ABSTRACT
Trichosporon asahii has recently been recognized as an emergent fungal pathogen able to cause invasive infections in neutropenic cancer patients as well as in critically ill patients submitted to invasive medical procedures and broad-spectrum antibiotic therapy. T. asahii is the main pathogen associated with invasive trichosporonosis worldwide. Treatment of patients with invasive trichosporonosis remains a controversial issue, but triazoles are mentioned by most authors as the best first-line antifungal therapy. There is mounting evidence supporting the claim that fluconazole (FLC) resistance in T. asahii is emerging worldwide. Since 2000, 15 publications involving large collections of T. asahii isolates described non-wild type isolates for FLC and/or voriconazole. However, very few papers have addressed the epidemiology and molecular mechanism of antifungal resistance in Trichosporon spp. Data available suggest that continuous exposure to azoles can induce mutations in the ERG11 gene, resulting in resistance to this class of antifungal drugs. A recent report characterizing T. asahii azole-resistant strains found several genes differentially expressed and highly mutated, including genes related to the Target of Rapamycin (TOR) pathway, indicating that evolutionary modifications on this pathway induced by FLC stress may be involved in developing azole resistance. Finally, we provided new data suggesting that hyperactive efflux pumps may play a role as drug transporters in FLC resistant T. asahii strains.
Subject(s)
Antifungal Agents/therapeutic use , Triazoles/therapeutic use , Trichosporon/drug effects , Trichosporonosis/drug therapy , HumansABSTRACT
We report the first two cases of Trichosporon mycotoxinivorans infections in Latin America. We also conducted a literature review and a microbiological investigation, including that of clinical and environmental isolates. A 30-year-old man with chronic renal failure had disseminated infection after dialysis and a 15-year-old boy with cystic fibrosis (CF) had pulmonary exacerbations with positive respiratory samples. A review of the relevant literature revealed that deep-seated infections were related to immunosuppression or invasive devices, while most of the CF patients showed a decline in lung function after positive cultures. Phylogenetic analyses revealed three distinct circulating genotypes. MALDI-TOF mass spectrometry analysis showed similar spectral profiles and correctly identified all strains/isolates. Biofilm production was documented in a bloodstream isolate and biofilm-producing cells showed high minimum inhibitory concentrations against antifungals.
Subject(s)
Trichosporon/genetics , Trichosporonosis/diagnosis , Adolescent , Adult , Antifungal Agents/pharmacology , Biofilms/growth & development , Brazil/epidemiology , Genotype , Humans , Latin America , Male , Microbial Sensitivity Tests , Trichosporon/classification , Trichosporon/drug effects , Trichosporonosis/epidemiology , Trichosporonosis/microbiologyABSTRACT
We report the first Brazilian case of pulmonary invasive aspergillosis caused by Aspergillus lentulus, a new opportunistic Aspergillus species included in the section fumigati that is usually resistant to amphotericin B and azoles.
Subject(s)
Aspergillus/isolation & purification , Invasive Pulmonary Aspergillosis/microbiology , Kidney Transplantation/adverse effects , Postoperative Complications/microbiology , Antifungal Agents/administration & dosage , Aspergillus/genetics , Aspergillus/physiology , Brazil , Humans , Invasive Pulmonary Aspergillosis/drug therapy , Invasive Pulmonary Aspergillosis/etiology , Male , Middle Aged , Postoperative Complications/drug therapy , Postoperative Complications/etiologyABSTRACT
Recently, Candida rugosa was characterized as a species complex comprising four taxa: C. rugosa sensu stricto, Candida pseudorugosa, Candida neorugosa and Candida mesorugosa. Although considered relatively rare, several clusters of candidemia due to C. rugosa complex had been reported presenting mortality rates close to 70%. In this work we discuss the systematization, phenotyping and molecular methods based on internal transcribed spacer region (ITS) sequencing and proteomic analyses for species identification, as well as clinical aspects of the C. rugosa complex. We performed a Bayesian phylogenetic analysis using 72 ITS sequences representative of C. rugosa complex isolates and related species within the genus. Biochemical, morphological and MALDI-TOF MS analyses were processed with C. rugosa complex type strains and related species isolates. We described that the phylogeny showed four distinct clades inferred with high posterior probabilities, corresponding to the four species within the C. rugosa complex, excluding C. pararugosa. Biochemical and morphological aspects distinguished only C. rugosa sensu stricto but were not sufficient to accurately identify species within the rest of the complex. Protein spectrum profiles differentiated all reference strains from different species analyzed. To our knowledge, we presented the first phylogenetic analysis using a large collection of ITS sequences as well as proteomic profiles generated from isolates of the C. rugosa complex and related species that can enlighten systematics, diagnostics and clinical research fields.
