Eficácia terapêutica, segurança clínica e ecotoxicológica da amoxicilina por via intramuscular para o tratamento de estreptococose em tilápias do Nilo
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Data
2017-12-07
Autores
Moraes, Alessandra Cristina de
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Universidade Estadual Paulista (Unesp)
Resumo
O presente estudo avaliou a eficácia terapêutica, segurança clínica e ecotoxicológica da amoxicilina triidratada, via intramuscular, para o tratamento de Streptococcus agalactiae em Oreochromis niloticus. Para tal, realizou-se vários ensaios elencados a seguir. Determinou-se a CIM da amoxicilina para o S. agalactiae pelo método de macrodiluição. Quantificou-se por cromatografia líquida com detecção por espectrometria de massas sequencial a concentração plasmática da amoxicilina administrada via intramuscular em O. niloticus nas doses de 30 mg.kg-1 e 60 mg.kg-1. Avaliou-se o perfil de infecção sistêmica do S. agalatiae em O. niloticus submetidos a infecção experimental por administração de inóculo na bexiga natatória nas concentrações de 104 e105 UFC. Estes animais foram avaliados quanto.a contagem de UFC. mL-1 em ágar sangue seletivo para S. agalactiae para os órgãos cérebro, coração e soro. Avaliou-se a eficácia terapêutica da amoxicilina administrada via intramuscular para o S. agalactiae pela avaliação de 3 grupos: tratados com 30 mg.kg-1, tratadas com 60 mg.kg-1 e não tratadas. Para este ensaio, submeteu-se os peixes a infecção sistêmica com inóculo na concentração de 105 e o avaliou pela contagem de UFC. mL-1 para os órgãos cérebro, coração e soro. Realizou-se a avaliação do hemograma e bioquímica sérica de O. niloticus submetidas a infecção experimental em 2 grupos: tratadas com 30 mg.kg-1 e não tratadas. Avaliou-se também a segurança clínica da amoxicilina pela análise do hemograma, bioquímica sérica, índice somático do coração, fígado, rim e baço e histopatológico do fígado e rim em 3 grupos: dose terapêutica 30 mg.kg-1, 150 mg.kg-1 e 300 mg.kg-1. Determinou-se de fator toxicidade ambiental para O. niloticus, Lemna minor e Daphnia magna. Com os resultados, constatou-se que a cepa de S. agalactiae empregada neste estudo é sensível ao princípio ativo amoxicilina, com concentração oscilando de 0,09 a 0,18 µg mL-1. A curva plasmática da amoxicilina triidratada para as concentrações de 30 e 60 mg. Kg-1 permitiram o intervalo entre doses de 48 horas em 48 horas para ambas as concentrações. O modelo experimental de aplicação de inóculo de bacteriano S. agalactiae via bexiga natatória na concentração de 105 UFC.mL-1 induziu com eficácia estreptococose nas tilápias do Nilo apresentando progressão crescente da contagem de UFC.mL-1 para os órgãos avaliados, com maior isolamento no sétimo dia de avaliação. A administração das doses de 30 e 60 mg/kg de amoxicilina triidratada via intramuscular em O. niloticus desafiados com inóculos vivos de S.agalactiae mostraram-se igualmente eficazes para tratamento da infecção. Os peixes infectados por S. agalactiae e tratados com a dose 30 mg.kg-1 de amoxicilina não diferiram clinicamente entre si em decorrência de ambos os grupos estarem com a doença já instalada, no entanto peixes que não foram tratados apresentaram maior recrutamento de leucócitos e queda no número de trombócitos. A amoxicilina na concentração de 10 vezes a dose terapêutica mostrou-se segura clinicamente, não apresentando alterações em comparação ao padrão fisiológico. As espécies L. minor, D. magna e O. niloticus não demonstraram toxicidade para amoxicilina na concentração de 2,6g L-1 nas condições experimentais aplicadas. A administração de amoxicilina via intramuscular na dose de 30mg.Kg-1 mostrou-se promissora para tratamento de S. agalactie em O. niloticus.
