PF. However, the use of antifungal drugs in combination with other antibiotics or immunomodulatory compounds, as well as biological therapies that include a monoclonal antibody specific to neutrophils, or prophylactic vaccination employing a recombinant antigen of Paracoccidioides brasiliensis that successfully attenuated PF, has been reported. Additionally, mesenchymal stem cell transplantation in combination with antifungal therapy slightly reduced the inflammatory response and profibrotic molecules induced by P. brasiliensis infection. In this review, I report experimental findings from several studies aiming to identify promising therapeutic strategies for treating PF developed in PCM.

Crohn's disease or histoplasmosis? A case of severe disseminated histoplasmosis mimicking Crohn's disease and literature review

Disseminated histoplasmosis (DH) often mimics other diseases, leading to misdiagnosis and delays in treatment. We present a patient who developed DH after treatment with immunosuppressants for an initial diagnosis of inflammatory bowel disease (IBD). Upon diagnosing her with DH, liposomal amphotericin B was started, and she eventually recovered after a prolonged hospitalization. Intrabdominal histoplasmosis has many similarities with IBD. Treatment with immunosuppressants in undiagnosed histoplasmosis can lead to dissemination with potentially catastrophic results.

Disseminated histoplasmosis and tuberculosis: dual infection in a non-endemic region

Histoplasmosis is a systemic fungal infection caused by Histoplasma capsulatum, a dimorphic fungus that spreads commonly by contamination of soil with bird and bat droppings. The infection remains latent in most patients until manifested by reduced immune status, for example, HIV/AIDS, corticosteroid/immunosuppressive therapy or in solid organ transplant recipients. Tuberculosis and histoplasmosis may cooccur rarely in HIV and the clinical resemblance of both diseases may hinder identification of patients' harbouring dual infection, especially in regions non-endemic for histoplasmosis. We report a case of disseminated histoplasmosis with disseminated tuberculosis in an incidentally detected patient with HIV-positive who presented with reports of fever and skin rash for 10 days. The Mantoux positivity and CT of chest and abdomen revealing multiple necrotic lymph nodes coupled with bone marrow and skin biopsy divulging histoplasmosis and tuberculosis helped us clinch the concurrent infection.

Factors influencing susceptibility testing of antifungal drugs: a critical review of document M27-A4 from the Clinical and Laboratory Standards Institute (CLSI)

Due to the increasing numbers of fungal infections and the emergence of drug-resistant fungi, optimization and standardization of diagnostic methods for the measurement of antifungal susceptibility are ongoing. The M27-A4 document by the US Clinical and Laboratory Standards Institute (CLSI) is presently used for the interpretation of minimum inhibitory concentrations of major opportunistic yeast species as measured by broth microdilution testing in many countries. Although microdilution is considered a benchmark for reproducible and accurate results, increased testing capacity, and limited human bias, the method is often inaccessible to routine clinical laboratories and researchers, especially in low-income countries. Furthermore, several studies suggest that there are still a considerable number of factors that make the estimation of in vitro activity of antifungal agents challenging. This review article summarizes the limitations of the M27-A4 standard which, despite the advances and improvements obtained by the standardization of antimicrobial resistance testing methods by CLSI, still persist.

Metabolomics and Machine Learning Approaches Combined in Pursuit for More Accurate Paracoccidioidomycosis Diagnoses

Brazil and many other Latin American countries are areas of endemicity for different neglected diseases, and the fungal infection paracoccidioidomycosis (PCM) is one of them. Among the clinical manifestations, pneumopathy associated with skin and mucosal lesions is the most frequent. PCM definitive diagnosis depends on yeast microscopic visualization and immunological tests, but both present ambiguous results and difficulty in differentiating PCM from other fungal infections. This research has employed metabolomics analysis through high-resolution mass spectrometry to identify PCM biomarkers in serum samples in order to improve diagnosis for this debilitating disease. To upgrade the biomarker selection, machine learning approaches, using Random Forest classifiers, were combined with metabolomics data analysis. The proposed combination of these two analytical methods resulted in the identification of a set of 19 PCM biomarkers that show accuracy of 97.1%, specificity of 100%, and sensitivity of 94.1%. The obtained results are promising and present great potential to improve PCM definitive diagnosis and adequate pharmacological treatment, reducing the incidence of PCM sequelae and resulting in a better quality of life.IMPORTANCE Paracoccidioidomycosis (PCM) is a fungal infection typically found in Latin American countries, especially in Brazil. The identification of this disease is based on techniques that may fail sometimes. Intending to improve PCM detection in patient samples, this study used the combination of two of the newest technologies, artificial intelligence and metabolomics. This combination allowed PCM detection, independently of disease form, through identification of a set of molecules present in patients' blood. The great difference in this research was the ability to detect disease with better confidence than the routine methods employed today. Another important point is that among the molecules, it was possible to identify some indicators of contamination and other infection that might worsen patients' condition. Thus, the present work shows a great potential to improve PCM diagnosis and even disease management, considering the possibility to identify concomitant harmful factors.

