Two specific strains of Histoplasma capsulatum causing mucocutaneous manifestations of histoplasmosis: preliminary analysis of a frequent manifestation of histoplasmosis in southern Brazil

Unusual Differences in the Pulmonary Histopathology of Mice after Intranasal Infection with Mycelial Propagules of Histoplasma capsulatum Strains Classified as LAm A2 and NAm 2 Phylogenetic Species

The ascomycete Histoplasma capsulatum is the causative agent of systemic respiratory mycosis histoplasmosis, which sometimes develops acute disseminated or chronic clinical forms, with the latter usually associated with granuloma formation. The present report shows differential histopathological changes in the pulmonary inflammatory response of mice infected intranasally with the mycelial morphotype of H. capsulatum strains with distinct genotypes, EH-46 and G-217B, classified as LAm A2 and NAm 2 phylogenetic species, respectively. Infected male BALB/c mice were sacrificed at different postinfection times, and their serial lung sections were stained with periodic acid-Schiff and analyzed via microscopy. In mice infected with the LAm A2 strain, the results showed progressive changes in the inflammatory infiltrate of the lung parenchyma during the first hours and days postinfection as well as granulomas with macrophages containing intracellular yeast cells, which prevailed at 14 and 21 days postinfection. Bronchiolar-associated lymphoid tissue was induced in mice infected with both strains, primarily in mice infected with the NAm 2 strain. Several lung sections from mice infected with the LAm A2 strain showed PAS-positive yeast cells aggregated in a perinuclear crown-like arrangement in macrophages from 3 h to 21 days postinfection. These findings highlight differences in the host pulmonary inflammatory response associated with distinct H. capsulatum species.

Considerations about the Geographic Distribution of Histoplasma Species

Histoplasmosis is a mycotic infection principally affecting pulmonary tissue; sometimes, histoplasmosis can progress into a systemic disease. This infection involves immunocompetent and immunosuppressed human and other mammalian hosts, depending on particular circumstances. Histoplasmosis infection has been documented worldwide. The infection is acquired by inhaling infective mycelial propagules of the dimorphic fungus Histoplasma capsulatum. New reports of clinical cases of histoplasmosis in extreme latitudes could be related to human social adaptations and climate changes in the world, which are creating new favorable environments for this fungus and for bats, its major natural reservoirs and dispersers. Histoplasma has been isolated from most continents, and it is considered a complex of cryptic species, consisting of various groups of isolates that differ genetically and correlate with a particular geographic distribution. Based on updated studies, Histoplasma taxonomy is adjusting to new genetic data. Here, we have suggested that Histoplasma has at least 14 phylogenetic species distributed worldwide and new genotypes that could be under deliberation. Histoplasma's geographic radiation began in South America millions of years ago when the continents were joined and the climate was favorable. For fungal spreading, the role of bats and some birds is crucial, although other natural factors could also participate.

Temporal trends of cutaneo-mucous histoplasmosis in persons living with HIV in French Guiana: Early diagnosis defuses South American strain dermotropism

Histoplasmosis is the most frequent opportunistic infection and the first cause of mortality in HIV-infected patients in French Guiana and presumably in much of Latin America. Mucocutaneous lesions of histoplasmosis are considered as rare and late manifestations of the disease. It has been debated whether the greater proportion of cutaneo-mucous presentations in South America relative to the USA was the reflection of Histoplasma strains with increased dermotropism or simply delayed diagnosis and advanced immunosuppression. The objective of this study was to describe the clinical presentation, frequency, prognosis and temporal trends of cutaneomucous histoplasmosis in French Guiana. A retrospective study of patients with AIDS-related disseminated histoplasmosis followed in the three hospitals of French Guiana was performed between 1981 and 2014. Incident cases of histoplasmosis, proved by pathology and/or mycological examinations, were studied. Mucocutaneous histoplasmosis was confirmed by a positive cutaneous or mucosal biopsy. Mucocutaneous lesions were polymorphic. Ninety percent of patients were profoundly immunocompromised patients (CD4<50/mm3) and over 80% were not on antiretroviral treatment. The frequency of mucocutaneous forms and case fatality of disseminated histoplasmosis within one month of antifungal treatment significantly decreased over time (p<0,001). In this South American territory, diagnostic and therapeutic improvements have led to the quasi disappearance of cutaneous manifestations. There may be South American dermotropism in the laboratory but at the bedside early diagnosis seems to be the main parameter explaining the proportion of cutaneomucous presentations in South America relative to the USA.

