Browsing by Author "Tavaria, Freni Kekhasharú"
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- Chitosan and hydroxyapatite based biomaterials to circumvent periprosthetic joint infectionsPublication . Costa-Pinto, Ana Rita; Lemos, Ana Luísa; Tavaria, Freni Kekhasharú; Pintado, ManuelaEvery year, worldwide, millions of people suffering from joint pain undergo joint replace-ment. For most patients, joint arthroplasty reduces pain and improve function, though a small fraction will experience implant failure. One of the main reasons includes prosthetic joint infection (PJI), involving the prosthesis and adjacent tissues. Few microorganisms (MO) are required to inocu-late the implant, resulting in the formation of a biofilm on its surface. Standard treatment includes not only removal of the infected prosthesis but also the elimination of necrotic bone fragments, local and/or systemic administration of antibiotics, and revision arthroplasty with a new prosthesis, immediately after the infection is cleared. Therefore, an alternative to the conventional therapeutics would be the incorporation of natural antimicrobial compounds into the prosthesis. Chitosan (Ch) is a potential valuable biomaterial presenting properties such as biocompatibility, biodegradability, low immunogenicity, wound healing ability, antimicrobial activity, and anti-inflammatory potential. Regarding its antimicrobial activity, Gram-negative and Gram-positive bacteria, as well as fungi are highly susceptible to chitosan. Calcium phosphate (CaP)-based materials are commonly utilized in orthopedic and dentistry for their excellent biocompatibility and bioactivity, particularly in the establishment of cohesive bone bonding that yields effective and rapid osteointegration. At present, the majority of CaP-based materials are synthetic, which conducts to the depletion of the natural resources of phosphorous in the future due to the extensive use of phosphate. CaP in the form of hydroxyapatite (HAp) may be extracted from natural sources as fish bones or scales, which are by-products of the fish food industry. Thus, this review aims to enlighten the fundamental characteristics of Ch and HAp biomaterials which makes them attractive to PJI prevention and bone regeneration, summarizing relevant studies with these biomaterials to the field.
- Distinction of different colony types by a smart-data-driven toolPublication . Rodrigues, Pedro Miguel; Ribeiro, Pedro; Tavaria, Freni KekhasharúBackground: Colony morphology (size, color, edge, elevation, and texture), as observed on culture media, can be used to visually discriminate different microorganisms. Methods: This work introduces a hybrid method that combines standard pre-trained CNN keras models and classical machine-learning models for supporting colonies discrimination, developed in Petri-plates. In order to test and validate the system, images of three bacterial species (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) cultured in Petri plates were used. Results: The system demonstrated the following Accuracy discrimination rates between pairs of study groups: 92% for Pseudomonas aeruginosa vs. Staphylococcus aureus, 91% for Escherichia coli vs. Staphylococcus aureus and 84% Escherichia coli vs. Pseudomonas aeruginosa. Conclusions: These results show that combining deep-learning models with classical machine-learning models can help to discriminate bacteria colonies with good accuracy ratios.
- Image analysis semi-automatic system for colony-forming-unit countingPublication . Rodrigues, Pedro Miguel; Luís, Jorge; Tavaria, Freni KekhasharúBackground: Accurate quantitative analysis of microorganisms is recognized as an essential tool for gauging safety and quality in microbiology settings in a wide range of fields. The enumeration process of viable microorganisms via traditional culturing techniques are methodically convenient and cost-effective, conferring high applicability worldwide. However, manual counting can be time-consuming, laborious and imprecise. Furthermore, particular cases require an urgent and accurate response for effective processing. Methods: To reduce time limitations and discrepancies, this work introduces an image processing method capable of semi-automatically quantifying the number of colony forming units (CFUs). This rapid enumeration technique enables the technician to provide an expeditious assessment of the microbial load of a given sample. To test and validate the system, three bacterial species were cultured, and a labeled database was created, with subsequent image acquisition. Results: The system demonstrated acceptable classification measures; the mean values of Accuracy, Recall and F-measure were: (1) 95%, 95% and 0.95 for E. coli; (2) 91%, 91% and 0.90 for P. aeruginosa; and (3) 84%, 86% and 0.85 for S. aureus. Conclusions: Evidence related to the time-saving potential of the system was achieved; the time spent on quantification tasks of plates with a high number of colonies might be reduced to a half and occasionally to a third.
- A quitosana como biomaterial odontológico: estado da artePublication . Tavaria, Freni Kekhasharú; Costa, Eduardo Manuel; Pina-Vaz, Irene; Carvalho, Manuel Fontes; Pintado, Maria ManuelaA impossibilidade de erradicar completamente os microrganismos da cavidade oral ou dos canais radiculares estimula a procura de novos materiais que permitam cada vez mais eficazmente, controlar ou prevenir o aparecimento de infeções. A quitosana é um biopolímero com uma estrutura química e características únicas que permitem que apresente excelente biocompatibilidade e que seja facilmente processado. A panóplia de aplicações é tão fascinante como ainda mal conhecida. A constatação do potencial e do valor industrial deste biopolímero conduziu à sua utilização em muitas aplicações de interesse tecnológico e, de uma forma acentuada, na área biomédica. As suas propriedades anti-oxidantes, anti-microbianas, anti-inflamatórias, cicatrizante e de inibição da formação de biofilmes tornam a sua aplicação na odontologia particularmente interessante. Com este trabalho pretendeu-se rever a literatura existente sobre aplicações da quitosana na área odontológica.
