RESUMO
Histoplasmosis is one of the commonest endemic mycoses in the Americas yet is often underdiagnosed and neglected as a public health priority. This review outlines the evolving understanding of its epidemiology and the clinical syndromes of histoplasmosis, in addition to up-to-date diagnostic and treatment guidelines. A focus on histoplasmosis in advanced HIV is included. The challenges pertinent to histoplasmosis management in Latin America, with recommendations made through international expert consensus are discussed.
Assuntos
Doenças Endêmicas , Infecções por HIV/complicações , Histoplasma/patogenicidade , Histoplasmose , Histoplasma/isolamento & purificação , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Histoplasmose/epidemiologia , Humanos , Hospedeiro ImunocomprometidoRESUMO
BACKGROUND: Disseminated Kaposi sarcoma (DKS) is present in patients with advanced HIV infection in whom co-infection with other opportunistic pathogens can occur. Bone marrow (BM) aspirate and biopsy comprise a robust diagnostic tool in patients with fever, cytopenias, and abnormal liver tests. However, the yield in patients with DKS has not been determined. OBJECTIVE: The aim of this study was to evaluate the utility of BM aspirate and biopsy in patients with DKS. METHODS: We included 40 male patients with a recent diagnosis of DKS. BM aspirate and biopsy was performed as part of the workup to rule out co-infections. RESULTS: In four patients, Mycobacterium avium complex (MAC) was recovered from culture. In other four patients, intracellular yeasts were observed in the Grocott stain, diagnosed as Histoplasma. The yield of BM was calculated in 20%. Only 12 patients (30%) had fever and 11 (27.5%) had pancytopenia. Alkaline phosphatase (ALP) above normal values and C-reactive protein (CRP) were higher in patients with positive results for BM than in those with negative results (63% vs. 21.9%, and 3.0 vs. 1.2 mg/L; p = 0.03 in both comparisons). No differences were found when complete blood-count abnormalities were compared. CONCLUSION: We recommend performing a BM aspirate for stains, culture, and biopsy in all HIV patients with DKS, as this will permit the early diagnosis of co-infections and prevent further complications in those who receive chemotherapy.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Medula Óssea/microbiologia , Infecções por HIV/diagnóstico , Histoplasma/crescimento & desenvolvimento , Histoplasmose/diagnóstico , Sarcoma de Kaposi/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Infecções Oportunistas Relacionadas com a AIDS/patologia , Infecções Oportunistas Relacionadas com a AIDS/virologia , Adulto , Fosfatase Alcalina/metabolismo , Biomarcadores/metabolismo , Biópsia , Hemocultura , Medula Óssea/metabolismo , Medula Óssea/cirurgia , Medula Óssea/virologia , Proteína C-Reativa/metabolismo , HIV/crescimento & desenvolvimento , HIV/patogenicidade , Infecções por HIV/microbiologia , Infecções por HIV/patologia , Infecções por HIV/virologia , Histoplasma/isolamento & purificação , Histoplasma/patogenicidade , Histoplasmose/microbiologia , Histoplasmose/patologia , Histoplasmose/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Sarcoma de Kaposi/microbiologia , Sarcoma de Kaposi/patologia , Sarcoma de Kaposi/virologiaRESUMO
Histoplasmosis is considered the most common invasive opportunistic fungal disease in the Americas, with outbreaks and micro-epidemics reported for over 80 years. In Brazil, this disease has been described since 1946, reaching a remarkable incidence in the population, especially during the HIV-AIDS pandemic. In this study, published and unpublished outbreaks and micro-epidemics of histoplasmosis in Brazil were revisited by accessing different database sources and evaluating epidemiological and clinical features. We have found reports spanning 1946-2017, across 10 Brazilian states and with involvement of 370 humans and 2 dogs, and 13 disseminated cases and 3 deaths were reported. Rio de Janeiro had the largest number of outbreaks (n = 20/40; 50%) reported in this study. The majority of outbreaks and micro-epidemics was reported in caves (n = 21/40; 52.5%), followed by reports in abandoned/deactivated sites (n = 6/40; 15%), mines (n = 5/40; 12.5%), chicken coops (n = 4/40; 10%). Histoplasmosis is a serious health issue in Brazil considering the attractive and growing market of ecotourism throughout more than 7000 caves, and all levels of poultry farming activity are important to raise awareness about how dangerous this neglected disease can be and establish ways to decrease exposure to contaminated environmental sources through adequate preventive measures.
