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Vigilância em saúde única da resistência a antifúngicos e a compostos de amônio quaternário em Candida spp. no Ceará e busca por alternativa terapêutica

Thu, 01 Jan 2026 00:00:00 GMT

Título: Vigilância em saúde única da resistência a antifúngicos e a compostos de amônio quaternário em Candida spp. no Ceará e busca por alternativa terapêutica Autor(es): Brasil, Jaiane Alves Abstract: From a One Health perspective, tackling antifungal resistance in Candida spp. requires an understanding of multiple factors, such as interaction with environments and chemical agents. Furthermore, drug repositioning and combination therapy are strategies to overcome therapeutic failures. This study aimed to isolate and identify Candida spp. from human clinical samples (n=59), hospital surfaces (n=25), production animals (n=107), and the environment of these animals (n=9); analyze the sensitivity profile to the antifungals FLC, MCF, and AMB; and the effect of benzalkonium chloride (BZ) and didecyl dimethyl ammonium chloride (DDAC) against isolates in planktonic and biofilm forms, as well as evaluate the effect of deferiprone (DEF), an iron chelator, on Candida spp. in planktonic and biofilm forms, isolated and in combination with the antifungals fluconazole (FLC), amphotericin B (AMB), and caspofungin (CAS). Finally, it was evaluated whether the inhibition of the fungus by DFP was reversed with ferrous sulfate (FeSO₄). Sensitivity to antifungals, quaternary ammonium compounds, and deferiprone was analyzed according to document m27-a3. The checkerboard method was used to evaluate the interaction between deferiprone and the antifungals. The antibiofilm activity of the antifungals, ammonium compounds, and deferiprone was evaluated by MTT reduction and biomass quantification by crystal violet. 109 Candida spp. yeasts were isolated. FLC showed variable MIC, from 0.125 to 64 µg/ml for isolates of human origin; 0.5 to 4 µg/ml for isolates from hospital environments; 0.125 to 64 µg/ml for isolates of animal origin, and 1 to 32 µg/ml for isolates from animal environments. MICs for MCF ranged from 0.0625 to 0.5 µg/ml for isolates of human origin; 0.0625 to 1 µg/ml for isolates from hospital environments; 0.0625 to 0.1 µg/ml for isolates of animal origin, and 0.03 µg/ml for isolates from animal environments. AMB exhibited MICs of 0.031 to 1 µg/ml for isolates of human origin; 0.125 to 0.5 µg/ml for isolates from hospital environments; 0.031 to 1 µg/ml for isolates of animal origin, and 0.06 and 0.25 µg/ml for isolates from animal environments. DDA showed MICs between 0.0625 and 1 µg/mL, and BZ showed MICs ranging from 0.0625–4 µg/mL. Forming and mature Candida spp. biofilms showed a significant reduction in metabolic activity and biomass after exposure to BZ and DDA. DEF showed MICs ranging from 16 to 1024 µg/mL against the tested isolates. In the checkerboard assay, DEF reduced the MICs of FLC, AMB, and CAS by up to 8, 32, and 64 times, respectively, against the planktonic form. In the MTT assay, DEF caused an increase in the metabolic activity of forming biofilms of C. tropicalis and C. glabrata; and a tendency towards reduced metabolic activity of mature Candida spp. biofilms (n=12) at 1024 µg/mL. Crystal violet analysis revealed an increase in the biomass of forming C. parapsilosis biofilms when treated with DEF; and a tendency towards a reduction in mature Candida spp. biofilms (n=12) at concentrations of 256 to 1024 µg/mL and 2 to 32 µg/mL, when compared to drug-free controls. Supplementation with (FeSO₄) reduced the antifungal efficacy of DEF against planktonic Candida spp. DEF demonstrated antifungal activity and synergism with FLC, AMB, and CAS against Candida spp., with greater efficacy observed against C. glabrata. Furthermore, DEF significantly influenced biofilm formation, showing a species-dependent effect. However, its effectiveness was significantly reduced by supplementation with FeSO₄, demonstrating that it acts directly on iron balance for Candida spp. Tipo: Tese

Perfil clínico-epidemiológico das infecções causadas por Trichosporon spp. em um hospital pediátrico de referência e busca de novas estratégias de controle do crescimento fúngico

