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- From Apple Waste to Antimicrobial Solutions: A Review of Phenolics from PGI ‘Maçã de Alcobaça’ and Related CultivarsPublication . Ribeiro, Jessica; Silva, Vanessa; Dapkevicius, Maria de Lurdes N. E.; Igrejas, Gilberto; Barros, Lillian; Heleno, Sandrina A.; Reis, Filipa S.; Poeta, PatríciaApple by-products represent a valuable source of phenolic compounds with significant antimicrobial potential, aligning with sustainable strategies for waste valorisation within the circular bioeconomy. This review focuses on the phenolic profile and antimicrobial relevance of ‘Maçã de Alcobaça,’ a Protected Geographical Indication (PGI) apple variety from Portugal. The main phenolics identified include phloridzin, phloretin, chlorogenic acid, quercetin glycosides, catechin, epicatechin, and procyanidins, which exhibit broad-spectrum antibacterial activity, particularly against Gram-positive pathogens such as Staphylococcus aureus. Their structure-activity relationships and mechanisms of action, namely membrane disruption, enzyme inhibition, oxidative stress induction, and quorum sensing interference, are discussed. Different extraction methods and solvents influence phenolic yield and bioactivity, with ethyl acetate and hydromethanolic extracts generally showing stronger effects. Studies reveal the potential of phenolics to interact synergistically with antibiotics and the promising applications in food preservation, medical formulations, and antimicrobial packaging. Overall, apple-derived phenolics, particularly those derived from industrial by-products, have significant potential as natural antimicrobial agents. Further exploration of these phenolics in the context of One Health and antimicrobial resistance mitigation is recommended.
- Development, characterization and stability of a novel sport drink based on thermal water, apple juice and hibiscusPublication . Radhouane, Maroua Fatma; Silveira, Tayse F. F. da; Ribeiro, Jessica; Rodrigues, Paula; Guimarães, Rafaela; Calhelha, Ricardo C.; Mandim, Filipa; Charfi, Ichrak; Ferreira, Isabel C.F.R.; Alves, Maria José; Barros, Lillian; Heleno, Sandrina A.Isotonic drinks are sports beverages that replenish minerals and rapidly absorbable carbohydrates. We proposed to surpass traditional formulations of isotonic drinks by integrating thermal water, which remains unexploited as a source of electrolytes in isotonic despite the high mineral content. The novel formula combined thermal water with apple juice and hibiscus extract (as sources of sugars and color, respectively, and bioactive compounds). Through comprehensive analysis of chemical, physicochemical, and microbiological properties over 45 days at 4◦C and 25◦C, the results unveiled an isotonic drink with satisfactory characteristics for this product category: pH of 3.72, 7.93 mg/100 mL of total sugars, and 148.30 mg/100 mL minerals, predominantly sodium (34.99 mg/ 100 mL) and potassium (73.20 mg/100 mL). It showed significant phenolic compounds, notably chlorogenic acid (2.75±0.10 mg/100 mL), and antioxidant activity (472.72 μmol Trolox eq/100 mL). It maintained a vibrant red hue derived from hibiscus anthocyanins (delphinidin 3-O-sambubioside and cyanidin 3-O-sambubioside, totaling 4.06±0.03 mg/100 mL), and demonstrated microbiological stability throughout the storage period in both temperatures studied. Therefore, by harnessing the potential of thermal water, this study paves the way for a novel approach to developing sports beverages and can serve as a model for countries rich in thermal springs.
- Antibiotic resistance among gastrointestinal bacteria in broilers: a review focused on Enterococcus spp. and Escherichia coliPublication . Ribeiro, Jessica; Silva, Vanessa; Monteiro, Andreia; Vieira-Pinto, Madalena; Igrejas, Gilberto; Reis, Filipa S.; Barros, Lillian; Poeta, PatríciaSimple Summary Chicken meat has become one of the most consumed meats worldwide, and antibiotics have been used to ensure high levels of production. However, antibiotic usage in animal production has contributed to the development of antibiotic-resistant bacteria, largely among intestinal microbiota. Enterococcus spp. and Escherichia coli are frequently found in the gastrointestinal tract of chickens, and the presence of resistant strains has been revealed by several studies. Enterococcus spp. isolated from broilers have shown resistance to at least seven classes of antibiotics, while E. coli have shown resistance to at least four. Furthermore, some clonal lineages, such as ST16, ST194, and ST195 in Enterococcus spp. and ST117 in E. coli, have been identified in broilers and humans. These data suggest that bacteria can be transmitted through the consumption of contaminated animal-source food, direct contact with animals, or environmental exposure. Therefore, the main goal of this review was to highlight the existing literature on the gastrointestinal microbiota in broilers and antibiotic-resistant Enterococcus spp. and E. coli of broiler origin. Chickens can acquire bacteria at different stages, and bacterial diversity can occur due to production practices, diet, and environment. The changes in consumer trends have led to increased animal production, and chicken meat is one of the most consumed meats. To ensure high levels of production, antimicrobials have been used in livestock for therapeutic purposes, disease prevention, and growth promotion, contributing to the development of antimicrobial resistance across the resident microbiota. Enterococcus spp. and Escherichia coli are normal inhabitants of the gastrointestinal microbiota of chickens that can develop strains capable of causing a wide range of diseases, i.e., opportunistic pathogens. Enterococcus spp. isolated from broilers have shown resistance to at least seven classes of antibiotics, while E. coli have shown resistance to at least four. Furthermore, some clonal lineages, such as ST16, ST194, and ST195 in Enterococcus spp. and ST117 in E. coli, have been identified in humans and animals. These data suggest that consuming contaminated animal-source food, direct contact with animals, or environmental exposure can lead to the transmission of antimicrobial-resistant bacteria. Therefore, this review focused on Enterococcus spp. and E. coli from the broiler industry to better understand how antibiotic-resistant strains have emerged, which antibiotic-resistant genes are most common, what clonal lineages are shared between broilers and humans, and their impact through a One Health perspective.
