Jejunal Perforation Due to Histoplasmosis Regarding a Case.

Histoplasmosis is an increasing infection that mainly affects immunocompromised individuals such as patients with HIV/AIDS, with the disseminated form, especially gastrointestinal, being common in this population. The clinical presentation ranges from asymptomatic to symptoms that mimic other abdominal diseases. Jejunal perforation due to histoplasmosis, although rare, has been reported in a few cases, typically in men living with HIV in their fourth decade of life. We present the case of a 34-year-old male, with a history of HIV and colonic histoplasmosis who presented with acute abdominal pain requiring exploratory laparotomy and intestinal resection due to jejunal perforation, with histological confirmation of histoplasmosis in the resected intestinal segment.

Histoplasmosis oral como diagnóstico diferencial de cáncer oral. Serie de casos y revisión de la literatura / Oral histoplasmosis as a differential diagnosis of oral cancer. Case series and literature review

Objetivo: La histoplasmosis es una infección fúngica sistémica prevalente en la región del Río de la Plata. Puede exhibir manifestaciones orales, cutáneas y/o sistémicas. Las lesiones bucales significan un desafío diagnóstico debido a su semejanza clínica con el carcinoma oral de células escamosas (COCE). El objetivo de este trabajo fue presentar una serie de casos de histoplasmosis oral enfatizando la importancia del diagnóstico diferencial clínico con el COCE. Casos clínicos: Se describen casos de histoplasmosis oral diagnosticados en los últimos 5 años en la Cátedra de Estomatología "A" de la Facultad de Odontología de la Universidad Nacional de Córdoba, Córdoba, Argentina. En forma paralela, se realizó una revisión de la literatura de los últimos 10 años. Los casos corresponden a 9 pacientes, 6 varones y 3 mujeres, cuya edad promedio fue de 58,6 años. 4 pacientes eran VIH positivos. Se planteó la sospecha de COCE en 5 pacientes, cuya presentación clínica intraoral consistía en úlceras o lesiones ulcerovegetantes, mayormente únicas, ubicadas en la encía. La revisión bibliográfica arrojó un resultado de 48 artículos que incluyeron 60 casos de histoplasmosis oral, con una prevalencia mayor en hombres y similitudes clínicas con COCE en el 80% de los casos. La lesión más predominante fue la úlcera en el 85% de los casos, ubicada en lengua, seguido por el paladar. El diagnóstico de histoplasmosis oral es desafiante y requiere un amplio diferencial, ya que se asemeja a múltiples patologías, debiendo ser considerada ante lesiones ulcerativas orales. Un diagnóstico preciso, de manera interdisciplinaria, es esencial para un tratamiento efectivo.(AU)

Aim: Histoplasmosis is a systemic fungal infection prevalent in the Río de la Plata region. It could present oral, cutaneous and/or systemic manifestations. Oral lesions represent a diagnostic challenge due to their clinical similarity to oral squamous cell carcinoma (OSCC). The objective of this work is to present a case series of oral histoplasmosis emphasizing the importance of clinical differential diagnosis with OSCC. Clinical cases: Cases of oral histoplasmosis diagnosed in the last 5 years in the Oral Medicine Department "A" of the Facultad de Odontología of the Universidad Nacional de Córdoba, Córdoba, Argentina are discribed. Alongside, a literature review of the last 10 years was carried out. 9 patients are described, 6 men and 3 women, whose average age was 58.6 years. 4 patients were HIV positive. The suspicion of OSCC was raised in 5 patients, whose intraoral clinical presentation consisted of single ulcers or vegetating ulcers, mostly single, located in the gingiva. The literature review included a total of 48 articles with 60 cases of oral histoplasmosis, with a higher prevalence in men and clinical similarities with OSCC in 80% of cases. The most predominant lesion was the ulcer in 85% of the cases, mostly located on the tongue, followed by the palate. The diagnosis of oral histoplasmosis is challenging and requires a wide differential, since it can mimic multiple pathologies, and should be considered in oral ulcerative lesions. An accurate diagnosis, in an interdisciplinary framework, is essential for effective treatment.(AU)

Histoplasmosis in non-immunosuppressed patients from an endemic area in Northeastern Brazil.

