Impact of COVID-19 on paracoccidioidomycosis. Which was the most influential: The pandemic or the virus?

The impact of COVID-19 on paracoccidioidomycosis (PCM) in Argentina and the consequences generated by the pandemic are discussed. From 2018 to 3 years after the pandemic declaration, 285 proven PCM patients were registered. No association between both diseases was documented. PCM frequency decreased to extremely low levels in 2020. Mandatory social isolation and the emotional and psychological effects generated under pandemic circumstances led to delays in diagnosis, severe disseminated cases, and other challenges for diagnosis in subsequent years. Probable underdiagnosis should be considered due to the overlap of clinical manifestations, the low index of suspicion and the lack of sensitive diagnostic tools.

Histoplasma antigens as novel players for the development of new enzyme immunoassays for the serodiagnosis of histoplasmosis: A comparative study of their analytical performance.

Definitive diagnosis of histoplasmosis relies on culture and/or cytology/histopathology; however, these procedures have limited sensitivity and cultures are time-consuming. Antibodies detection by immunodiffusion has low sensitivity in immunocompromised individuals and uses histoplasmin (HMN), a crude antigenic extract, as reagent. Novel protein antigen candidates have been recently identified and produced by DNA-recombinant techniques to obtain standardized and specific reagents for diagnosing histoplasmosis. To compare the analytical performance of novel enzyme-linked immunosorbent assays (ELISAs) for antibodies testing for diagnosing histoplasmosis using different Histoplasma capsulatum antigens as reagents. The H. capsulatum 100 kDa protein (Hcp100), the M antigen and its immunoreactive fragment F1 were produced by DNA-recombinant techniques. Galactomannan was purified from both the yeast and mycelial cell walls (yGM and mGM, respectively). The analytical performance of the ELISA tests for the serological detection of antibodies against these antigens was evaluated and compared with those obtained using HMN as reagent. Antibodies detection by the Hcp100 ELISA demonstrated 90.0% sensitivity and 92.0% specificity, versus 43.3% sensitivity and 95.0% specificity of the M ELISA, 33.3% sensitivity and 84.0% specificity of the F1 ELISA, 96.7% sensitivity and 94.0% specificity of the yGM ELISA, 83.3% sensitivity and 88.0% specificity of the mGM ELISA, and 70.0% sensitivity and 86.0% specificity for the HMN ELISA. In summary, Hcp100 is proposed as the most promising candidate for the serodiagnosis of histoplasmosis. The primary immunoreactive element in HMN proved to be GM rather than the M antigen. Nevertheless, a higher incidence of cross-reactions was noted with GM compared to M.

Hcp100 is a promising serodiagnostic candidate for histoplasmosis, boasting high sensitivity and specificity. Notably, GM, rather than M antigen, emerged as the primary immunoreactive element in HMN, despite a higher incidence of cross-reactions with GM compared to M.

Epidemiology of coccidioidomycosis in Argentina, an update.

The National Reference Laboratory in Clinical Mycology of Argentina conducted a retrospective review of human coccidioidomycosis cases diagnosed by the National Mycology Laboratory Network of Argentina between 2010 and 2022 to determine the burden of the disease in the country. A total of 100 human coccidioidomycosis cases were documented, with a higher prevalence in male patients (male-to-female ratio of 1.9:1), with a median age of 41 years. Comparing the number of cases between two 10-year periods (2000-2009 and 2010-2019), the increase was 36.51% (from 63 to 86 cases). Among the 100 recorded cases, 79 tested positive using the double immunodiffusion test. Spherules were observed in 19 cases through histopathology or direct microscopic examination and the fungus was isolated in 39 cases. Thirty-six isolates were identified as Coccidioides posadasii through partial sequencing of the Ag2/PRA gene. Catamarca province had the highest number of cases, comprising 64% of the total, with an incidence rate above 1.0-2.5/100,000 inhabitants until 2018. However, there has been a recent downward trend in the region from 2018 to 2022. It is concerning that more than half of diagnosed cases were chronic pulmonary or disseminated forms, indicating a lack of early disease detection. To rectify this issue, it is imperative to conduct targeted training programs for healthcare personnel and enhance public awareness within the endemic area. This will contribute to a better understanding of the true burden of coccidioidomycosis and enable the implementation of appropriate sanitary control measures.

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.

Antifungal susceptibility patterns for Aspergillus, Scedosporium, and Exophiala isolates recovered from cystic fibrosis patients against amphotericin B, and three triazoles and their impact after long-term therapies.