Histoplasmosis is the most frequent opportunistic infection and the first cause of mortality in HIV-infected patients in French Guiana and presumably in much of Latin America. Mucocutaneous lesions of histoplasmosis are considered as rare and late manifestations of the disease. It has been debated whether the greater proportion of cutaneo-mucous presentations in South America relative to the USA was the reflection of Histoplasma strains with increased dermotropism or simply delayed diagnosis and advanced immunosuppression. The objective of this study was to describe the clinical presentation, frequency, prognosis and temporal trends of cutaneomucous histoplasmosis in French Guiana. A retrospective study of patients with AIDS-related disseminated histoplasmosis followed in the three hospitals of French Guiana was performed between 1981 and 2014. Incident cases of histoplasmosis, proved by pathology and/or mycological examinations, were studied. Mucocutaneous histoplasmosis was confirmed by a positive cutaneous or mucosal biopsy. Ninety percent of patients were profoundly immunocompromised patients (CD4<50/mm3) and over 80% were not on antiretroviral treatment. The frequency of mucocutaneous forms and case fatality of disseminated histoplasmosis within one month of antifungal treatment significantly decreased over time. Hence, in this South American territory, diagnostic and therapeutic improvements have led to the quasi-disappearance of cutaneous manifestations. There may be South American dermotropism in the laboratory but at the bedside early diagnosis seems to be the main parameter explaining the proportion of cutaneomucous presentations in South America relative to the USA.

Comparison of Disseminated Histoplasmosis with and without Cutaneo-Mucous Lesions in Persons Living with HIV in French Guiana

Introduction: Histoplasmosis is the main opportunistic infection and cause of death in HIV-infected persons living with HIV in French Guiana and probably in most of Latin America. The objective of the present study was to compare cutaneomucous histoplasmosis to non-cutaneomucous histoplasmosis in French Guiana. Methods: Between 1981 and 2014 AIDS-related disseminated histoplasmosis patients followed in the three hospitals of French Guiana were retrospectively studied. Only proven incident cases of histoplasmosis, either by pathology and/or mycological analysis, were considered. Mucocutaneous histoplasmosis was ascertained by a positive mucosal or cutaneous biopsy. Results: Thirty-one patients had mucocutaneous lesions, and 318 had no mucocutaneous lesions. Patients with cutaneomucous lesions were more likely to have had prior opportunistic infections (35.5%) than those who did not have cutaneomucous lesions (19.5%). They were more likely to be very severely immunocompromised (CD4 count < 50) (90.3% versus 62.8%) and less likely to have digestive signs (32.3% versus 74.1%) and superficial adenopathies (29% versus 50.2%) than those without cutaneomucous lesions. In terms of simple biological examinations, patients with cutaneomucous lesions had fewer signs of cholestasis. The diagnosis was significantly more likely to be performed by direct examination and pathology in those with cutaneomucous lesions than in those without such lesions. On the contrary, patients with cutaneomucous lesions were less likely to be diagnosed by fungal culture than those without cutaneomucous lesions. There was a greater but non-significant risk of early death in those with cutaneomucous lesions relative to those without (OR = 2.28 (95%CI = 0.83–5.7), p = 0.056. Conclusions: Mucocutaneous forms were associated with more profound immunosuppression and perhaps risk of early death. They are easily accessible for diagnosis.

Postpartum histoplasmosis in an HIV-negative woman: a case report and phylogenetic characterization by internal transcribed spacer region analysis

The present report describes the first case of postpartum disseminated histoplasmosis in a 24-year-old HIV-negative woman. On the tenth day after vaginal delivery, the patient presented with dyspnea, fever, hypotension, tachycardia, and painful hepatomegaly. Yeast-like Histoplasma capsulatum features were isolated in the buffy coat. The phylogenetic analysis demonstrated that the fungal isolate was similar to other H. capsulatum isolates identified in HIV patients from Ceará and Latin America. Thus, histoplasmosis development in individuals with transitory immunosuppression or during the period of immunological recovery should be carefully examined.

