RESUMO
Pneumocystis is a respiratory fungal pathogen that is among the most frequent causes of life-threatening pneumonia (PcP) in immunocompromised hosts. Alveolar macrophages play an important role in host defense against Pneumocystis, and several studies have suggested that M2 polarized macrophages have anti-Pneumocystis effector activity. Our prior work found that the immunomodulatory drug sulfasalazine (SSZ) provides a dual benefit during PcP-related immune reconstitution inflammatory syndrome (IRIS) by concurrently suppressing immunopathogenesis while also accelerating macrophage-mediated fungal clearance. The benefits of SSZ were associated with heightened Th2 cytokine production and M2 macrophage polarization. Therefore, to determine whether SSZ improves the outcome of PcP through a mechanism that requires Th2-dependent M2 polarization, RAG2-/- mice lacking interleukin 4 receptor alpha chain (IL-4Rα) on macrophage lineage cells were generated. As expected, SSZ treatment dramatically reduced the severity of PcP-related immunopathogenesis and accelerated fungal clearance in immune-reconstituted RAG2-/- mice. Similarly, SSZ treatment was also highly effective in immune-reconstituted RAG2/IL-4Rα-/- and RAG2/gamma interferon receptor (IFN-γR)-/- mice, demonstrating that neither IL-4Rα-dependent M2 nor IFN-γR-dependent M1 macrophage polarization programs were required for the beneficial effects of SSZ. Despite the fact that macrophages from RAG2/IL-4Rα-/- mice could not respond to the Th2 cytokines IL-4 and IL-13, M2-biased alveolar macrophages were identified in the lungs following SSZ treatment. These data demonstrate that not only does SSZ enhance phagocytosis and fungal clearance in the absence of macrophage IL-4Rα signaling, but also that SSZ promotes M2 macrophage polarization in an IL-4Rα-independent manner. These findings could have implications for the treatment of PcP and other diseases in which M2 polarization is beneficial.
Assuntos
Pneumocystis , Pneumonia por Pneumocystis , Camundongos , Animais , Sulfassalazina/farmacologia , Pneumonia por Pneumocystis/tratamento farmacológico , Antifúngicos/farmacologia , Macrófagos , Macrófagos Alveolares/microbiologiaRESUMO
After cardiovascular diseases, infectious diseases are the second most common cause of death worldwide. Although these infections are caused mainly by viruses or bacteria, a systematically growing prevalence of human and animal opportunistic fungal infections is noticeable worldwide. More attention is being paid to this problem, especially due to the growing frequency of recalcitrant and recurrent mycoses. The latter are classically divided into superficial, which are the most common type, subcutaneous, and systemic. This work discusses opportunistic fungal pathogens without proven horizontal transmission between different animal species including humans and microsporidia as spore-forming unicellular parasites related to fungi; however, with a yet undetermined taxonomic position. The review also mentions aetiological agents, risk factors, epidemiology, geographical distribution, and finally symptoms characteristic for individual disease entities. This paper provides insight into fungal infections from a global perspective and simultaneously draws attention to emerging pathogens, whose prevalence is continuously increasing. Finally, this work also takes into consideration the correct nomenclature of fungal disease entities and the importance of secondary metabolites in the pathogenesis of fungal infections.
Assuntos
Microsporidiose , Micoses , Infecções Oportunistas , Vírus , Animais , Fungos , Humanos , Micoses/epidemiologia , Infecções Oportunistas/epidemiologiaRESUMO
Opulente et al. (Opulente DA, Langdon QK, Buh KV et al. Pathogenic budding yeasts isolated outside of clinical settings. FEMS Yeast Res 2019;19:foz032) published early this year a study aiming to investigate the diversity of wild yeast species, by collecting 1000 environmental samples coming from different substrates across the United States of America. The main finding of this work is the recovery of 54 strains of budding yeasts of which several are having a pathogenic potential in the clinical setting, such as Candida albicans, C. parapsilosis, C. tropicalis, Nakaseomyces glabrata and Pichia kudriavzevii. These findings, discussed here in light of other recent studies highlighting the role of fungicides in the rise of antifungal resistance in the clinical setting or the emergence of Candida auris, demonstrate that our environment can represent an alternative niche for several opportunistic fungal pathogens that can be a concern for human health.
