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Research paper thumbnail of Development and evaluation of combined PCRs for detecting Salmonella in swine lymph nodes

XIV Jordanas Sobre Produccion Animal, Zaragoza, Espana, 17 y 18 de Mayo de 2011., 2011

... Conference, Jornadas sobre Producción Animal, 14., Zaragoza (España), 17-18 May 2011. Publish... more ... Conference, Jornadas sobre Producción Animal, 14., Zaragoza (España), 17-18 May 2011. Publisher, AIDA, Zaragoza (España). ... ISBN, 978-84-615-0062-8. Full-text, http://s346050484. mialojamiento.es/aida-itea/TOMO%202%20Jornadas%20AIDA%20XIV.pdf. Notes, 1 tabla, 5 ...

Research paper thumbnail of Simultaneous infections by different Salmonellastrains in mesenteric lymph nodes of finishing pigs

BMC Veterinary Research, Mar 7, 2014

Background: Salmonellosis is a major worldwide zoonosis, and Salmonella-infected finishing pigs a... more Background: Salmonellosis is a major worldwide zoonosis, and Salmonella-infected finishing pigs are considered one of the major sources of human infections in developed countries. Baseline studies on salmonellosis prevalence in fattening pigs in Europe are based on direct pathogen isolation from mesenteric lymph nodes (MLN). This procedure is considered the most reliable for diagnosing salmonellosis in apparently healthy pigs. The presence of simultaneous infections by different Salmonella strains in the same animal has never been reported and could have important epidemiological implications. Results: Fourteen finishing pigs belonging to 14 farms that showed high salmonellosis prevalence and a variety of circulating Salmonella strains, were found infected by Salmonella spp, and 7 of them were simultaneously infected with strains of 2 or 3 different serotypes. Typhimurium isolates showing resistance to several antimicrobials and carrying mobile integrons were the most frequently identified in the colonized MLN. Four animals were found infected by Salmonella spp. of a single serotype (Rissen or Derby) but showing 2 or 3 different antimicrobial resistance profiles, without evidence of mobile genetic element exchange in vivo. Conclusion: This is the first report clearly demonstrating that pigs naturally infected by Salmonella may harbour different Salmonella strains simultaneously. This may have implications in the interpretation of results from baseline studies, and also help to better understand human salmonellosis outbreaks and the horizontal transmission of antimicrobial resistance genes.

Research paper thumbnail of <i>Salmonella</i> Infection in Mesenteric Lymph Nodes of Breeding Sows

Foodborne Pathogens and Disease, Jun 1, 2020

Salmonellosis is one of the main foodborne diseases worldwide. Breeding sows asymptomatically inf... more Salmonellosis is one of the main foodborne diseases worldwide. Breeding sows asymptomatically infected with Salmonella can transmit the pathogen to piglets and humans. The isolation of Salmonella from mesenteric lymph nodes (MLNs) is considered a demonstration of asymptomatic infection in swine. As previous breeding sow studies have been performed using feces, the aim of this work was to study the occurrence of Salmonella infections by sampling MLNs, in comparison to their serological status. First, Salmonella fecal shedding was studied in 12/16 large breeding farms to establish the framework of study. Then, MLN (n = 264) and blood (n = 237) samples were obtained at an abattoir from sows of 15 of these 16 breeding farms. Additionally, risk factors associated with Salmonella MLN infection were analyzed. A total of 6.1% (16/264) sows, distributed in 40% (6/15) of the farms, had the pathogen in MLN. Salmonella Typhimurium was the most frequent serovar isolated. Interestingly, 43.8% (7/16) of MLN isolates were susceptible to all the antimicrobials tested and were found distributed throughout all farms with at least one sow positive. As well, one isolate of the emerging DT195 clone was detected and found to be resistant to six antibiotic families (ASSuTNx-Cfx). The serovars and the resistance profiles of the Salmonella isolates from feces were completely different to those obtained from MLNs. The seroprevalence (41.8% of sows and 100% of farms) was higher than that of MLN infections, showing no concordance (k = 0.15) between these two diagnostic tests in sows. Strategies directed to correct two risk factors (i.e., administration of dry food and old premises) would most likely help to reduce Salmonella infections in breeding sows.