The Broad Clinical Spectrum of Disseminated Histoplasmosis in HIV-Infected Patients: A 30 Years' Experience in French Guiana

Histoplasmosis is a common but neglected AIDS-defining condition in endemic areas for Histoplasma capsulatum. At the advanced stage of HIV infection, the broad spectrum of clinical features may mimic other frequent opportunistic infections such as tuberculosis and makes it difficult for clinicians to diagnose histoplasmosis in a timely manner. Diagnosis of histoplasmosis is difficult and relies on a high index of clinical suspicion along with access to medical mycology facilities with the capacity to implement conventional diagnostic methods (direct examination and culture) in a biosafety level 3 laboratory as well as indirect diagnostic methods (molecular biology, antibody, and antigen detection tools in tissue and body fluids). Time to initiation of effective antifungals has an impact on the patient's prognosis. The initiation of empirical antifungal treatment should be considered in endemic areas for Histoplasma capsulatum and HIV. Here, we report on 30 years of experience in managing HIV-associated histoplasmosis based on a synthesis of clinical findings in French Guiana with considerations regarding the difficulties in determining its differential diagnosis with other opportunistic infections.

Histoplasmosis, An Underdiagnosed Disease Affecting People Living With HIV/AIDS in Brazil: Results of a Multicenter Prospective Cohort Study Using Both Classical Mycology Tests and Histoplasma Urine Antigen Detection

Background

Histoplasmosis is highly endemic in the American continent. This condition is associated with a high mortality, particularly in people living with HIV/AIDS (PLWHA). Diagnosis of histoplasmosis is usually late in South America, as Histoplasma antigen detection is rarely available. Here we determined the prevalence, risk factors, and outcome of histoplasmosis in PLWHA in Brazilian hospitals.

Methods

This was a prospective cohort study (2016-2018) involving 14 tertiary medical centers in Brazil. We included hospitalized PLWHA presenting with fever and additional clinical findings. Patients were investigated at each participant center with classical mycology methods. Also, Histoplasma antigen detection was performed in urine samples (IMMY). Probable/proven histoplasmosis was defined according to European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group/National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria.

Results

From 616 eligible patients, 570 were included. Histoplasmosis was identified in 21.6% (123/570) of patients. Urine antigen testing increased the diagnostic yield in 53.8%, in comparison with standard mycology methods. Variables independently associated with histoplasmosis were CD4+ count <50 cells/mm³, use of an antiretroviral (protective effect), and sample collection in the Northeast region of Brazil. Dyspnea at presentation was independently associated with death. Histoplasmosis was more frequent than tuberculosis in patients with low CD4+ counts. Overall 30-day mortality was 22.1%, decreasing to 14.3% in patients with antigen-based diagnosis.

Conclusions

Histoplasmosis is a very frequent condition affecting PLWHA in Brazil, particularly when CD4+ counts are lower than 50 cells/mm³. Antigen detection may detect earlier disease, with a probable impact on outcomes. Access to this diagnostic tool is needed to improve clinical management of PLWHA in endemic countries.

Acute histoplasmosis in immunocompetent travelers: a systematic review of literature

Background

Histoplasmosis is a fungal infection highly endemic in the American continent. The disease can be severe in immunocompromised subjects. In immunocompetent subjects the clinical manifestations are variable. Aim of this work was to review the cases of acute histoplasmosis in immunocompetent travelers reported in literature.

Methods

A systematic review of literature was conducted. Electronic search was performed in Pubmed and LILACS. Two reviewers independently extracted data on demographic, clinical and radiological features, and treatment. Cases were classified according to Wheat’s definitions.

Results

Seventy-one studies were included in the analysis, comprising a total of 814 patients. Twenty-one patients diagnosed at the Centre of Tropical Diseases, Negrar (VR), Italy were also included. The most common travel destination was Central America (168 people, 29.8%); the most common way of exposure to histoplasma was the exploration of caves and/or contact with bat guano (349 people, 60.9%). The multivariate logistic regression model showed association between the development of disseminated histoplasmosis (DH) and activities that involved the exploration of caves and/or the contact with bats’ guano (adjusted OR: 34.20 95% CI: 5.29 to 220.93) or other outdoor activities (adjusted OR: 4.61 95% CI: 1.09 to 19.56). No significant difference in the attack rate between countries of destination was observed (p-value: 0.8906, Kruskal-Wallis test).