Subject(s)
Candida/classification , Candida/genetics , Candida/chemistry , Candida/metabolism , Cluster Analysis , DNA, Fungal/chemistry , DNA, Fungal/genetics , DNA, Ribosomal Spacer/chemistry , DNA, Ribosomal Spacer/genetics , Genotype , Mycological Typing Techniques , Phylogeny , Proteome/analysis , Sequence Analysis, DNA , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
The short time between the first cases of COVID-19 and the declaration of a pandemic initiated the search for ways to stop the spread of SARS-CoV-2. There are great expectations regarding the development of effective vaccines that protect against all variants, and in the search for it, we hypothesized the obtention of a predicted rational immunogenic peptide from structural components of SARS-CoV-2 might help the vaccine research direction. In the search for a candidate of an immunogenic peptide of the SARS-CoV-2 envelope (E), membrane (M), nucleocapsid (N), or spike (S) proteins, we access the predicted sequences of each protein after the genome sequenced worldwide. We obtained the consensus amino acid sequences of about 14,441 sequences of each protein of each continent and the worldwide consensus sequence. For epitope identification and characterization from each consensus structural protein related to MHC-I or MHC-II interaction and B-cell receptor recognition, we used the IEDB reaching 68 epitopes to E, 174 to M, 245 to N, and 833 to S proteins. To select an epitope with the highest probability of binding to the MHC or BCR, all epitopes of each consensus sequence were aligned. The curation indicated 1, 4, 8, and 21 selected epitopes for E, M, N, and S proteins, respectively. Those epitopes were tested in silico for antigenicity obtaining 16 antigenic epitopes. Physicochemical properties and allergenicity evaluation of the obtained epitopes were done. Ranking the results, we obtained one epitope of each protein except for the S protein that presented two epitopes after the selection. To check the 3D position of each selected epitope in the protein structure, we used molecular homology modeling. Afterward, each selected epitope was evaluated by molecular docking to reference MHC-I or MHC-II allelic protein sequences. Taken together, the results obtained in this study showed a rational search for a putative immunogenic peptide of SARS-CoV-2 structural proteins that can improve vaccine development using in silico approaches. The epitopes selected represent the most conserved sequence of new coronavirus and may be used in a variety of vaccine development strategies since they are also presented in the described variants of SARS-CoV-2.
ABSTRACT
Cryptococcosis is an infectious disease of worldwide distribution, caused by encapsulated yeasts belonging to the phylum Basidiomycota. The genus Cryptococcus includes several species distributed around the world. The C. gattii/neoformans species complex is largely responsible for most cases of cryptococcosis. However, clinical series have been published of infections caused by Papiliotrema (Cryptococcus) laurentii and Naganishia albida (Cryptococcus albidus), among other related genera. Here, we examined the pathogenic potential and antifungal susceptibility of C. gattii/neoformans species complex (clades I and II) and related genera (Papiliotrema and Naganishia) isolated from environmental and clinical samples. P. laurentii (clade III), N. liquefasciens/N. albidosimilis (clade IV); and N. adeliensis/N. albida (clade V) strains produced higher levels of phospholipase and hemolysins, whereas the C. gattii/neoformans species complex strains (clades I and II) had markedly thicker capsules, produced more biofilm biomass and melanin, which are known virulence attributes. Interestingly, 40% of C. neoformans strains (clade II) had MICs above the ECV established for this species to amphotericin B. Several non-C. gattii/neoformans species complex (clades III to V) had MICs equal to or above the ECVs established for C. deuterogattii and C. neoformans for all the three antifungal drugs tested. Finally, all the non-C. gattii/neoformans clinical isolates (clades III to V) produced more melanin than the environmental isolates might reflect their particularly enhanced need for melanin during in vivo protection. It is very clear that C. gattii/neoformans species complex (clades I and II) strains, in general, show more similar virulence phenotypes between each other when compared to non-C. gattii/neoformans species complex (clades III to V) isolates. These observations together with the fact that P. laurentii and Naganishia spp. (clades III to V) strains were collected from the outside of a University Hospital, identify features of these yeasts important for environmental and patient colonization and furthermore, define mechanisms for infections with these uncommon pathogens.
