Los dispositivos intravaginales (DIV) con 300 mg de progesterona (P4) pueden reutilizarse en los ... more Los dispositivos intravaginales (DIV) con 300 mg de progesterona (P4) pueden reutilizarse en los protocolos de sincronización en ovinos con una duración de hasta 7 días. La reutilización de DIV con menor concentración hormonal, así como estudios far- maco-cinéticos a través del análisis no compartimental de las concentraciones hormonales luego de la colocación de dispositivos de 1° o 2° uso no han sido descriptos previamente. El objetivo del presente trabajo fue evaluar la utilización y reutilización de dispositivos intrava- ginales con una concentración inicial de 160 mg de P4. Para ello se utilizaron 20 ovejas que conformaron cinco grupos: control (sin DIV), CIDN (DIV 300 mg P4 1° uso), CIDU (DIV 300 mg P4 2° uso), CRON (DIV 160 mg P4 1° uso) y CROU (DIV 300 mg P4 2° uso). Las valoraciones séricas hormonales se realizaron a través de radioinmunoensayo. La concentración máxima y el tiempo medio de residencia fueron similares entre CIDN Y CRON, en cambio CIDU presentó una concentrac...
Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompat... more Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompatibility and osteo-inductive behaviour. The generation of mesoporous bioactive glass (nano) particles adds a high surface area for the dissolution and release of bioactive ions, and the possibility to load them with different drugs for antibacterial purposes. Essential oils (EO) are an interesting resource for alternative medical therapy, providing antimicrobial compounds that come from organic/natural resources like aromatic plants. Also, a biological polymer, such as chitosan, could be used to control the release of active agents from mesoporous bioactive glass (MBG) loaded particles. This work presents MBG particles with nominal composition (in mol) 60% SiO2, 30% CaO and 10% P2O5, loaded with essential oil of Melaleuca armillaris, which contains 1,8-cineol as the main active component, with an inhibitory in vitro activity against several bacterial species. Also, co-loading with a broad...
Staphylococcus aureus frequently causes subclinical mastitis around the world with a high impact ... more Staphylococcus aureus frequently causes subclinical mastitis around the world with a high impact on the milk industry and public health. Essential oils (EO) are recognized antimicrobials that can be synergistic with antibiotics. The main objective of this study was to evaluate the essential oil (EO) of Melaleuca armillaris as an adjuvant of erythromycin (ERY) for the alternative treatment of bovine mastitis caused by S. aureus. The Minimum Inhibitory and Bactericidal Concentrations (MIC and MBC) of EO, ERY, and its combinations were established against S. aureus at different pHs (7.4, 6.5 and 5.0), emulating extra and intracellular conditions. Sensitive (N = 3) and resistant (N = 3) strains to ERY and S. aureus ATCC 29213 as control were used. Math models were applied to describe the antibacterial activity of EO and combinations EO-ERY. The EO was bactericidal against all the strains independently of the pH with a slight improvement in acid conditions. The synergism between EO and E...
Control measures are being introduced globally to reduce the prevalence of antibiotic resistant (... more Control measures are being introduced globally to reduce the prevalence of antibiotic resistant (ABR) bacteria on farms. However, little is known about the current prevalence and molecular ecology of ABR in key opportunistic human pathogens such asEscherichia colion South American farms. Working with 30 dairy cattle farms and 40 pig farms across two provinces in central-eastern Argentina, we report a comprehensive genomic analysis of third-generation cephalosporin resistance (3GC-R) inE. coli. 3GC-R isolates were recovered from 34.8% (cattle) and 47.8% (pigs) of samples from faecally contaminated sites. Phylogenetic analysis revealed substantial diversity suggestive of long-term horizontal transmission of 3GC-R mechanisms. Despite this, mechanisms such as CTX-M-15 and CTX-M-2 were detected more often in dairy farms, while CTX-M-8 and CMY-2, and co-carriage of amoxicillin/clavulanate resistance and florfenicol resistance were more commonly detected in pig farms. This suggests differe...