Conclusions

Histoplasmosis often causes no or mild symptoms in immunocompetent individuals, although a severe syndrome may occur. The infection can mimic other diseases, and the epidemiological risk of exposure is an important clue to raise the index of suspicion.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3476-z) contains supplementary material, which is available to authorized users.

High Mortality and Coinfection in a Prospective Cohort of Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome Patients with Histoplasmosis in Guatemala

Histoplasmosis is one of the most common and deadly opportunistic infections among persons living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome in Latin America, but due to limited diagnostic capacity in this region, few data on the burden and clinical characteristics of this disease exist. Between 2005 and 2009, we enrolled patients ≥ 18 years of age with suspected histoplasmosis at a hospital-based HIV clinic in Guatemala City. A case of suspected histoplasmosis was defined as a person presenting with at least three of five clinical or radiologic criteria. A confirmed case of histoplasmosis was defined as a person with a positive culture or urine antigen test for Histoplasma capsulatum. Demographic and clinical data were also collected and analyzed. Of 263 enrolled as suspected cases of histoplasmosis, 101 (38.4%) were confirmed cases. Median time to diagnosis was 15 days after presentation (interquartile range [IQR] = 5-23). Crude overall mortality was 43.6%; median survival time was 19 days (IQR = 4-69). Mycobacterial infection was diagnosed in 70 (26.6%) cases; 26 (25.7%) histoplasmosis cases were coinfected with mycobacteria. High mortality and short survival time after initial symptoms were observed in patients with histoplasmosis. Mycobacterial coinfection diagnoses were frequent, highlighting the importance of pursuing diagnoses for both diseases.

A Review of Diagnostic Methods for Invasive Fungal Diseases: Challenges and Perspectives

Invasive fungal diseases are associated with a high morbidity and mortality, particularly in the context of immunosuppression. Diagnosis of invasive fungal diseases is usually complicated by factors such as poor clinical suspicion and unspecific clinical findings. Access to modern diagnostic tools is frequently limited in developing countries. Here, we describe five real-life clinical cases from a Brazilian tertiary hospital, in order to illustrate how to best select diagnostic tests in patients with different fungal infections.

Disseminated histoplasmosis and AIDS: a prospective and multicentre study to evaluate the performance of different diagnostic tests

The burden of histoplasmosis has been poorly documented in most of the endemic areas for the disease, including Brazil. Also, modern non-culture-based diagnostic tests are often non-available in these regions. This was a prospective cohort study in HIV-infected patients with suspected disseminated disease evaluated with different diagnostic tests. Patients were enrolled in three referral medical centres in Porto Alegre, Brazil. Among 78 evaluated patients, disseminated histoplasmosis was confirmed in eight individuals (10.3%) by the means of classical (culture/histopathology) tests. Antigen detection in the urine was found to be more sensitive: IMMY^® ALPHA ELISA detected 13 positive cases (16.7%) and the in-house ELISA test developed by the Centers for Disease Prevention and Control (CDC) detected 14 (17.9%). IMMY^® and CDC tests provided concordant results in 96.2% of cases. This is the first study to compare the performance of the in-house CDC ELISA test with the IMMY^® commercial test for the diagnosis of histoplasmosis, and a high degree of concordance was observed. The study revealed that H. capsulatum is an important agent of disseminated disease in AIDS patients in Brazil, reinforcing the importance of making available modern diagnostic tests as well as safer antifungal agents for the treatment of histoplasmosis.

Cutaneous presentation of disseminated histoplasmosis as a solitary peri-anal ulcer. Case report and discussion

Disseminated histoplasmosis has a diverse and non-specific range of clinical signs and symptoms. In a significant minority of patients, cutaneous lesions are apparent at the time of initial presentation, affording an opportunity to establish the diagnosis from a skin biopsy. The most frequently reported clinical scenario in immunocompromised patients with cutaneous involvement is that of multiple papulo-nodular lesions on the face, trunk or extremities. The following report features an immunocompetent patient who presented with a solitary ulcerated plaque on the buttocks close to the anal verge. This case presentation underscores the broad spectrum of clinical presentations as well as the potential for diagnostic confusion with protozoa such as Leishmania or Trypanosoma species during histopathologic examination if special stains for fungal organisms are not performed.