In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus, Scedosporium genus, and Exophiala dermatitidis are the most commonly isolated moulds from the respiratory tract secretions of CF patients. The aim of this 5-year surveillance study was to identify trends in species distribution and susceptibility patterns of 212 mould strains identified as Aspergillus spp., Scedosporium spp., and Exophiala spp., isolated from sputum of 63 CF patients who received long-term therapy with itraconazole (ITR) and/or voriconazole (VRC). The Aspergillus isolates were identified as members of the sections Fumigati (n = 130), Flavi (n = 22), Terrei (n = 20), Nigri (n = 8), Nidulantes (n = 1), and Usti (n = 1). Among the 16 species of the genus Scedosporium, 9 were S. apiospermum, 3 S. aurantiacum, and 4 S. boydii. Among the 14 Exophiala species, all were molecularly identified as E. dermatitidis. Overall, 94% (15/16) of Scedosporium spp., 50% (7/14) of E. dermatitidis, and 7.7% (14/182) of Aspergillus spp. strains showed high MIC values (≥8 µg/ml) for at least one antifungal. Particularly, 8.9% (19/212) of isolates showed high MIC values for amphotericin B, 11.7% (25/212) for ITR, 4.2% (9/212) for VRC, and 3.3% (7/212) for posaconazole. In some cases, such as some A. fumigatus and E. dermatitidis isolates recovered from the same patient, susceptibility to antifungal azoles decreased over time. We show that the use of azoles for a long time in CF patients causes the selection/isolation of mould strains with higher MIC values.

The use of azoles for a long time in cystic fibrosis patients causes the selection/isolation of Aspergillus, Scedosporium, and Exophiala species with higher MIC values.

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.

Clinical and Demographic Features of Paracoccidioidomycosis in Argentina: A Multicenter Study Analysis of 466 Cases.

Information on paracoccidioidomycosis (PCM) in Argentina is fragmented and has historically been based on estimates, supported only by a series of a few reported cases. Considering the lack of global information, a national multicentric study in order to carry out a more comprehensive analysis was warranted. We present a data analysis including demographic and clinical aspects of a historical series of 466 cases recorded over 10 years (2012-2021). Patients were aged from 1 to 89 years. The general male: female (M:F) ratio was 9.5:1 with significant variation according to the age group. Interestingly, the age range 21-30 shows an M:F ratio of 2:1. Most of the cases (86%) were registered in northeast Argentina (NEA), showing hyperendemic areas in Chaco province with more than 2 cases per 10,000 inhabitants. The chronic clinical form occurred in 85.6% of cases and the acute/subacute form occurred in 14.4% of cases, but most of these juvenile type cases occurred in northwestern Argentina (NWA). In NEA, the incidence of the chronic form was 90.6%; in NWA, the acute/subacute form exceeded 37%. Diagnosis by microscopy showed 96% positivity but antibody detection displays 17% of false negatives. Tuberculosis was the most frequent comorbidity, but a diverse spectrum of bacterial, fungal, viral, parasitic, and other non-infectious comorbidities was recorded. This national multicenter registry was launched in order to better understand the current status of PCM in Argentina and shows the two endemic zones with a highly diverse epidemiology.

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.

High prevalence of triazole-resistant Aspergillus fumigatus sensu stricto in an Argentinean cohort of patients with cystic fibrosis.

BACKGROUND: Triazole resistance in Aspergillus fumigatus sensu stricto due to mutations in the cyp51A gene has been widely reported. Data from Argentina, and particularly from cystic fibrosis (CF) patients, are limited. OBJECTIVES: To investigate the prevalence and molecular mechanisms of azole resistance in A. fumigatus sensu stricto recovered from this population. METHODS: Ninety-three A. fumigatus isolates from 50 CF patients were retrospectively analysed for azole resistance using the standard microbroth dilution method according to CLSI M38-A2 guidelines. Sequencing analysis of the cyp51A gene and its promoter region was conducted in those isolates displaying high MIC values to itraconazole, voriconazole and/or posaconazole. RESULTS: Overall, 14% of isolates displayed high MIC values to at least one azole. Of them, 30.7% had the mutation TR34-L98H. No mutations in the cyp51A gene or its promoter were found in the remaining non-wild-type strains. Therefore, other mechanisms associated with azole resistance can be highly prevalent in these isolates. CONCLUSIONS: To the best of our knowledge, this is the first study in Latin America reporting azole-resistant A. fumigatus strains recovered from respiratory secretions of CF patients. Noteworthy, the prevalence of azole resistance in A. fumigatus sensu stricto in the studied Argentinean CF population is alarmingly high.

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.

[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.