Assuntos
Antifúngicos , Candida/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Humanos , Testes de Sensibilidade MicrobianaRESUMO
We surveyed the diversity of cultivable fungi isolated from cold and hot volcanic soils of Deception Island, Antarctica. Seventy-four fungal isolates were identified; these belonged to 17 taxa in the genera Aspergillus, Penicillium, Pseudogymnoascus, Purpureocillium, and Mortierella. The fungal assemblages showed low diversity, richness, and dominance indices. The Aspergillus taxa were dominant in the soils at 0 °C, 50 °C, and 100 °C. Aspergillus lacticoffeatus, Aspergillus cf. ruber, Penicillium citrinun, and Purpureocillium sodanum were present only in soils having a temperature of 100 °C. Aspergillus calidoustus was present in all thermal soils and displayed the highest densities. The majority of fungi displayed mesophilic behavior; however, different isolates of Aspergillus lacticoffeatus and Aspergillus niger were able to grow at 50 °C; these are phylogenetically close to the causative agents of aspergillosis in immunocompromised individuals. Deception Island perhaps represents one of the most visited regions in Antarctica and the tourism there has increased over the last 20 years, especially by elderly tourists, probably with weak immune systems, come in contact with the resident microorganisms, including the thermo-resistant opportunistic Aspergillus species.
Assuntos
Solo , Idoso , Regiões Antárticas , Ascomicetos , Fungos , Humanos , Ilhas , Microbiologia do SoloRESUMO
Exophiala is a genus comprising several species of opportunistic black yeasts. Exophiala species identification by morphological, physiological, and biochemical characteristics is challenging because of the low degree of phenotypic differences between species and its polyphyletic nature. We aimed to develop a high-resolution melting (HRM) assay based on the internal transcribed spacer (ITS) region to differentiate between pairs of clinical and environmental Exophiala species. HRM primers were designed based on the conserved ITS region of five Exophiala species (E. dermatitidis, E. phaeomuriformis, E. heteromorpha, E. xenobiotica, and E. crusticola). Environmental and clinical Exophiala isolates representing these five species (n = 109) were analyzed. The HRM assay was optimized using clinical and environmental reference isolates (n = 22), and then the results were compared with those obtained with nonreference isolates of Exophiala (n = 87) using two designed primer sets. The designed HRM assay was based on the normalized melting peak approach and two primer sets, and successfully distinguished between the five Exophiala species. The HRM1 primer set provided sufficient resolution, with a melting temperature (Tm) difference of approximately 2.5°C among the analyzed species and of approximately 1°C between E. dermatitidis and E. phaeomuriformis. HRM typing results were in agreement with those of ITS-sequence typing (100% sensitivity and specificity). The developed HRM assay can be used to ascertain the identity of Exophiala species, which may differ in clinical significance, with high accuracy. Its application to identify species directly in clinical samples and/or environmental niches may be possible in the future.
Assuntos
DNA Fúngico/isolamento & purificação , DNA Espaçador Ribossômico/isolamento & purificação , Exophiala/classificação , Exophiala/genética , Exophiala/isolamento & purificação , Técnicas de Tipagem Micológica , Variação Genética , Genótipo , FenótipoRESUMO
Pneumocystis pneumonia is a life-threatening opportunistic fungal infection observed in individuals with severe immunodeficiencies, such as AIDS. Molecules with the ability to bind ß-glucan and signal at Fcγ receptors enhance defense against Pneumocystis f. sp. murina, though it is unclear whether antibodies reactive with fungal cell wall carbohydrates are induced during Pneumocystis infection. We observed that systemic and lung mucosal immunoglobulins cross-reactive with ß-glucan and chitosan/chitin are generated after Pneumocystis infection, with increased quantities within the lung mucosal fluid after challenge. While IgG responses against Pneumocystis protein antigens are markedly CD4+ T cell dependent, CD4+ T cell depletion did not impact quantities of IgG cross-reactive with ß-glucan or chitosan/chitin in the serum or mucosa after challenge. Notably, lung mucosal quantities of IgA cross-reactive with ß-glucan or chitosan/chitin are decreased in the setting of CD4+ T cell deficiency, occurring in the setting of concurrent reduced quantities of active transforming growth factor ß, while mucosal IgM is significantly increased in the setting of CD4+ T cell deficiency. Interleukin-21 receptor deficiency does not lead to reduction in mucosal IgA reactive with fungal carbohydrate antigens after Pneumocystis challenge. These studies demonstrate differential CD4+ T cell-dependent regulation of mucosal antibody responses against ß-glucan and chitosan/chitin after Pneumocystis challenge, suggesting that different B cell subsets may be responsible for the generation of these antibody responses, and suggest a potential immune response against fungi that may be operative in the setting of CD4+ T cell-related immunodeficiency.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Pneumocystis/imunologia , Pneumonia por Pneumocystis/imunologia , Linfócitos T Reguladores/imunologia , Animais , Parede Celular/metabolismo , Quitina/análise , Quitosana/análise , Reações Cruzadas/imunologia , Imunoglobulina G/imunologia , Pulmão/metabolismo , Depleção Linfocítica , Camundongos Endogâmicos BALB C , beta-Glucanas/imunologiaRESUMO
Cryptococcus neoformans is an opportunistic human pathogen that causes cryptococcosis, a life-threatening infection that usually manifests as meningoencephalitis in immunocompromised patients. Pigeon (Columba livia) droppings can spread pathogenic yeasts and mold fungi, such as C neoformans, in the environment. The objective of this study was to isolate C neoformans and other opportunistic fungi from feral pigeon droppings. One hundred twenty samples of feral pigeon droppings were suspended 1:10 in saline solution and then cultured. The fungi were identified by standard mycological techniques. Fungal contamination was detected in all examined samples. Yeast and mold fungi were isolated from 114 samples (95%) and 103 samples (85.8%), respectively, out of 120 samples. The highest frequency of yeast and mold fungi isolated from collected samples was C neoformans 77.5% and Rhizopus species 38.3%, respectively. Several types of fungi exist in pigeon droppings that can be spread in the environment and transmitted to children and elderly, as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases.