The use of genetic markers in the molecular epidemiology of histoplasmosis: a systematic review

Histoplasmosis is a systemic mycosis caused by Histoplasma capsulatum, a dimorphic fungal pathogen that can infect both humans and animals. This disease has worldwide distribution and affects mainly immunocompromised individuals. In the environment, H. capsulatum grows as mold but undergoes a morphologic transition to the yeast morphotype under special conditions. Molecular techniques are important tools to conduct epidemiologic investigations for fungal detection, identification of infection sources, and determination of different fungal genotypes associated to a particular disease symptom. In this study, we performed a systematic review in the PubMed database to improve the understanding about the molecular epidemiology of histoplasmosis. This search was restricted to English and Spanish articles. We included a combination of specific keywords: molecular typing [OR] genetic diversity [OR] polymorphism [AND] H. capsulatum; molecular epidemiology [AND] histoplasmosis; and molecular epidemiology [AND] Histoplasma. In addition, we used the specific terms: histoplasmosis [AND] outbreaks. Non-English or non-Spanish articles, dead links, and duplicate results were excluded from the review. The results reached show that the main methods used for molecular typing of H. capsulatum were: restriction fragment length polymorphism, random amplified polymorphic DNA, microsatellites polymorphism, sequencing of internal transcribed spacers region, and multilocus sequence typing. Different genetic profiles were identified among H. capsulatum isolates, which can be grouped according to their source, geographical origin, and clinical manifestations.

Cutaneous histoplasmosis disclosing an HIV-infection

Histoplasmosis is a systemic mycosis endemic in extensive areas of the Americas. The authors report on an urban adult male patient with uncommon oral-cutaneous lesions proven to be histoplasmosis. Additional investigation revealed unnoticed HIV infection with CD4+ cell count of 7/mm³. The treatment was performed with amphotericin B, a 2065 mg total dose followed by itraconazole 200mg/daily plus antiretroviral therapy with apparent cure. Histoplasmosis is an AIDS-defining opportunistic disease process; therefore, its clinical diagnosis must drive full laboratory investigation looking for unnoted HIV-infection.

Urine antigen tests for the diagnosis of respiratory infections: legionellosis, histoplasmosis, pneumococcal pneumonia

Urinary antigen testing has grown in popularity for several significant respiratory infections, particularly Legionella pneumophila, Streptococcus pneumoniae, and Histoplasma capsulatum. By capitalizing on the concentration of shed antigen from a variety of pathogens in the kidneys for excretion in the urine, urinary antigen testing can be used to obtain rapid test results related to respiratory infection, independent of an invasive collection such as a bronchoalveolar lavage. This article describes the 3 aforementioned organisms, their role in respiratory disease, and the current status of urinary antigen testing in their respective diagnosis.

Histoplasmosis in HIV-Infected Patients: A Review of New Developments and Remaining Gaps

Histoplasma capsulatum is responsible for histoplasmosis, a fungal disease with worldwide distribution that can affect both immunocompromised and imunocompetent individuals. During the highly active antiretroviral therapy (HAART) era, morbidity and mortality due to histoplasmosis remained a public heatlh problem in low-income and high-income countries. The true burden of HIV-associated histoplasmosis is either not fully known or neglected since it is not a notifiable disease. Progress has been made in DNA patterns of strains and understanding of pathogenesis, and hopefully these will help identify new therapeutic targets. Unfortunately, histoplasmosis is still widely mistaken for multidrug-resistant tuberculosis, leading to numerous avoidable deaths, even if they are easily distinguishable. The new diagnostic tools and therapeutics developments have still not been made available in most endemic regions. Still, recent developments are promising because of their good clinical characteristics and also because they will be commercially available and affordable. This review of published data and gaps may help define and guide future research.

