Browsing by Author "Zeferino, Ana Sofia"
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- Cytotoxicity effects of bisphenol A in Hep2 and MRC5 cell lines: is established TDI protective enough?Publication . Ribeiro, Edna; Zeferino, Ana Sofia; Dias, Ana; Cristovam, Elisabete; Viegas, SusanaEndocrine disrupting chemicals (EDCs) are exogenous compounds generally employed in the food and drinks processing and packing, with potential associated hazardous effects for human health. Bisphenol A (BPA) stands out as a paradigmatic xenoestrogen for which human exposure is widespread, omnipresent and persistent, particularly trough ingestion of contaminated food and beverages. European Food Safety Authority (EFSA) experts on the latest comprehensive re-evaluation of BPA exposure and toxicity reduced the tolerable daily intake (TDI) from 50 μg/kg bw/day to 4 μg/kg bw/day. This compound is included in the Priority List of Chemicals within the EU Strategy for Endocrine Disruptors and classified as high concern in terms of human/wildlife exposure. BPA even at very low concentrations can influence cell fate in a cell type specific manner and epidemiological studies have demonstrated positive correlations between BPA levels detected in human biological samples and etiology of numerous pathologies. Here we aimed to evaluate potential cytotoxic effects of BPA concentrations within the range detected in human biological samples consistent to exposure levels below the established TDI, namely 4.4 μM, 4.4 nM and 0.44 nM in Hep2 and MRC5 cell lines. Cytotoxic effects were assessed trough the fluorometric method CellTiter-Blue assay and expression of BPA high affinity receptor GPER, in MRC5 cells, was performed trough immunofluorescence technique. We demonstrate that MCR5 cells express GPER receptor and no significant differences in viability associated with BPA exposure was observed in both cell lines. Our results indicate that BPA concentrations below the EFSA established TDI do not affect Hep2 or MRC5 cellular viability which sustains the indication of safe levels. Nevertheless, further research must be performed in order to assess potential effects that are not reflected by cytotoxicity such as genotoxicity and mixtures interactions.
- Drug resistance and epigenetic modulatory potential of epigallocatechin-3-gallate against Staphylococcus aureusPublication . Zeferino, Ana Sofia; Mira, Ana Rita; Delgadinho, Mariana; Brito, Miguel; Ponte, Tomás; Ribeiro, EdnaAntimicrobial resistance of human pathogens, such as methicillin-resistant Staphylococcus aureus, is described by the World Health Organization as a health global challenge and efforts must be made for the discovery of new effective and safe compounds. This work aims to evaluate epigallocatechin-3-gallate (EGCG) epigenetic and modulatory drug potential against S. aureus in vitro and in vivo. S. aureus strains were isolated from the commensal flora of healthy volunteers. Antibiotic susceptibility and synergistic assay were assessed through disk diffusion accordingly to EUCAST guidelines with and without co-exposure to EGCG at final concentrations of 250 µg/ml, 100 µg/ml, 50 µg/ml, and 25 µg/ml. Transcriptional expression of orfx, spdC, and WalKR was performed through qRT-PCR. A 90-day interventional study was performed with daily consumption of 225 mg of EGCG. Obtained data revealed a high prevalence of S. aureus colonization in healthcare workers and clearly demonstrated the antimicrobial and synergistic potential of EGCG as well as divergent resistant phenotypes associated with altered transcriptional expression of epigenetic and drug response modulators genes. Here, we demonstrate the potential of EGCG for antimicrobial treatment and/or therapeutic adjuvant against antibiotic-resistant microorganisms and report divergent patterns of epigenetic modulators expression associated with phenotypic resistance profiles.
- Efeito modulador da EGCG na transcrição de genes de virulência em Staphylococcus aureus com perfis fenotípicos de resistência divergentesPublication . Ribeiro, Edna; Santos, Raquel; Almeida, Raquel; Delgadinho, Mariana; Mira, Ana Rita; Zeferino, Ana SofiaIntrodução: A resistência de patógenos humanos a múltiplos antibióticos é considerada pela Organização Mundial de Saúde uma ameaça global à saúde humana. Nos últimos anos, vários grupos de investigação têm investido na descoberta de novas moléculas com potencial antimicrobiano para utilização em terapêutica e/ou como adjuvante terapêutico. Um dos microrganismos de interesse, com resistência associada, é o Staphylococcus aureus resistente à meticilina (MRSA). Estirpes de MRSA têm diferenças significativas a nível de fatores de risco, resistência a antibióticos, taxa de crescimento, toxinas e/ou fatores de virulência. A Epigalocatequina-3-galato (EGCG), a principal catequina constituinte do chá verde, tem sido descrita como eficaz na reversão do fenótipo de resistência no MRSA, demonstrando ter um efeito sinérgico contra diferentes antibióticos, incluindo B-lactâmicos, como amoxicilina e imipenem, capazes de interferir na síntese da parede celular bacteriana e tetraciclina e gentamicina, classificados como antibióticos inibidores da síntese de proteínas. Objetivos: Neste estudo pretende-se avaliar o potencial da EGCG na modulação da expressão génica associada a genes de virulência (atividade hemolítica), nomeadamente hlgA, hly e hlgB, em estirpes de MRSA com divergências fenotípicas associadas à resistência antimicrobiana, incluindo reversão do fenótipo de resistência.