Assuntos
Histoplasma , Histoplasmose , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Infecções Oportunistas Relacionadas com a AIDS/prevenção & controle , Animais , Brasil/epidemiologia , Cavernas/microbiologia , Surtos de Doenças , Cães , Histoplasma/classificação , Histoplasma/isolamento & purificação , Histoplasma/patogenicidade , Histoplasmose/epidemiologia , Histoplasmose/microbiologia , Histoplasmose/prevenção & controle , Histoplasmose/veterinária , Humanos , Incidência , Doenças Negligenciadas/epidemiologia , Doenças Negligenciadas/microbiologia , Doenças Negligenciadas/prevenção & controle , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Zoonoses/epidemiologia , Zoonoses/microbiologiaRESUMO
Histoplasmosis is a worldwide-distributed deep mycosis that affects healthy and immunocompromised hosts. Severe and disseminated disease is especially common in HIV-infected patients. At least 11 phylogenetic species are recognized and the majority of diversity is found in Latin America. The northeastern region of Brazil has one of the highest HIV/AIDS prevalence in Latin America and Ceará State has one of the highest death rates due to histoplasmosis in the world, where the mortality rate varies between 33-42%. The phylogenetic distribution and population genetic structure of 51 clinical isolates from Northeast Brazil was studied. For that morphological characteristics, exoantigens profile, and fungal mating types were evaluated. The genotypes were deduced by a MSLT in order to define local population structure of this fungal pathogen. In addition, the relationships of H. capsulatum genotypes with clinically relevant phenotypes and clinical aspects were investigated. The results suggest two cryptic species, herein named population Northeast BR1 and population Northeast BR2. These populations are recombining, exhibit a high level of haplotype diversity, and contain different ratios of mating types MAT1-1 and MAT1-2. However, differences in phenotypes or clinical aspects were not observed within these new cryptic species. A HIV patient can be co-infected by two or more genotypes from Northeast BR1 and/or Northeast BR2, which may have significant impact on disease progression due to the impaired immune response. We hypothesize that co-infections could be the result of multiple exposure events and may indicate higher risk of disseminated histoplasmosis, especially in HIV infected patients.
Assuntos
Infecções por HIV/genética , Histoplasma/genética , Histoplasmose/genética , Filogenia , Adulto , Brasil/epidemiologia , Feminino , Variação Genética/genética , Genótipo , HIV/genética , HIV/patogenicidade , Infecções por HIV/microbiologia , Infecções por HIV/patologia , Infecções por HIV/virologia , Haplótipos/genética , Histoplasma/patogenicidade , Histoplasmose/microbiologia , Histoplasmose/patologia , Histoplasmose/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Free-living amoebae (FLAs) are major reservoirs for a variety of bacteria, viruses, and fungi. The most studied mycophagic FLA, Acanthamoeba castellanii (Ac), is a potential environmental host for endemic fungal pathogens such as Cryptococcus spp., Histoplasma capsulatum, Blastomyces dermatitides, and Sporothrix schenckii. However, the mechanisms involved in this interaction are poorly understood. The aim of this work was to characterize the molecular instances that enable Ac to interact with and ingest fungal pathogens, a process that could lead to selection and maintenance of possible virulence factors. The interaction of Ac with a variety of fungal pathogens was analysed in a multifactorial evaluation that included the role of multiplicity of infection over time. Fungal binding to Ac surface by living image consisted of a quick process, and fungal initial extrusion (vomocytosis) was detected from 15 to 80 min depending on the organism. When these fungi were cocultured with the amoeba, only Candida albicans and Cryptococcus neoformans were able to grow, whereas Paracoccidioides brasiliensis and Sporothrix brasiliensis displayed unchanged viability. Yeasts of H. capsulatum and Saccharomyces cerevisiae were rapidly killed by Ac; however, some cells remained viable after 48 hr. To evaluate changes in fungal virulence upon cocultivation with Ac, recovered yeasts were used to infect Galleria mellonella, and in all instances, they killed the larvae faster than control yeasts. Surface biotinylated extracts of Ac exhibited intense fungal binding by FACS and fluorescence microscopy. Binding was also intense to mannose, and mass spectrometry identified Ac proteins with affinity to fungal surfaces including two putative transmembrane mannose-binding proteins (MBP, L8WXW7 and MBP1, Q6J288). Consistent with interactions with such mannose-binding proteins, Ac-fungi interactions were inhibited by mannose. These MBPs may be involved in fungal recognition by amoeba and promotes interactions that allow the emergence and maintenance of fungal virulence for animals.