Differently from immunocompromised patients, very little information is available in the literature regarding the clinical presentation, epidemiology, and outcomes of histoplasmosis in non-immunosuppressed individuals living in endemic areas. This retrospective case series study was carried out by reviewing the medical records of non-immunocompromised patients with histoplasmosis, residents in a hyperendemic area in northeastern Brazil, between 2011 and 2022. Thirty HIV-negative patients were identified with histoplasmosis, and 19 cases met the inclusion criteria: three had acute, five subacute and one chronic pulmonary forms; two with mediastinal picture and eight had disseminated disease (two with severe symptoms). The median age of our sample was 32.7 years old [interquartile range: 24-45]. Most of the patients were male (male-to-female ratio = 15:4) and resided in the state capital (n = 9). The majority had a previous history of exposure to well-known risk factors for Histoplasma infection. Pulmonary nodules were observed in all subacute form, two patients (acute and subacute forms) were initially treated empirically for pulmonary tuberculosis; one death was registered in the subacute form. The chronic pulmonary form of histoplasmosis was diagnosed in one patient only after the symptoms persisted despite specific treatment. The primary clinical manifestations of the moderate form of DH were enlarged lymph nodes, with histopathology being the main diagnostic method. The cases were detected as isolated occurrences and not as an outbreak, suggesting that exposure to Histoplasma can be more widespread than presumed. Despite the self-limiting nature of the disease, death can occur even in previously heathy patients.

This study aimed to describe the presentation of histoplasmosis outside the context of immunosuppression, including the diagnostic methods, epidemiology, and main radiological and clinical features. A better understanding of the various forms of this disease will help improve case management.

Histoplasmosis in Non-HIV Infected Patients: Another Neglected Infection in French Guiana.

(1) Background: Only a few studies on histoplasmosis in immunocompetent patients have been reported in French Guiana. Therefore, we conducted a detailed clinical description of hospitalized patients suffering with histoplasmosis among non-HIV patients. (2) Methods: This is a single-center, retrospective study conducted at Cayenne Hospital Center between 2008 and 2022. (3) Results: Our cohort was composed of 31 (91%) adults (>18 years of age) and 3 (9%) children, with a sex ratio, M:F, of 1:2. The median age was higher among the women than among the men (70 versus 54 years). The collection of respiratory samples constituted the majority of the performed examinations (38%). Fever (>37 °C) was found in 56% of patients. Surprisingly, the histoplasmosis was disseminated in 82% of patients with an overall case fatality rate of 14.7%. However, immunosuppressive conditions were found in 52% (16/31) of the adult patients, including lymphoid hemopathies, diabetes and immunosuppressive drugs. Conclusions: This disease, though rare and usually considered a mostly benign disease in non-HIV patients, presented a relatively high mortality rate in our cohort. Thus, histoplasmosis should be suspected, screened and investigated as a first line of defense in highly endemic areas, even in immunocompetent and non-HIV patients, especially those with fever or chronic respiratory symptoms.

Histoplasmosis Beyond Human Immunodeficiency Virus (HIV): Clinical Characteristics and Outcomes in a Non-HIV Population.

Histoplasmosis is an endemic and invasive mycosis caused by Histoplasma capsulatum. We conducted a retrospective study comparing immunosuppressed patients without human immunodeficiency virus (HIV) with a historical cohort of people with HIV and histoplasmosis. We included 199 patients with proven or probable histoplasmosis, of which 25.1% were people without HIV. Diabetes mellitus, chronic kidney disease, hematologic neoplasms, rheumatologic diseases, and transplantations were more frequent among people without HIV (P < .01). Forty-four percent of immunocompromised patients without HIV died within the first 6-week period following their diagnosis. A high suspicion index for histoplasmosis should be kept in immunosuppressed patients.

Proceedings of the second international meeting on endemic mycoses of the Americas (IMEMA) and first international symposium on implantation mycoses (ISIM).