Assuntos
Doenças das Aves/epidemiologia , Doenças das Aves/microbiologia , Columbidae/microbiologia , Criptococose/veterinária , Cryptococcus neoformans/isolamento & purificação , Fezes/microbiologia , Animais , Criptococose/epidemiologia , Criptococose/microbiologia , Fungos/isolamento & purificação , Irã (Geográfico)/epidemiologia , Infecções Oportunistas/epidemiologia , Infecções Oportunistas/microbiologia , Infecções Oportunistas/veterinária , Prevalência , Leveduras/isolamento & purificaçãoRESUMO
The echinocandins are a class of antifungal agents that target ß-1,3-d-glucan (BG) biosynthesis. In the ascigerous Pneumocystis species, treatment with these drugs depletes the ascus life cycle stage, which contains BG, but large numbers of forms which do not express BG remain in the infected lungs. In the present study, the gene expression profiles of Pneumocystis murina were compared between infected, untreated mice and mice treated with anidulafungin for 2 weeks to understand the metabolism of the persisting forms. Almost 80 genes were significantly up- or downregulated. Like other fungi exposed to echinocandins, genes associated with sexual replication, cell wall integrity, cell cycle arrest, and stress comprised the strongest upregulated signals in P. murina from the treated mice. The upregulation of the P. murina ß-1,3-d-glucan endohydrolase and endo-1,3-glucanase was notable and may explain the disappearance of the existing asci in the lungs of treated mice since both enzymes can degrade BG. The biochemical measurement of BG in the lungs of treated mice and fluorescence microscopy with an anti-BG antibody supported the loss of BG. Downregulated signals included genes involved in cell replication, genome stability, and ribosomal biogenesis and function and the Pneumocystis-specific genes encoding the major surface glycoproteins (Msg). These studies suggest that P. murina attempted to undergo sexual replication in response to a stressed environment and was halted in any type of proliferative cycle, likely due to a lack of BG. Asci appear to be a required part of the life cycle stage of Pneumocystis, and BG may be needed to facilitate progression through the life cycle via sexual replication.
Assuntos
Anidulafungina/farmacologia , Antifúngicos/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Pneumocystis/efeitos dos fármacos , Pneumocystis/genética , Animais , Proliferação de Células/efeitos dos fármacos , Masculino , Camundongos , Pneumocystis/patogenicidade , Pneumonia por Pneumocystis/tratamento farmacológico , Pneumonia por Pneumocystis/microbiologia , Pneumonia por Pneumocystis/prevenção & controleRESUMO
Extreme habitats are not only limited to natural environments, but also exist in manmade systems, for instance, household appliances such as dishwashers. Limiting factors, such as high temperatures, high and low pHs, high NaCl concentrations, presence of detergents, and shear force from water during washing cycles, define microbial survival in this extreme system. Fungal and bacterial diversity in biofilms isolated from rubber seals of 24 different household dishwashers was investigated using next-generation sequencing. Bacterial genera such as Pseudomonas, Escherichia, and Acinetobacter, known to include opportunistic pathogens, were represented in most samples. The most frequently encountered fungal genera in these samples belonged to Candida, Cryptococcus, and Rhodotorula, also known to include opportunistic pathogenic representatives. This study showed how specific conditions of the dishwashers impact the abundance of microbial groups and investigated the interkingdom and intrakingdom interactions that shape these biofilms. The age, usage frequency, and hardness of incoming tap water of dishwashers had significant impact on bacterial and fungal community compositions. Representatives of Candida spp. were found at the highest prevalence (100%) in all dishwashers and are assumed to be one of the first colonizers in recently purchased dishwashers. Pairwise correlations in tested microbiomes showed that certain bacterial groups cooccur, as did the fungal groups. In mixed bacterial-fungal biofilms, early adhesion, contact, and interactions were vital in the process of biofilm formation, where mixed complexes of bacteria and fungi could provide a preliminary biogenic structure for the establishment of these biofilms.IMPORTANCE Worldwide demand for household appliances, such as dishwashers and washing machines, is increasing, as is the number of immunocompromised individuals. The harsh conditions in household dishwashers should prevent the growth of most microorganisms. However, our research shows that persisting polyextremotolerant groups of microorganisms in household appliances are well established under these unfavorable conditions and supported by the biofilm mode of growth. The significance of our research is in identifying the microbial composition of biofilms formed on dishwasher rubber seals, how diverse abiotic conditions affect microbiota, and which key microbial members were represented in early colonization and contamination of dishwashers, as these appliances can present a source of domestic cross-contamination that leads to broader medical impacts.
Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes/crescimento & desenvolvimento , Fungos/fisiologia , Utensílios Domésticos , Microbiota/fisiologia , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Fungos/crescimento & desenvolvimento , Fungos/isolamento & purificaçãoRESUMO
The present literature review summarizes information about the diseases of the upper respiratory tract and the ears caused by opportunistic fungi. The factors responsible for the increased frequency of opportunistic infections, among which mycosis is the leading one, are given. The exogenous and endogenous risk factors are described. The main pathogens of opportunistic mycotic infections of the ENT-organs are listed. Special attention is given to the mechanism underlying the development of anti-colonial immunity of the upper respiratory tract and the ears and the formation of the antifungal immunity of the macroorganism as a whole. The data on the pathogenetic factors of mycelial and yeast-like micromycetes are presented. The main variants of the pathogenetic mechanisms, such as adhesion, invasive growth, and penetration, behind the formation of the mycotic lesions are considered. These biological properties of the fungi contribute to their ability to cause a wide range of pathological changes - from the superficial lesions of the skin and mucous membranes of the ENT organs to the deep invasive processes. The protective cellular and humoral immune reactions of a macroorganism that develop in response to the introduction of a pathogenic fungus are described. The review lists the main nosological forms of mycosis known to affect the ENT-organs with special reference to the leading role of the yeast-like fungi belonging to the genus Candida in the development of mycotic lesions of these biotopes (64.65%). The most pathogenic species, Candida albicans, prevails in the structure of the yeast-like fungi biome whereas the leading role in the development of mycosis of the ENT organs by micromycetes of mold belongs to the species Aspergillus niger.
Assuntos
Antifúngicos , Otopatias , Micoses , Doenças Nasais , Infecções Oportunistas , Antifúngicos/uso terapêutico , Candida , Otopatias/tratamento farmacológico , Otopatias/microbiologia , Fungos , Humanos , Micoses/diagnóstico , Micoses/tratamento farmacológico , Doenças Nasais/tratamento farmacológico , Doenças Nasais/microbiologia , Infecções Oportunistas/diagnóstico , Infecções Oportunistas/tratamento farmacológico , FaringeRESUMO
Natural habitats of opportunistic fungal pathogens are outside of the host; therefore, it is critically important to understand their ecology and routes of transmission. In this study, we investigated the presence of human pathogenic opportunistic fungi in lake water and incidence of fungal infections in associated population in Kashmir, India. Six hundred forty water samples were taken on seasonal basis from a wide network of sampling stations of the lake for an extended period of two years for screening their occurrence. The samples were inoculated onto rose bengal agar, malt extract agar, potato dextrose agar and other specified culture media supplemented with Chloramphenicol and Streptomycin followed by incubation at 37 °C. All the samples were positive for fungi, which were later identified by sequencing the rDNA internal transcribed spacer region aided by classical morphological culture techniques and physiological profiling. The whole process led to the isolation of sixteen species of opportunistic fungal pathogens belonging to genus Aspergillus, Candida, Penicillium, Cryptococcus, Fusarium, Rhizopus and Mucor in decreasing order of prevalence. Furthermore, 20% population (n = 384) of Dal inhabitants was examined for possible fungal infections and it was observed that only 8.07% individuals were positive for fungal infections with 4.68% skin infection cases, 2.34% onychomycosis cases and 1.04% candidiasis cases. Scrapings from onychomycosis and candidiasis patients showed the presence of Aversicolor and Calbicans respectively, resembling exactly the strains isolated from the lake water. However, the skin infection was because of a dermatophyte not isolated for the lake water. Higher prevalence of infection (6.77%) was seen in people using lake water followed by a positive prevalence of 1.30% using tap water. The results of present study suggest that the lake inhabitants are at a greater risk of getting life threatening fungal diseases which may lead to various morbidities.