Research paper thumbnail of Serotypes and multidrug-resistance profiles of Salmonellae isolated from pigs infected simultaneously with various strains

Poster presentado en el 4th Symposium on Antimicrobial Resistance in Animals and the Environment ... more Poster presentado en el 4th Symposium on Antimicrobial Resistance in Animals and the Environment celebrado en Tours-Vinci del 27 al 29 de junio de 2011.

Research paper thumbnail of Relationship between Salmonella infection, shedding and serology in fattening pigs in low–moderate prevalence areas

Zoonoses and Public Health, 2018

SummarySalmonella is a major foodborne pathogen causing important zoonosis worldwide. Pigs asympt... more SummarySalmonella is a major foodborne pathogen causing important zoonosis worldwide. Pigs asymptomatically infected in mesenteric lymph nodes (MLN) can be intermittent shedders of the pathogen through faeces, being considered a major source of human infections. European baseline studies of fattening pig salmonellosis are based on Salmonella detection in MLN. This work studies the relationship between Salmonella infection in MLN and intestinal content (IC) shedding at slaughter and the relationship between the presence of the pathogen and the serologic status at farm level. Mean Salmonella prevalence in the selected pigs (vertically integrated production system of Navarra, Spain) was 7.2% in MLN, 8.4% in IC and 9.6% in serum samples. In this low–moderate prevalence context, poor concordance was found between MLN infection and shedding at slaughter and between bacteriology and serology. In fact, most of shedders were found uninfected in MLN (83%) or carrying different Salmonella stra...

Research paper thumbnail of Desarrollo y evaluación de cuatro PCRs para la detección de Salmonella en ganglios linfáticos porcinos

Research paper thumbnail of Caracterización geno-fenotípica de aislados de Escherichia coli (AEEC) de pacientes pediátricos con procesos diarreicos infecciosos en la ciudad de La Paz: Implicancias para el diagnóstico y epidemiología de las enfermedades diarreicas agudas

Resumen En el presente estudio se realizo la caracterizacion de Escherichia coli enteropatogenica... more Resumen En el presente estudio se realizo la caracterizacion de Escherichia coli enteropatogenica (EPEC) y Escherichia coli enterohemorragica (EHEC), dos categorias patogenicas de E. coli, causantes de la lesion de adherencia y esfacelacion (EAEE), en muestras de heces diarreicas de ninos menores de 5 anos. El perfil patogenico de EAEE se realizo mediante el analisis por PCR, de los genes intimina (eae), bundlina (bfpA) y toxinas siga (stx1 y stx2). Estas pruebas se complementaron con ensayos fenotipicos de la resistencia a antibioticos, fermentacion de sorbitol y produccion de b-D-glucoronidasa. La prevalencia de EAEE fue del 7% con preponderancia de las cepas EPEC (95%) sobre EHEC. Se encontro una mayor proporcion (83%) de cepas EPEC atipicas que tipicas. Un alto porcentaje de los aislados de EPEC es resistente a mas de cinco antibioticos analizados. La frecuencia de multirresistencia a bloques de cinco y dos antibioticos sugiere que la resistencia es transmisible por via horizontal. La correlacion entre la pertenencia a un serogrupo particular de EPEC y las caracteristicas genotipicas, mostro heterogeneidad en el perfil de patogenicidad, tanto entre un mismo como entre diferentes serogrupos, demostrando que el diagnostico de DEC mediante serotipificacion no es util en nuestro medio. Los aislados de EHEC, se caracterizan por presentar una marcada susceptibilidad a los antibioticos. Se reporta la presencia de los serogrupos O157 y O6. Este estudio constituye el primer reporte en nuestro medio sobre la determinacion y caracterizacion geno-fenotipica de EPEC y EHEC por metodos moleculares. En conjunto, los datos obtenidos tienen relevancia para el diagnostico, tratamiento y estudio de la epidemiologia de AEEC en las EDA en Bolivia.(AU) Summary In this study, enteropathogenic (EPEC) and enterohemorrhagic (EHEC) E. coli, two E. coli categories causing attaching and effacing lesions, were isolated and characterized from children with diarrhea less than 5 years of age. The AEEC pathogenic profile was analyzed by PCR for the presence of the intimin (eae), bundle-forming pilus (bfpA) and Shiga toxin (stx, stx2) genes. Phenotypic analysis for the presence of antibiotic multi-resistance, sorbitol fermentation and B-D glucoronidase were also performed. AEEC prevalence was 7%. EPEC accounted for 95% of the isolates of which 83% were atypical. A high percentage of EPEC isolates is resistant to more than 5 antibiotics. The multi-resistance frequency to 5 and 2 antibiotics suggest antibiotic resistance transmission by lateral transfer. The lack of correlations between EPEC serogroups and genotypic strain profile demonstrates that serological DEC diagnosis is not useful for local isolates. EHEC isolates were remarkably susceptible to most of the antibiotics tested. The isolation of 0157 and 06 serogroups is reported. This is the first report of EPEC and EHEC molecular strain characterization. The results described are relevant for EAEE diagnosis, treatment and epidemiology of diarrheal diseases in Bolivia.(AU)