Wed, 01 Jan 2025 00:00:00 GMT

Título: Perfil clínico-epidemiológico das infecções causadas por Trichosporon spp. em um hospital pediátrico de referência e busca de novas estratégias de controle do crescimento fúngico Autor(es): Silva, Bruno Nascimento da Abstract: Invasive fungal infections (IFIs) involve contamination of the bloodstream and invasion of sterile tissues and/or organs and are considered highly relevant public health issues due to high morbidity and mortality rates. Trichosporon spp. are considered opportunistic fungi, as they take advantage of microbial dysbiosis and host immune imbalance to cause serious invasive infections. This study investigated the clinical and epidemiological profile of invasive infections by Trichosporon spp., as well as the impact of calcineurin and Hsp90 protein inhibition on the growth of this pathogen. The epidemiological study included 28 isolates of interest. Data from these patients were collected and analyzed regarding: age, sex, most prevalent species of the genus, distribution by hospital unit, reasons for care, use of invasive devices, clinical specimens from which pathogens were isolated, use of antimicrobials and other conditioning drugs, co-infection, and treatment measures – all of which were associated with the clinical outcome (discharge or death). The strains isolated and selected in the prospective phase (n=12) were studied for their ability to form biofilms and their sensitivity profile to amphotericin B (AMB), voriconazole (VRZ), and fluconazole (FLZ). The second phase of the work concerns the inhibition of calcineurin by the use of Cyclosporine A (CsA), against planktonic cells and biofilms of Trichosporon spp. strains in n=13 already contained in stock. These biofilms were formed in the presence of CsA at concentrations of 25 µg/mL, 50 µg/mL, and 100 µg/mL for the planktonic state and 50 µg/mL and 100 µg/mL for the biofilms. Subsequently, CsA at the same concentrations mentioned above were associated with the antifungals AMB (10 µg/mL), VRZ (50 µg/mL), and FLZ (64 µg/mL) and subjected to the same tests. The impact of CsA on the ultrastructure of the biofilms was evaluated by Scanning Electron Microscopy (SEM) both in isolation and in combination with the antifungals. Bioinformatics analyses were performed to investigate the antibiofilm potential caused by calcineurin inhibition in T. asahii. In the inhibition of Hsp90 using Radicicol (RAD), the strains were subjected to planktonic sensitivity testing and subsequently studied with mature biofilms (48h) exposed to RAD at concentrations of 6.25 µg/mL for T. asahii and 10 µg/mL for T. inkin. Then, the same concentrations of RAD in the mature biofilms were associated with AMB 4 µg/mL for T. asahii and 2 µg/mL for T. inkin and VRZ 0.125 µg/mL for an additional 24h in contact with the mature biofilm in vitro, the morphology of the biofilms was assessed by SEM, and virulence was evaluated using an experimental infection model with Galleria mellonella larvae. The epidemiological study showed that the most affected pediatric population over the years were boys, most of whom were admitted to Intensive Care Units (ICUs). Patients with neurological diseases and cancer; those using various invasive medical devices, such as feeding tubes; most samples isolated from urine; a significant portion used prophylactic antimicrobials; mortality rates are considerable; the most prevalent species is T. asahii; the strains obtained are capable of forming biofilms. CsA and RAD, isolated and in combination with antifungals, are able to inhibit the fungal growth of T. inkin and T. asahii in vitro and significantly alter the ultrastructure of biofilms. RAD is effective in treating infected G. mellonella larvae. These results suggest new and promising therapeutic targets for invasive trichosporonosis, considering the difficulty and resistance in treating these infections Tipo: Tese

Análise do perfil sorológico, clínico, sociodemográfico e da influência dos polimorfismos -174 G/C (rs1800795) do gene IL-6 e -308 G/A (rs1800629) do gene TNFα em pacientes acometidos por febre Chikungunya no estado do Ceará

Fri, 01 Jan 2021 00:00:00 GMT

Título: Análise do perfil sorológico, clínico, sociodemográfico e da influência dos polimorfismos -174 G/C (rs1800795) do gene IL-6 e -308 G/A (rs1800629) do gene TNFα em pacientes acometidos por febre Chikungunya no estado do Ceará Autor(es): Maciel, Mariella Sousa Coêlho Abstract: The chikungunya fever (CHIKF) is a viral disease of acute onset, characterized by cause arthralgia involving one or more joints. The disease is caused by infection with Chikungunya virus (CHIKV) and affects thousands of people annually. Some affected individuals persist with joint symptoms for months or years, giving rise to the chronic phase of the disease. Factors inherent to both the microorganism and the host may be involved in susceptibility, progression or protection against CHIKF. Among the host factors, stand out the type of immune response and genetic factors, such as single nucleotide genetic polymorphisms (SNPs) in cytokine genes. The present study aimed to analyze the sociodemographic and serological profile, the prevalence and influence of SNPs -174 G/C (rs1800795) of the IL-6 gene and -308 G/A (rs1800629) of the TNFα gene in control patients and affected individuals by CHIKF in the state of Ceará. Serological ELISA tests and DNA extraction were performed. All samples were genotyped using the real-time PCR technique for variants in the IL-6 and TNFα genes. Statistical analyzes were performed using the Bioestat 5.0 software and included Fisher's Exact Test and Chi-square (x²), considering p < 0.05 as the level of statistical significance. A total of 313 subjects composed the study, of which 102 were allocated to the positive cases (PC) group, 182 to the negative control (NC) group and 29 were asymptomatic (ASY). The arthralgia was present in 100% of the cases in the PC group, statistically significant differences (p < 0.05) were evidenced for joint pain intensities between male and female genders. A higher frequency of the G/A genotype of the SNP -308 G/A in the TNFα gene was observed in the PC group in relation to the NC, as well as a higher frequency of the A allele. The mutant allele A was also identified more frequently in the PC group in compared to the ASY group. However, without statistical significance. For the -174 G/C SNP in the IL-6 gene, a higher frequency of the G/C heterozygote was observed in the NC group in relation to the PC, as well as the C mutant allele was more frequent in the NC group in relation to the PC and in the NC group compared to ASY. However, with no statistical significance. On the other hand, statistically significant differences (p < 0.05) were observed between the allele frequencies obtained for the variants analyzed in this study in relation to the distributions found in the genomic association studies for other populations Tipo: Dissertação

