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Abstract(s)
O uso indiscriminado dos agentes antimicrobianos, nomeadamente antibiĂłticos e biocidas, levou ao desenvolvimento de resistĂȘncias em bactĂ©rias de origem alimentar e hospitalar. Estas resistĂȘncias representam uma ameaça Ă saĂșde pĂșblica, pois reduzem a eficĂĄcia dos mesmos compostos, aumentando desta forma a mortalidade e a morbidade. Assim, torna-se fundamental o estudo de novos compostos antimicrobianos no controlo do crescimento e disseminação dos mesmos agentes patogĂ©nicos. Os compostos de origem natural tĂȘm sido apresentados como alternativas promissoras aos agentes antimicrobianos atualmente utilizados, nĂŁo sĂł como possĂveis conservantes alimentares, mas tambĂ©m como adjuvantes do processo de desinfeção de superfĂcies. Em alguns casos, a exposição das bactĂ©rias a concentraçÔes subinibitĂłrias dos compostos naturais pode levar a adaptação aos mesmos e ao desenvolvimento de resistĂȘncias homĂłlogas e/ou cruzadas a outros agentes. Neste trabalho, foi avaliada a influĂȘncia de concentraçÔes subinibitĂłrias de resveratrol sobre bactĂ©rias problemĂĄticas, Listeria monocytogenes e Staphylococcus aureus relativamente ao desenvolvimento de resistĂȘncia homĂłloga e cruzada a antibiĂłticos, habitualmente utilizados no tratamento de infeçÔes causadas por estas bactĂ©rias, e a um desinfetante frequentemente utilizado no sector alimentar. Foi ainda avaliado, se as mesmas concentraçÔes de resveratrol poderiam levar a uma proteção celular contra condiçÔes adversas, nomeadamente stress ĂĄcido e tĂ©rmico. Os resultados sugeriram, de um modo geral, que o resveratrol nĂŁo levou ao desenvolvimento de resistĂȘncia homĂłloga nem cruzada, evidenciado, no entanto, um aumento da tolerĂąncia ao stress tĂ©rmico e ĂĄcido em L. monocytogenes, mas para S. aureus este comportamento nĂŁo foi muito evidente. Estes resultados apoiam a possibilidade da utilização do resveratrol como conservante alimentar. Por outro lado, a desinfeção representa um processo fundamental no controlo e disseminação dos microrganismos, sendo tambĂ©m relevante encontrar novas alternativas para colmatar a falta de antimicrobianos eficazes na eliminação de bactĂ©rias problemĂĄticas na prĂĄtica clĂnica. Assim, no presente trabalho foi tambĂ©m avaliado o potencial sinĂ©rgico do linalool, composto maioritĂĄrio do Ăłleo essencial de coentros, em combinação com desinfetantes habitualmente utilizados em ambiente hospitalar, sobre Acinetobacter baumannii e S. aureus. Em A. baumannii, foi observado que o linalool em combinação com o cloreto de benzalcĂłnio ou a clorohexidina digluconato tem um efeito sinĂ©rgico, e em combinação com o ĂĄcido peracĂ©tico ou o hipoclorito de sĂłdio tem um efeito aditivo. No caso do S. aureus evidenciou-se um efeito aditivo para todas as interaçÔes. Assim, o linalool apresenta potencial em futuras combinaçÔes com desinfetantes.
The indiscriminate use of antimicrobials, namely antibiotics and biocides, has led to the development of resistance in foodborne and hospital pathogens. This resistance represents a serious threat to public health, because it reduces the overall effectiveness of antimicrobials, thereby increasing mortality and morbidity. Thus, it becomes extremely relevant to study new antimicrobial compounds that can control the growth and spread of these pathogens. Natural products have been considered as promising alternatives to the antimicrobial agents currently used, not only as possible food preservatives but also as adjuvants for the disinfection process of surfaces. In some cases, exposure of the bacteria to subinhibitory concentrations of natural compounds can lead to adaptations to the same products and to the development of homologous and/or cross-resistance to other agents. In this study, the influence of subinhibitory concentrations of resveratrol on Listeria monocytogenes and Staphylococcus aureus was studied, by evaluating the development of homologous resistance or cross-resistance to the antibiotics commonly used to treat infections caused by these bacteria as well as to one disinfectant often used in the food sector. The development of cellular protection against adverse conditions, including acid and heat stress, by the influence of the same resveratrol concentrations was also evaluated. In general, the results suggest that resveratrol did not lead to homologous or cross-resistance development, nonetheless evidencing an increased tolerance to acid and heat stress in L. monocytogenes, although this behaviour was not very evident for S. aureus. These results, thus, support the possibility of using resveratrol as a food preservative. Similarly, disinfection represents a fundamental process in the control and spread of microorganisms, being extremely important to find new alternatives to overcome the lack of effective antimicrobial agents that can control or eliminate problematic bacteria in clinical practice. Thus, in the present study, the synergistic potential of linalool, the major compound of essential oil of coriander, in combination with disinfectants commonly used in hospitals was evaluated against Acinetobacter baumannii and S. aureus. In A. baumannii, it was observed that linalool in combination with benzalkonium chloride or chlorhexidine digluconate had a synergistic effect, and in combination with peracetic acid or sodium hypochlorite presented an additive effect. In the case of S. aureus an additive effect was demonstrated for all interactions. For these reasons, the linalool presents potential for future combinations with disinfectants.
The indiscriminate use of antimicrobials, namely antibiotics and biocides, has led to the development of resistance in foodborne and hospital pathogens. This resistance represents a serious threat to public health, because it reduces the overall effectiveness of antimicrobials, thereby increasing mortality and morbidity. Thus, it becomes extremely relevant to study new antimicrobial compounds that can control the growth and spread of these pathogens. Natural products have been considered as promising alternatives to the antimicrobial agents currently used, not only as possible food preservatives but also as adjuvants for the disinfection process of surfaces. In some cases, exposure of the bacteria to subinhibitory concentrations of natural compounds can lead to adaptations to the same products and to the development of homologous and/or cross-resistance to other agents. In this study, the influence of subinhibitory concentrations of resveratrol on Listeria monocytogenes and Staphylococcus aureus was studied, by evaluating the development of homologous resistance or cross-resistance to the antibiotics commonly used to treat infections caused by these bacteria as well as to one disinfectant often used in the food sector. The development of cellular protection against adverse conditions, including acid and heat stress, by the influence of the same resveratrol concentrations was also evaluated. In general, the results suggest that resveratrol did not lead to homologous or cross-resistance development, nonetheless evidencing an increased tolerance to acid and heat stress in L. monocytogenes, although this behaviour was not very evident for S. aureus. These results, thus, support the possibility of using resveratrol as a food preservative. Similarly, disinfection represents a fundamental process in the control and spread of microorganisms, being extremely important to find new alternatives to overcome the lack of effective antimicrobial agents that can control or eliminate problematic bacteria in clinical practice. Thus, in the present study, the synergistic potential of linalool, the major compound of essential oil of coriander, in combination with disinfectants commonly used in hospitals was evaluated against Acinetobacter baumannii and S. aureus. In A. baumannii, it was observed that linalool in combination with benzalkonium chloride or chlorhexidine digluconate had a synergistic effect, and in combination with peracetic acid or sodium hypochlorite presented an additive effect. In the case of S. aureus an additive effect was demonstrated for all interactions. For these reasons, the linalool presents potential for future combinations with disinfectants.
Description
Keywords
Acinetobacter Baumannii Adaptação Linalool Listeria Monocytogenes Proteção Celular Resveratrol Sinergismo Staphylococcus Aureus