Evaluation of the Histoplasma capsulatum 100-kilodalton antigen dot blot for the rapid diagnosis of progressive histoplasmosis in HIV/AIDS patients.

Among people living with HIV (PLHIV), progressive disseminated histoplasmosis (PDH) represents an important cause of mortality. Since antigen detection allows a rapid diagnosis and the instauration of a specific treatment this study aimed to evaluate the analytical performance of the Hcp100 dot blot, an in-house assay that detects the Histoplasma capsulatum 100-kilodalton antigen in urine and compare it with 2 commercially available assays the Histoplasma Urine Antigen Lateral Flow Assay (MVD-LFA) (MiraVista® Diagnostics) and the Clarus Histoplasma Galactomannan EIA (Clarus HGM) (IMMY). Urine specimens from 23 PLHIV with PDH, 13 patients with other infectious diseases, and 20 healthy individuals were tested. The Hcp100 dot blot showed higher sensitivity (87.0%), specificity (97.0%) and accuracy (92.9%) than the MVD-LFA (73.9%, 78.8%, and 76.8%, respectively) and the Clarus HGM (78.3%, 90.9%, and 85.7%, respectively). The Hcp100 dot blot had high analytical performance and would be a valuable screening tool for diagnosing PDH among PLHIV.

Evidence of anti-Hcp100 antibodies in COVID-19 critically ill patients with detectable anti-histoplasmin antibodies in a highly endemic area for histoplasmosis.

Patients with severe COVID-19 are at increased risk for invasive fungal infections, which are underestimated. Histoplasmosis reactivation in endemic areas should not be overlooked in this population. In a previous study, seroconversion to anti-histoplasmin antibodies by ELISA was detected in 6/39 (15.4%) patients with severe COVID-19. In this work, samples were further investigated to detect seroconversion to antibodies against the Histoplasma capsulatum 100-kDa antigen (Hcp100) by ELISA. Seroconversion to anti-Hcp100 antibodies was detected in 7/39 patients, of whom 6 also seroconverted anti-histoplasmin antibodies. These results reinforce previous findings that show histoplasmosis as an underdiagnosed fungal entity complicating COVID-19.

This study verifies that patients with severe COVID-19 at intensive care units are at risk for histoplasmosis reactivation in endemic areas. Accurate diagnosis of this deadly fungal disease among critically ill patients with COVID-19 living in endemic areas for histoplasmosis is needed.

Role of recombinant Histoplasma capsulatum 100-kilodalton antigen in the diagnosis of histoplasmosis among HIV/AIDS patients: Antigenuria and antibodies detection.

BACKGROUND: Diagnosing progressive disseminated histoplasmosis (PDH) is still challenging in many countries where this disease is highly endemic. Definitive diagnosis is established by culture and/or by cytology/histopathology but both procedures have limited sensitivity and cultures are time-consuming. Antibodies detection by immunodiffusion has a low sensitivity in immunocompromised individuals. Commercially available antigen detection assays have high sensitivity in PDH cases; however, they are expensive and only performed in few laboratories. AIMS: To describe the potential use of a novel ELISA for antibodies testing and a dot blot assay for antigen testing for diagnosing PDH using the recombinant 100 kDa protein of Histoplasma capsulatum (Hcp100) and their polyclonal antibodies as novel reagents, respectively. METHODS: Serum and urine samples from a cohort of patients with HIV/AIDS and proven PDH were studied for the detection of anti-Hcp100 antibodies by ELISA and Hcp100 antigen by dot blot, respectively. Sensitivity, specificity and cross-reactions with other diseases were estimated for each assay and compared with those obtained using histoplasmin (HMN) as a reagent for antibodies detection by ELISA and immunodiffusion, and using a commercial antigenuria test. RESULTS: Antibodies detection by the Hcp100 ELISA demonstrated 78.6% sensitivity and 88.4% specificity, versus 85.7% sensitivity and 81.0% specificity for the HMN ELISA and 26.1% sensitivity and 100% specificity for the immunodiffusion assay. Antigen detection by the Hcp100 dot blot demonstrated 89.3% sensitivity and 97.0% specificity versus 82.1% sensitivity and 90.9% specificity for the commercial test. CONCLUSION: The immunoassays described herein based on Hcp100 would be a valuable screening tool for diagnosing PDH.