Assuntos
Acanthamoeba castellanii/metabolismo , Fungos/patogenicidade , Lectina de Ligação a Manose/metabolismo , Acanthamoeba castellanii/química , Acanthamoeba castellanii/microbiologia , Acanthamoeba castellanii/ultraestrutura , Animais , Candida albicans/patogenicidade , Candida albicans/ultraestrutura , Concanavalina A/metabolismo , Cryptococcus neoformans/patogenicidade , Cryptococcus neoformans/ultraestrutura , Histoplasma/patogenicidade , Histoplasma/ultraestrutura , Interações Hospedeiro-Patógeno , Larva/microbiologia , Lepidópteros/microbiologia , Manose/química , Manose/metabolismo , Lectina de Ligação a Manose/química , Espectrometria de Massas , Microscopia Eletrônica de Varredura , Paracoccidioides/patogenicidade , Paracoccidioides/ultraestrutura , Saccharomyces cerevisiae/patogenicidade , Saccharomyces cerevisiae/ultraestrutura , Fatores de Tempo , Imagem com Lapso de Tempo , Virulência , Fatores de Virulência/metabolismoRESUMO
We describe a Venezuelan visitor to Japan who was diagnosed with hemophagocytic lymphohistiocytosis (HLH). The patient was also diagnosed with human immunodeficiency virus (HIV) and Epstein-Barr virus infection by the Western blot and polymerase chain reaction (PCR) tests, respectively. The cause of HLH was considered to be these two infections at first; however, the patient did not recover with antiretroviral/anti-herpes virus therapy. Thereafter, diagnosis of disseminated histoplasmosis was confirmed with an antigen detection test, culture, and PCR test of blood, urine, and bone marrow, and the patient improved gradually after the initiation of liposomal amphotericin B. This case highlights the importance of ruling out endemic mycosis as a cause of HLH even if other probable causes exist in patients from endemic areas.
Assuntos
Infecções por Vírus Epstein-Barr/diagnóstico , Infecções por HIV/diagnóstico , Histoplasmose/diagnóstico , Linfo-Histiocitose Hemofagocítica/diagnóstico , Anfotericina B/uso terapêutico , Antivirais/uso terapêutico , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Infecções por Vírus Epstein-Barr/virologia , Feminino , HIV/efeitos dos fármacos , HIV/patogenicidade , HIV/fisiologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Herpesvirus Humano 4/efeitos dos fármacos , Herpesvirus Humano 4/patogenicidade , Herpesvirus Humano 4/fisiologia , Histoplasma/efeitos dos fármacos , Histoplasma/patogenicidade , Histoplasma/fisiologia , Histoplasmose/complicações , Histoplasmose/tratamento farmacológico , Histoplasmose/virologia , Humanos , Japão , Linfo-Histiocitose Hemofagocítica/complicações , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/virologia , Pessoa de Meia-Idade , Viagem , VenezuelaRESUMO
The fungal APSES protein family of transcription factors is characterized by a conserved DNA-binding motif facilitating regulation of gene expression in fungal development and other biological processes. However, their functions in the thermally dimorphic fungal pathogen Histoplasma capsulatum are unexplored. Histoplasma capsulatum switches between avirulent hyphae in the environment and virulent yeasts in mammalian hosts. We identified five APSES domain-containing proteins in H. capsulatum homologous to Swi6, Mbp1, Stu1 and Xbp1 proteins and one protein found in related Ascomycetes (APSES-family protein 1; Afp1). Through transcriptional analyses and RNA interference-based functional tests we explored their roles in fungal biology and virulence. Mbp1 serves an essential role and Swi6 contributes to full yeast cell growth. Stu1 is primarily expressed in mycelia and is necessary for aerial hyphae development and conidiation. Xbp1 is the only factor enriched specifically in yeast cells. The APSES proteins do not regulate conversion of conidia into yeast and hyphal morphologies. The APSES-family transcription factors are not individually required for H. capsulatum infection of cultured macrophages or murine infection, nor do any contribute significantly to resistance to cellular stresses including cell wall perturbation, osmotic stress, oxidative stress or antifungal treatment. Further studies of the downstream genes regulated by the individual APSES factors will be helpful in revealing their functional roles in H. capsulatum biology.