Subject(s)
Basidiomycota , Cryptococcus gattii , Cryptococcus neoformans , Antifungal Agents/pharmacology , Humans , Virulence , Virulence FactorsABSTRACT
Enteropathogenic Escherichia coli (EPEC) forms attaching and effacing lesions in the intestinal mucosa characterized by intimate attachment to the epithelium by means of intimin (an outer membrane adhesin encoded by eae). EPEC is subgrouped into typical (tEPEC) and atypical (aEPEC); only tEPEC carries the EAF (EPEC adherence factor) plasmid that encodes the bundle-forming pilus (BFP). Characteristically, after 3 h of incubation, tEPEC produces localized adherence (LA) (with compact microcolonies) in HeLa/HEp-2 cells by means of BFP, whereas most aEPEC form looser microcolonies. We have previously identified nine aEPEC strains displaying LA in extended (6 h) assays (LA6). In this study, we analysed the kinetics of LA6 pattern development and the role of intimin in the process. Transmission electron microscopy and confocal laser microscopy showed that the invasive process of strain 1551-2 displays a LA phenotype. An eae-defective mutant of strain 1551-2 prevented the invasion although preserving intense diffused adherence. Sequencing of eae revealed that strain 1551-2 expresses the omicron subtype of intimin. We propose that the LA phenotype of aEPEC strain 1551-2 is mediated by intimin omicron and hypothesize that this strain expresses an additional novel adhesive structure. The present study is the first to report the association of compact microcolony formation and an intense invasive ability in aEPEC.
Subject(s)
Adhesins, Bacterial/physiology , Bacterial Adhesion/physiology , Enteropathogenic Escherichia coli/pathogenicity , Escherichia coli Proteins/physiology , Actins/metabolism , Adhesins, Bacterial/chemistry , Amino Acid Sequence , Enteropathogenic Escherichia coli/genetics , Enteropathogenic Escherichia coli/ultrastructure , Escherichia coli Proteins/chemistry , Escherichia coli Proteins/metabolism , HeLa Cells , Humans , Microscopy, Electron, Transmission , Molecular Sequence Data , Phenotype , Phosphorylation , Receptors, Cell Surface/metabolism , Sequence AlignmentABSTRACT
Objetivo: Oferecer uma visão geral sobre os efeitos que as intervenções com o uso de probióticos, prebióticos ou Transplante de Microbiota Fecal (TMF) e suas combinações provocam nos sintomas neurocomportamentais e gastrointestinais (GI) em indivíduos com Transtorno do Espectro Autista (TEA). Metodologia: Foi realizada uma revisão integrativa (RI) da literatura nas plataformas PubMed, SciELO, LILACS e Scopus, a partir dos descritores "autistic disorder", "autism", "prebiotics", "probiotics", "fecal microbiota transplantation" e "fecal transplantation", utilizando os operadores booleanos "AND" e "OR". Foram selecionados apenas artigos dos anos de 2013 a 2022, publicados em português, inglês ou espanhol e que possuíam relação direta com o tema. Resultados: Foram analisados 24 artigos na íntegra, dos quais 14 obedeciam aos critérios de inclusão e tiveram seus resultados analisados na presente revisão. Desses, dois relataram melhora dos sintomas GI com uso de probiótico, prebiótico e/ou TMF, nove mencionaram melhora tanto dos sintomas GI como dos neurocomportamentais com as terapias utilizadas e os outros três avaliaram a mudança dos sintomas neurocomportamentais. Conclusão: As terapias com probióticos, prebióticos e TMF possuem um efeito promissor na modificação da microbiota e na melhora dos sintomas neurocomportamentais e GI em pessoas com TEA.
Objective: To provide an overview of the effects that interventions with the use of probiotics, prebiotics, or fecal microbiota transplantation and their combinations have on neurobehavioral and gastrointestinal (GI) symptoms in individuals with Autism Spectrum Disorder (ASD). Methodology: An integrative review of the literature was conducted on the PubMed, SciELO, LILACS, and Scopus platforms using the descriptors "autistic disorder", "autism", "prebiotics", "probiotics", "fecal microbiota transplantation", and "fecal transplantation", using the Boolean operators "AND" and "OR". Only articles published between 2013 and 2022 in Portuguese, English, or Spanish and directly related to the topic were selected. Results: Twenty-four articles were fully analyzed, of which fourteen met the inclusion criteria and had their results analyzed in this review. Of these, two reported improvement in GI symptoms with the use of probiotics, prebiotics, and/or fecal microbiota transplantation, nine mentioned improvement in both GI and neurobehavioral symptoms with the therapies used, and the other three evaluated the change in neurobehavioral symptoms. Conclusion: Probiotic, prebiotic, and fecal microbiota transplantation therapies have a promising effect on modifying the microbiota and improving neurobehavioral and GI symptoms in individuals with ASD.