The second international meeting on endemic mycoses of the Americas (IMEMA) and the first international symposium on implantation mycoses (ISIM) took place in Santiago del Estero, Argentina, on September 25-27, 2023. The conference provided a platform for researchers, clinicians, and experts to discuss the latest developments in the field of endemic and implantation mycoses. Topics included epidemiology, diagnostic advances, treatment strategies, and the impact of environmental factors on the spread of these fungal diseases. IMEMA and ISIM contributed to the regional discourse on the mycoses, emphasizing the importance of international cooperation in addressing these public health challenges.

IMEMA/ISIM, held in Santiago del Estero, Argentina, convened experts to discuss endemic and implantation mycoses, covering topics such as epidemiology, diagnostics, treatment, and advocacy. The event highlighted ongoing efforts in combating these diseases.

Management of disseminated histoplasmosis in a high-complexity clinic in Cali, Colombia.

Histoplasmosis presents a substantial clinical challenge globally, with a particular prevalence in South America, especially among patients with concurrent Human Immunodeficiency Virus (HIV) infection. Despite itraconazole's established efficacy, investigating alternative therapeutic approaches remains imperative. This is the largest study in our region to date, assessing the effectiveness of the less explored posaconazole treatment. This observational study, conducted at Fundación Valle del Lili (FVL) from 2016 to 2022, encompassed adults with disseminated histoplasmosis. Patients (n = 31) were treated with liposomal amphotericin B as an initial treatment, followed by consolidation treatment with posaconazole or itraconazole. Patients with single-organ cases, those lacking microbiological diagnosis, those who received initial treatment with antifungals other than liposomal Amphotericin B and those with < 6 months follow-up were excluded (Figure 1). Analyses considered population characteristics, treatments, and outcomes. Patients (average age: 45.6; 58.1% female) had common comorbidities (HIV 38.7%, solid organ transplantation 29% and oncologic disease 12.9%). Lungs (48.4%) and lymph nodes (16.1%) were commonly affected. Biopsy (64.5%) was the primary diagnostic method. Initial treatment with liposomal amphotericin B (100%) was given for 14 days on average. Follow-up indicated 71% completion with 19.4% requiring treatment modifications. Notably, 70.9% completed a posaconazole consolidation regimen over 350 days on average. Drug interactions during consolidation (80.6%) were common. No relapses occurred, and three deaths unrelated to histoplasmosis were reported. Traditionally, itraconazole has been the prevalent initial treatment; however, in our cohort, 55.9% of patients received posaconazole as the primary option. Encouragingly, posaconazole showed favorable tolerance and infection resolution, suggesting its potential as an effective and well-tolerated alternative for consolidation treatment. This finding prompts further exploration of posaconazole, potentially leading to more effective patient care and better outcomes.

Histoplasmosis is a critical concern in South America, notably among human immunodeficiency virus patients, leading to high mortality rates. This study, the largest in our region, investigates the effectiveness of posaconazole as an alternative treatment to itraconazole. The results offer the potential for enhanced patient care and improved outcomes.

Molecular detection of Histoplasma capsulatum in organ samples from bats randomly captured in urban areas of Araraquara, São Paulo state, Brazil.

The mycosis histoplasmosis is also considered a zoonosis that affects humans and other mammalian species worldwide. Among the wild mammals predisposed to be infected with the etiologic agent of histoplasmosis, bats are relevant because they are reservoir of Histoplasma species, and they play a fundamental role in maintaining and spreading fungal propagules in the environments since the infective mycelial phase of Histoplasma grows in their accumulated guano. In this study, we detected the fungal presence in organ samples of bats randomly captured in urban areas of Araraquara City, São Paulo, Brazil. Fungal detection was performed using a nested polymerase chain reaction to amplify a molecular marker (Hcp100) unique to H. capsulatum, which revealed the pathogen presence in organ samples from 15 out of 37 captured bats, indicating 40.5% of infection. Out of 22 Hcp100-amplicons generated, 41% corresponded to lung and trachea samples and 59% to spleen, liver, and kidney samples. Data from these last three organs suggest that bats develop disseminated infections. Considering that infected bats create environments with a high risk of infection, it is important to register the percentage of infected bats living in urban areas to avoid risks of infection to humans, domestic animals, and wildlife.

Influence of Zinc on Histoplasma capsulatum Planktonic and Biofilm Cells.