Assuntos
Regulação Fúngica da Expressão Gênica , Histoplasma/citologia , Histoplasma/crescimento & desenvolvimento , Hifas/citologia , Hifas/crescimento & desenvolvimento , Fatores de Transcrição/metabolismo , Transcrição Gênica , Animais , Adesão Celular , Linhagem Celular , Perfilação da Expressão Gênica , Histoplasma/genética , Histoplasma/patogenicidade , Histoplasmose/microbiologia , Histoplasmose/patologia , Pulmão/patologia , Macrófagos/microbiologia , Camundongos Endogâmicos C57BL , Interferência de RNA , Virulência , Fatores de Virulência/metabolismoRESUMO
Histoplasma capsulatum is a dimorphic fungus that develops a yeast-like morphology in host's tissue, responsible for the pulmonary disease histoplasmosis. The recent increase in the incidence of histoplasmosis in immunocompromised patients highlights the need of understanding immunological controls of fungal infections. Here, we describe our discovery of the role of endogenous galectin-1 (Gal-1) in the immune pathophysiology of experimental histoplasmosis. All infected wild-type (WT) mice survived while only 1/3 of Lgals1-/- mice genetically deficient in Gal-1 survived 30 days after infection. Although infected Lgals1-/- mice had increased proinflammatory cytokines, nitric oxide (NO), and elevations in neutrophil pulmonary infiltration, they presented higher fungal load in lungs and spleen. Infected lung and infected macrophages from Lgals1-/- mice exhibited elevated levels of prostaglandin E2 (PGE2, a prostanoid regulator of macrophage activation) and prostaglandin E synthase 2 (Ptgs2) mRNA. Gal-1 did not bind to cell surface of yeast phase of H. capsulatum, in vitro, suggesting that Gal-1 contributed to phagocytes response to infection rather than directly killing the yeast. The data provides the first demonstration of endogenous Gal-1 in the protective immune response against H. capsulatum associated with NO and PGE2 as an important lipid mediator in the pathogenesis of histoplasmosis.
Assuntos
Citocinas/metabolismo , Dinoprostona/metabolismo , Galectina 1/metabolismo , Histoplasma/patogenicidade , Óxido Nítrico/metabolismo , Animais , Citometria de Fluxo , Galectina 1/genética , Histoplasmose/metabolismo , Histoplasmose/microbiologia , Humanos , Pulmão/metabolismo , Pulmão/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Healthcare-associated infections (HAI) are described in diverse settings. The main etiologic agents of HAI are bacteria (85%) and fungi (13%). Some factors increase the risk for HAI, particularly the use of medical devices; patients with severe cuts, wounds, and burns; stays in the intensive care unit, surgery, and hospital reconstruction works. Several fungal HAI are caused by Candida spp., usually from an endogenous source; however, cross-transmission via the hands of healthcare workers or contaminated devices can occur. Although other medically important fungi, such as Blastomyces dermatitidis, Paracoccidioides brasiliensis, and Histoplasma capsulatum, have never been considered nosocomial pathogens, there are some factors that point out the pros and cons for this possibility. Among these fungi, H. capsulatum infection has been linked to different medical devices and surgery implants. The filamentous form of H. capsulatum may be present in hospital settings, as this fungus adapts to different types of climates and has great dispersion ability. Although conventional pathogen identification techniques have never identified H. capsulatum in the hospital environment, molecular biology procedures could be useful in this setting. More research on H. capsulatum as a HAI etiologic agent is needed, since it causes a severe and often fatal disease in immunocompromised patients.
Assuntos
Infecção Hospitalar/etiologia , Infecção Hospitalar/microbiologia , Equipamentos e Provisões/microbiologia , Histoplasma/patogenicidade , Blastomyces/patogenicidade , Candida/patogenicidade , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/patologia , Humanos , Paracoccidioides/patogenicidadeRESUMO
The present paper is an overview of the primary events that are associated with the histoplasmosis immune response in the murine model. Valuable data that have been recorded in the scientific literature have contributed to an improved understanding of the clinical course of this systemic mycosis, which is caused by the dimorphic fungus Histoplasma capsulatum. Data must be analyzed carefully, given that misinterpretation could be generated because most of the available information is based on experimental host-parasite interactions that used inappropriate proceedings, i.e., the non-natural route of infection with the parasitic and virulent fungal yeast-phase, which is not the usual infective phase of the etiological agent of this mycosis. Thus, due to their versatility, complexity, and similarities with humans, several murine models have played a fundamental role in exploring the host-parasite interaction during H. capsulatum infection.