Staphylococcus aureus frequently causes subclinical mastitis around the world with high impact in... more Staphylococcus aureus frequently causes subclinical mastitis around the world with high impact in milk industry and public health. Essential oils (EO) are recognized antimicrobials that can be synergistic with antibiotics. The main objective of this study was evaluating the essential oil (EO) of Melaleuca armillaris as an adjuvant of erythromycin (ERY) for the alternative treatment of bovine mastitis caused by S. aureus. The Minimum Inhibitory and Bactericidal Concentrations (MIC and MBC) of EO, ERY, and its combinations were established against S. aureus at different pHs (7.4, 6.5 and 5.0), emulating extra and intracellular conditions. Sensible (N=3) and resistant (N=3) strains to ERY and S. aureus ATCC 29213 as control were used. Math models were applied to described the antibacterial activity of EO and combinations EO-ERY. The EO was bactericidal against all the strains independently of the pH with a slightly improvement in acid conditions. The synergism between EO and ERY was es...
The aim of this study was to determine imidacloprid's lethal activity against fifth-instar nymphs... more The aim of this study was to determine imidacloprid's lethal activity against fifth-instar nymphs of Triatoma infestans. In the first stage of this work, it was assayed the topical application of this insecticide on non-fed and repletion-fed nymphs. Results showed a DL 50 three times greater in non-fed bugs than in those fully engorged. The presence of food determined less time for the insecticide's maximum lethal effect: 24 h post topical application in fed nymphs and 72 h in non-fed nymphs. In the study's second stage, we assayed a xenointoxication assay on dogs. The commercial products, Advantage®, Bayer (imidacloprid 10 % p/v) and Power Ultra®, Brouwer (imidacloprid 5.15 %, permethrin 40 % and piperonyl butoxide [PBO] 3%) were evaluated. Following administration of the insecticide, nymphs were fed on dogs 24, 72, 168, 240 and 336 h. Blood intake was similar in nymphs exposed to treated dogs versus controls. Although both commercial products showed low triatomicidal activity, a higher efficacy of the product combining imidacloprid with the synergist piperonyl butoxide and permethrin versus the product with imidacloprid as the only active ingredient was observed, causing in nymphs a mortality rate of 36.3 % and 20.7 %, respectively. Our results suggest that imidacloprid, alone or in combination with permethrin and PBO, is not an alternative for control of T. infestans.
El objetivo principal de esta Tesis Doctoral fue evaluar la capacidad del aceite esencial (AE) de... more El objetivo principal de esta Tesis Doctoral fue evaluar la capacidad del aceite esencial (AE) de Melaleuca armillaris de actuar como coadyuvante de antimicrobianos utilizados en el tratamiento de la mastitis bovina por Staphylococcus aureus, en busca de una alternativa más eficaz frente a infecciones de difícil resolución. El AE fue obtenido de plantas cultivadas en la provincia de Buenos Aires. Se caracterizó fisicoquímicamente para establecer parámetros de calidad, presentando 1.8 cineol (72.3%), limoneno (7.8%) y alfa-pineno (6%) como componentes principales. Se determinaron las Concentraciones Inhibitoria y Bactericida Mínimas (CIM y CBM) del AE y de cloxacilina, eritromicina y rifaximina, frente a S. aureus a diferentes pHs (7.4; 6.5 y 5.0), emulando condiciones extra e intracelulares. Utilizamos cepas sensibles a los 3 antimicrobianos, resistentes a eritromicina, una cepa meticilino resistente (SARM) y S. aureus ATCC 29213 como control. El sinergismo entre el AE y los antimic...
Azaperona es un tranquilizante de tipo butirofenona usado en ganado porcino. Los cerdos son parti... more Azaperona es un tranquilizante de tipo butirofenona usado en ganado porcino. Los cerdos son particularmente sensibles al estres durante el manejo y transporte al matadero. La azaperona es parcialmente metabolizada in vivo a azaperol, un metabolito con actividad farmacologica. Las concentraciones altas y persistentes de azaperona y azaperol en el lugar de inyeccion contraindican el uso de azaperona por via intramuscular para el transporte de cerdos de produccion de carne al matadero; el uso oral podria ser una alternativa para evitar residuos en el lugar de inyeccion. El presente estudio determino la deplecion en los tejidos de azaperona y su metabolito azaperol despues de la administracion oral de la formulacion Stresnil®. Cerdos machos (30-45 kg de peso corporal) fueron tratados con Stresnil® (dosis oral unica de 4 mg azaperona/kg de peso corporal) y se sacrificaron 6, 24 y 48 horas despues de la administracion. De cada animal se obtuvo musculo, piel + grasa, higado y rinon. Azaper...
