Food animals may serve as a reservoir of bacteria that carry antimicrobial resistance genes that ... more Food animals may serve as a reservoir of bacteria that carry antimicrobial resistance genes that may be transferred to microorganisms found in humans and thereby limit the medical value of antimicrobials. In contrast to Escherichia coli from humans and several other animal species, there is little information on the frequency and mechanisms of antimicrobial resistance of that bacteria isolated from rabbits. The objective of the present study was to determine the antimicrobial resistance profile of 478 Escherichia coli isolates from healthy rabbits. Another objective was to assess the diversity and distribution of the major resistance genes [tetA, tetB, tetC, and tetM for doxycycline, bla(TEM), bla(OXA-1), bla(SHV), and bla(CTX-M-9) for amoxicillin, aac(3)II, aac(3)IV, and ant(2")I for gentamicin, and qnrA, qnrB, qnrS, aaC(6)Ib, and qepA for enrofloxacin], as well as the mutations in the quinolone resistance-determining region of the gyrA and parC genes, in these isolates. The p...
It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial ... more It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial species, including Salmonella typhimurium. In this study it has been shown that the intracellular concentration of cyclic AMP (cAMP) is lower in a knockout S. typhimurium fur mutant than in the wild-type strain. According to this, the expression of two cAMP-regulated genes, such as pepE (encoding an alpha-aspartyl dipeptidase) and the Escherichia coli lac operon, is decreased in S. typhimurium fur cells in comparison with wild-type cells. Introduction of an additional mutation in cpdA, encoding a cyclic 3',5'-cAMP phosphodiesterase, recovers wild-type intracellular cAMP concentration in the S. typhimurium fur mutant. Likewise, expression of pepE and the E. coli lac operon was the same in the S. typhimurium fur cpdA double mutant and the wild-type strain. Moreover, these results also demonstrate that the S. typhimurium Fur protein positively regulates the expression of the flhD ma...
Iron-dependent outer membrane proteins (IROMPs) play an important role in bacterial pathogenesis ... more Iron-dependent outer membrane proteins (IROMPs) play an important role in bacterial pathogenesis and present several attributes of potential vaccine candidates. TBLASTN analysis of the Pasteurella multocida Pm70 genome using the same molecules of other bacterial pathogens as a query identified eight putative haemin and haemoglobin receptors for this organism. Quantitative binding assays have demonstrated that the proteins PM0040, PM0236, PM0741, PM1081, PM1428, PM0592 and HgbA bind both haemin and haemoglobin, whereas PM0576 and PM1282 ORFs only bind either haemoglobin or haemin, respectively. Furthermore, Western blot analysis showed that P. multocida-infected mice generate specific antibodies against PM0040, PM0236, PM0741, PM1081, PM1428, PM0592 and HgbA proteins. Nevertheless, inoculation of mice with any single one of these receptors alone did not protect against P. multocida infection.
Haemophilus parasuis is a member of the family Pasteurellaceae and an important respiratory-tract... more Haemophilus parasuis is a member of the family Pasteurellaceae and an important respiratory-tract pathogen of swine, which is the etiological agent of Glasser's disease. Because no genetic manipulation system is available for H. parasuis so far, in vivo studies about the role of its genes involved in virulence are unfeasible. Here we demonstrate that H. parasuis has a cyclic AMP (cAMP)-dependent natural transformation system that enables the uptake of DNA in which the ACCGAACTC sequence signal must be present. After improving DNA transformation parameters, such as cAMP and DNA concentration and exposition time of the exogenous DNA, a knockout mutant of H. parasuis defective in the thy gene, encoding the thymidylate synthase enzyme, has been constructed. Data presented in this work open the possibility for the functional analysis of genes involved in the infectious process of this animal pathogen.