Objetivo: Proporcionar una visión general de los efectos que las intervenciones con el uso de probióticos, prebióticos o trasplante de microbiota fecal y sus combinaciones tienen sobre los síntomas neuroconductuales y gastrointestinales (GI) en individuos con Trastorno del Espectro Autista (TEA). Metodología: Se realizó una revisión integradora de la literatura en las plataformas PubMed, SciELO, LILACS y Scopus utilizando los descriptores "autistic disorder", "autism", "prebiotics", "probiotics", "fecal microbiota transplantation" y "fecal transplantation", utilizando los operadores booleanos "AND" y "OR". Solo se seleccionaron artículos publicados entre 2013 y 2022 en portugués, inglés o español y directamente relacionados con el tema. Resultados: Veinticuatro artículos fueron analizados en su totalidad, de los cuales catorce cumplieron los criterios de inclusión y sus resultados fueron analizados en esta revisión. De estos, dos reportaron mejoría en los síntomas GI con el uso de probióticos, prebióticos y/o trasplante de microbiota fecal, nueve mencionaron mejoría tanto en los síntomas GI como neuroconductuales con las terapias utilizadas, y los otros tres evaluaron el cambio en los síntomas neuroconductuales. Conclusiones: Las terapias con probióticos, prebióticos y trasplante de microbiota fecal tienen un efecto prometedor en la modificación de la microbiota y la mejora de los síntomas neuroconductuales y GI en individuos con TEA. PALABRAS CLAVE: Autismo; Microbiota; Prebióticos; Probióticos; Trasplante de Microbiota Fecal.
ABSTRACT
Invasive infections caused by Trichosporon spp. have increased considerably in recent years, especially in neutropenic and critically ill patients using catheters and antibiotics. The genus presents limited sensitivity to different antifungal agents, but triazoles are the first choice for treatment. Here, we investigated the biofilm production and antifungal susceptibility to triazoles and amphotericin B of 54 Trichosporon spp. isolates obtained from blood samples (19), urine (20) and superficial mycosis (15). All isolates and 7 reference strains were identified by sequence analysis and phylogenetic inferences of the IGS1 region of the rDNA. Biofilms were grown on 96-well plates and quantitation was performed using crystal violet staining, complemented with Scanning Electron Microscopy (SEM). Susceptibility tests for fluconazole, itraconazole, voriconazole and amphotericin B were processed using the microdilution broth method (CLSI) for planktonic cells and XTT reduction assay for biofilm-forming cells. Our results showed that T. asahii was the most frequent species identified (66.7%), followed by T. faecale (11.1%), T. asteroides (9.3%), T. inkin (7.4%), T. dermatis (3.7%) and one T. coremiiforme (1.8%). We identified 4 genotypes within T. asahii isolates (G1, G3, G4 and G5) and 2 genotypes within T. faecale (G1 and G3). All species exhibited high adhesion and biofilm formation capabilities, mainly T. inkin, T. asteroides and T. faecale. Microscopy images of high biofilm-producing isolates showed that T. asahii presented mainly hyphae and arthroconidia, whereas T. asteroides exhibited mainly short arthroconidia and few filaments. Voriconazole exhibited the best in vitro activity against all species tested. Biofilm-forming cells of isolates and reference strains were highly resistant to all antifungals tested. We concluded that levels of biofilm formation by Trichosporon spp. were similar or even greater than those described for the Candida genus. Biofilm-forming cells were at least 1,000 times more resistant to antifungals than planktonic cells, especially to voriconazole.
Subject(s)
Amphotericin B/pharmacology , Antifungal Agents/pharmacology , Biofilms/drug effects , Trichosporon/drug effects , Blood/microbiology , Brazil , DNA, Ribosomal , Drug Resistance, Fungal/drug effects , Humans , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Triazoles/pharmacology , Trichosporon/isolation & purification , Trichosporon/physiology , Trichosporonosis/microbiology , Urine/microbiologyABSTRACT
We report the first two cases of Trichosporon mycotoxinivorans infections in Latin America. We also conducted a literature review and a microbiological investigation, including that of clinical and environmental isolates. A 30-year-old man with chronic renal failure had disseminated infection after dialysis and a 15-year-old boy with cystic fibrosis (CF) had pulmonary exacerbations with positive respiratory samples. A review of the relevant literature revealed that deep-seated infections were related to immunosuppression or invasive devices, while most of the CF patients showed a decline in lung function after positive cultures. Phylogenetic analyses revealed three distinct circulating genotypes. MALDI-TOF mass spectrometry analysis showed similar spectral profiles and correctly identified all strains/isolates. Biofilm production was documented in a bloodstream isolate and biofilm-producing cells showed high minimum inhibitory concentrations against antifungals.