Assuntos
Histoplasma/imunologia , Histoplasmose/imunologia , Imunidade Inata , Imunidade Adaptativa , Células Epiteliais Alveolares/imunologia , Células Epiteliais Alveolares/microbiologia , Animais , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/microbiologia , Parede Celular/química , Parede Celular/imunologia , Células Dendríticas/imunologia , Células Dendríticas/microbiologia , Modelos Animais de Doenças , Histoplasma/crescimento & desenvolvimento , Histoplasma/patogenicidade , Histoplasmose/microbiologia , Histoplasmose/patologia , Especificidade de Hospedeiro , Humanos , Camundongos , Especificidade da Espécie , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/microbiologiaRESUMO
The bioactive lipid mediator leukotriene B4 (LTB4) greatly enhances phagocyte antimicrobial functions against a myriad of pathogens. In murine histoplasmosis, inhibition of the LT-generating enzyme 5-lypoxigenase (5-LO) increases the susceptibility of the host to infection. In this study, we investigated whether murine resistance or susceptibility to Histoplasma capsulatum infection is associated with leukotriene production and an enhancement of in vivo and/or in vitro antimicrobial effector function. We show that susceptible C57BL/6 mice exhibit a higher fungal burden in the lung and spleen, increased mortality, lower expression levels of 5-LO and leukotriene B4 receptor 1 (BLT1) and decreased LTB4 production compared to the resistant 129/Sv mice. Moreover, we demonstrate that endogenous and exogenous LTs are required for the optimal phagocytosis of H. capsulatum by macrophages from both murine strains, although C57BL/6 macrophages are more sensitive to the effects of LTB4 than 129/Sv macrophages. Therefore, our results provide novel evidence that LTB4 production and BLT1 signaling are required for a histoplasmosis-resistant phenotype.
Assuntos
Histoplasma/imunologia , Histoplasmose/veterinária , Leucotrieno B4 , Receptores do Leucotrieno B4/imunologia , Doenças dos Roedores/imunologia , Animais , Araquidonato 5-Lipoxigenase/genética , Araquidonato 5-Lipoxigenase/imunologia , Suscetibilidade a Doenças , Inibidores Enzimáticos/farmacologia , Expressão Gênica/imunologia , Histoplasma/patogenicidade , Histoplasmose/genética , Histoplasmose/imunologia , Histoplasmose/metabolismo , Especificidade de Hospedeiro , Interações Hospedeiro-Patógeno , Leucotrieno B4/metabolismo , Leucotrieno B4/farmacologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/microbiologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Fagocitose/efeitos dos fármacos , Receptores do Leucotrieno B4/genética , Doenças dos Roedores/genética , Doenças dos Roedores/metabolismo , Transdução de Sinais , Baço/efeitos dos fármacos , Baço/imunologia , Baço/microbiologiaRESUMO
Prostaglandins act as mediators of inflammation and, similar to cytokines, function as immune modulators during innate and adaptive immune responses. Therefore, using a pharmacological inhibitor, celecoxib, we investigated the role of prostaglandins in host defense against Histoplasma capsulatum infection in C57BL/6 mice. Our results showed that treatment with celecoxib inhibited cyclooxygenase 2, reduced the total fungal burden, and reduced the concentration of PGE2, cytokines, lymphocytes, neutrophils, and mononuclear cells in the bronchoalveolar space and lung parenchyma. In addition, celecoxib treatment increased the synthesis of nitric oxide, IFN- γ, LTB4, and the phagocytic capacity of alveolar macrophages. Moreover, celecoxib treatment increased the survival of mice after infection with a lethal inoculum of H. capsulatum. These results suggest that prostaglandins alter the host immune response and play an important role in the pathogenesis of histoplasmosis. Thus, the inhibition of prostaglandins could be a valuable immunomodulatory strategy and antifungal therapy for histoplasmosis treatment.
Assuntos
Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Histoplasma/patogenicidade , Histoplasmose/tratamento farmacológico , Histoplasmose/metabolismo , Pirazóis/uso terapêutico , Sulfonamidas/uso terapêutico , Animais , Celecoxib , Histoplasma/efeitos dos fármacos , Interferon gama/metabolismo , Leucotrieno B4/metabolismo , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismoRESUMO
Non-mammalian models have been used to investigate fungal virulence. In this work we have explored the use of Galleria mellonella as an infection model for the pathogenic dimorphic fungi Histoplasma capsulatum and Paracoccidioides lutzii. In mammalian models these fungi cause similar infections, and disease outcomes are influenced by the quantity of the infective inocula. We describe a similar aspect in a G. mellonella model and characterize the pathogenesis features in this system. Infection with P. lutzii or H. capsulatum, in all inoculum used, killed larvae at 25 and 37°C. However, there was a lack of correlation between the number of yeast cells used for infection and the time to larvae death, which may indicate that the fungi induce protective responses in a dynamic manner as the lowest concentrations of fungi induced the most rapid death. For both fungi, the degree of larvae melanization was directly proportional to the inocula size, and this effect was visibly more apparent at 37°C. Histological evaluation of the larvae showed a correlation between the inoculum and granuloma-like formation. Our results suggest that G. mellonella is a potentially useful model to study virulence of dimorphic fungi.