Research paper thumbnail of Sulfate-reducing bacteria in floating macrophyte rhizospheres from an Amazonian floodplain lake in Bolivia and their association with Hg methylation

Applied and …, 2005

Five subgroups of sulfate-reducing bacteria (SRB) were detected by PCR in three macrophyte rhizos... more Five subgroups of sulfate-reducing bacteria (SRB) were detected by PCR in three macrophyte rhizospheres (Polygonum densiflorum, Hymenachne donacifolia, and Ludwigia helminthorriza) and three subgroups in Eichhornia crassipes from La Granja, a floodplain lake from the upper Madeira basin. The SRB community varied according to the macrophyte species but with different degrees of association with their roots. The rhizosphere of the C 4 plant Polygonum densiflorum had higher frequencies of SRB subgroups as well as higher mercury methylation potentials (27.5 to 36.1%) and carbon (16.06 ؎ 5.40%), nitrogen (2.03 ؎ 0.64%), Hg (94.50 ؎ 6.86 ng Hg g ؊1), and methylmercury (8.25 ؎ 1.45 ng Hg g ؊1) contents than the rhizosphere of the C 3 plant Eichhornia crassipes. Mercury methylation in Polygonum densiflorum and Eichhornia crassipes was reduced when SRB metabolism was inhibited by sodium molybdate.

Research paper thumbnail of Development and evaluation of combined PCRs for detecting Salmonella in swine lymph nodes

XIV Jordanas Sobre Produccion Animal, Zaragoza, Espana, 17 y 18 de Mayo de 2011., 2011

... Conference, Jornadas sobre Producción Animal, 14., Zaragoza (España), 17-18 May 2011. Publish... more ... Conference, Jornadas sobre Producción Animal, 14., Zaragoza (España), 17-18 May 2011. Publisher, AIDA, Zaragoza (España). ... ISBN, 978-84-615-0062-8. Full-text, http://s346050484. mialojamiento.es/aida-itea/TOMO%202%20Jornadas%20AIDA%20XIV.pdf. Notes, 1 tabla, 5 ...

Research paper thumbnail of Simultaneous infections by different Salmonellastrains in mesenteric lymph nodes of finishing pigs