- Screening of chemical composition, antimicrobial and antioxidant activities in pomegranate, quince, and persimmon leaf, peel, and seed: valorization of autumn fruits by-products for a one health perspectivePublication . Silva, Vanessa; Silva, Adriana; Ribeiro, Jessica; Aires, Alfredo; Carvalho, Rosa Paula; Amaral, Joana S.; Barros, Lillian; Igrejas, Gilberto; Poeta, PatríciaAntimicrobial resistance is increasing globally and is now one of the major public health problems. Therefore, there is a need to search for new antimicrobial agents. The food industry generates large amounts of by-products that are rich in bioactive compounds, such as phenolic compounds, which are known to have several health benefits, including antioxidant and antimicrobial properties. Thus, we aimed to characterize the phenolic compounds present in pomegranate, quince, and persimmon by-products, as well as their antioxidant and antimicrobial activities. Phenolic compounds were extracted from pomegranate, quince, and persimmon leaves, seeds, and peels using a mixture of ethanol/water (80/20). The polyphenol profile of the extracts was determined by high-performance liquid chromatography. The antioxidant activity of the extracts was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) methods. Antimicrobial susceptibility was evaluated using the Kirby–Bauer disk diffusion method. In general, leaves showed higher concentrations of phenolics than the peel and seeds of fruits. In total, 23 phenolic compounds were identified and quantified, with sanguiin and apigenin-3-O-galactoside being present in the highest concentrations. Leaf extracts of pomegranate showed higher antioxidant activities than the other components in all methods used. In general, all extracts had a greater antimicrobial activity against Gram-positive bacteria. Persimmon leaf and seed extracts inhibited a greater number of bacteria, both Gram-positive and -negative. The lowest minimum inhibitory concentration (MIC) detected among Gram-positive and -negative bacteria was 10 mg/mL for pomegranate peel and leaf extracts against Staphylococcus aureus and S. pseudintermedius and for pomegranate leaf extract against Escherichia coli. Our results reinforce the need to value food industry by-products that could be used as food preservatives and antibiotic adjuvants against multiresistant bacteria.
- Genomic and phenotypic characterization of Enterococcus faecalis from broiler sternal bursitis: antimicrobial resistance and one health risksPublication . Ribeiro, Jessica; Silva, Vanessa; Pinto, Pedro; Vieira-Pinto, Madalena; Batista, Rita; Nunes, Alexandra; Gomes, João Paulo; Igrejas, Gilberto; Barros, Lillian; Heleno, Sandrina A.; Reis, Filipa S.; Poeta, PatríciaEnterococcus spp. are opportunistic bacteria capable of acquiring antimicrobial resistance and virulence traits, facilitating their adaptation to multiple ecological niches. Sternal bursitis, a condition affecting poultry welfare and carcass quality, remains poorly characterized from a microbiological perspective. This study provides the first genomic and phenotypic characterization of Enterococcus isolates from bursitis lesions in broilers, aiming to assess their antimicrobial resistance profiles, virulence determinants, and genetic diversity within a One Health framework. A total of 44 Enterococcus isolates were recovered from 48 sternal bursitis lesions, all identified as E. faecalis. Resistance was common for tetracycline (70.5%) and erythromycin (27.3%), while all isolates remained susceptible to critically important antimicrobials, including vancomycin and linezolid. Whole genome sequencing revealed a genetically diverse population, comprising multiple sequence types, plasmid replicons, and virulence gene profiles, including determinants for adhesion, biofilm formation, capsule synthesis, and extracellular proteases. Ionophore resistance genes (narA, narB) were also detected in several lineages. The coexistence of antimicrobial resistance and virulence determinants, often linked to mobile genetic elements, highlights the potential of lesion-associated with E. faecalis to act as reservoirs of relevant genes with zoonotic implications. Overall, this work highlights the diverse and ecological role of Enterococcus in extraintestinal poultry infections, reinforcing the need for continued genomic surveillance to promote animal health, food safety, and antimicrobial stewardship.