Assuntos
Modelos Animais de Doenças , Histoplasma/crescimento & desenvolvimento , Lepidópteros/microbiologia , Paracoccidioides/crescimento & desenvolvimento , Animais , Granuloma/patologia , Histocitoquímica , Histoplasma/patogenicidade , Humanos , Larva/microbiologia , Larva/fisiologia , Lepidópteros/fisiologia , Paracoccidioides/patogenicidade , Análise de Sobrevida , Temperatura , VirulênciaRESUMO
In the cell walls of the pathogenic yeast phases of Paracoccidioides brasiliensis, Blastomyces dermatitidis and Histoplasma capsulatum, the outer α-(1,3)-glucan layer behaves as a virulence factor. In H. capsulatum, an α-(1,4)-amylase gene (AMY1) is essential for the synthesis of this polysaccharide, hence related to virulence. An orthologous gene to H. capsulatum AMY1 was identified in P. brasiliensis and also labeled AMY1. P. brasiliensis AMY1 transcriptional levels were increased during the yeast phase, which correlates with the presence of α-(1,3)-glucan as the major yeast cell wall polysaccharide. Complementation of a H. capsulatum amy1 mutant strain with P. brasiliensis AMY1, suggests that P. brasiliensis Amy1p may play a role in the synthesis of cell wall α-(1,3)-glucan. To study some biochemical properties of P. brasiliensis Amy1p, the enzyme was overexpressed, purified and studied its activity profile with starch and amylopeptin. It showed a relatively higher hydrolyzing activity on amylopeptin than starch, producing oligosaccharides from 4 to 5 glucose residues. Our findings show that P. brasiliensis Amy1p produces maltooligosaccharides which may act as a primer molecule for the fungal cell wall α-(1,3)-glucan biosynthesis by Ags1p.
Assuntos
Parede Celular/genética , Proteínas Fúngicas/genética , Glucanos/biossíntese , Histoplasma/genética , Paracoccidioides/genética , alfa-Amilases/genética , Sequência de Aminoácidos , Amilopectina/metabolismo , Parede Celular/enzimologia , Proteínas Fúngicas/metabolismo , Expressão Gênica , Teste de Complementação Genética , Histoplasma/enzimologia , Histoplasma/patogenicidade , Dados de Sequência Molecular , Mutação , Paracoccidioides/enzimologia , Paracoccidioides/patogenicidade , Filogenia , Alinhamento de Sequência , Amido/metabolismo , Especificidade por Substrato , Virulência , alfa-Amilases/metabolismoRESUMO
Histoplasmosis is a granulomatous infection caused by Histoplasma capsulatum, a dimorphic fungus. It is distributed worldwide and prevalent in certain regions of North and Central America. Pulmonary involvement is the most common clinical presentation. Cutaneous manifestations are reported to occur in 10% to 25% of AIDS patients with disseminated histoplasmosis. The skin lesions are polymorphic papules, plaques with or without crusts, pustules, nodules, mucosal ulcers, erosions, punched out ulcers, lesions resembling molluscum contagiosum, acneiform eruptions, erythematosus papules and keratotic plaques, purpuric lesions, and localized and generalized vegetant forms of dermatitis, sometimes an eruption similar to rosacea, keratotic papules with transepidermal elimination, polymorphous erythema, erythroderma syndromes, pyoderma gangrenosum, panniculitis, diffuse hyperpigmentation, abscesses, and cellulitis.
