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 during September 25-27th, 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 in 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.

Application of Real-Time PCR Assays for the Diagnosis of Histoplasmosis in Human FFPE Tissues Using Three Molecular Targets.

Histoplasmosis is a fungal infection caused by the thermally dimorphic fungus Histoplasma capsulatum. This infection causes significant morbidity and mortality in people living with HIV/AIDS, especially in countries with limited resources. Currently used diagnostic tests rely on culture and serology but with some limitations. No molecular assays are commercially available and the results from different reports have been variable. We aimed to evaluate quantitative real-time PCR (qPCR) targeting three protein-coding genes of Histoplasma capsulatum (100-kDa, H and M antigens) for detection of this fungus in formalin-fixed paraffin-embedded (FFPE) samples from patients with proven histoplasmosis. The sensitivity of 100-kDa, H and M qPCR assays were 93.9%, 91% and 57%, respectively. The specificity of 100-kDa qPCR was 93% when compared against samples from patients with other mycoses and other infections, and 100% when samples from patients with non-infectious diseases were used as controls. Our findings demonstrate that real-time PCR assays targeting 100-kDa and H antigen showed the most reliable results and can be successfully used for diagnosing this mycosis when testing FFPE samples.

Tackling Histoplasmosis Infection in People Living with HIV from Latin America: From Diagnostic Strategy to Public Health Solutions.

Histoplasmosis, caused by the thermally dimorphic fungus Histoplasma spp., is a disease with a broad clinical spectrum, presenting from asymptomatic/flu-like symptoms to progressive disseminated disease in people with immunosuppression. In recent years, the concept of histoplasmosis as a disease restricted to the American continent has changed, as now histoplasmosis is reported in many regions around the world. In Latin America, histoplasmosis represents a threat, especially in people with advanced HIV disease (AHD). Diagnosis of histoplasmosis in people living with HIV (PLHIV) is challenging due to the low index of suspicion of the disease, non-specificity of signs and symptoms, and limited access to specific laboratory testing, while the diagnostic delay is significantly associated with mortality. In the last decade, novel diagnostic tests have been developed for the rapid detection of histoplasmosis, such as commercial kits for antigen detection. Furthermore, advocacy groups were created that presented histoplasmosis as a public health problem, with emphasis on patients at risk of progressive disseminated disease. This review aims to discuss the impact of histoplasmosis associated with AHD in Latin America and the strategies employed to tackle histoplasmosis, from the implementation of laboratory testing to disease advocacy and public health interventions.

Evaluation of OIDx Histoplasma Urinary Antigen EIA.

A sandwich enzyme immunoassay (EIA) for the detection of Histoplasma antigens (Ag) in urine, developed by Optimum Imaging Diagnostics (OIDx) was evaluated. A verification using a standardized reference panel of urine samples found sensitivity of 92%, specificity of 32% and accuracy of 51%. In this study, the OIDx Histoplasma urinary Ag EIA displayed high sensitivity, however, in non-histoplasmosis cases this EIA displayed false-positive results in 68% of specimens tested.

Validation and Concordance Analysis of a New Lateral Flow Assay for Detection of Histoplasma Antigen in Urine.

Histoplasmosis is a major cause of mortality in people living with HIV (PLHIV). Rapid methods to diagnose Histoplasma capsulatum disease could dramatically decrease the time to initiate treatment, resulting in reduced mortality. The aim of this study was to validate a MiraVista® Diagnostics (MVD) Histoplasma urine antigen lateral flow assay (MVD LFA) for the detection of H. capsulatum antigen (Ag) in urine and compare this LFA against the MVista® Histoplasma Ag quantitative enzyme immunoassays (MVD EIA). We assessed the MVD LFA using a standardized reference panel of urine specimens from Colombia. We tested 100 urine specimens, 26 from PLHIV diagnosed with histoplasmosis, 42 from PLHIV with other infectious diseases, and 32 from non-HIV infected persons without histoplasmosis. Sensitivity and specificity of the MVD LFA was 96%, compared with 96% sensitivity and 77% specificity of the MVD EIA. Concordance analysis between MVD LFA and the MVD EIA displayed an 84% agreement, and a Kappa of 0.656. The MVD LFA evaluated in this study has several advantages, including a turnaround time for results of approximately 40 min, no need for complex laboratory infrastructure or highly trained laboratory personnel, use of urine specimens, and ease of performing.

Evaluation of a Histoplasma antigen lateral flow assay for the rapid diagnosis of progressive disseminated histoplasmosis in Colombian patients with AIDS.