Histoplasma capsulatum causes a fungal respiratory disease. Some studies suggest that the fungus requires zinc to consolidate the infection. This study aimed to investigate the influence of zinc and the metal chelator TPEN on the growth of Histoplasma in planktonic and biofilm forms. The results showed that zinc increased the metabolic activity, cell density, and cell viability of planktonic growth. Similarly, there was an increase in biofilm metabolic activity but no increase in biomass or extracellular matrix production. N'-N,N,N,N-tetrakis-2-pyridylmethylethane-1,2 diamine (TPEN) dramatically reduced the same parameters in the planktonic form and resulted in a decrease in metabolic activity, biomass, and extracellular matrix production for the biofilm form. Therefore, the unprecedented observations in this study highlight the importance of zinc ions for the growth, development, and proliferation of H. capsulatum cells and provide new insights into the role of metal ions for biofilm formation in the dimorphic fungus Histoplasma, which could be a potential therapeutic strategy.

Presentación atípica de histoplasmosis diseminada / Atypical presentation of disseminated histoplasmosis

La histoplasmosis es una micosis sistémica producida por una variedad de hongo dimorfo perteneciente al complejo Histoplasma capsulatum. Es una enfermedad prevalente en nuestro medio y sobre todo en pacientes viviendo con HIV con recuento de <200 linfocitos CD4/ml y con cargas virales mayores a 100.000 copias/ml. La presentación de la forma diseminada raramente suele afectar al aparato reproductor; siendo la forma más frecuente pulmonar

Tracing histoplasmosis genomic epidemiology and species occurrence across the USA.

ABSTRACTHistoplasmosis is an endemic mycosis in North America frequently reported along the Ohio and Mississippi River Valleys, although autochthonous cases occur in non-endemic areas. In the United States, the disease is provoked by two genetically distinct clades of Histoplasma capsulatum sensu lato, Histoplasma mississippiense (Nam1) and H. ohiense (Nam2). To bridge the molecular epidemiological gap, we genotyped 93 Histoplasma isolates (62 novel genomes) including clinical, environmental, and veterinarian samples from a broader geographical range by whole-genome sequencing, followed by evolutionary and species niche modelling analyses. We show that histoplasmosis is caused by two major lineages, H. ohiense and H. mississippiense; with sporadic cases caused by H. suramericanum in California and Texas. While H. ohiense is prevalent in eastern states, H. mississipiense was found to be prevalent in the central and western portions of the United States, but also geographically overlapping in some areas suggesting that these species might co-occur. Species Niche Modelling revealed that H. ohiense thrives in places with warmer and drier conditions, while H. mississippiense is endemic to areas with cooler temperatures and more precipitation. In addition, we predicted multiple areas of secondary contact zones where the two species co-occur, potentially facilitating gene exchange and hybridization. This study provides the most comprehensive understanding of the genomic epidemiology of histoplasmosis in the USA and lays a blueprint for the study of invasive fungal diseases.

Estimated burden of fungal infections in Panama.

Data published on Panamanian fungal disease are scarce, mostly case reports. To date, there is no paper that compiles the burden of fungal disease Here we estimate for the first time the incidence and prevalence of fungal diseases in Panama. Data on fungal disease were obtained from different search engines: PubMed, Google Scholar, Scielo and Lilacs. For population and at risk diseases, we used statistics from worldometer, UNAIDS, and WHO. Incidence, prevalence, and absolute numbers were calculated based on the population at risk. Panamanian population in 2022 was 4,429,739. We estimated that 85,530 (1.93 %) people suffer from fungal diseases. The most frequent fungal infection was recurrent Candida vaginitis (3285/100,000). There are 31,000 HIV-infected people in Panama and based on the number of cases not receiving anti-retroviral therapy (14,570), and previous reports of prevalence of opportunistic infections, we estimated annual incidences of 4.0/100,000 for cryptococcal meningitis, 29.5/100,000 for oral candidiasis, 23.1/100,000 for esophageal candidiasis, 29.5/100,000 for Pneumocystis pneumonia, 15.1/100,000, and for histoplasmosis. For chronic pulmonary aspergillosis (CPA) and fungal asthma we used data from Guatemala and Colombia to estimate COPD and asthma prevalence and WHO report for tuberculosis. We estimated annual incidences of 6.1/100,000 for invasive aspergillosis and prevalence of 31.5/100,000 for CPA, 60.2/100,000 for allergic bronchopulmonary aspergillosis, and 79.5/100,000 for severe asthma with fungal sensitisation. Other incidence estimates were 5.0/100,000 for candidaemia, 0.20/100,000 for mucormycosis, and 4.97/100,000 for fungal keratitis. Even though this report on burden of fungal disease is a forward step, more epidemiological studies to validate these estimates are needed.

