Evaluation of the antimicrobial activity of lipids extracted from canned fish industry waste streams

Tese de mestrado, Qualidade Alimentar e Saúde, 2020, Universidade de Lisboa, Faculdade de Farmácia.As perceções negativas do público acerca dos conservantes químicos têm gerado um elevado interesse no uso de compostos alternativos de origem natural, com potencial uso como conservantes com atividade antimicrobiana. Os conservantes naturais podem ser obtidos através de diversas fontes que incluem as plantas, polímeros naturais, ácidos orgânicos ou animais. Assim sendo, neste trabalho experimental, o objetivo foi avaliar a atividade antimicrobiana de lípidos extraídos de resíduos alimentares da indústria do peixe. Foram obtidos extratos lipídicos por dois métodos distintos, extração por solvente (Bligh and Dyer) e extração por CO2 supercrítico. O uso do método de CO2 supercrítico oferece uma aplicação menos poluente, ao contrário de um método convencional que normalmente envolve solventes tóxicos e inflamáveis, além de que, é mais fácil de separar do extrato por ser um gás a pressões e temperaturas ambientais. Uma caracterização lipídica dos extratos ajudou a perceber os diferentes componentes na sua composição que na sua totalidade levaram a uma atividade antimicrobiana. Esta atividade foi avaliada por diversos métodos, como a difusão em poço, difusão em disco, microdiluição em agar e microdiluição líquida. As atividades antimicrobianas dos extratos lipídicos foram avaliadas contra diversos microrganismos (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa e Candida albicans) que podem representar problemas de segurança alimentar em matrizes alimentares. Os resultados obtidos sugerem um potencial antimicrobiano destes lípidos para aplicações como conservantes naturais.The public’s negative perception towards chemical preservatives has sparked an increased interest regarding the use of alternative compounds of natural origin, which hold the potential to be used as preservatives with antimicrobial activity. Natural preservatives can be obtained from a variety of sources, including plants, natural polymers, organic acids or animals. Thus, in this experimental work, the main objective was to evaluate the antimicrobial activity of lipids extracted from canned fish industry waste streams. Lipid extracts were obtained by using two different methods: solvent extraction (Bligh and Dyer) and supercritical CO2 extraction. In opposition to conventional methods, which typically involve toxic and flammable solvents, using a supercritical CO2 methodology offers a less polluting alternative, making it easier to separate the solvent from the extract as it is a gas at ambient temperatures and pressures. A lipid characterization of the extracts with antimicrobial activity helped define the components present in their composition. This activity was evaluated by several methods such as well diffusion, disk diffusion, agar microdilution and liquid microdilution. The antimicrobial activities of lipid extracts were evaluated against several microorganisms (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans) that can represent food safety issues in food matrices. The results suggest an antimicrobial potential of these lipids for applications as natural preservatives.Com o patrocínio do iBET — Instituto de Biologia Experimental e Tecnológico, Estação Agronómica Nacional, INTERFACE Programme, through the Innovation, Technology and Circular Economy Fund (FITEC)

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research