- Phenolic Compounds from Pyrus communis Residues: Mechanisms of Antibacterial Action and Therapeutic ApplicationsPublication . Ribeiro, Jessica; Silva, Vanessa; Igrejas, Gilberto; Barros, Lillian; Heleno, Sandrina A.; Reis, Filipa S.; Poeta, PatríciaThe food industry produces substantial amounts of fruit byproducts, which are often discarded despite their high content of bioactive compounds with potential therapeutic applications. Pyrus communis (pear) residues, which are particularly rich in phenolic compounds, represent a valuable yet underutilized resource. These byproducts have demonstrated significant antioxidant and antibacterial properties, suggesting their potential for medical and pharmaceutical applications. This review aims to provide a comprehensive analysis of the phenolic profile of P. communis byproducts, emphasizing their antioxidant and antibacterial mechanisms and their prospective use in combating oxidative stress and antibacterial resistance. Methods: A comprehensive review of the key phenolic compounds from P. communis residues was conducted using ScienceDirect and Google Scholar databases (from 2014 to 2024). Studies assessing antioxidant and antibacterial activities were reviewed, with a focus on their mechanisms of action against Gram-positive and Gram-negative bacterial pathogens. Results: A minimum of 14 distinct phenolic compounds were identified among P. communis residues. However, chlorogenic acid and catechin were identified as the primary contributors to the antioxidant activity of P. communis residues. Hydroquinone and chlorogenic acid exhibited strong antibacterial effects through membrane disruption, enzyme inhibition, and metabolic interference. Despite this potential, hydroquinone’s cytotoxicity and regulatory concerns limit its direct pharmaceutical application. Conclusions: While P. communis phenolics show promise as natural antibacterial agents, future research should address bioavailability, extraction standardization, and safe formulation strategies. Investigating their synergy with conventional antibiotics and improving stability for cosmetic applications are key steps toward their practical use. In vivo and clinical studies are crucial to validating their therapeutic potential and ensuring regulatory approval.
- Genomic Analysis of Antibiotic Resistance and Virulence Profiles in Escherichia coli Linked to Sternal Bursitis in Chickens: A One Health PerspectivePublication . Ribeiro, Jessica; Silva, Vanessa; Freitas, Catarina; Pinto, Pedro; Vieira-Pinto, Madalena; Batista, Rita; Nunes, Alexandra; Gomes, João Paulo; Pereira, José Eduardo; Igrejas, Gilberto; Barros, Lillian; Heleno, Sandrina A.; Reis, Filipa S.; Poeta, PatríciaSternal bursitis is an underexplored lesion in poultry, often overlooked in microbiological diagnostics. In this study, we characterized 36 Escherichia coli isolates recovered from sternal bursitis in broiler chickens, combining phenotypic antimicrobial susceptibility testing, PCR-based screening, and whole genome sequencing (WGS). The genetic analysis revealed a diverse population spanning 15 sequence types, including ST155, ST201, and ST58. Resistance to tetracycline and ciprofloxacin was common, and several isolates carried genes encoding beta-lactamases, including blaTEM-1B. Chromosomal mutations associated with quinolone and fosfomycin resistance (e.g., gyrA p.S83L, glpT_E448K) were also identified. WGS revealed a high number of virulence-associated genes per isolate (58-96), notably those linked to adhesion (fim, ecp clusters), secretion systems (T6SS), and iron acquisition (ent, fep, fes), suggesting strong pathogenic potential. Many isolates harbored virulence markers typical of ExPEC/APEC, such as iss, ompT, and traT, even in the absence of multidrug resistance. Our findings suggest that E. coli from sternal bursitis may act as reservoirs of resistance and virulence traits relevant to animal and public health. This highlights the need for including such lesions in genomic surveillance programs and reinforces the importance of integrated One Health approaches.
- Platanus hybrida’s phenolic profile, antioxidant power, and antibacterial activity against methicillin-resistant staphylococcus aureus (MRSA)Publication . Ribeiro, Jessica; Silva, Vanessa; Aires, Alfredo; Carvalho, Rosa Paula; Barros, Lillian; Gaivão, Isabel; Igrejas, Gilberto; Poeta, PatríciaMethicillin-resistant S. aureus (MRSA) are a threat to public health as they frequently reveal a multidrug-resistant pattern. Researchers all over the world are on an urgent hunt for new treatments to help fight infections before antibiotics become obsolete, and some natural alternatives, such as polyphenols, have already exhibited therapeutic properties. Therefore, this study aimed to determine the phenolic profile, antioxidant capacity, and antimicrobial activity against MRSA of the leaf, fruit, and stem bark extracts of Platanus hybrida. The polyphenols were extracted with a water/ethanol (20:80) mixture and the methodology included HPLC-DAD, DPPH, FRAP, and CuPRAC. To address this issue from a One Health perspective, the Kirby–Bauer disc diffusion method was performed against nine MRSA strains from three different sources (livestock, wild animals, and humans). Fourteen phenolics were identified and the leaf extract showed the highest phenolic content, followed by the fruit extract. The leaf extract also showed the highest antioxidant capacity while the fruit extract had the lowest antioxidant capacity. Both leaf and fruit extracts inhibited the growth of strains from all sources, while the stem bark extract did not inhibit the growth of human strains. This work highlights the complex chemical composition and the antioxidative and antimicrobial potential of extracts derived from P. hydrida.