Detection of anti-Histoplasma capsulatum antibodies and seroconversion patterns in critically ill patients with COVID-19: An underdiagnosed fungal entity complicating COVID-19?

The patients with severe COVID-19 are at increased risk for invasive fungal infections, such as invasive pulmonary aspergillosis and candidiasis, which increase morbidity and mortality. However, clinicians should also consider the possibility of reactivating latent Histoplasma capsulatum in patients with severe COVID-19 living within areas of endemicity who have worsening respiratory function or sepsis, even if they do not have classical risk factors for histoplasmosis (e.g., HIV/AIDS). Bearing in mind this scenario, serum samples of 39 non-HIV/AIDS patients from Buenos Aires hospitalized due to severe COVID-19 pneumonia were analyzed for anti-H. capsulatum-specific IgG antibodies by an in-house ELISA. Antibodies against H. capsulatum were detected in the sera of 8/39 patients (20.51%). To exclude the possibility that these antibodies arose from past exposure of these patients to the fungus, paired serum samples obtained after an interval of at least 10 days were evaluated. Of them, five patients (62.5%) with negative anti-H. capsulatum antibodies at baseline became seropositive 7-10 days later. Three patients (37.5%) had positive anti-H. capsulatum antibodies at baseline, but at time point 2, one of them became seronegative and the other one diminished the antibody titers (4000 vs. 16000 at baseline). The remaining patients displayed higher antibody titers at time point 2 (4000 vs. 1000 at baseline) and died immediately thereafter. In conclusion, awareness of the possibility of fungal co-infections is essential to reduce delays in diagnosis and treatment in order to help prevent severe illness and death from these infections. LAY SUMMARY: This study verifies that patients with severe COVID-19 at ICU are at risk for histoplasmosis reactivation in endemic areas. Accurate diagnosis of this deadly fungal disease among critically ill patients with COVID-19 living in endemic areas for histoplasmosis is needed.

Invasive fusariosis in a critically ill patient with severe COVID-19 pneumonia: A case report.

Invasive fungal infections as aspergillosis and candidiasis are well-documented complications in critically ill patients with acute respiratory distress syndrome due to COVID-19. However, invasive infections by other molds are rarely reported. We describe a case of invasive fusariosis in a patient with severe COVID-19 with a fatal outcome.

COVID-19 associated pulmonary aspergillosis in ICU patients: Report of five cases from Argentina.

Invasive pulmonary aspergillosis is a complication in critically ill patients with acute respiratory distress syndrome, especially those with severe coronavirus disease-associated pneumonia. In this study, five cases of presumed invasive pulmonary aspergillosis in one immunocompromised and four immunocompetent patients with COVID-19 in Buenos Aires are described. In all cases, the underlying conditions, clinical presentation, fungal diagnostic tests used and their results, features of the chest scan images, antifungals used and clinical outcomes are detailed.

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.

[Disseminated histoplasmosis. An oportunistic infection in HIV positive patients Experience in the Hospital Nacional Prof. A. Posadas, 2011-2017]. / Histoplasmosis diseminada. Una infección oportunista en pacientes con infección por VIH. Experiencia en el Hospital Nacional Prof. A. Posadas, 2011-2017.

Disseminated histoplasmosis is an endemic systemic mycosis, caused by the dimorphic fungus Histoplasma capsulatum. The clinical manifestations depend on the inhaled fungal load, the immunological state of the patient and the virulence of the infecting fungal strain. The disseminated variant is most frequent in immunocompromised patients, with 90% of cases in patients with positive serology for HIV, In this series, 37 patients with diagnosis of HIV and disseminated histoplasmosis were evaluated. The 43.2% of the patients did not know their serology prior to the consultation due to histoplasmosis. The main clinical causes were impregnation syndrome (67.6%), fever (64.9%), respiratory symptoms (62.2%) and mucocutaneous manifestations (67.6%), among others. The 94.6% of the patients presented anemia, 75.7% had bicytopenia and 32.4% pancytopenia. The sensitivity of the blood cultures was 70.4%. The 86.5% of the patients did not have another opportunistic infection concomitant at the time of diagnosis. In 83.8% of patients, disseminated histoplasmosis was the first AIDS disease. A mortality of 14.7% was recorded.