Genetic diversity of Histoplasma capsulatum strains isolated from Argentina based on nucleotide sequence variations in the internal transcribed spacer regions of rDNA

The internal transcribed spacer (ITS) regions of rDNA genes of 49 Histoplasma capsulatum (48 from clinical samples and one from soil) isolates were examined. Nucleotide sequence heterogeneity within this region was useful for phylogenetic classification of H. capsulatum and species identification. Thus, in 45 of 49 isolates we observed higher percentages of identity in the nucleotide sequences of ITS regions when the isolates studied herein were compared with those reported in our country in the South America B clade. Phylogenetic analyses of rDNA sequences corresponding to the 537 bp of the ITS region obtained from H. capsulatum isolates assigned South America type B clade (45 isolates), North America type 1 and Asia clade (2 isolates each one). H. capsulatum strains isolated from soil and from patients living in Argentina (45 of 49) clustered together with the H. capsulatum isolates of the South America B clade. The high level of genetic similarity among our isolates suggests that almost one genetic population is present in the microenvironment. Isolates described as H. capsulatum var. capsulatum or var. farciminosum (2 isolates) did not form a monophyletic group and were found in the Asia clade. Subsequent studies are needed to properly identify these isolates.

Prolonged fever and splinter hemorrhages in an immunocompetent traveler with disseminated histoplasmosis

We present a case of progressive disseminated histoplasmosis in an immunocompetent traveler. Histoplasmosis was acquired in South America; its manifestations included prolonged fever, splinter hemorrhages, erythema multiforme, arthritis, and mediastinal lymphadenopathy. To the best of our knowledge no splinter hemorrhages had previously been reported in a patient with histoplasmosis.

Epidemiology of Invasive Fungal Infections in Latin America

The pathogenic role of invasive fungal infections (IFIs) has increased during the past two decades in Latin America and worldwide, and the number of patients at risk has risen dramatically. Working habits and leisure activities have also been a focus of attention by public health officials, as endemic mycoses have provoked a number of outbreaks. An extensive search of medical literature from Latin America suggests that the incidence of IFIs from both endemic and opportunistic fungi has increased. The increase in endemic mycoses is probably related to population changes (migration, tourism, and increased population growth), whereas the increase in opportunistic mycoses may be associated with the greater number of people at risk. In both cases, the early and appropriate use of diagnostic procedures has improved diagnosis and outcome.

Epidemiology of endemic systemic fungal infections in Latin America

Although endemic mycoses are a frequent health problem in Latin American countries, clinical and epidemiological data remain scarce and fragmentary. These mycoses have a significant impact on public health, and early diagnosis and appropriate treatment remain important. The target population for endemic disease in Latin America is mostly represented by low-income rural workers with limited access to a public or private health system. Unfortunately, diagnostic tools are not widely available in medical centers in Latin America; consequently, by the time patients are diagnosed with fungal infection, many are already severely ill. Among immunocompromised patients, endemic mycoses usually behave as opportunistic infections causing disseminated rather than localized disease. This paper reviews the epidemiology of the most clinically significant endemic mycoses in Latin America: paracoccidioidomycosis, histoplasmosis, and coccidioidomycosis. The burdens of disease, typically affected populations, and clinical outcomes also are discussed.

Systematic internal transcribed spacer sequence analysis for identification of clinical mold isolates in diagnostic mycology: a 5-year study

The implementation of internal transcribed spacer (ITS) sequencing for routine identification of molds in the diagnostic mycology laboratory was analyzed in a 5-year study. All mold isolates (n = 6,900) recovered in our laboratory from 2005 to 2009 were included in this study. According to a defined work flow, which in addition to troublesome phenotypic identification takes clinical relevance into account, 233 isolates were subjected to ITS sequence analysis. Sequencing resulted in successful identification for 78.6% of the analyzed isolates (57.1% at species level, 21.5% at genus level). In comparison, extended in-depth phenotypic characterization of the isolates subjected to sequencing achieved taxonomic assignment for 47.6% of these, with a mere 13.3% at species level. Optimization of DNA extraction further improved the efficacy of molecular identification. This study is the first of its kind to testify to the systematic implementation of sequence-based identification procedures in the routine workup of mold isolates in the diagnostic mycology laboratory.