- Epigenetic and drug response modulation of epigalocaten-in-3-gallate in staphylococcus aureus with divergent resistance phenotypesPublication . Mira, Ana Rita; Zeferino, Ana Sofia; Inácio, Raquel; Delgadinho, Mariana; Brito, Miguel; Calado, Cecília; Ribeiro, EdnaHealthcare-associated methicillin-resistant Staphylococcus aureus infections represent extremely high morbidity and mortality rates worldwide. We aimed to assess the antimicrobial potential and synergistic effect between Epigalocatenin-3-gallate (EGCG) and different antibiotics in S. aureus strains with divergent resistance phenotypes. EGCG exposure effects in epigenetic and drug resistance key modulators were also evaluated. S. aureus strains (n = 32) were isolated from infected patients in a Lisbon hospital. The identification of the S. aureus resistance phenotype was performed through automatized methods. The antibiotic synergistic assay was performed through disk diffusion according to EUCAST guidelines with co-exposure to EGCG (250, 100, 50 and 25 µg/mL). The bacteria’s molecular profile was assessed through FTIR spectroscopy. The transcriptional expression of OrfX, SpdC and WalKR was performed by using qRT-PCR. FTIR-spectroscopy analysis enabled the clear discrimination of MRSA/MSSA strains and the EGCG exposure effect in the bacteria’s molecular profiles. Divergent resistant phenotypes were associated with divergent transcriptional expression of the epigenetic modulator OrfX, particularly in MRSA strains, as well as the key drug response modulators SpdC and WalKR. These results clearly demonstrate that EGCG exposure alters the expression patterns of key epigenetic and drug response genes with associated divergent-resistant profiles, which supports its potential for antimicrobial treatment and/or therapeutic adjuvant against antibiotic-resistant microorganisms.
- Epigenetic and drug response modulation of Epigalocaten-in-3-gallate in Staphylococcus aureus with divergent resistance phenotypesPublication . Mira, Ana Rita; Zeferino, Ana Sofia; Inácio, Raquel; Delgadinho, Mariana; Brito, Miguel; Calado, Cecília R. C.; Ribeiro, EdnaHealthcare-associated methicillin-resistant Staphylococcus aureus infections represent extremely high morbidity and mortality rates worldwide. We aimed to assess the antimicrobial potential and synergistic effect between Epigalocatenin-3-gallate (EGCG) and different antibiotics in S. aureus strains with divergent resistance phenotypes. EGCG exposure effects in epigenetic and drug resistance key modulators were also evaluated. S. aureus strains (n = 32) were isolated from infected patients in a Lisbon hospital. The identification of the S. aureus resistance phenotype was performed through automatized methods. The antibiotic synergistic assay was performed through disk diffusion according to EUCAST guidelines with co-exposure to EGCG (250, 100, 50, and 25 µg/mL). The bacteria's molecular profile was assessed through FTIR spectroscopy. The transcriptional expression of OrfX, SpdC, and WalKR was performed by using qRT-PCR. FTIR-spectroscopy analysis enabled the clear discrimination of MRSA/MSSA strains and the EGCG exposure effect in the bacteria's molecular profiles. Divergent resistant phenotypes were associated with divergent transcriptional expression of the epigenetic modulator OrfX, particularly in MRSA strains, as well as the key drug response modulators SpdC and WalKR. These results clearly demonstrate that EGCG exposure alters the expression patterns of key epigenetic and drug response genes with associated divergent-resistant profiles, which supports its potential for antimicrobial treatment and/or therapeutic adjuvant against antibiotic-resistant microorganisms.
- Livestock-associated MRSA colonization of occupational exposed workers and households in Europe: a reviewPublication . Ribeiro, Edna; Zeferino, Ana SofiaHuman Methicillin-Resistant Staphylococcus Aureus (MRSA) carriers have increased risk for subsequent clinical associated diseases and become a bacterial reservoir with associated high risk to transfer the infection to others, including household members. Animals such as pigs are important reservoir of livestock-associated clones, which can be transferred to humans. The colonization of animals with MRSA is a professional hazard for workers that spend several daily hours in direct contact with MRSA-possitive animals and consequently have a high risk of nasal colonization. Although MRSA human infections are one of the leading causes of morbidity and mortality in industrialized countries, exposure assessment procedures in occupational environments are not adapted to animal production settings at least in European countries. This work raise awareness to the relevance of monitoring MRSA strains associated with animal carriers and the requirement to create occupational standards and take effective preventive measures to protect exposed workers from MRSA colonization/infection.
- Livestock-associated MRSA colonization of occupational exposed workers and households in Europe: a reviewPublication . Ribeiro, Edna; Zeferino, Ana SofiaThe worldwide escalation in antibiotic resistant microorganisms has sustained the increasing concerns regarding antibiotics extensive use in animal food industry, which can result in a selection pressure that is driving the emergence of strains such as methicillin-resistant staphylococcus aureus (MRSA). Human MRSA infections are a well-known cause of numerous hospitalizations and deaths associated with extremely high mortality rates for invasive infections. Both animals and humans can become bacterial reservoirs of Livestock Associated MRSA (LA-MRSA) in which colonization predisposes to staphylococcal acquisition in clinical settings and to transfer the infection to others including household members. Biomonitoring of occupational exposed individuals which spend several hours per day in direct contact with MRSA-positive animals and thus are irrefutably exposed to a high risk of nasal colonization is imperative in order to develop effective preventive strategies. Here we performed an extensive review regarding the prevalence of LA- MRSA colonization in both occupational exposed individuals and their house-holds in a European context.