Clinical characteristics, diagnosis, treatment and outcomes of patients living with HIV and co-infected with tuberculosis and histoplasmosis: a 5-y retrospective case series.

BACKGROUND: In Latin America, tuberculosis (TB) and histoplasmosis are two of the most frequent opportunistic infections affecting people living with human immunodeficiency virus (HIV). However, there are limited data on the clinical characteristics and outcomes of patients with concurrent TB and histoplasmosis infections. METHODS: This was a retrospective observational study to describe the clinical, epidemiological and laboratory characteristics and outcomes of 21 patients living with HIV (PLHIV) who were diagnosed with concurrent histoplasmosis and TB between 2017 and 2021 in Guatemala City, Guatemala. RESULTS: Most patients were male and were newly diagnosed with HIV. All patients had advanced HIV disease (AHD). They presented with a median CD4 count of 20 cells/µl. The most common symptoms reported by the patients were fever, weight loss, cough and diarrhoea. Twelve patients died within 6 months of baseline evaluation, for a mortality rate of 57.1%. CONCLUSIONS: PLHIV with concurrent TB and histoplasmosis infections are characterised by AHD, predominantly presenting with disseminated forms of these infections and with unspecific symptoms and signs. This evidence calls for early HIV and opportunistic infection screening and insights into the challenges and opportunities for the efficient diagnostic and therapeutic management of patients with AHD with concurrent histoplasmosis and TB infections.

Design of a Multi-Epitope Vaccine against Histoplasma capsulatum through Immunoinformatics Approaches.

Histoplasmosis is a widespread systemic disease caused by Histoplasma capsulatum, prevalent in the Americas. Despite its significant morbidity and mortality rates, no vaccines are currently available. Previously, five vaccine targets and specific epitopes for H. capsulatum were identified. Immunoinformatics has emerged as a novel approach for determining the main immunogenic components of antigens through in silico methods. Therefore, we predicted the main helper and cytotoxic T lymphocytes and B-cell epitopes for these targets to create a potential multi-epitope vaccine known as HistoVAC-TSFM. A total of 38 epitopes were found: 23 common to CTL and B-cell responses, 11 linked to HTL and B cells, and 4 previously validated epitopes associated with the B subunit of cholera toxin, a potent adjuvant. In silico evaluations confirmed the stability, non-toxicity, non-allergenicity, and non-homology of these vaccines with the host. Notably, the vaccine exhibited the potential to trigger both innate and adaptive immune responses, likely involving the TLR4 pathway, as supported by 3D modeling and molecular docking. The designed HistoVAC-TSFM appears promising against Histoplasma, with the ability to induce important cytokines, such as IFN-γ, TNF-α, IL17, and IL6. Future studies could be carried out to test the vaccine's efficacy in in vivo models.

Screening with urine Histoplasma antigen test in asymptomatic patients starting TNF-alpha inhibitor therapy: a cohort study.