Chronic progressive pulmonary paracoccidioidomycosis in a female immigrant from Venezuela

Paracoccidioidomycosis (PCM) is a fungal infection caused by Paracoccidioides brasiliensis and P. lutzii. It is endemic to South and Central America. While PCM frequently remains latent, the disease can reactivate years after the initial infection. As the disease is rare outside the endemic area, and symptoms can mimic other pulmonary diseases, correct diagnosis can be challenging for clinicians in developed countries. In this report, we present the case of a 57-year-old female Venezuelan immigrant with PCM. She was initially misdiagnosed with sarcoidosis and treated with corticosteroids, leading to an exacerbation of the infection requiring intensive care. Because cultivation of Paracoccidioides sp. is slow and unsensitive, we opted for microscopic observation of fungal elements and molecular testing on a tissue biopsy and bronchoalveolar lavage (BAL) together with antibody detection. This allowed the diagnosis of PCM, enabling specific management. PCM and other imported mycoses should be considered as a differential diagnosis in patients originating from South and Central America displaying symptoms suggestive of sarcoidosis. The reviews of this paper are available via the supplemental material section.

IL-22 Promotes IFN-γ-Mediated Immunity against Histoplasma capsulatum Infection

Histoplasma capsulatum is the agent of histoplasmosis, one of the most frequent mycoses in the world. The infection initiates with fungal spore inhalation, transformation into yeasts in the lungs and establishment of a granulomatous disease, which is characterized by a Th1 response. The production of Th1 signature cytokines, such as IFN-γ, is crucial for yeast clearance from the lungs, and to prevent dissemination. Recently, it was demonstrated that IL-17, a Th17 signature cytokine, is also important for fungal control, particularly in the absence of Th1 response. IL-22 is another cytokine with multiple functions on host response and disease progression. However, little is known about the role of IL-22 during histoplasmosis. In this study, we demonstrated that absence of IL-22 affected the clearance of yeasts from the lungs and increased the spreading to the spleen. In addition, IL-22 deficient mice (Il22-/-) succumbed to infection, which correlated with reductions in the numbers of CD4+ IFN-γ+ T cells, reduced IFN-γ levels, and diminished nitric oxide synthase type 2 (NOS2) expression in the lungs. Importantly, treatment with rIFN-γ mitigated the susceptibility of Il22-/- mice to H. capsulatum infection. These data indicate that IL-22 is crucial for IFN-γ/NO production and resistance to experimental histoplasmosis.

Histoplasma capsulatum 100-kilodalton antigen: recombinant production, characterization, and evaluation of its possible application in the diagnosis of histoplasmosis

The goal of the present work was to develop a novel reagent with potential for histoplasmosis diagnosis. For this purpose, the genetic sequence of the 100 kDa protein of Histoplasma capsulatum (Hcp100) was cloned and expressed as a secretory protein in Pichia pastoris. After optimizing the culture conditions and purifying by immobilized metal ion affinity chromatography, the highest yield of Hcp100 reached approximately 1.3 mg/l with > 90% purity in shake flasks using basal salt medium supplemented with casamino acids after 72 h of methanol induction. To investigate its potential for diagnosis, its detection in urine samples using specific polyclonal antibodies as reagent was evaluated by dot blot in 6 patients with progressive disseminated histoplasmosis (PDH), of whom all had AIDS. Antigen was detected in urine from all 6 (100%) PDH patients. Urine samples from a pool of 20 healthy individuals did not react with the anti-Hcp100 antibodies. The dot blot assay performed in this study provides preliminary data of a simple technology that can be performed in medical institutions with limited resources to facilitate the rapid diagnosis of histoplasmosis, particularly the disseminated forms. Hence, use of these assays may provide a rapid diagnostic tool of PDH in endemic areas for histoplasmosis where PDH-related mortality is high, hastening treatment and improving patient survival. Finally, this novel antigen and its specific antibodies may provide an alternative diagnostic reagent to the largely unknown and poorly characterized polysaccharide antigens (HPA, galactomannan, histoplasmin) frequently used in the diagnostic tests. KEY POINTS: Few antigens are used as laboratory tools for the immunodiagnosis of histoplasmosis. P. pastoris was an excellent system for recombinant Hcp100 expression. Maximum expression levels of rHcp100 were achieved in BSM with 1% casamino acids. Dot blot assays with anti-rHcp100 antisera can be successfully used for diagnosing PHD.