Assuntos
Fungos/isolamento & purificação , Lagos/microbiologia , Micoses/microbiologia , Adolescente , Adulto , Feminino , Fungos/classificação , Fungos/genética , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Micoses/epidemiologia , Estações do Ano , Poluição da Água , Adulto JovemRESUMO
Severe skin diseases and systemic fungaemia are caused by Malassezia pachydermatis and Candida albicans respectively. Antifungal therapies are less effective because of chronic character of infections and high percentage of relapses. Therefore, there is a great need to develop new strategies of antifungal therapies. We previously found that oxythiamine decreases proliferation of yeast (Saccharomyces cerevisiae), therefore we suggest that thiamine antivitamins can be considered as antifungal agents. The aim of this study was the comparison of thiamine antivitamins (oxythiamine, amprolium, thiochrome, tetrahydrothiamine and tetrahydrooxythiamine) inhibitory effect on the growth rate and energetic metabolism efficiency in non-pathogenic S. cerevisiae and two potentially pathogenic species M. pachydermatis and C. albicans. Investigated species were cultured on a Sabouraud medium supplemented with trace elements in the presence (40 mg l(-1)) or absence of each tested antivitamins to estimate their influence on growth rate, enzyme activity and kinetic parameters of pyruvate decarboxylase and malate dehydrogenase of each tested species. Oxythiamine was the only antivitamin with antifungal potential. M. pachydermatis and S. cerevisiae were the most sensitive, whereas C. albicans was the least sensitive to oxythiamine action. Oxythiamine can be considered as supportive agent in superficial mycoses treatment, especially those caused by species from the genus Malassezia.
Assuntos
Antifúngicos/farmacologia , Antimetabólitos/farmacologia , Candida albicans/efeitos dos fármacos , Candidíase Cutânea/tratamento farmacológico , Dermatomicoses/tratamento farmacológico , Malassezia/efeitos dos fármacos , Tiamina/antagonistas & inibidores , Antifúngicos/uso terapêutico , Antimetabólitos/uso terapêutico , Candida albicans/crescimento & desenvolvimento , Candidíase Cutânea/microbiologia , Dermatomicoses/microbiologia , Fungemia/tratamento farmacológico , Fungemia/microbiologia , Humanos , Malassezia/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Oxitiamina/farmacologia , Oxitiamina/uso terapêutico , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
Centromeres are constricted chromosomal regions that are essential for cell division. In eukaryotes, centromeres display a remarkable architectural and genetic diversity. The basis of centromere-accelerated evolution remains elusive. Here, we focused on Pneumocystis species, a group of mammalian-specific fungal pathogens that form a sister taxon with that of the Schizosaccharomyces pombe, an important genetic model for centromere biology research. Methods allowing reliable continuous culture of Pneumocystis species do not currently exist, precluding genetic manipulation. CENP-A, a variant of histone H3, is the epigenetic marker that defines centromeres in most eukaryotes. Using heterologous complementation, we show that the Pneumocystis CENP-A ortholog is functionally equivalent to CENP-ACnp1 of S. pombe. Using organisms from a short-term in vitro culture or infected animal models and chromatin immunoprecipitation (ChIP)-Seq, we identified CENP-A bound regions in two Pneumocystis species that diverged ~35 million years ago. Each species has a unique short regional centromere (<10 kb) flanked by heterochromatin in 16-17 monocentric chromosomes. They span active genes and lack conserved DNA sequence motifs and repeats. These features suggest an epigenetic specification of centromere function. Analysis of centromeric DNA across multiple Pneumocystis species suggests a vertical transmission at least 100 million years ago. The common ancestry of Pneumocystis and S. pombe centromeres is untraceable at the DNA level, but the overall architectural similarity could be the result of functional constraint for successful chromosomal segregation.IMPORTANCEPneumocystis species offer a suitable genetic system to study centromere evolution in pathogens because of their phylogenetic proximity with the non-pathogenic yeast S. pombe, a popular model for cell biology. We used this system to explore how centromeres have evolved after the divergence of the two clades ~ 460 million years ago. To address this question, we established a protocol combining short-term culture and ChIP-Seq to characterize centromeres in multiple Pneumocystis species. We show that Pneumocystis have short epigenetic centromeres that function differently from those in S. pombe.