Haemophilus parasuis is a colonizer of the upper respiratory tract and the causative agent of Glä... more Haemophilus parasuis is a colonizer of the upper respiratory tract and the causative agent of Glässer's disease in swine. This study focused on the nasal carriage of H. parasuis after treatment with marbofloxacin. Three marbofloxacin treatments (three doses of 2mg/kg body weight [bw] every 24h, two doses of 4 mg/kg bw every 48 h and 8 mg/kg bw in one single shot) were used and all of them reduce significantly (p<0.05) the nasal carriage of H. parasuis as compared to control animals. Moreover, H. parasuis was not detected in the nasal cavities of piglets after administering the highest dose. The effect of a dose of 8 mg marbofloxacin/kg bw in one shot was further studied in a farm with clinical cases of Glässer's disease using a longitudinal study. Statistically significant reduction of nasal carriage of H. parasuis was detected during the first week after treatment in comparison with the control group. However, a clear relationship between the minimum inhibitory concentration (MIC) of the different strains, their putative virulence or the treatment group (antibiotic or control) from which they were isolated was not detected. Finally, the effect induced by the antibiotic treatment on the bacterial strains seemed to be transitory, since diverse H. parasuis strains (with high and low marbofloxacin MICs) were observed 7 days after finishing the treatment.
The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits,... more The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits, intestinal microbiota and performance was studied in weaned rabbits. A control diet (DA) containing 103 g NDSF/kg DM included dehydrated alfalfa as the main source of fibre. Another diet (B-AP) was formulated by replacing half of the dehydrated alfalfa with a mixture of beet and apple pulp resulting
3 Departamento de Histología de la Facultad de Veterinaria de la Universidad de Zaragoza. 4 Depar... more 3 Departamento de Histología de la Facultad de Veterinaria de la Universidad de Zaragoza. 4 Departamento de Producción Animal de la Universidad Politécnica de Madrid. 5 Departamento de Ciencia Animal de la Universidad Politécnica de Valencia. 6 ...
Resumen La utilización de los antimicrobianos en producción animal, ha supuesto un gran avance en... more Resumen La utilización de los antimicrobianos en producción animal, ha supuesto un gran avance en la reducción de los problemas infecciosos de los animales que se utilizan como fuente fundamental de proteína de origen animal. Esta reducción de los problemas ...
El objetivo del presente trabajo fue el de estudiar el efecto de una variación en el nivel y tipo... more El objetivo del presente trabajo fue el de estudiar el efecto de una variación en el nivel y tipo de pro-teína, para provocar una reducción del flujo ileal, sobre los parámetros digestivos, productivos y mortalidad en gazapos destetados a 25 días. Para cumplir con este objetivo se ...
Food animals may serve as a reservoir of bacteria that carry antimicrobial resistance genes that ... more Food animals may serve as a reservoir of bacteria that carry antimicrobial resistance genes that may be transferred to microorganisms found in humans and thereby limit the medical value of antimicrobials. In contrast to Escherichia coli from humans and several other animal species, there is little information on the frequency and mechanisms of antimicrobial resistance of that bacteria isolated from rabbits. The objective of the present study was to determine the antimicrobial resistance profile of 478 Escherichia coli isolates from healthy rabbits. Another objective was to assess the diversity and distribution of the major resistance genes [tetA, tetB, tetC, and tetM for doxycycline, bla(TEM), bla(OXA-1), bla(SHV), and bla(CTX-M-9) for amoxicillin, aac(3)II, aac(3)IV, and ant(2")I for gentamicin, and qnrA, qnrB, qnrS, aaC(6)Ib, and qepA for enrofloxacin], as well as the mutations in the quinolone resistance-determining region of the gyrA and parC genes, in these isolates. The p...
It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial ... more It is known that the Fur protein negatively regulates iron-uptake systems in different bacterial species, including Salmonella typhimurium. In this study it has been shown that the intracellular concentration of cyclic AMP (cAMP) is lower in a knockout S. typhimurium fur mutant than in the wild-type strain. According to this, the expression of two cAMP-regulated genes, such as pepE (encoding an alpha-aspartyl dipeptidase) and the Escherichia coli lac operon, is decreased in S. typhimurium fur cells in comparison with wild-type cells. Introduction of an additional mutation in cpdA, encoding a cyclic 3',5'-cAMP phosphodiesterase, recovers wild-type intracellular cAMP concentration in the S. typhimurium fur mutant. Likewise, expression of pepE and the E. coli lac operon was the same in the S. typhimurium fur cpdA double mutant and the wild-type strain. Moreover, these results also demonstrate that the S. typhimurium Fur protein positively regulates the expression of the flhD ma...