Background: Histoplasmosis is the second most frequent granulomatous disease in patients treated with tumor necrosis factor (TNF)-α inhibitors, second only to tuberculosis. However, there is limited information about pre-therapy screening procedures and the need for preventive treatments for patients who will start immunobiologicals. Methods: This is a cohort study that evaluated the prevalence of histoplasmosis in asymptomatic HIV-negative patients before initiation of TNF-α inhibitors by testing for Histoplasma antigen in urine samples. The patients included completed a 180-day follow-up after the initiation of the biologics to assess the onset of symptoms suggestive of histoplasmosis. Results: From January 2021 to December 2022, 54 patients who were prescribed a TNF-α inhibitor agent for treating autoimmune diseases in centers in southern Brazil were included. In the screening before therapy, the prevalence of a positive urinary Histoplasma antigen test was 14.8%. None of the 54 patients developed histoplasmosis after 6 months of immunobiological therapy, including the eight patients who tested positive. Conclusion: The prevalence of Histoplasma capsulatum infection in chronic patients may be higher than expected, but the impact of latent infection in asymptomatic patients is still uncertain, including those starting treatment with immunobiological drugs such as TNF-α inhibitors. Our study did not identify risk factors for the diagnosis of disseminated histoplasmosis in this group, including a positive result in an antigen test performed before immunobiological therapy. To date, there is no evidence to recommend routine antigen-based screening or preventive therapy for histoplasmosis before initiating a TNF-α inhibitor.

Using a urine test for fungal infection to screen people without symptoms who are about to start taking immunobiologic medications This study looked at the prevalence of histoplasmosis, a fungal infection, in asymptomatic patients who were about to start treatment with TNF-α inhibitors, which are medications used for autoimmune diseases. The researchers tested urine samples for Histoplasma antigen before the patients started the treatment and followed them for 180 days after starting the medication to see if they developed any symptoms of histoplasmosis. The study included 54 patients in southern Brazil, and they found that 14.8% of the patients tested positive for the Histoplasma antigen before starting the treatment. However, none of the patients, including those who tested positive, developed histoplasmosis during the 6-month follow-up. The researchers concluded that histoplasmosis infection may be more common in these patients than previously thought, but it's still not clear if asymptomatic patients with a positive antigen test will develop the infection when starting TNF-α inhibitor treatment. The study did not find any specific risk factors for developing histoplasmosis in this group of patients, and based on their findings, they did not recommend routine screening or preventive therapy for histoplasmosis before starting TNF-α inhibitor treatment.

Histoplasmosis in a fingolimod-treated patient: case report and scoping review

ABSTRACT Fingolimod is a sphingosine-1-phosphate receptor modulator used to treat multiple sclerosis. While fingolimod has been associated with an increased risk of cryptococcal meningitis, its correlation with other deep mycoses remains unclear. In this study, we conducted a scoping review of fingolimod associated with histoplasmosis, based on a case report, a literature review, and data from the FDA Adverse Events Reporting System (FAERS) as of January 24th, 2023. A 30-year-old Brazilian woman diagnosed with relapsing-remitting multiple sclerosis, receiving a daily dose of 0.5 mg of fingolimod, presented with a two-month history of fever and unintended weight loss, accompanied by lymphadenopathy, splenomegaly, and lung involvement was investigated. Biopsy of a lung nodule revealed fungal structures suggestive of Histoplasma sp. Additionally, serological testing yielded positive for Histoplasma capsulatum. Disseminated histoplasmosis should be considered in the differential diagnosis of febrile syndromes in patients undergoing fingolimod therapy for multiple sclerosis, particularly in the Americas, where this mycosis is endemic. Treatment with itraconazole and modification of immunotherapy can achieve excellent clinical outcomes.

Evaluation of an enzyme immunoassay technique on detecting urinary Histoplasma capsulatum antigen in the diagnosis of disseminated histoplasmosis in Argentina.

INTRODUCTION: Histoplasmosis is a systemic mycosis of universal distribution, highly endemic in the Americas. It is caused by a dimorphic fungus Histoplasma capsulatum var. capsulatum. It affects both immunocompetent and immunocompromised individuals where progressive and disseminated forms are observed. A very important risk factor is HIV infection/AIDS, with a mortality rate of 20-40% in Latin America. The diagnosis of this mycosis is made by conventional and molecular methods or by antigen and antibody detection. METHODS: In this retrospective, longitudinal and analytical study, carried out over a period of 2 years, the sensitivity (S) and specificity (E) of a commercial kit for the detection of Histoplasma antigen by EIA technique (HC-Ag) was evaluated in 50 patients with AIDSassociated histoplasmosis. In addition, its performance was compared with that of other diagnostic techniques routinely used in our laboratory. RESULTS: HC-Ag had a S of 94%, E 96%, positive likelihood coefficient (CVP): 20.68 and negative likelihood coefficient (CVN): 0.06. The delay time of the results was 4 days, similar to that of antibody detection and n-PCR and much less than that of blood cultures. The combination of methods improved S to 100%; with similar values in E. CONCLUSION: The HC-Ag method demonstrated its usefulness in the diagnosis of progressive disseminated histoplasmosis and the combination of methods is a good option to increase sensitivity and decrease the time to reach the diagnosis of certainty. This allows improving the strategy in the management of the disease and decreasing its case-fatality rate.