BACKGROUND: Progressive disseminated histoplasmosis (PDH) is an important cause of mortality in persons living with HIV (PLHIV), especially in countries where patients have limited access to antiretroviral therapies and diagnostic testing. OBJECTIVE: A lateral flow assay (LFA) to detect Histoplasma capsulatum antigen in serum developed by MiraVista® was evaluated. METHODS: We tested 75 serum samples: 24 from PLHIV and culture-proven PDH and 51 from PLHIV with other fungal and bacterial infections as well as people without HIV. LFA devices were read manually (read by eye) and by an automated reader. RESULTS: When the LFA was read manually, sensitivity was 96% and specificity was 90%. When an automated reader was used, sensitivity was 92% and specificity was 94%. The Kappa index comparing manual and automated reader was 0.90. Cross-reactions were observed principally in samples from patients with proven diagnosis of paracoccidioidomycosis. CONCLUSIONS: The MiraVista® Diagnostics Histoplasma antigen LFA had high analytical performance and good agreement between manual and automated reader. This LFA allows Histoplasma antigen testing with minimal laboratory equipment and infrastructure requirements.

Multicenter Validation of Commercial Antigenuria Reagents To Diagnose Progressive Disseminated Histoplasmosis in People Living with HIV/AIDS in Two Latin American Countries.

Histoplasmosis is an important cause of mortality in patients with AIDS, especially in countries with limited access to antiretroviral therapies and diagnostic tests. However, many disseminated infections in Latin America go undiagnosed. A simple, rapid method to detect Histoplasma capsulatum infection in regions where histoplasmosis is endemic would dramatically decrease the time to diagnosis and treatment, reducing morbidity and mortality. The aim of this study was to validate a commercial monoclonal Histoplasma galactomannan (HGM) enzyme-linked immunosorbent assay (Immuno-Mycologics [IMMY], Norman, OK, USA) in two cohorts of people living with HIV/AIDS (PLHIV). We analyzed urine samples from 589 people (466 from Guatemala and 123 from Colombia), including 546 from PLHIV and 43 from non-PLHIV controls. Sixty-three of these people (35 from Guatemala and 28 from Colombia) had confirmed histoplasmosis by isolation of H. capsulatum Using the standard curve provided by the quantitative commercial test, the sensitivity was 98% (95% confidence interval [CI], 95 to 100%) and the specificity was 97% (95% CI, 96 to 99%) (cutoff = 0.5 ng/ml). Semiquantitative results, using a calibrator of 12.5 ng/ml of Histoplasma galactomannan to calculate an enzyme immunoassay index value (EIV) for the samples, showed a sensitivity of 95% (95% CI, 89 to 100%) and a specificity of 98% (95% CI, 96 to 99%) (cutoff ≥ 2.6 EIV). This relatively simple-to-perform commercial antigenuria test showed a high performance with reproducible results in both countries, suggesting that it can be used to detect progressive disseminated histoplasmosis in PLHIV in a wide range of clinical laboratories in countries where histoplasmosis is endemic.

The important role of co-infections in patients with AIDS and progressive disseminated histoplasmosis (PDH): A cohort from Colombia.

A total of 23/45 (51%) patients with AIDS and histoplasmosis from Medellín, Colombia had other infections. Tuberculosis was the most common (n = 16/23, 70%). Pneumocystosis and cryptococcosis were found in three patients each (13%), bacterial infection and cytomegalovirus occurred each in two patients (9%) while toxoplasmosis, herpes virus and esophageal candidiasis were recorded in one patient each (4%). Of all co-infected patients, 18/23 (78%) had one, four (17%) had two and one (4%) had three additional opportunistic infections.

Standardization and validation of real time PCR assays for the diagnosis of histoplasmosis using three molecular targets in an animal model.