Adrenal paracoccidioidomycosis

Primary adrenal insufficiency is a defect in glucocorticoid, mineralocorticoid and sexual androgens production. Patients with this disorder have low cortisol levels and aldosterone deficiency with concomitant hyponatremia and hyperkalemia. The most common etiology of this disease is the production of antibodies against the enzyme 21 hydroxylase. Another common cause, particularly in low income countries, are infectious diseases. Several micro-organisms have been reported as a causal agent in adrenal insufficiency including Mycobacterium tuberculosis, Mycobacterium avium complex, Neisseria meningitidis, Pseudomonas aeruginosa, Haemophilus influenzae, cytomegalovirus, Pneumocystis jirovecii, Histoplasma capsulatum, Blastomyces dermatiditis, Cryptococcus neoformans, Cocciodiodes immitis, Nocardia spp. and Paracoccidioides brasiliensis. In this article, we present the computerized tomography and the adrenal biopsy of a patient with adrenal insufficiency. The final diagnosis was paracoccidioidomycosis.

Frequency of Invasive Fungal Disease in Adults: Experience of a Specialized Laboratory in Medellín, Colombia (2009-2015)

Invasive fungal diseases (IFD) contribute significantly to worldwide morbidity and mortality, but their frequency is not well-described in some countries. The present work describes the frequency of IFD in a specialized laboratory in Colombia. A retrospective, descriptive study was implemented between March 2009 and December 2015. Results: 13,071 patients with clinical suspicion of IFD were referred during the study period, from which 33,516 biological samples were processed and analyzed using 14 laboratory methods. Diagnosis was confirmed in 1425 patients (11%), distributed according to the mycoses of interest analyzed here: histoplasmosis in 641/11,756 patients (6%), aspergillosis in 331/10,985 patients (3%), cryptococcosis in 239/8172 patients (3%), pneumocystosis in 111/1651 patients (7%), paracoccidioidomycosis in 60/10,178 patients (0.6%), and invasive candidiasis in 48/7525 patients (0.6%). From the first year of the study period to the last year, there was a 53% increase in the number of cases of IFD diagnosed. Our laboratory experienced a high frequency of IFD diagnosis, possibly attributable to the availability of a greater range of diagnostic tools. Frequency of IFD in this study was atypical compared with other studies, probably as a result of the single laboratory-site analysis. This demonstrates that implementing educational strategies helps to create a high index of clinical suspicion, while the availability and utilization of appropriate diagnostic assays assure greater reliability in identification of these cases.

The global epidemiology of emerging Histoplasma species in recent years

Histoplasmosis is a serious infectious disease in humans caused by Histoplasma spp. (Onygenales), whose natural reservoirs are thought to be soil enriched with bird and bat guano. The true global burden of histoplasmosis is underestimated and frequently the pulmonary manifestations are misdiagnosed as tuberculosis. Molecular data on epidemiology of Histoplasma are still scarce, even though there is increasing recognition of histoplasmosis in recent years in areas distant from the traditional endemic regions in the Americas. We used multi-locus sequence data from protein coding loci (ADP-ribosylation factor, H antigen precursor, and delta-9 fatty acid desaturase), DNA barcoding (ITS1/2+5.8s), AFLP markers and mating type analysis to determine the genetic diversity, population structure and recognise the existence of different phylogenetic species among 436 isolates of Histoplasma obtained globally. Our study describes new phylogenetic species and the molecular characteristics of Histoplasma lineages causing outbreaks with a high number of severe outcomes in Northeast Brazil between 2011 and 2015. Genetic diversity levels provide evidence for recombination, common ancestry and clustering of Brazilian isolates at different geographic scales with the emergence of LAm C, a new genotype assigned to a separate population cluster in Northeast Brazil that exhibited low diversity indicative of isolation. The global survey revealed that the high genetic variability among Brazilian isolates along with the presence of divergent cryptic species and/or genotypes may support the hypothesis of Brazil being the center of dispersion of Histoplasma in South America, possibly with the contribution of migratory hosts such as birds and bats. Outside Brazil, the predominant species depends on the region. We confirm that histoplasmosis has significantly broadened its area of occurrence, an important feature of emerging pathogens. From a practical point of view, our data point to the emergence of histoplasmosis caused by a plethora of genotypes, and will enable epidemiological analysis focused on understanding the processes that lead to histoplasmosis. Further, the description of this diversity opens avenues for comparative genomic studies, which will allow progress toward a consensus taxonomy, improve understanding of the presence of hybrids in natural populations of medically relevant fungi, test reproductive barriers and to explore the significance of this variation.