Histoplasmosis diseminada. Una infección oportunista en pacientes con infección por VIH. Experiencia en el Hospital Nacional Prof. A. Posadas, 2011-2017 / Disseminated histoplasmosis. An oportunistic infection in HIV positive patients Experience in the Hospital Nacional Prof. A. Posadas, 2011-2017

Resumen La histoplasmosis diseminada es una micosis sistémica endémica, causada por el hongo dimórfico Histoplasma capsulatum. Las manifestaciones clínicas dependen de la carga fúngica inhalada, del estado inmunológico del paciente y de la virulencia de la cepa infectante. La variante diseminada es más frecuente en inmunocomprometidos, registrándose 90% de los casos en pacientes con serología positiva para VIH. En esta serie se evaluaron 37 pacientes con diagnóstico de infección por VIH e histoplasmosis diseminada. El 43,2% de los pacientes no sabía su serología en forma previa a la consulta por histoplasmosis. Las principales manifestaciones clínicas fueron síndrome de impregnación (67,6%), fiebre (64,9%), síntomas respiratorios (62,2%) y manifestaciones muco-cutáneas (67,6%), entre otras. El 94,6% de los pacientes presentó anemia, 75,7% tenía bicitopenia y 32,4% pancitopenia. La sensibilidad de los hemocultivos fue de 70,4%. El 86,5% no tuvo otra infección oportunista concomitante al momento del diagnóstico. En 83,8% de los pacientes la histoplasmosis diseminada fue la primera enfermedad marcadora de SIDA. Se registró una mortalidad de 14,7%.

Disseminated histoplasmosis is an endemic systemic mycosis, caused by the dimorphic fungus Histoplasma capsulatum. The clinical manifestations depend on the inhaled fungal load, the immunological state of the patient and the virulence of the infecting fungal strain. The disseminated variant is most frequent in immunocompromised patients, with 90% of cases in patients with positive serology for HIV, In this series, 37 patients with diagnosis of HIV and disseminated histoplasmosis were evaluated. The 43.2% of the patients did not know their serology prior to the consultation due to histoplasmosis. The main clinical causes were impregnation syndrome (67.6%), fever (64.9%), respiratory symptoms (62.2%) and mucocutaneous manifestations (67.6%), among others. The 94.6% of the patients presented anemia, 75.7% had bicytopenia and 32.4% pancytopenia. The sensitivity of the blood cultures was 70.4%. The 86.5% of the patients did not have another opportunistic infection concomitant at the time of diagnosis. In 83.8% of patients, disseminated histoplasmosis was the first AIDS disease. A mortality of 14.7% was recorded.

Viability of small seeds found in feces of the Central American tapir on Barro Colorado Island, Panama.

Tapirs are known as effective dispersers of large-seeded tree species, but their role in dispersing small-seeded plant species has yet to be established. Tapir feces have been reported to contain large numbers of small seeds, but whether these are viable has rarely been evaluated. We determined the abundance and viability of small seeds in feces of Central American tapir (Tapirus bairdii) on Barro Colorado Island, Panama. A total of 72 fecal samples were collected opportunistically from 4 tapir latrine sites. Seeds were manually extracted from feces and classified by size. Seed viability was estimated by opening each seed and examining for the presence of at least 1 intact firm white endosperm. In total, we obtained 8166 seeds of at least 16 plant species. Small-seeded species dominated, with 96% of all seeds found measuring <5 mm. The canopy tree Laetia procera was the most abundant species in the samples. Of all small seeds found, 69% contained an intact endosperm and appeared viable. This suggests that small seeds, like large seeds, often pass through the digestive tract of T. bairdii intact. Thus, tapirs potentially serve as effective dispersers of a wide range of small-seeded plant species.