BMC Veterinary Research, Mar 7, 2014

Background: Salmonellosis is a major worldwide zoonosis, and Salmonella-infected finishing pigs a... more Background: Salmonellosis is a major worldwide zoonosis, and Salmonella-infected finishing pigs are considered one of the major sources of human infections in developed countries. Baseline studies on salmonellosis prevalence in fattening pigs in Europe are based on direct pathogen isolation from mesenteric lymph nodes (MLN). This procedure is considered the most reliable for diagnosing salmonellosis in apparently healthy pigs. The presence of simultaneous infections by different Salmonella strains in the same animal has never been reported and could have important epidemiological implications. Results: Fourteen finishing pigs belonging to 14 farms that showed high salmonellosis prevalence and a variety of circulating Salmonella strains, were found infected by Salmonella spp, and 7 of them were simultaneously infected with strains of 2 or 3 different serotypes. Typhimurium isolates showing resistance to several antimicrobials and carrying mobile integrons were the most frequently identified in the colonized MLN. Four animals were found infected by Salmonella spp. of a single serotype (Rissen or Derby) but showing 2 or 3 different antimicrobial resistance profiles, without evidence of mobile genetic element exchange in vivo. Conclusion: This is the first report clearly demonstrating that pigs naturally infected by Salmonella may harbour different Salmonella strains simultaneously. This may have implications in the interpretation of results from baseline studies, and also help to better understand human salmonellosis outbreaks and the horizontal transmission of antimicrobial resistance genes.

Research paper thumbnail of <i>Salmonella</i> Infection in Mesenteric Lymph Nodes of Breeding Sows

Foodborne Pathogens and Disease, Jun 1, 2020

Salmonellosis is one of the main foodborne diseases worldwide. Breeding sows asymptomatically inf... more Salmonellosis is one of the main foodborne diseases worldwide. Breeding sows asymptomatically infected with Salmonella can transmit the pathogen to piglets and humans. The isolation of Salmonella from mesenteric lymph nodes (MLNs) is considered a demonstration of asymptomatic infection in swine. As previous breeding sow studies have been performed using feces, the aim of this work was to study the occurrence of Salmonella infections by sampling MLNs, in comparison to their serological status. First, Salmonella fecal shedding was studied in 12/16 large breeding farms to establish the framework of study. Then, MLN (n = 264) and blood (n = 237) samples were obtained at an abattoir from sows of 15 of these 16 breeding farms. Additionally, risk factors associated with Salmonella MLN infection were analyzed. A total of 6.1% (16/264) sows, distributed in 40% (6/15) of the farms, had the pathogen in MLN. Salmonella Typhimurium was the most frequent serovar isolated. Interestingly, 43.8% (7/16) of MLN isolates were susceptible to all the antimicrobials tested and were found distributed throughout all farms with at least one sow positive. As well, one isolate of the emerging DT195 clone was detected and found to be resistant to six antibiotic families (ASSuTNx-Cfx). The serovars and the resistance profiles of the Salmonella isolates from feces were completely different to those obtained from MLNs. The seroprevalence (41.8% of sows and 100% of farms) was higher than that of MLN infections, showing no concordance (k = 0.15) between these two diagnostic tests in sows. Strategies directed to correct two risk factors (i.e., administration of dry food and old premises) would most likely help to reduce Salmonella infections in breeding sows.

Research paper thumbnail of Serotypes and multidrug-resistance profiles of Salmonellae isolated from pigs infected simultaneously with various strains

Poster presentado en el 4th Symposium on Antimicrobial Resistance in Animals and the Environment ... more Poster presentado en el 4th Symposium on Antimicrobial Resistance in Animals and the Environment celebrado en Tours-Vinci del 27 al 29 de junio de 2011.

Research paper thumbnail of Relationship between Salmonella infection, shedding and serology in fattening pigs in low–moderate prevalence areas

Zoonoses and Public Health, 2018

SummarySalmonella is a major foodborne pathogen causing important zoonosis worldwide. Pigs asympt... more SummarySalmonella is a major foodborne pathogen causing important zoonosis worldwide. Pigs asymptomatically infected in mesenteric lymph nodes (MLN) can be intermittent shedders of the pathogen through faeces, being considered a major source of human infections. European baseline studies of fattening pig salmonellosis are based on Salmonella detection in MLN. This work studies the relationship between Salmonella infection in MLN and intestinal content (IC) shedding at slaughter and the relationship between the presence of the pathogen and the serologic status at farm level. Mean Salmonella prevalence in the selected pigs (vertically integrated production system of Navarra, Spain) was 7.2% in MLN, 8.4% in IC and 9.6% in serum samples. In this low–moderate prevalence context, poor concordance was found between MLN infection and shedding at slaughter and between bacteriology and serology. In fact, most of shedders were found uninfected in MLN (83%) or carrying different Salmonella stra...