Assuntos
Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Proteína Centromérica A/genética , Filogenia , Proteínas Cromossômicas não Histona/genética , Centrômero/metabolismo , Schizosaccharomyces/genética , DNA/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Saccharomyces cerevisiae/genéticaRESUMO
SUMMARYEvery human being is presumed to be infected by the fungus Pneumocystis jirovecii at least once in his or her lifetime. This fungus belongs to a large group of species that appear to exclusively infect mammals, with P. jirovecii being the only one known to cause disease in humans. The mystery of P. jirovecii origin and speciation is just beginning to unravel. Here, we provide a review of the major steps of P. jirovecii evolution. The Pneumocystis genus likely originated from soil or plant-associated organisms during the period of Cretaceous ~165 million years ago and successfully shifted to mammals. The transition coincided with a substantial loss of genes, many of which are related to the synthesis of nutrients that can be scavenged from hosts or cell wall components that could be targeted by the mammalian immune system. Following the transition, the Pneumocystis genus cospeciated with mammals. Each species specialized at infecting its own host. Host specialization is presumably built at least partially upon surface glycoproteins, whose protogene was acquired prior to the genus formation. P. jirovecii appeared at ~65 million years ago, overlapping with the emergence of the first primates. P. jirovecii and its sister species P. macacae, which infects macaques nowadays, may have had overlapping host ranges in the distant past. Clues from molecular clocks suggest that P. jirovecii did not cospeciate with humans. Molecular evidence suggests that Pneumocystis speciation involved chromosomal rearrangements and the mounting of genetic barriers that inhibit gene flow among species.
Assuntos
Filogenia , Pneumocystis carinii , Humanos , Animais , Pneumocystis carinii/genética , Pneumocystis carinii/classificação , Pneumocystis carinii/patogenicidade , Infecções por Pneumocystis/microbiologia , Pneumocystis/genética , Pneumocystis/classificação , Evolução Molecular , Especificidade de Hospedeiro , Pneumonia por Pneumocystis/microbiologia , Genoma Fúngico/genética , Mamíferos/microbiologia , Evolução BiológicaRESUMO
Pneumocystis jirovecii pneumonia (PjP) poses a serious risk to individuals with compromised immune systems, such as individuals with HIV/AIDS or undergoing immunosuppressive therapies for cancer or solid organ transplants. Severe PjP triggers excessive lung inflammation, resulting in lung function decline and consequential alveolar damage, potentially culminating in acute respiratory distress syndrome. Non-HIV patients face a 30%-60% mortality rate, emphasizing the need for a deeper understanding of inflammatory responses in PjP. Prior research emphasized macrophages in Pneumocystis infections, neglecting neutrophils' role in tissue damage. Consequently, the overemphasis on macrophages led to an incomplete understanding of the role of neutrophils and inflammatory responses. In the current investigation, our RNAseq studies on a murine surrogate model of PjP revealed heightened activation of the NLRP3 inflammasome and NETosis cell death pathways in their lungs. Immunofluorescence staining confirmed neutrophil extracellular trap (NET) presence in the lungs of the P. murina-infected mice, validating our findings. Moreover, isolated neutrophils exhibited NETosis when directly stimulated with P. murina. Isolated NETs compromised P. murina viability in vitro, highlighting the potential role of neutrophils in controlling fungal growth and promoting inflammation during P. murina pneumonia through NLRP3 inflammasome assembly and NETosis. These pathways, essential for inflammation and pathogen elimination, bear the risk of uncontrolled activation leading to excessive tissue damage and persistent inflammation. This pioneering study is the first to identify the formation of NETs and inflammasomes during Pneumocystis infection, paving the way for comprehensive investigations into treatments aimed at mitigating lung damage and augmenting survival rates for individuals with PjP.IMPORTANCEPneumocystis jirovecii pneumonia (PjP) affects individuals with weakened immunity, such as HIV/AIDS, cancer, and organ transplant patients. Severe PjP triggers lung inflammation, impairing function and potentially causing acute respiratory distress syndrome. Non-HIV individuals face a 30%-60% mortality rate, underscoring the need for deeper insight into PjP's inflammatory responses. Past research focused on macrophages in managing Pneumocystis infection and its inflammation, while the role of neutrophils was generally overlooked. In contrast, our findings in P. murina-infected mouse lungs showed neutrophil involvement during inflammation and increased expression of NLRP3 inflammasome and NETosis pathways. Detection of neutrophil extracellular traps further indicated their involvement in the inflammatory process. Although beneficial in combating infection, unregulated neutrophil activation poses a potential threat to lung tissues. Understanding the behavior of neutrophils in Pneumocystis infections is crucial for controlling detrimental reactions and formulating treatments to reduce lung damage, ultimately improving the survival rates of individuals with PjP.