- A review of chitosan's effect on oral biofilms: perspectives from the tube to the mouthPublication . Costa, Eduardo Manuel; Silva, Sara; Veiga, Mariana; Tavaria, Freni Kekhasharú; Pintado, Maria ManuelaBackground: The oral cavity is a propitious environment for bacteria with different tissue tropisms to colonize and grow due to its diverse surfaces. For bacterial survival in the oral cavity, where tissues are continuously bathed in fluids, biofilm formation is necessary. Dental biofilm, i.e. dental plaque, is notoriously hard to inhibit and traditional oral care solutions are either ineffective at managing oral bio-films or cause secondary effects, such as teeth staining, that make them unattractive. Highlight: Chitosan has high biocompatibility and antimicrobial activity that is heralded by the pharmaceutical industry for its applicability in biofabrication. Therefore, this material is a potential substitute for the antimicrobials traditionally used in oral care. Conclusion: Currently, the body of work on chitosan and the oral cavity ranges from planktonic studies in vitro to biofilm control/removal studies in vivo. With a wide range of topics available for analysis, this review provides a working understanding of chitosan's role in the control and management of oral biofilms.
- The impact of bioactive textiles on human skin microbiotaPublication . Oliveira, Cláudia Suellen Ferro de; Tavaria, Freni KekhasharúIn order to support the elevated market demand for the development of textiles with specific benefits for a healthy and safe lifestyle, several bioactive textiles with defined properties, including antimicrobial, antioxidant, anti-inflammatory, anti-odor, and anti-repellent, anti-ultraviolet (UV) radiation, have been proposed. Antimicrobial textiles, particularly, have received special interest considering the search for smart, protective textiles that also impact health and well-being. Although the incorporation of antimicrobials into textile material has been well succeeded, the addition of such components in textile clothing can influence the balance of the skin microbiota of the wearer. While most antimicrobial textiles have demonstrated good biocompatibility and antimicrobial performance against bacteria, fungi, and viruses, some problems such as textile biodegradation, odor, and dissemination of unwanted microorganisms might arise. However, little is known about the impact of such antimicrobial textile-products on human skin microbiota. To address this issue, the present review, for the first time, gives an overview about the main effects of antimicrobial textiles, i.e., antibacterial, antifungal, and antiviral, on skin microbiota while driving future investigation to elucidate their putative clinical relevance and possible applications according to their impact on skin microbiota. This knowledge may open doors for the development of more microbiota friendly textiles or antimicrobial textile-products able to target specific populations of the skin microbiota aiming to alleviate skin disorders, malodor, and allergies by avoiding the growth and spread of pathogenic microorganisms.
- Therapeutic textiles: a promising approach for human skin dysbiosis?Publication . Oliveira, Cláudia Sullen Ferro de; Tavaria, Freni KekhasharúThe close interaction between skin and clothing has become an attractive cornerstone for the development of therapeutic textiles able to alleviate skin disorders, namely those correlated to microbiota dysregulation. Skin microbiota imbalance is known in several skin diseases, including atopic dermatitis (AD), psoriasis, seborrheic dermatitis, rosacea, acne and hidradenitis suppurative (HS). Such microbiota dysregulation is usually correlated with inflammation, discomfort and pruritus. Although conventional treatments, that is, the administration of steroids and antibiotics, have shown some efficacy in treating and alleviating these symptoms, there are still disadvantages that need to be overcome. These include their long-term usage with side effects negatively impacting resident microbiota members, antibiotic resistance and the elevated rate of recurrence. Remarkably, therapeutic textiles as a non-pharmacological measure have emerged as a promising strategy to treat, alleviate the symptoms and control the severity of many skin diseases. This systematic review showcases for the first time the effects of therapeutic textiles on patients with skin dysbiosis, focusing on efficacy, safety, adverse effects and antimicrobial, antioxidant and anti-inflammatory properties. The main inclusion criteria were clinical trials performed in patients with skin dysbiosis who received treatment involving the use of therapeutic textiles. Although there are promising outcomes regarding clinical parameters, safety and adverse effects, there is still a lack of information about the impact of therapeutic textiles on the skin microbiota of such patients. Intensive investigation and corroboration with clinical trials are needed to strengthen, define and drive the real benefit and the ideal biomedical application of therapeutic textiles.
- Topical use of probiotics: the natural balancePublication . Tavaria, Freni Kekhasharú