The present study evaluated the therapeutic efficacy, clinical and ecotoxicological safety of amoxicillin trihydrate, administered through intramuscular (I.M.) route, for the tre atment of Streptococcus agalactiae in Oreochromis niloticus . To this end, the following tests were performed: MIC (minimal inhibitory concentration) of amoxicillin for S. agalactiae was determined by the macrodilution method. The plasma concentration of am oxicillin administered by I.M. route in O. niloticus at doses of 30 mg.kg - 1 and 60 mg.kg - 1 was quantified by liquid chromatography with sequential mass spectrometry detection. The profile of systemic infection of S. agalactiae in O. niloticus submitted t o experimental infection by the administration of 10 4 and 10 5 CFU inoculum in the swimming bladder was evaluated. These animals were evaluated for S. agalactiae infection by the counting of CFU mL - 1 in brain, heart and blood. The therapeutic efficacy of am oxicillin by I.M. route to S. agalactiae was evaluated in three groups: treated with 30 mg.kg - 1 , treated with 60 mg.kg - 1 and untreated (Control). For this assay, fish were subjected to systemic infection with inoculum at the concentration of 10 5 and evalua ted by the count CFU. mL - 1 in brain, heart, and blood. The hemogram and serum biochemistry of Nile tilapia submitted to experimental infection were evaluated in 2 groups: treated with 30 mg.kg - 1 and untreated. The clinical safety of amoxicillin was evaluat ed by hemogram, serum biochemistry, somatic index of the heart, liver, kidney and spleen and histopathology of liver and kidney in fish from three groups: therapeutic dose 30 mg.kg - 1 , 150 mg.kg - 1 and 300 mg.kg - 1 . Environmental toxicity factor was determin ed for O. niloticus , Lemna minor and Daphnia magna . The results showed that the S. agalactiae strain used in this study is sensitive to the active principle amoxicillin, with a concentration ranging from 0.09 to 0.18 μ g mL - 1 . The plasma curve of amoxicilli n trihydrate at concentrations of 30 and 60 mg. Kg - 1 allowed an interval of 48 h for both concentrations. The experimental model of bacterial inoculum application of S. agalactiae via the swimming bladder at the concentration of 10 5 CFU.mL - 1 effectively i nduced streptococci disease in Nile tilapia showing an progressive increase of CFU.mL - 1 counts in the evaluated organs, with isolation in the seventh day of evaluation. Administration of 30 and 60 mg. Kg - 1 doses of amoxicillin trihydrate by I.M. route in O . niloticus challenged with live S.agalactiae inoculum were equally effective. Fish infected with S. agalactiae and treated with the dose 30 mg.kg - 1 amoxicillin did not differ clinically as a result of both groups having the disease already installed, howe ver fish that were not treated showed higher leukocyte recruitment and fall in the number of thrombocytes. Amoxicillin, even at a concentration of 10 times the therapeutic dose, demonstrated to be clinically safety for tilapias, with no alterations in the tests performed in comparison to the physiological standard fish. Amoxicillin in the concentration of 2.6 g.L - 1 showed low toxicity for L. minor , D. magna and O. niloticus under the experimental conditions applied. Amoxicillin at the dose of 30mg.Kg - 1 admi nistered by I.M. route in O. niloticus presented promising results for the treatment of S. agalactiae
The present study evaluated the therapeutic efficacy, clinical and ecotoxicological safety of amoxicillin trihydrate, administered through intramuscular (I.M.) route, for the tre atment of Streptococcus agalactiae in Oreochromis niloticus . To this end, the following tests were performed: MIC (minimal inhibitory concentration) of amoxicillin for S. agalactiae was determined by the macrodilution method. The plasma concentration of am oxicillin administered by I.M. route in O. niloticus at doses of 30 mg.kg - 1 and 60 mg.kg - 1 was quantified by liquid chromatography with sequential mass spectrometry detection. The profile of systemic infection of S. agalactiae in O. niloticus submitted t o experimental infection by the administration of 10 4 and 10 5 CFU inoculum in the swimming bladder was evaluated. These animals were evaluated for S. agalactiae infection by the counting of CFU mL - 1 in brain, heart and blood. The therapeutic efficacy of am oxicillin by I.M. route to S. agalactiae was evaluated in three groups: treated with 30 mg.kg - 1 , treated with 60 mg.kg - 1 and untreated (Control). For this assay, fish were subjected to systemic infection with inoculum at the concentration of 10 5 and evalua ted by the count CFU. mL - 1 in brain, heart, and blood. The hemogram and serum biochemistry of Nile tilapia submitted to experimental infection were evaluated in 2 groups: treated with 30 mg.kg - 1 and untreated. The clinical safety of amoxicillin was evaluat ed by hemogram, serum biochemistry, somatic index of the heart, liver, kidney and spleen and histopathology of liver and kidney in fish from three groups: therapeutic dose 30 mg.kg - 1 , 150 mg.kg - 1 and 300 mg.kg - 1 . Environmental toxicity factor was determin ed for O. niloticus , Lemna minor and Daphnia magna . The results showed that the S. agalactiae strain used in this study is sensitive to the active principle amoxicillin, with a concentration ranging from 0.09 to 0.18 μ g mL - 1 . The plasma curve of amoxicilli n trihydrate at concentrations of 30 and 60 mg. Kg - 1 allowed an interval of 48 h for both concentrations. The experimental model of bacterial inoculum application of S. agalactiae via the swimming bladder at the concentration of 10 5 CFU.mL - 1 effectively i nduced streptococci disease in Nile tilapia showing an progressive increase of CFU.mL - 1 counts in the evaluated organs, with isolation in the seventh day of evaluation. Administration of 30 and 60 mg. Kg - 1 doses of amoxicillin trihydrate by I.M. route in O . niloticus challenged with live S.agalactiae inoculum were equally effective. Fish infected with S. agalactiae and treated with the dose 30 mg.kg - 1 amoxicillin did not differ clinically as a result of both groups having the disease already installed, howe ver fish that were not treated showed higher leukocyte recruitment and fall in the number of thrombocytes. Amoxicillin, even at a concentration of 10 times the therapeutic dose, demonstrated to be clinically safety for tilapias, with no alterations in the tests performed in comparison to the physiological standard fish. Amoxicillin in the concentration of 2.6 g.L - 1 showed low toxicity for L. minor , D. magna and O. niloticus under the experimental conditions applied. Amoxicillin at the dose of 30mg.Kg - 1 admi nistered by I.M. route in O. niloticus presented promising results for the treatment of S. agalactiae
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Palavras-chave
Aquicultura, Tilapicultura, LC-MS/MS, CIM, Streptococcus agalactiae, Antimicrobiano