Assuntos
Dermatomicoses/epidemiologia , Histoplasmose/epidemiologia , Antifúngicos/uso terapêutico , Dermatomicoses/diagnóstico , Dermatomicoses/tratamento farmacológico , Histoplasma/patogenicidade , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Humanos , Pneumopatias Fúngicas , Testes CutâneosRESUMO
The pathogenic fungus, Histoplasma capsulatum, causes the respiratory and systemic disease 'histoplasmosis'. This disease is primarily acquired via inhalation of aerosolized microconidia or hyphal fragments of H. capsulatum. Evolution of this respiratory disease depends on the ability of H. capsulatum yeasts to survive and replicate within alveolar macrophages. It is known that adhesion to host cells is the first step in colonization and biofilm formation. Some microorganisms become attached to biological and non-biological surfaces due to the formation of biofilms. Based on the importance of biofilms and their persistence on host tissues and cell surfaces, the present study was designed to investigate biofilm formation by H. capsulatum yeasts, as well as their ability to adhere to pneumocyte cells. H. capsulatum biofilm assays were performed in vitro using two different clinical strains of the fungus and biofilms were characterized using scanning electron microscopy. The biofilms were measured using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium-hydroxide (XTT) reduction assay. The results showed that both the H. capsulatum strains tested were very efficient at adhering to host cells and forming biofilm. Therefore, this is a possible survival strategy adopted by this fungus.
Assuntos
Células Epiteliais Alveolares/microbiologia , Biofilmes , Histoplasma/patogenicidade , Células Epiteliais Alveolares/metabolismo , Adesão Celular , Linhagem Celular , Histoplasma/metabolismo , Histoplasma/fisiologia , Histoplasmose/microbiologia , Interações Hospedeiro-Patógeno , Humanos , Microscopia Eletrônica de Varredura , Sais de Tetrazólio/metabolismoRESUMO
This study contains a descriptive analysis of histoplasmosis in AIDS patients between 2006 and 2010 in the state of Ceará, Brazil. Additionally, the in vitro susceptibility of Histoplasma capsulatum isolates obtained during this period was assessed. We report 208 cases of patients with histoplasmosis and AIDS, describing the epidemiological, clinical, laboratory and therapeutic aspects. The in vitro antifungal susceptibility test was carried out by the microdilution method, according to Clinical and Laboratory Standards Institute, with H. capsulatum in the filamentous and yeast phases, against the antifungals amphotericin B, fluconazole, itraconazole, voriconazole and caspofungin. In 38.9% of the cases, histoplasmosis was the first indicator of AIDS and in 85.8% of the patients the CD4 cell count was lower than 100 cells/mm(3). The lactate dehydrogenase levels were high in all the patients evaluated, with impairment of hepatic and renal function and evolution to death in 42.3% of the cases. The in vitro susceptibility profile demonstrated there was no antifungal resistance among the isolates evaluated. There was a significant increase in the number of histoplasmosis cases in HIV-positive patients during the period surveyed in the state of Ceará, northeastern Brazil, but no antifungal resistance among the recovered isolates of H. capsulatum.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Antifúngicos/uso terapêutico , Histoplasma/patogenicidade , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , L-Lactato Desidrogenase/sangue , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Adulto , Anfotericina B/uso terapêutico , Brasil/epidemiologia , Contagem de Linfócito CD4 , Caspofungina , Equinocandinas/uso terapêutico , Feminino , Fluconazol/uso terapêutico , Histoplasma/isolamento & purificação , Histoplasmose/epidemiologia , Histoplasmose/microbiologia , Humanos , Itraconazol/uso terapêutico , Lipopeptídeos , Masculino , Testes de Sensibilidade Microbiana , Pirimidinas/uso terapêutico , Triazóis/uso terapêutico , VoriconazolRESUMO
Analysis of membrane lipids of Histoplasma capsulatum showed that ~40% of fungal ergosterol is present in membrane microdomain fractions resistant to treatment with non-ionic detergent at 4°C. Specific proteins were also enriched in these fractions, particularly Pma1p a yeast microdomain protein marker (a plasma membrane proton ATPase), a 30kDa laminin-binding protein, and a 50kDa protein recognized by anti-α5-integrin antibody. To better understand the role of ergosterol-dependent microdomains in fungal biology and pathogenicity, H. capsulatum yeast forms were treated with a sterol chelator, methyl-beta-cyclodextrin (mßCD). Removal of ergosterol by mßCD incubation led to disorganization of ergosterol-enriched microdomains containing Pma1p and the 30kDa protein, resulting in displacement of these proteins from detergent-insoluble to -soluble fractions in sucrose density gradient ultracentrifugation. mßCD treatment did not displace/remove the 50kDa α5-integrin-like protein nor had effect on the organization of glycosphingolipids present in the detergent-resistant fractions. Ergosterol-enriched membrane microdomains were also shown to be important for infectivity of alveolar macrophages; after treatment of yeasts with mßCD, macrophage infectivity was reduced by 45%. These findings suggest the existence of two populations of detergent-resistant membrane microdomains in H. capsulatum yeast forms: (i) ergosterol-independent microdomains rich in integrin-like proteins and glycosphingolipids, possibly involved in signal transduction; (ii) ergosterol-enriched microdomains containing Pma1p and the 30kDa laminin-binding protein; ergosterol and/or the 30kDa protein may be involved in macrophage infectivity.