Histoplasmosis is considered one of the most important endemic and systemic mycoses worldwide. Until now few molecular techniques have been developed for its diagnosis. The aim of this study was to develop and evaluate three real time PCR (qPCR) protocols for different protein-coding genes (100-kDa, H and M antigens) using an animal model. Fresh and formalin-fixed and paraffin-embedded (FFPE) lung tissues from BALB/c mice inoculated i.n. with 2.5x106 Histoplasma capsulatum yeast or PBS were obtained at 1, 2, 3, 4, 8, 12 and 16 weeks post-infection. A collection of DNA from cultures representing different clades of H. capsulatum (30 strains) and other medically relevant pathogens (36 strains of related fungi and Mycobacterium tuberculosis) were used to analyze sensitivity and specificity. Analytical sensitivity and specificity were 100% when DNAs from the different strains were tested. The highest fungal burden occurred at first week post-infection and complete fungal clearance was observed after the third week; similar results were obtained when the presence of H. capsulatum yeast cells was demonstrated in histopathological analysis. In the first week post-infection, all fresh and FFPE lung tissues from H. capsulatum-infected animals were positive for the qPCR protocols tested except for the M antigen protocol, which gave variable results when fresh lung tissue samples were analyzed. In the second week, all qPCR protocols showed variable results for both fresh and FFPE tissues. Samples from the infected mice at the remaining times post-infection and uninfected mice (controls) were negative for all protocols. Good agreement was observed between CFUs, histopathological analysis and qPCR results for the 100-kDa and H antigen protocols. We successfully standardized and validated three qPCR assays for detecting H. capsulatum DNA in fresh and FFPE tissues, and conclude that the 100-kDa and H antigen molecular assays are promising tests for diagnosing this mycosis.

Clinical and Laboratory Profile of Persons Living with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome and Histoplasmosis from a Colombian Hospital.

Histoplasmosis is common among persons living with human immunodeficiency virus/acquired immune deficiency syndrome (PLWHA) in Latin America, but its diagnosis is difficult and often nonspecific. We conducted prospective screening for histoplasmosis among PLWHA with signs or symptoms suggesting progressive disseminated histoplasmosis (PDH) and hospitalized in Hospital La María in Medellín, Colombia. The study's aim was to obtain a clinical and laboratory profile of PLWHA with PDH. During 3 years (May 2008 to August 2011), we identified 89 PLWHA hospitalized with symptoms suggestive of PDH, of whom 45 (51%) had histoplasmosis. We observed tuberculosis (TB) coinfection in a large proportion of patients with PDH (35%), so all analyses were performed adjusting for this coinfection and, alternatively, excluding histoplasmosis patients with TB. Results showed that the patients with PDH were more likely to have Karnofsky score ≤ 30 (prevalence ratio [PR] = 1.98, 95% confidence interval [CI] = 0.97-4.06), liver compromised with hepatomegaly and/or splenomegaly (PR = 1.77, CI = 1.03-3.06) and elevation in serum of alanine aminotransferase and aspartate aminotransferase to values > 40 mU/mL (PR = 2.06, CI = 1.09-3.88 and PR = 1.53, CI = 0.99-2.35, respectively). Using multiple correspondence analyses, we identified in patients with PDH a profile characterized by the presence of constitutional symptoms, namely weight loss and Karnofsky classification ≤ 30, gastrointestinal manifestations with alteration of liver enzymes and hepatosplenomegaly and/or splenomegaly, skin lesions, and hematological alterations. Study of the profiles is no substitute for laboratory diagnostics, but identifying clinical and laboratory indicators of PLWHA with PDH should allow development of strategies for reducing the time to diagnosis and thus mortality caused by Histoplasma capsulatum.

Childhood histoplasmosis in Colombia: Clinical and laboratory observations of 45 patients.

Histoplasmosis is an important mycosis in the Americas; and in children with no immune system abnormalities, histoplasmosis is typically a self-limited process. In contrast, in children with immune problems, disease manifestations are frequently more severe and include dissemination. From 1984 to 2010, a retrospective study of paediatric patients who had been diagnosed with histoplasmosis was performed. A total of 45 pediatric cases of histoplasmosis were identified. The most important risk factor was malnutrition (37%), followed by environmental exposure (33%). The patients exhibited pulmonary infiltrates (83%), fever (76%), cough, constitutional symptoms (38%), headache (35%), and lymph node hypertrophy (33%). Concerning the clinical forms, 64% of the patients presented with the progressive disseminated form that frequently affected the central nervous system (48%). Diagnostic laboratory tests indicated that the cultures were positive for 80% of the patients, the agar gel immunodiffusion was reactive in 95%, the M band of the precipitate was more commonly observed (81%), and the complement fixation tests were reactive in 88% of the patients. The timely diagnosis of histoplasmosis is important, and for this reason, it is hoped that the results of this study will lead pediatricians toward a better understanding of this mycosis in children.

Validation of an enzyme-linked immunosorbent assay that detects Histoplasma capsulatum antigenuria in Colombian patients with AIDS for diagnosis and follow-up during therapy.