Iron-dependent outer membrane proteins (IROMPs) play an important role in bacterial pathogenesis ... more Iron-dependent outer membrane proteins (IROMPs) play an important role in bacterial pathogenesis and present several attributes of potential vaccine candidates. TBLASTN analysis of the Pasteurella multocida Pm70 genome using the same molecules of other bacterial pathogens as a query identified eight putative haemin and haemoglobin receptors for this organism. Quantitative binding assays have demonstrated that the proteins PM0040, PM0236, PM0741, PM1081, PM1428, PM0592 and HgbA bind both haemin and haemoglobin, whereas PM0576 and PM1282 ORFs only bind either haemoglobin or haemin, respectively. Furthermore, Western blot analysis showed that P. multocida-infected mice generate specific antibodies against PM0040, PM0236, PM0741, PM1081, PM1428, PM0592 and HgbA proteins. Nevertheless, inoculation of mice with any single one of these receptors alone did not protect against P. multocida infection.
Haemophilus parasuis is a member of the family Pasteurellaceae and an important respiratory-tract... more Haemophilus parasuis is a member of the family Pasteurellaceae and an important respiratory-tract pathogen of swine, which is the etiological agent of Glasser's disease. Because no genetic manipulation system is available for H. parasuis so far, in vivo studies about the role of its genes involved in virulence are unfeasible. Here we demonstrate that H. parasuis has a cyclic AMP (cAMP)-dependent natural transformation system that enables the uptake of DNA in which the ACCGAACTC sequence signal must be present. After improving DNA transformation parameters, such as cAMP and DNA concentration and exposition time of the exogenous DNA, a knockout mutant of H. parasuis defective in the thy gene, encoding the thymidylate synthase enzyme, has been constructed. Data presented in this work open the possibility for the functional analysis of genes involved in the infectious process of this animal pathogen.
Haemophilus parasuis is a colonizer of the upper respiratory tract and the causative agent of Glä... more Haemophilus parasuis is a colonizer of the upper respiratory tract and the causative agent of Glässer's disease in swine. This study focused on the nasal carriage of H. parasuis after treatment with marbofloxacin. Three marbofloxacin treatments (three doses of 2mg/kg body weight [bw] every 24h, two doses of 4 mg/kg bw every 48 h and 8 mg/kg bw in one single shot) were used and all of them reduce significantly (p<0.05) the nasal carriage of H. parasuis as compared to control animals. Moreover, H. parasuis was not detected in the nasal cavities of piglets after administering the highest dose. The effect of a dose of 8 mg marbofloxacin/kg bw in one shot was further studied in a farm with clinical cases of Glässer's disease using a longitudinal study. Statistically significant reduction of nasal carriage of H. parasuis was detected during the first week after treatment in comparison with the control group. However, a clear relationship between the minimum inhibitory concentration (MIC) of the different strains, their putative virulence or the treatment group (antibiotic or control) from which they were isolated was not detected. Finally, the effect induced by the antibiotic treatment on the bacterial strains seemed to be transitory, since diverse H. parasuis strains (with high and low marbofloxacin MICs) were observed 7 days after finishing the treatment.
The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits,... more The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits, intestinal microbiota and performance was studied in weaned rabbits. A control diet (DA) containing 103 g NDSF/kg DM included dehydrated alfalfa as the main source of fibre. Another diet (B-AP) was formulated by replacing half of the dehydrated alfalfa with a mixture of beet and apple pulp resulting
3 Departamento de Histología de la Facultad de Veterinaria de la Universidad de Zaragoza. 4 Depar... more 3 Departamento de Histología de la Facultad de Veterinaria de la Universidad de Zaragoza. 4 Departamento de Producción Animal de la Universidad Politécnica de Madrid. 5 Departamento de Ciencia Animal de la Universidad Politécnica de Valencia. 6 ...
Resumen La utilización de los antimicrobianos en producción animal, ha supuesto un gran avance en... more Resumen La utilización de los antimicrobianos en producción animal, ha supuesto un gran avance en la reducción de los problemas infecciosos de los animales que se utilizan como fuente fundamental de proteína de origen animal. Esta reducción de los problemas ...
El objetivo del presente trabajo fue el de estudiar el efecto de una variación en el nivel y tipo... more El objetivo del presente trabajo fue el de estudiar el efecto de una variación en el nivel y tipo de pro-teína, para provocar una reducción del flujo ileal, sobre los parámetros digestivos, productivos y mortalidad en gazapos destetados a 25 días. Para cumplir con este objetivo se ...
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