Avaliaçãoin vitro da atividade antimicrobiana de biosurfactante complexado com arginina frente a Staphylococcus aureus resistente à meticilina (SARM) e Candida spp. e seu potencial para desagregação de biofilmes em cateteres venosos periférico

Wed, 01 Jan 2025 00:00:00 GMT

Título: Avaliaçãoin vitro da atividade antimicrobiana de biosurfactante complexado com arginina frente a Staphylococcus aureus resistente à meticilina (SARM) e Candida spp. e seu potencial para desagregação de biofilmes em cateteres venosos periférico Autor(es): Barroso, Fatima Daiana Dias Abstract: The spectrum of microbial resistance has been expanding globally, challenging theeffectiveness of antimicrobial therapies and representing a serious threat to public health. Thisissue is further exacerbated by the increasing incidence of biofilm-associated infections.Medical devices, which are widely used in various procedures and treatments, provide afavorable environment for biofilm formation, particularly in catheters, prostheses, and implants.The aim of this study was to evaluate the antimicrobial efficacy of a rhamnolipid complexedwith the amino acid arginine (RLMIX_Arg) against planktonic cells, methicillin-resistantStaphylococcus aureus (MRSA) biofilms, and polymicrobial biofilms formed by MRSA andfluconazole-resistant Candida albicans on polystyrene plates and peripheral venous catheters(PVCs). Additionally, the study assessed the interference of RLMIX_Arg, both in its isolatedform and formulated in a gel, with the biofilm formation process in impregnated catheters.Theminimum inhibitory concentration (MIC) was determined in accordance with CLSI documentsM07-A10 and M23-A3. The assessment of thepharmacological interaction was alsodetermined using the checkerboard methodology. Biofilm formation was assessed throughMTT reduction assays, crystal violet staining, and scanning electron microscopy (SEM).Biofilm formation on catheters was analyzed by counting colony-forming units (CFU/mL).Furthermore, flow cytometry assays were performed to evaluate cell viability and DNAfragmentation in bacterial cells. The MIC of the compound against planktonic MRSA cellsranged from 4 to 16 μg/mL, demonstrating bactericidal activity. Notably, synergy with oxacillinwas observed in 37.5% of the strains, resulting in up to a threefold reduction in oxacillin MIC.For Candida strains, MICs rangedfrom 2 to 13 μg/mL. In addition, concentrations of 64 μg/mLand 80 μg/mL led to asignificant (90%) reduction in biofilm cell viability on polystyrene platesand PVCs, both during the initial formation stage and in mature MRSA biofilms. Forpolymicrobial biofilms formed by MRSA and C. albicans, a concentration of 112 μg/mL(16×MIC) reduced cell viability by approximately 81.8% on plates. Catheters impregnated with RLMIX_Arg at a concentration of 4 mg/mL alone were able to reduce MRSA cell adhesion by29.5%. Prevention of mixed biofilm formation was observed in PVCs impregnated with 10 mg/mL of RLMIX_Arg alone, with approximately 93.8% reduction in cell adhesion. The formulation containing 0.9 μg/mL RLMIX_Arg incorporated into Pluronic F-127 gel provedtobe more effective in preventing mixed biofilms on PVCs, reducing adhesion by about99.1%.Impregnated catheters maintained their antimicrobial effect after 28 days of storage. Themechanism of action against planktonic cells possibly involves membrane damage and concentration-dependent DNA fragmentation. These effects were more pronounced when the compound was combined with oxacillin. The findings indicate that RLMIX_Arg shows potential for application in the prevention of infections associated with MRSA biofilms, both isolated and in combination with C. albicans. Tipo: Tese