We validated an antigen capture enzyme-linked immunosorbent assay (ELISA) in Colombian persons with AIDS and proven histoplasmosis and evaluated the correlation between antigenuria and clinical improvement during follow-up. The sensitivity of the Histoplasma capsulatum ELISA was 86%, and the overall specificity was 94%. The antigen test successfully monitored the response to therapy.

Tuberculosis and histoplasmosis co-infection in AIDS patients.

Abstract. Coinfection with tuberculosis in some countries occurs in 8-15% of human immunodeficiency virus (HIV) -infected patients who have histoplasmosis. This coinfection interferes with prompt diagnosis, and treatment is difficult because of drug interactions. We retrospectively reviewed the cases of 14 HIV-infected patients who had concomitant tuberculosis and histoplasmosis. The most frequent clinical manifestations were weight loss (85.7%), asthenia (78.5%), and fever (64.2%). The diagnosis of histoplasmosis was made primarily by histopathology (71.4%), and the diagnosis of tuberculosis was made by means of direct microscopic examination (71.4%). Death occurred in two patients, and relapse of both infections occurred in one patient. Moxifloxacin was substituted for rifampicin in six patients, with good outcomes noted for both infections. The clinical presentation does not readily identify acquired immunodeficiency syndrome (AIDS) patients who have tuberculosis and histoplasmosis. The use of a fluoroquinolone as an alternative agent in place of rifampicin for tuberculosis allows effective therapy with itraconazole for histoplasmosis.

Epidemiology of opportunistic fungal infections in Latin America.

This review discusses the epidemiology of the most clinically relevant opportunistic fungal infections in Latin America, including candidiasis, cryptococcosis, trichosporonosis, aspergillosis, and fusariosis. The epidemiologic features, including incidence, of some of these mycoses are markedly different in Latin America than they are in other parts of the world. The most consistent epidemiologic data are available for candidemia, with a large prospective study in Brazil reporting an incidence that is 3- to 15-fold higher than that reported in studies from North America and Europe. Species distribution also differs: in Latin America, the most common Candida species (other than Candida albicans) causing bloodstream infections are Candida parapsilosis or Candida tropicalis, rather than Candida glabrata.

Adrenal function status in patients with paracoccidioidomycosis after prolonged post-therapy follow-up.

This study assessed adrenal function in patients with paracoccididioidomycosis who had been treated to determine a possible connection between high antibody titers and adrenal dysfunction attributable to persistence of the fungus in adrenal gland. Adrenal gland function was studied in 28 previously treated patients, 2 (7.1%) of whom were shown to have adrenal insufficiency and 7 (259%) who showed a below normal response to stimuli by adrenocorticotropic hormone. Paracoccidioides brasiliensis was detected in the adrenal gland from one of the patients with adrenal insufficiency. Although the study failed to demonstrate a significant difference between high antibody titers and low cortisol levels, the proportion of adrenal insufficiency detected and the subnormal response to adrenocorticotropic hormone confirmed that adrenal damage is an important sequela of paracoccidioidomycosis. Studies with a larger number of patients should be conducted to confirm the hypothesis of persistence of P. brasiliensis in adrenal gland after therapy.

Posaconazole as salvage therapy in patients with invasive fungal infections after solid organ transplant.

BACKGROUND: The incidence of invasive fungal infections (IFIs) in solid organ transplant (SOT) recipients has increased during the past 20 years and is associated with significant morbidity and mortality. In this post hoc analysis of a large, open-label, multicenter study, we evaluated efficacy and safety of posaconazole, a new extended-spectrum triazole, as salvage therapy for IFIs in SOT recipients. METHODS: Twenty-three SOT recipients with proven or probable IFI and evidence of disease refractory to, or intolerant of, standard antifungal therapies received posaconazole oral suspension (40 mg/mL) 800 mg daily in divided doses. An independent, blinded data-review committee assessed patient diagnosis and outcome. RESULTS: Complete or partial response was documented in 13 of 23 (57%) SOT recipients with proven or probable IFIs, including 1 of 2 (50%) refractory patients, 5 of 8 (63%) intolerant to prior therapy, and 7 of 13 (54%) who were both. Successes by type of IFI included 7 of 12 with invasive aspergillosis, 2 of 2 with invasive fusariosis, 1 of 1 with cryptococcosis, and 1 of 2 with zygomycosis. Treatment-related adverse events (TRAEs) were reported in 12 of 23 patients. Severe TRAEs occurred in 4 of 23 patients including increased levels of cyclosporine or tacrolimus requiring immunosuppressive dose adjustments in three patients and in one, termination of posaconazole. Severe TRAEs associated with renal and liver toxicities were uncommon. CONCLUSION: Posaconazole was well tolerated and effective against IFIs including invasive aspergillosis, zygomycosis, fusariosis, and cryptococcosis in SOT recipients intolerant of or failing other antifungal therapies. Calcineurin inhibitor levels should be closely monitored in patients treated concomitantly with posaconazole to avoid toxicity from drug interaction.

