Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli

Detalhes bibliográficos
Autor(a) principal: Valério, Nádia Castanho
Data de Publicação: 2016
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10773/22360
Resumo: Escherichia coli is part of the normal flora of the gastrointestinal tract of humans and various mammals. This opportunistic microorganism is capable of cause several infections, such as urinary tract infections (UTI). E. coli is resistant to a large number of antibiotics, becoming harder the control of infections caused by this bacterium. Phage therapy may be a useful tool to control infections caused by antibiotic resistant strains. However, the major concern of the phage therapy is also the emergence of phage resistant bacteria. In this study, was evaluated the combination of two different therapies, chemotherapy and phage therapy, to evaluate the possibility of synergic effects between them. It was used the phage ECA2 (a phage previously isolated by the research group) and various antibiotics (ampicillin, kanamycin, piperacillin, tetracycline, chloramphenicol and ciprofloxacin) with different mechanisms of action. The E. coli strain used in this study is sensitive to the antibiotics ciprofloxacin, tetracycline and chloramphenicol and resistant to the antibiotics ampicillin, kanamycin and piperacillin The phage ECA2 caused a reduction in E. coli concentration of ≈ 4.5 log after 2 hours of treatment in phosphate buffered saline (PBS). The results obtained with the mixtures of the phage with ampicillin, kanamycin and piperacillin did not cause significantly differences when compared with the results obtained just with the phage. As the bacterium E. coli showed resistance to those antibiotics, the bacterial inactivation was just due the action of the phage. Otherwise, the results obtained using the mixtures of ECA2 with tetracycline and chloramphenicol were worse than the results obtained just with the phage. The conjugation of the phage with ciprofloxacin resulted in a bacterial inactivation of about 8.3 log, compared to the ≈4.5 log of bacterial inactivation obtained with the phage alone. In addition, the conjugation of the phage ECA2 with ciprofloxacin resulted in a decrease of the bacterial resistances obtained the phage and the antibiotic individually. The efficacy of phage therapy in urine was also evaluated, with the phage and the mix of phage and ciprofloxacin. The inactivation of E. coli in urine samples was similar to that obtained in PBS. It was observed a decrease of 4.3 log after 4 hours of treatment. Furthermore, a cocktail with two phages, the phage ECA2 and another E. coli specific phage, previously isolated by the research group, the phage phT4A, was also tested. The E. coli inactivation was 3.5 log after 4 hours. The results indicate that phage and antibiotic combinations could result in synergistic effect in the inactivation of bacteria, but only when the bacterium is sensitive to the antibiotic. Also, the combination of antibiotics with phages contributes to managing resistance levels, controlling the antibiotic resistance and phage-resistant mutants. The phages limit the emergence of antibiotic resistant variants in combined treatments independently of antibiotic type, but the antibiotics limit the resistance of phage-mutants only when bacteria are sensitive to the antibiotic. However, overall, in the presence of antibiotics the resistance of phage-mutants was the same or less than when phages were tested alone. The high bacterial inactivation efficiency with phages combined with a higher bacterial inactivation in the presence of antibiotic and the long periods of phage survival in urine samples, paves the way for depth studies to control urinary tract infection and to overcome the development of resistances by E. coli, the bacterium most frequently isolated in UTI at the community level and at hospital settings
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spelling Potential effects between bacteriophages and antibiotics to inactivate Escherichia coliResistência a antibióticosBacteriófagosEscherichia coli is part of the normal flora of the gastrointestinal tract of humans and various mammals. This opportunistic microorganism is capable of cause several infections, such as urinary tract infections (UTI). E. coli is resistant to a large number of antibiotics, becoming harder the control of infections caused by this bacterium. Phage therapy may be a useful tool to control infections caused by antibiotic resistant strains. However, the major concern of the phage therapy is also the emergence of phage resistant bacteria. In this study, was evaluated the combination of two different therapies, chemotherapy and phage therapy, to evaluate the possibility of synergic effects between them. It was used the phage ECA2 (a phage previously isolated by the research group) and various antibiotics (ampicillin, kanamycin, piperacillin, tetracycline, chloramphenicol and ciprofloxacin) with different mechanisms of action. The E. coli strain used in this study is sensitive to the antibiotics ciprofloxacin, tetracycline and chloramphenicol and resistant to the antibiotics ampicillin, kanamycin and piperacillin The phage ECA2 caused a reduction in E. coli concentration of ≈ 4.5 log after 2 hours of treatment in phosphate buffered saline (PBS). The results obtained with the mixtures of the phage with ampicillin, kanamycin and piperacillin did not cause significantly differences when compared with the results obtained just with the phage. As the bacterium E. coli showed resistance to