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.

Case Report: Hemophagocytic Lymphohistiocytosis Caused by Disseminated Histoplasmosis in a Venezuelan Patient with HIV and Epstein-Barr Virus Reactivation Who Traveled to Japan

We describe a Venezuelan visitor to Japan who was diagnosed with hemophagocytic lymphohistiocytosis (HLH). The patient was also diagnosed with human immunodeficiency virus (HIV) and Epstein-Barr virus infection by the Western blot and polymerase chain reaction (PCR) tests, respectively. The cause of HLH was considered to be these two infections at first; however, the patient did not recover with antiretroviral/anti-herpes virus therapy. Thereafter, diagnosis of disseminated histoplasmosis was confirmed with an antigen detection test, culture, and PCR test of blood, urine, and bone marrow, and the patient improved gradually after the initiation of liposomal amphotericin B. This case highlights the importance of ruling out endemic mycosis as a cause of HLH even if other probable causes exist in patients from endemic areas.

An Outbreak of Febrile Histoplasmosis Among Chinese Manganese-Mine Workers in Cooperative Republic of Guyana in 2019

What is already known on this topic? Cases of histoplasmosis have been reported in every continent except Antarctica but are fairly rare in China. High prevalence of histoplasmosis has been observed in Central America, Caribbean, and South America. Infections of Histoplasma are acquired through a respiratory route, particularly inhalation of aerosols from disturbed soils enriched with excreta from birds and bats. These infections are most common in persons involved with removing soil, visiting caves, cleaning old houses, or felling trees, etc. What is added by this report? This is the first report of cluster infections of Histoplasmaamong overseas Chinese workers. A strong dose-dependent association of illness onset and disease severity with the exposure intensity to the soils and wastes possibly contaminated by the Histoplasmahas been proposed. Long labor times, repeated entering of contaminated tunnels, working in high-dust environments are likely to result in earlier illness onsets, more severe clinical courses, and even fatal outcomes. More importantly, none of the patients used reliable personal protection equipment (PPE), such as common masks while working, that would prevent the inhalation of more Histoplasmaspores. What are the implications for public health practice? The epidemiological findings of this outbreak investigation highlight a probable risk of infection with Histoplasma when entering without PPE into the environment with bats living around, such as caves or mines. Effective education and communication might be needed among residents and travelers. This outbreak expands our knowledge of the control and prevention of fungal disease in China.

Down-regulation of TUFM impairs host cell interaction and virulence by Paracoccidioides brasiliensis

The genus Paracoccidioides consist of dimorphic fungi geographically limited to the subtropical regions of Latin America, which are responsible for causing deep systemic mycosis in humans. However, the molecular mechanisms by which Paracoccidioides spp. causes the disease remain poorly understood. Paracoccidioides spp. harbor genes that encode proteins involved in host cell interaction and mitochondrial function, which together are required for pathogenicity and mediate virulence. Previously, we identified TufM (previously known as EF-Tu) in Paracoccidioides brasiliensis (PbTufM) and suggested that it may be involved in the pathogenicity of this fungus. In this study, we examined the effects of downregulating PbTUFM using a silenced strain with a 55% reduction in PbTUFM expression obtained by antisense-RNA (aRNA) technology. Silencing PbTUFM yielded phenotypic differences, such as altered translation elongation, respiratory defects, increased sensitivity of yeast cells to reactive oxygen stress, survival after macrophage phagocytosis, and reduced interaction with pneumocytes. These results were associated with reduced virulence in Galleria mellonella and murine infection models, emphasizing the importance of PbTufM in the full virulence of P. brasiliensis and its potential as a target for antifungal agents against paracoccidioidomycosis.