Los dispositivos intravaginales (DIV) con 300 mg de progesterona (P4) pueden reutilizarse en los ... more Los dispositivos intravaginales (DIV) con 300 mg de progesterona (P4) pueden reutilizarse en los protocolos de sincronización en ovinos con una duración de hasta 7 días. La reutilización de DIV con menor concentración hormonal, así como estudios far- maco-cinéticos a través del análisis no compartimental de las concentraciones hormonales luego de la colocación de dispositivos de 1° o 2° uso no han sido descriptos previamente. El objetivo del presente trabajo fue evaluar la utilización y reutilización de dispositivos intrava- ginales con una concentración inicial de 160 mg de P4. Para ello se utilizaron 20 ovejas que conformaron cinco grupos: control (sin DIV), CIDN (DIV 300 mg P4 1° uso), CIDU (DIV 300 mg P4 2° uso), CRON (DIV 160 mg P4 1° uso) y CROU (DIV 300 mg P4 2° uso). Las valoraciones séricas hormonales se realizaron a través de radioinmunoensayo. La concentración máxima y el tiempo medio de residencia fueron similares entre CIDN Y CRON, en cambio CIDU presentó una concentrac...
Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompat... more Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompatibility and osteo-inductive behaviour. The generation of mesoporous bioactive glass (nano) particles adds a high surface area for the dissolution and release of bioactive ions, and the possibility to load them with different drugs for antibacterial purposes. Essential oils (EO) are an interesting resource for alternative medical therapy, providing antimicrobial compounds that come from organic/natural resources like aromatic plants. Also, a biological polymer, such as chitosan, could be used to control the release of active agents from mesoporous bioactive glass (MBG) loaded particles. This work presents MBG particles with nominal composition (in mol) 60% SiO2, 30% CaO and 10% P2O5, loaded with essential oil of Melaleuca armillaris, which contains 1,8-cineol as the main active component, with an inhibitory in vitro activity against several bacterial species. Also, co-loading with a broad...
Staphylococcus aureus frequently causes subclinical mastitis around the world with a high impact ... more Staphylococcus aureus frequently causes subclinical mastitis around the world with a high impact on the milk industry and public health. Essential oils (EO) are recognized antimicrobials that can be synergistic with antibiotics. The main objective of this study was to evaluate the essential oil (EO) of Melaleuca armillaris as an adjuvant of erythromycin (ERY) for the alternative treatment of bovine mastitis caused by S. aureus. The Minimum Inhibitory and Bactericidal Concentrations (MIC and MBC) of EO, ERY, and its combinations were established against S. aureus at different pHs (7.4, 6.5 and 5.0), emulating extra and intracellular conditions. Sensitive (N = 3) and resistant (N = 3) strains to ERY and S. aureus ATCC 29213 as control were used. Math models were applied to describe the antibacterial activity of EO and combinations EO-ERY. The EO was bactericidal against all the strains independently of the pH with a slight improvement in acid conditions. The synergism between EO and E...
Control measures are being introduced globally to reduce the prevalence of antibiotic resistant (... more Control measures are being introduced globally to reduce the prevalence of antibiotic resistant (ABR) bacteria on farms. However, little is known about the current prevalence and molecular ecology of ABR in key opportunistic human pathogens such asEscherichia colion South American farms. Working with 30 dairy cattle farms and 40 pig farms across two provinces in central-eastern Argentina, we report a comprehensive genomic analysis of third-generation cephalosporin resistance (3GC-R) inE. coli. 3GC-R isolates were recovered from 34.8% (cattle) and 47.8% (pigs) of samples from faecally contaminated sites. Phylogenetic analysis revealed substantial diversity suggestive of long-term horizontal transmission of 3GC-R mechanisms. Despite this, mechanisms such as CTX-M-15 and CTX-M-2 were detected more often in dairy farms, while CTX-M-8 and CMY-2, and co-carriage of amoxicillin/clavulanate resistance and florfenicol resistance were more commonly detected in pig farms. This suggests differe...