Onicomicosis: estudio multicéntrico clínico, epidemiológico y micológico / Onychomycosis: multicentre epidemiological, clinical and mycological study

Antecedentes. Las onicomicosis representan aproximadamente el 50% de las onicopatías, pueden ser causadas por dermatofitos, levaduras u hongos filamentosos no dermatofitos. Objetivos y metodología. Se realizó un estudio multicéntrico para conocer la prevalencia de onicomicosis, los agentes causales y las formas clínicas más frecuentes. Se evaluaron todas las muestras de uñas de manos y pies durante el período de un año en 9 centros asistenciales. Resultados. Se procesaron 5.961 muestras, el 82,3% correspondieron a uñas de pies y el 17,7% a uñas de manos. La edad promedio de los pacientes fue 49,7 años y el 66% perteneció al sexo femenino. Los exámenes directos fueron positivos en el 61% de los casos. En adultos, las uñas de los pies presentaron un 61,2% de resultados positivos en el examen directo, y los cultivos fueron positivos en un 43,7%. Los hongos predominantes fueron los dermatofitos (82,8%) y la forma clínica más frecuente fue la distal subungueal. En uñas de manos la positividad del examen directo fue del 59,8% y los cultivos fueron positivos en un 52,9%; los hongos predominantes fueron de tipo levaduriforme y la forma clínica más frecuente fue la onicolisis. Conclusiones. Se encontró un 61% de positividad en el examen directo, valor superior al de otras investigaciones. En las uñas de los pies prevalecieron los dermatofitos en ambos sexos, y en uñas de manos las levaduras, en el sexo femenino, y dermatofitos, en el masculino. El 4,8% de los aislamientos de uñas de pies y el 2,05% de los de uñas de manos fueron de hongos filamentosos no dermatofíticos(AU)

Background. Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds. Objectives and methods. A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included. Results. A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion. Conclusions. Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates(AU)

[Onychomycosis: multicentre epidemiological, clinical and mycological study]. / Onicomicosis: estudio multicéntrico clínico, epidemiológico y micológico.

BACKGROUND: Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds. OBJECTIVES AND METHODS: A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included. RESULTS: A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion. CONCLUSIONS: Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates.

Dishidrosis: estudio de 89 pacientes / Dyshidrosis: a study of 89 patients

Se llevó a cabo un estudio de 89 pacientes portadores de lesiones de aspecto dishidrótico, desde diciembre de 1990 hasta marzo de 1994. El grupo estaba constituido por 55 mujeres y 34 varones, con un promedio de edad de 37,7 años. A todos los pacientes se les realizó rutina de laboratorio, parasitológico de materia fecal y estudios micológicos de la lesión, hallándose en estos últimos un 55 por ciento de positividad (siendo en su mayoría T. rubrum). Esto nos permitió inferir que en realidad se trataban de verdaderas tiñas, a pesar de cumplir con algunas de las cuatro variantes clínicas de la enfermedad (vesiculosa-descamativa-pustulosa o ampollar), por lo que consideramos que es imprescindible el estudio micológico de estas lesiones

Dishidrosis: estudio de 89 pacientes / Dyshidrosis: a study of 89 patients

Se llevó a cabo un estudio de 89 pacientes portadores de lesiones de aspecto dishidrótico, desde diciembre de 1990 hasta marzo de 1994. El grupo estaba constituido por 55 mujeres y 34 varones, con un promedio de edad de 37,7 años. A todos los pacientes se les realizó rutina de laboratorio, parasitológico de materia fecal y estudios micológicos de la lesión, hallándose en estos últimos un 55 por ciento de positividad (siendo en su mayoría T. rubrum). Esto nos permitió inferir que en realidad se trataban de verdaderas tiñas, a pesar de cumplir con algunas de las cuatro variantes clínicas de la enfermedad (vesiculosa-descamativa-pustulosa o ampollar), por lo que consideramos que es imprescindible el estudio micológico de estas lesiones (AU)