Assuntos
Armadilhas Extracelulares , Inflamassomos , Neutrófilos , Pneumocystis , Pneumonia por Pneumocystis , Animais , Armadilhas Extracelulares/imunologia , Inflamassomos/imunologia , Inflamassomos/metabolismo , Pneumonia por Pneumocystis/imunologia , Pneumonia por Pneumocystis/microbiologia , Camundongos , Neutrófilos/imunologia , Pneumocystis/imunologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/patologia , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , FemininoRESUMO
BACKGROUND: Invasive fungal infections cause considerable morbidity and mortality in immunocompromised hosts. Pigeon droppings could especially be a potential carrier in the spread of pathogenic yeasts and mold fungi into the environment. The objective of this study was to isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings. MATERIALS AND METHODS: One hundred twenty samples of pigeon droppings were suspended 1:10 in saline solution and then cultured. Identification of C. neoformans was performed on bird seed agar, presence of a capsule on India ink preparation, urease production on urea agar medium and RapID yeast plus system. The identification of candida species was based on micro-morphological analysis on corn meal-Tween 80 agar, RapID yeast plus system and growth in CHROMagar candida. The identification of other fungi was based on macromorphologic, microscopic, biochemical and physiological characteristics. RESULTS: The highest frequency of yeasts and mold fungi were observed in Candida albicans 6.6% and Penicillium spp. 25%. The frequency rate of C. neoformans isolation was 2.5%. CONCLUSION: Several types of fungi are present in pigeon droppings that can spread in environment and transmit to children and elderly as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases.
RESUMO
The common cause of skin infections are dermatophytes and opportunistic fungi. Aim of present study is to find predominant etiological agent of dermatophytoses and to isolate various fungal agents from clinical samples of patients with different mycoses and Clinical samples from 260 patients were subjected to potassium hydroxide (KOH) examination and culture isolation; causative agents were identified macroscopically and microscopically. One hundred sixty three (62.7%) were found to be positive by KOH examination while 132 (50.8%) were culture positive. Dermatophytes were isolated in 90/140 (64.3%) specimens. Trichophyton rubrum (75.5%) was the commonest isolate among the patients suffering from dermatophytoses. Candida spp. and Malassezia furfur were isolated from patient suffering from candidiasis and pityriasis versicolor.
RESUMO
Increasing evidence shows that the gut fungal mycobiota is implicated in human disease. However, its relationship with chronic helminth infections, which cause immunosuppression and affect over 1 billion people worldwide, remains unexplored. In this study, we investigated the gut mycobiome and its associations with gut homeostasis in a severe helminth disease worldwide: liver echinococcosis. Fecal samples from 63 patients and 42 healthy controls were collected to characterize the fungal signatures using ITS1 sequencing, QIIME pipeline, and machine learning analysis. The levels of fecal calprotectin and serological anti-Saccharomyces cerevisiae antibodies (ASCA) in these subjects were experimentally measured. We found that fungal microbiota was significantly skewed in disease, with an overrepresentation of Aspergillus, Candida, Geotrichum, Kazachstania, and Penicillium and a decrease of Fusarium. Machine learning analysis revealed that the altered fungal features could efficiently predict infection with high sensitivity and specificity (area under the curve [AUC] = 0.93). The dysbiosis was characterized by expansions of multiple opportunistic pathogens (Aspergillus spp. and Candida spp.). Clinical association analysis revealed that host immunity might link to the expansions of the invasive fungi. Accompanying the opportunistic pathogen expansion, the levels of fungi-associated fecal calprotectin and serological ASCA in the patients were elevated, suggesting that gut inflammation and microbiota translocation occurred in this generally assumed extraintestinal disease. This study highlights enteric fungal pathogen expansions and increased levels of markers for fungi-associated mucosal inflammation and intestinal permeability as hallmarks of liver echinococcosis. IMPORTANCE Helminth infection affects over 1 billion people worldwide. However, its relationship with the gut mycobiome remains unknown. Among the most prevalent helminth diseases, human hydatid disease (echinococcosis) is highlighted as one of the most important (second/third for alveolar/cystic echinococcosis) foodborne parasitic diseases at the global level. Herein, we investigated the mycobiome and gut homeostasis (i.e., inflammation and permeability) in human echinococcosis. Our results revealed that fungal dysbiosis with an expansion of opportunistic pathogens and increased levels of fecal calprotectin and serum ASCA are hallmarks of human liver echinococcosis. Host immunity is associated with enteric fungal expansions. These findings suggest that an extraintestinal helminth infection is able to alter gut fungal microbiota and impair gut homeostasis, which resembles concomitant gut symptoms in inflammatory gut-related diseases (e.g., AIDS). In clinical practice, physicians need to take cautious medical consideration of gut health for nonintestinal helminth diseases.