those antibiotics, the bacterial inactivation was just due the action of the phage. Otherwise, the results obtained using the mixtures of ECA2 with tetracycline and chloramphenicol were worse than the results obtained just with the phage. The conjugation of the phage with ciprofloxacin resulted in a bacterial inactivation of about 8.3 log, compared to the ≈4.5 log of bacterial inactivation obtained with the phage alone. In addition, the conjugation of the phage ECA2 with ciprofloxacin resulted in a decrease of the bacterial resistances obtained the phage and the antibiotic individually. The efficacy of phage therapy in urine was also evaluated, with the phage and the mix of phage and ciprofloxacin. The inactivation of E. coli in urine samples was similar to that obtained in PBS. It was observed a decrease of 4.3 log after 4 hours of treatment. Furthermore, a cocktail with two phages, the phage ECA2 and another E. coli specific phage, previously isolated by the research group, the phage phT4A, was also tested. The E. coli inactivation was 3.5 log after 4 hours. The results indicate that phage and antibiotic combinations could result in synergistic effect in the inactivation of bacteria, but only when the bacterium is sensitive to the antibiotic. Also, the combination of antibiotics with phages contributes to managing resistance levels, controlling the antibiotic resistance and phage-resistant mutants. The phages limit the emergence of antibiotic resistant variants in combined treatments independently of antibiotic type, but the antibiotics limit the resistance of phage-mutants only when bacteria are sensitive to the antibiotic. However, overall, in the presence of antibiotics the resistance of phage-mutants was the same or less than when phages were tested alone. The high bacterial inactivation efficiency with phages combined with a higher bacterial inactivation in the presence of antibiotic and the long periods of phage survival in urine samples, paves the way for depth studies to control urinary tract infection and to overcome the development of resistances by E. coli, the bacterium most frequently isolated in UTI at the community level and at hospital settingsEscherichia coli é uma bactéria oportunista que pode ser encontrada como parte da flora normal do trato gastrointestinal humano e de alguns mamíferos. Este microrganismo é capaz de provocar diversas infeções, sendo responsável pela maioria das infeções do trato urinário (ITU). E. coli é resistente a uma grande variedade de antibióticos, tornando difícil o tratamento de infeções por ela causadas. Deste modo, a terapia fágica pode ser uma ferramenta útil no tratamento de infeções causadas por estirpes de E. coli resistentes aos antibióticos. Contudo, também a terapia fágica também leva ao desenvolvimento de bactérias mutantes resistentes aos fagos. Por esta razão, neste trabalho, foi avaliada a combinação de duas terapias, quimioterapia e terapia fágica, de modo a avaliar possíveis efeitos sinérgicos e atenuar o desenvolvimento de resistências aos fagos e antibióticos. Foi usado o fago ECA2, isolado num estudo prévio, e vários antibioticos (ampicilina, canamicina, piperacilina, ciprofloxacina tetraciclina e cloranfenicol) com diferentes mecanismos de ação. A estirpe de E. coli usada é sensível aos antibióticos ciprofloxacina, tetraciclina e cloranfenicol e resistente aos antibióticos ampicilina, canamicina e piperacilina. O fago ECA2 inativou eficientemente a bactéria E. coli, causando uma redução de ≈4,5 log na concentração da bactéria após 2 horas de tratamento em phosphate buffered saline (PBS). A inativação bacteriana com a mistura de fago e antibióticos ampicilina, canamicina e piperacilina foram similares aos resultados obtidos apenas com o fago. Como a estirpe bacteriana apresentava resistência a estes antibióticos, a inativação bacteriana resultante foi devida apenas à ação do fago. As misturas do fago ECA2 com cloranfenicol e com tetraciclina mostraram ser menos eficazes na inativação da bactéria do que o fago sozinho. A conjugação do fago com a ciprofloxacina resultou numa inativação bacteriana de cerca de 8,3 log, em detrimento dos ≈ 4,5 log de inativação bacteriana obtidos com apenas o fago. Além disso, a conjugação do fago ECA2 com a ciprofloxacina resultam numa diminuição das resistências bacterianas obtidas em relação ao fago e ao antibiótico individualmente. A terapia fágica também foi avaliada em urina com vista a avaliar o uso desta terapia no controlo de infeções urinárias. A inativação de E. coli na urina foi semelhante à obtida nos ensaios em PBS, tanto para o fago como para a conjugação do fago ECA2 com a ciprofloxacina. Foi ainda testado na urina um cocktail com dois fagos, o fago ECA2 e com outro fago específico para esta bactéria, o fagophT4A (previamente isolado pelo grupo de trabalho). Observou-se numa redução bacteriana de 3,5 log. Os resultados indicam que a combinação fagos e antibióticos pode resultar num efeito sinérgico na inativação de bactérias, mas apenas quando a bactéria é sensível ao antibiótico. Além disso, a combinação de antibióticos com fagos contribui para a gestão dos níveis de resistência, controlando a resistência aos antibióticos e os mutantes resistentes ao fago. Os fagos limitam o desenvolvimento de variantes resistentes a antibióticos em tratamentos combinados independentemente do tipo de antibiótico, mas os antibióticos limitam a resistência de mutantes aos fagos apenas quando as bactérias são sensíveis ao antibiótico. Contudo, em geral, na presença de antibióticos, a resistência dos mutantes aos fagos foi a mesma ou menor do que quando os fagos foram testados isoladamente. A elevada eficiência de inativação bacteriana por fagos combinada com uma maior inativação bacteriana na presença de antibiótico, e a elevada sobrevivência dos fagos em urina, abre o caminho para estudos mais aprofundados para controlar a UTI e o desenvolvimento de resistências em E. coli, a bactéria mais frequentemente isolada em UTI ao nível da comunidade e em ambientes hospitalares.Universidade de Aveiro2016-12-212016-12-21T00:00:00Z2018-12-15T13:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/22360TID:201936593engValério, Nádia Castanhoinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T11:43:52Zoai:ria.ua.pt:10773/22360Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T02:56:32.009042Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
title Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
spellingShingle Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
Valério, Nádia Castanho
Resistência a antibióticos
Bacteriófagos
title_short Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
title_full Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
title_fullStr Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
title_full_unstemmed Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
title_sort Potential effects between bacteriophages and antibiotics to inactivate Escherichia coli
author Valério, Nádia Castanho
author_facet Valério, Nádia Castanho
author_role author
dc.contributor.author.fl_str_mv Valério, Nádia Castanho
dc.subject.por.fl_str_mv Resistência a antibióticos
Bacteriófagos
topic Resistência a antibióticos
Bacteriófagos
description Escherichia coli is part of the normal flora of the gastrointestinal tract of humans and various mammals. This opportunistic microorganism is capable of cause several infections, such as urinary tract infections (UTI). E. coli is resistant to a large number of antibiotics, becoming harder the control of infections caused by this bacterium. Phage therapy may be a useful tool to control infections caused by antibiotic resistant strains. However, the major concern of the phage therapy is also the emergence of phage resistant bacteria. In this study, was evaluated the combination of two different therapies, chemotherapy and phage therapy, to evaluate the possibility of synergic effects between them. It was used the phage ECA2 (a phage previously isolated by the research group) and various antibiotics (ampicillin, kanamycin, piperacillin, tetracycline, chloramphenicol and ciprofloxacin) with different mechanisms of action. The E. coli strain used in this study is sensitive to the antibiotics ciprofloxacin, tetracycline and chloramphenicol and resistant to the antibiotics ampicillin, kanamycin and piperacillin The phage ECA2 caused a reduction in E. coli concentration of ≈ 4.5 log after 2 hours of treatment in phosphate buffered saline (PBS). The results obtained with the mixtures of the phage with ampicillin, kanamycin and piperacillin did not cause significantly differences when compared with the results obtained just with the phage. As the bacterium E. coli showed resistance to those antibiotics, the bacterial inactivation was just due the action of the phage. Otherwise, the results obtained using the mixtures of ECA2 with tetracycline and chloramphenicol were worse than the results obtained just with the phage. The conjugation of the phage with ciprofloxacin resulted in a bacterial inactivation of about 8.3 log, compared to the ≈4.5 log of bacterial inactivation obtained with the phage alone. In addition, the conjugation of the phage ECA2 with ciprofloxacin resulted in a decrease of the bacterial resistances obtained the phage and the antibiotic individually. The efficacy of phage therapy in urine was also evaluated, with the phage and the mix of phage and ciprofloxacin. The inactivation of E. coli in urine samples was similar to that obtained in PBS. It was observed a decrease of 4.3 log after 4 hours of treatment. Furthermore, a cocktail with two phages, the phage ECA2 and another E. coli specific phage, previously isolated by the research group, the phage phT4A, was also tested. The E. coli inactivation was 3.5 log after 4 hours. The results indicate that phage and antibiotic combinations could result in synergistic effect in the inactivation of bacteria, but only when the bacterium is sensitive to the antibiotic. Also, the combination of antibiotics with phages contributes to managing resistance levels, controlling the antibiotic resistance and phage-resistant mutants. The phages limit the emergence of antibiotic resistant variants in combined treatments independently of antibiotic type, but the antibiotics limit the resistance of phage-mutants only when bacteria are sensitive to the antibiotic. However, overall, in the presence of antibiotics the resistance of phage-mutants was the same or less than when phages were tested alone. The high bacterial inactivation efficiency with phages combined with a higher bacterial inactivation in the presence of antibiotic and the long periods of phage survival in urine samples, paves the way for depth studies to control urinary tract infection and to overcome the development of resistances by E. coli, the bacterium most frequently isolated in UTI at the community level and at hospital settings
publishDate 2016
dc.date.none.fl_str_mv 2016-12-21
2016-12-21T00:00:00Z
2018-12-15T13:00:00Z
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dc.publisher.none.fl_str_mv Universidade de Aveiro
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