Staphylococcus aureus frequently causes subclinical mastitis around the world with high impact in... more Staphylococcus aureus frequently causes subclinical mastitis around the world with high impact in milk industry and public health. Essential oils (EO) are recognized antimicrobials that can be synergistic with antibiotics. The main objective of this study was evaluating the essential oil (EO) of Melaleuca armillaris as an adjuvant of erythromycin (ERY) for the alternative treatment of bovine mastitis caused by S. aureus. The Minimum Inhibitory and Bactericidal Concentrations (MIC and MBC) of EO, ERY, and its combinations were established against S. aureus at different pHs (7.4, 6.5 and 5.0), emulating extra and intracellular conditions. Sensible (N=3) and resistant (N=3) strains to ERY and S. aureus ATCC 29213 as control were used. Math models were applied to described the antibacterial activity of EO and combinations EO-ERY. The EO was bactericidal against all the strains independently of the pH with a slightly improvement in acid conditions. The synergism between EO and ERY was es...
The aim of this study was to determine imidacloprid's lethal activity against fifth-instar nymphs... more The aim of this study was to determine imidacloprid's lethal activity against fifth-instar nymphs of Triatoma infestans. In the first stage of this work, it was assayed the topical application of this insecticide on non-fed and repletion-fed nymphs. Results showed a DL 50 three times greater in non-fed bugs than in those fully engorged. The presence of food determined less time for the insecticide's maximum lethal effect: 24 h post topical application in fed nymphs and 72 h in non-fed nymphs. In the study's second stage, we assayed a xenointoxication assay on dogs. The commercial products, Advantage®, Bayer (imidacloprid 10 % p/v) and Power Ultra®, Brouwer (imidacloprid 5.15 %, permethrin 40 % and piperonyl butoxide [PBO] 3%) were evaluated. Following administration of the insecticide, nymphs were fed on dogs 24, 72, 168, 240 and 336 h. Blood intake was similar in nymphs exposed to treated dogs versus controls. Although both commercial products showed low triatomicidal activity, a higher efficacy of the product combining imidacloprid with the synergist piperonyl butoxide and permethrin versus the product with imidacloprid as the only active ingredient was observed, causing in nymphs a mortality rate of 36.3 % and 20.7 %, respectively. Our results suggest that imidacloprid, alone or in combination with permethrin and PBO, is not an alternative for control of T. infestans.
El objetivo principal de esta Tesis Doctoral fue evaluar la capacidad del aceite esencial (AE) de... more El objetivo principal de esta Tesis Doctoral fue evaluar la capacidad del aceite esencial (AE) de Melaleuca armillaris de actuar como coadyuvante de antimicrobianos utilizados en el tratamiento de la mastitis bovina por Staphylococcus aureus, en busca de una alternativa más eficaz frente a infecciones de difícil resolución. El AE fue obtenido de plantas cultivadas en la provincia de Buenos Aires. Se caracterizó fisicoquímicamente para establecer parámetros de calidad, presentando 1.8 cineol (72.3%), limoneno (7.8%) y alfa-pineno (6%) como componentes principales. Se determinaron las Concentraciones Inhibitoria y Bactericida Mínimas (CIM y CBM) del AE y de cloxacilina, eritromicina y rifaximina, frente a S. aureus a diferentes pHs (7.4; 6.5 y 5.0), emulando condiciones extra e intracelulares. Utilizamos cepas sensibles a los 3 antimicrobianos, resistentes a eritromicina, una cepa meticilino resistente (SARM) y S. aureus ATCC 29213 como control. El sinergismo entre el AE y los antimic...
Azaperona es un tranquilizante de tipo butirofenona usado en ganado porcino. Los cerdos son parti... more Azaperona es un tranquilizante de tipo butirofenona usado en ganado porcino. Los cerdos son particularmente sensibles al estres durante el manejo y transporte al matadero. La azaperona es parcialmente metabolizada in vivo a azaperol, un metabolito con actividad farmacologica. Las concentraciones altas y persistentes de azaperona y azaperol en el lugar de inyeccion contraindican el uso de azaperona por via intramuscular para el transporte de cerdos de produccion de carne al matadero; el uso oral podria ser una alternativa para evitar residuos en el lugar de inyeccion. El presente estudio determino la deplecion en los tejidos de azaperona y su metabolito azaperol despues de la administracion oral de la formulacion Stresnil®. Cerdos machos (30-45 kg de peso corporal) fueron tratados con Stresnil® (dosis oral unica de 4 mg azaperona/kg de peso corporal) y se sacrificaron 6, 24 y 48 horas despues de la administracion. De cada animal se obtuvo musculo, piel + grasa, higado y rinon. Azaper...
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