Co-existence of integumentary lesions and lung x-ray abnormalities in patients with paracoccidioidomycosis (PCM).

In paracoccidioidomycosis (PCM), the primary lung infection remains silent. In this study, attempts were done to define the primary target organ by correlating lung radiographic abnormalities with the time course of mucosal/skin lesions concurrently exhibited at diagnosis by 63 patients in whom microscopy and/or isolation of Paracoccidioides brasiliensis from respiratory secretions had been positive. Mucosal and skin lesions were found in 65.1% and 12.7% of the patients, respectively. Odynophagia and dysphagia were present in 38.1% each. All patients had lung interstitial infiltrates, and 31.7% had also alveolar lesions; fibrosis was recorded in 46% of them. An inverse correlation was shown for fibrosis and presence of either odynophagia or dysphagia. Cluster analyzes strongly supported two sets of patients: those with mucosal damage, odynophagia/dysphagia, and alveolo-interstitial infiltrates and those with dermal lesions, dyspnea, and lung fibrosis. These groups may represent novel stages in the natural course of PCM.

Pulmonary paracoccidioidomycosis.

Paracoccidioidomycosis (formerly known as South American blastomycosis) is produced by the thermally dimorphic fungus Paracoccidioides brasiliensis. Most often this mycosis runs a chronic progressive course affecting preferentially the lungs followed by the skin, mucous membranes, adrenals, and reticuloendothelial organs. Acute-subacute presentations can be observed in children and immunosuppressed patients. Occasionally, self-limited infections have been documented. Two types of clinical presentations are described, the acute-subacute (juvenile) and the chronic (adult) forms of the disease. Paracoccidioidomycosis predominates in adult males (13:1); this gender difference is not observed in children or adolescents. The mycosis is limited geographically to various Latin American countries, with the greatest number of cases originating in Brazil, The fungus's natural habitat has not been precisely defined, although it is supposed to be a soil-inhabiting microorganism. No outbreaks have been reported. P. brasiliensis is capable of entering into prolonged periods of latency as is demonstrated by its diagnosis in patients who have moved outside the recognized endemic areas. This review updates clinicians and laboratory workers on the characteristics of a mycosis seldom reported outside of the Latin American countries.

Disseminated histoplasmosis: a comparative study between patients with acquired immunodeficiency syndrome and non-human immunodeficiency virus-infected individuals.

We studied 52 patients with disseminated histoplasmosis, 30 with the acquired immunodeficiency syndrome (AIDS) (cohort 1) and 22 not co-infected with the human immunodeficiency virus (cohort 2). Demographic, clinical, laboratory, mycologic findings, as well as antifungal therapy and highly active antiretroviral (HAART), were analyzed. Skin lesions were significantly higher in cohort 1 than in cohort 2 (P = 0.001). Anemia, leukopenia, and an elevated erythrocyte sedimentation rate were also more pronounced in cohort 1 than in cohort 2 (P < 0.001). Histoplasma capsulatum was isolated more often in cohort 1 than in cohort 2 (P < 0.05) patients, but antibodies to H. capsulatum were detected more frequently in cohort 2 than in cohort 1 (P < 0.05). Itraconazole treatment was less effective in cohort 1 than in cohort 2 (P = 0.012). In cohort 1 patients, HAART improved response to antifungals when compared with individuals not given HAART (P = 0.003), who exhibited higher mortality rates (P = 0.025). Cohort 1 patients who were given dual antifungal and anti-retroviral therapies responded as well as the non-HIV patients in cohort 2, who were treated only with itraconazole. These results indicate the need to promote restoration of the immune system in patients with AIDS and histoplasmosis.

Posaconazole therapy for severe abdominal candidiasis: a case report.

We report the successful treatment of a fluconazole-resistant intra-abdominal Candida infection (Candida albicans and Candida tropicalis) with posaconazole (SCH56592) in a 68-year-old woman with a recent history of intra-abdominal surgery.