Assuntos
Disbiose , Equinococose , Infecções Oportunistas , Humanos , Candida , Disbiose/microbiologia , Equinococose/complicações , Fezes/microbiologia , Fungos , Inflamação , Complexo Antígeno L1 Leucocitário , Fígado , Aspergillus , Infecções Oportunistas/microbiologiaRESUMO
Cryptococcus neoformans, an opportunistic yeast pathogen, relies on a complex network of stress response pathways that allow for proliferation in the host. In Saccharomyces cerevisiae, stress responses are regulated by integral membrane proteins containing a transient receptor potential (TRP) domain, including the flavin carrier protein 1 (Flc1), which regulates calcium homeostasis and flavin transport. Here, we report that deletion of C. neoformans FLC1 results in cytosolic calcium elevation and increased nuclear content of calcineurin-dependent transcription factor Crz1, which is associated with an aberrant cell wall chitin overaccumulation observed in the flc1Δ mutant. Absence of Flc1 or inhibition of calcineurin with cyclosporine A prevents vacuolar fusion under conditions of combined osmotic and temperature stress, which is reversed in the flc1Δ mutant by the inhibition of TORC1 kinase with rapamycin. Flc1-deficient yeasts exhibit compromised vacuolar fusion under starvation conditions, including conditions that stimulate formation of carbohydrate capsule. Consequently, the flc1Δ mutant fails to proliferate under low nutrient conditions and displays a defect in capsule formation. Consistent with the previously uncharacterized role of Flc1 in vacuolar biogenesis, we find that Flc1 localizes to the vacuole. The flc1Δ mutant presents a survival defect in J774A.1 macrophage cell-line and profound virulence attenuation in both the Galleria mellonella and mouse pulmonary infection models, demonstrating that Flc1 is essential for pathogenicity. Thus, cryptococcal Flc1 functions in calcium homeostasis and links calcineurin and TOR signaling with vacuolar biogenesis to promote survival under conditions associated with vacuolar fusion required for this pathogen's fitness and virulence. IMPORTANCE Cryptococcosis is a highly lethal infection with limited drug choices, most of which are highly toxic or complicated by emerging antifungal resistance. There is a great need for new drug targets that are unique to the fungus. Here, we identify such a potential target, the Flc1 protein, which we show is crucial for C. neoformans stress response and virulence. Importantly, homologues of Flc1 exist in other fungal pathogens, such as Candida albicans and Aspergillus fumigatus, and are poorly conserved in humans, which could translate into wider spectrum therapy associated with minimal toxicity. Thus, Flc1 could be an "Achille's heel" of C. neoformans to be leveraged therapeutically in cryptococcosis and possibly other fungal infections.
Assuntos
Criptococose , Cryptococcus neoformans , Humanos , Camundongos , Animais , Virulência , Cálcio/metabolismo , Calcineurina/genética , Calcineurina/metabolismo , Antifúngicos/farmacologia , Antifúngicos/metabolismo , Ciclosporina/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Criptococose/microbiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Quitina/metabolismo , Fatores de Transcrição/metabolismo , Homeostase , Proteínas de Membrana/metabolismo , Flavinas/metabolismo , Proteínas de Transporte/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina , SirolimoRESUMO
Background: Onychomycosis is a common refractory fungal infection associated with significant morbidity. The objective of this study was to determine the prevalence of onychomycosis, and the diversity and species composition of fungal etiological agents. Materials and Methods: A clinic-based, prospective, non-randomized cross-sectional study was carried out between October 2018 and June 2019 at Rank Higher Specialized Dermatology Clinic, Addis Ababa, Ethiopia. Nail scrapings were collected aseptically from 200 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures. Results: Among 200 nail scrapings, 161 (80.5%) samples were found out to be culture positive. Of these, 135 (83.9%) samples yielded single colonies while 26 (16.1%) mixed colonies gave a total of 190 isolates. Among the isolates, 25.8% were dermatophytes while 61.1% were non- dermatophytes molds, and 13.1% were yeasts. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant species. Conclusion: The prevalence rate of onychomycosis in the present study was high. The isolation rate of non-dermatophyte molds was higher than dermatophytes and yeasts. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant etiological agents. Females and patients in the middle age group were more affected. An increase in the prevalence of non-dermatophyte molds in nail infections dictates further investigation demonstrating how this group of fungi causes onychomycosis.