Assuntos
Proteínas Fúngicas/metabolismo , Histoplasma/metabolismo , Histoplasma/patogenicidade , Histoplasmose/metabolismo , Macrófagos Alveolares/metabolismo , Microdomínios da Membrana/metabolismo , Proteínas de Membrana/metabolismo , Animais , Ergosterol/metabolismo , Histoplasmose/microbiologia , Histoplasmose/patologia , Macrófagos Alveolares/microbiologia , Macrófagos Alveolares/patologia , Camundongos , Camundongos Endogâmicos BALB C , beta-Ciclodextrinas/farmacologiaRESUMO
Moulds are common and important allergens. They are more abundant outdoors but patients affected by mould allergy stay indoors much longer than outdoors. So, indoor sampling could help to assess the influence of the concentration of allergens in allergic symptoms. The aim of this study was to assess the relative efficiencies of two air sampling methods, viable and non viable, for the quantification of airborne indoor fungi in the homes of patients sensitized to Alternaria. Furthermore, outdoor sampling was carried out to compare results. Samples were taken over six months in Badajoz (SW Spain). Two houses were selected according to the presence of allergic patients to Alternaria. They were sampled once a month using both viable and non viable personal samplers at solar noon. A Burkard personal sampler was used to record spores and a Samplair AES Chemunex sampler was used for colonies. Three rooms were selected in each home: living room, kitchen and bathroom. Temperature and relative humidity were registered at each sample. Outdoor sampling was performed one day per week at the Faculty of Science, using a seven day Burkard sampler for spores and the same personal sampler for colonies. On average, 200-300 CFU/ m3 were found from more than 40 taxa identified. The highest number of colonies was recorded in the kitchen, then in the bathroom and finally in the living room. Nevertheless, there were minor differences between rooms. The houses studied showed a similar temporal pattern, with maximum values in December and minimum in January. Cladosporium colonies showed statistical differences between homes, but these differences were not found with Alternaria, Aspergillus or Penicillium colonies. Differences between rooms appeared for Alternaria colonies and Cladosporium herbarium spores. Temperature was positively correlated in most cases and relative humidity negatively with Alternaria spores.
Los hongos son alérgenos comunes e importantes. Son más abundantes en exteriores pero los pacientes afectados por alergia a los hongos permanecen en interiores mucho más tiempo que en exteriores. Por esto, el muestreo en interiores puede ayudar a evaluar la influencia de la concentración de alérgenos en los síntomas de la alergia. El objetivo de este trabajo ha sido valorar la eficiencia relativa de dos métodos de muestreo del aire, viable y no viable, para la cuantificación de hongos aerovagantes de interiores en hogares de pacientes sensibilizados a Alternaria. Adicionalmente, se ha realizado un muestreo en exteriores para comparar los resultados. Las muestras se tomaron durante seis meses en Badajoz (SO de España). Dos casas fueron seleccionadas de acuerdo a la presencia de pacientes alérgicos a Alternaria spp. Fueron muestreadas hacia el mediodía de forma mensual utilizando simultáneamente captadores personales con métodos viables y no viables. Un captador personal Burkard se utilizó para el registro de las esporas y un captador Samplair AES Chemunex para las colonias de hongos. Se seleccionaron tres habitaciones en cada casa, el salón, la cocina y el cuarto de baño. La temperatura y la humedad relativa fueron registradas en cada muestreo. El muestreo en el exterior se llevó cabo un día a la semana en la Facultad de Ciencias utilizando un captador Burkard 7-day para las esporas y el mismo captador personal para las colonias. En promedio se encontraron 200-300 CFU/m3 pertenecientes a más de 40 taxones identificados. El mayor número de colonias fue registrado en la cocina, luego en el cuarto de baño y finalmente en el salón. Sin embargo las diferencias entre las habitaciones fueron mínimas. Las casas estudiadas mostraron un patrón temporal similar, con valores máximos en Diciembre y mínimos en Enero.