Introducción: La histoplasmosis es una micosis sistémica de distribución universal, altamente endémica en las Américas. Es causada por un hongo dimórfico: Histoplasma capsulatum var. capsulatum. Afecta tanto a inmunocompetentes como a inmunocomprometidos, se observan formas progresivas y diseminadas. Un factor de riesgo muy importante es la infección por HIV/sida, con una tasa de mortalidad del 20-40% en América Latina. El diagnóstico de esta micosis se realiza por métodos convencionales y moleculares o por detección de antígenos y anticuerpos. Métodos: En este estudio retrospectivo, longitudinal y analítico, realizado en un periodo de 2 años, se evaluó la sensibilidad (S) y especificidad (E) de un kit comercial para la detección de antígeno de Histoplasma por técnica de EIA (HC-Ag) en 50 pacientes con histoplasmosis asociada a sida. Además, se comparó su rendimiento con el de otras técnicas diagnósticas utilizadas habitualmente en nuestro laboratorio. Resultados: HC-Ag tuvo una S del 94%, E del 96%, coeficiente de verosimilitud positiva (CVP) de 20.68 y coeficiente de verosimilitud negativa (CVN) de 0.06. El tiempo de demora de los resultados fue de 4 días, similar al de la detección de anticuerpos y n-PCR y mucho menor que el de los hemocultivos. La combinación de métodos mejoró la S a 100%; con valores similares en E. Conclusión: El método HC-Ag demostró su utilidad en el diagnóstico de histoplasmosis diseminada progresiva y la combinación de métodos es una buena opción para aumentar la sensibilidad y disminuir el tiempo para llegar al diagnóstico de certeza. Esto permite mejorar la estrategia en el manejo de la enfermedad y reducir su tasa de letalidad.

Antifungal Activity of Chitosan against Histoplasma capsulatum in Planktonic and Biofilm Forms: A Therapeutic Strategy in the Future?

Histoplasmosis is a respiratory disease caused by Histoplasma capsulatum, a dimorphic fungus, with high mortality and morbidity rates, especially in immunocompromised patients. Considering the small existing therapeutic arsenal, new treatment approaches are still required. Chitosan, a linear polysaccharide obtained from partial chitin deacetylation, has anti-inflammatory, antimicrobial, biocompatibility, biodegradability, and non-toxicity properties. Chitosan with different deacetylation degrees and molecular weights has been explored as a potential agent against fungal pathogens. In this study, the chitosan antifungal activity against H. capsulatum was evaluated using the broth microdilution assay, obtaining minimum inhibitory concentrations (MIC) ranging from 32 to 128 µg/mL in the filamentous phase and 8 to 64 µg/mL in the yeast phase. Chitosan combined with classical antifungal drugs showed a synergic effect, reducing chitosan's MICs by 32 times, demonstrating that there were no antagonistic interactions relating to any of the strains tested. A synergism between chitosan and amphotericin B or itraconazole was detected in the yeast-like form for all strains tested. For H. capsulatum biofilms, chitosan reduced biomass and metabolic activity by about 40% at 512 µg/mL. In conclusion, studying chitosan as a therapeutic strategy against Histoplasma capsulatum is promising, mainly considering its numerous possible applications, including its combination with other compounds.

Evaluation of an enzyme immunoassay technique on detecting urinary Histoplasma capsulatum antigen in the diagnosis of disseminated histoplasmosis in Argentina / Evaluación de una técnica de inmunoensayo enzimático para la detección del antígeno urinario de Histoplasma capsulatum en el diagnóstico de histoplasmosis diseminada en Argentina

Abstract Introduction : Histoplasmosis is a systemic mycosis of universal distribution, highly endemic in the Americas. It is caused by a dimorphic fungus Histoplasma capsulatum var. capsulatum. It affects both immunocompetent and immunocompromised individuals where progressive and disseminated forms are observed. A very important risk factor is HIV infection/AIDS, with a mortality rate of 20-40% in Latin America. The diagnosis of this mycosis is made by conventional and molecular methods or by antigen and antibody detection. Methods : In this retrospective, longitudinal and ana lytical study, carried out over a period of 2 years, the sensitivity (S) and specificity (E) of a commercial kit for the detection of Histoplasma antigen by EIA technique (HC-Ag) was evaluated in 50 patients with AIDS-associated histoplasmosis. In addition, its performance was compared with that of other diagnostic techniques routinely used in our laboratory. Results : HC-Ag had a S of 94%, E 96%, positive likeli hood coefficient (CVP): 20.68 and negative likelihood coefficient (CVN): 0.06. The delay time of the results was 4 days, similar to that of antibody detection and n-PCR and much less than that of blood cultures. The combination of methods improved S to 100%; with simi lar values in E. Conclusion : The HC-Ag method demonstrated its usefulness in the diagnosis of progressive disseminated histoplasmosis and the combination of methods is a good option to increase sensitivity and decrease the time to reach the diagnosis of certainty. This allows improv ing the strategy in the management of the disease and decreasing its case-fatality rate.

Resumen Introducción : La histoplasmosis es una micosis sis témica de distribución universal, altamente endémica en las Américas. Es causada por un hongo dimórfico: Histoplasma capsulatum var. capsulatum. Afecta tanto a inmunocompetentes como a inmunocomprometidos, se observan formas progresivas y diseminadas. Un factor de riesgo muy importante es la infección por HIV/sida, con una tasa de mortalidad del 20-40% en América Latina. El diagnóstico de esta micosis se realiza por métodos convencionales y moleculares o por detección de antígenos y anticuerpos. Métodos : En este estudio retrospectivo, longitudinal y analítico, realizado en un periodo de 2 años, se evaluó la sensibilidad (S) y especificidad (E) de un kit comercial para la detección de antígeno de Histoplasma por técnica de EIA (HC-Ag) en 50 pacientes con histoplasmosis aso ciada a sida. Además, se comparó su rendimiento con el de otras técnicas diagnósticas utilizadas habitualmente en nuestro laboratorio. Resultados : HC-Ag tuvo una S del 94%, E del 96%, coeficiente de verosimilitud positiva (CVP) de 20.68 y coeficiente de verosimilitud negativa (CVN) de 0.06. El tiempo de demora de los resultados fue de 4 días, simi lar al de la detección de anticuerpos y n-PCR y mucho menor que el de los hemocultivos. La combinación de métodos mejoró la S a 100%; con valores similares en E. Conclusión : El método HC-Ag demostró su utilidad en el diagnóstico de histoplasmosis diseminada progresiva y la combinación de métodos es una buena opción para aumentar la sensibilidad y disminuir el tiempo para llegar al diagnóstico de certeza. Esto permite mejorar la estrategia en el manejo de la enfermedad y reducir su tasa de letalidad.

Traversing the Cell Wall: The Chitinolytic Activity of Histoplasma capsulatum Extracellular Vesicles Facilitates Their Release.

Histoplasma capsulatum is the causative agent of histoplasmosis. Treating this fungal infection conventionally has significant limitations, prompting the search for alternative therapies. In this context, fungal extracellular vesicles (EVs) hold relevant potential as both therapeutic agents and targets for the treatment of fungal infections. To explore this further, we conducted a study using pharmacological inhibitors of chitinase (methylxanthines) to investigate their potential to reduce EV release and its subsequent impact on fungal virulence in an in vivo invertebrate model. Our findings revealed that a subinhibitory concentration of the methylxanthine, caffeine, effectively reduces EV release, leading to a modulation of H. capsulatum virulence. To the best of our knowledge, this is the first reported instance of a pharmacological inhibitor that reduces fungal EV release without any observed fungicidal effects.