Research paper thumbnail of Desarrollo y evaluación de cuatro PCRs para la detección de Salmonella en ganglios linfáticos porcinos

Research paper thumbnail of Caracterización geno-fenotípica de aislados de Escherichia coli (AEEC) de pacientes pediátricos con procesos diarreicos infecciosos en la ciudad de La Paz: Implicancias para el diagnóstico y epidemiología de las enfermedades diarreicas agudas

Resumen En el presente estudio se realizo la caracterizacion de Escherichia coli enteropatogenica... more Resumen En el presente estudio se realizo la caracterizacion de Escherichia coli enteropatogenica (EPEC) y Escherichia coli enterohemorragica (EHEC), dos categorias patogenicas de E. coli, causantes de la lesion de adherencia y esfacelacion (EAEE), en muestras de heces diarreicas de ninos menores de 5 anos. El perfil patogenico de EAEE se realizo mediante el analisis por PCR, de los genes intimina (eae), bundlina (bfpA) y toxinas siga (stx1 y stx2). Estas pruebas se complementaron con ensayos fenotipicos de la resistencia a antibioticos, fermentacion de sorbitol y produccion de b-D-glucoronidasa. La prevalencia de EAEE fue del 7% con preponderancia de las cepas EPEC (95%) sobre EHEC. Se encontro una mayor proporcion (83%) de cepas EPEC atipicas que tipicas. Un alto porcentaje de los aislados de EPEC es resistente a mas de cinco antibioticos analizados. La frecuencia de multirresistencia a bloques de cinco y dos antibioticos sugiere que la resistencia es transmisible por via horizontal. La correlacion entre la pertenencia a un serogrupo particular de EPEC y las caracteristicas genotipicas, mostro heterogeneidad en el perfil de patogenicidad, tanto entre un mismo como entre diferentes serogrupos, demostrando que el diagnostico de DEC mediante serotipificacion no es util en nuestro medio. Los aislados de EHEC, se caracterizan por presentar una marcada susceptibilidad a los antibioticos. Se reporta la presencia de los serogrupos O157 y O6. Este estudio constituye el primer reporte en nuestro medio sobre la determinacion y caracterizacion geno-fenotipica de EPEC y EHEC por metodos moleculares. En conjunto, los datos obtenidos tienen relevancia para el diagnostico, tratamiento y estudio de la epidemiologia de AEEC en las EDA en Bolivia.(AU) Summary In this study, enteropathogenic (EPEC) and enterohemorrhagic (EHEC) E. coli, two E. coli categories causing attaching and effacing lesions, were isolated and characterized from children with diarrhea less than 5 years of age. The AEEC pathogenic profile was analyzed by PCR for the presence of the intimin (eae), bundle-forming pilus (bfpA) and Shiga toxin (stx, stx2) genes. Phenotypic analysis for the presence of antibiotic multi-resistance, sorbitol fermentation and B-D glucoronidase were also performed. AEEC prevalence was 7%. EPEC accounted for 95% of the isolates of which 83% were atypical. A high percentage of EPEC isolates is resistant to more than 5 antibiotics. The multi-resistance frequency to 5 and 2 antibiotics suggest antibiotic resistance transmission by lateral transfer. The lack of correlations between EPEC serogroups and genotypic strain profile demonstrates that serological DEC diagnosis is not useful for local isolates. EHEC isolates were remarkably susceptible to most of the antibiotics tested. The isolation of 0157 and 06 serogroups is reported. This is the first report of EPEC and EHEC molecular strain characterization. The results described are relevant for EAEE diagnosis, treatment and epidemiology of diarrheal diseases in Bolivia.(AU)

Research paper thumbnail of Sulfate-reducing bacteria in floating macrophyte rhizospheres from an Amazonian floodplain lake in Bolivia and their association with Hg methylation

Applied and …, 2005

Five subgroups of sulfate-reducing bacteria (SRB) were detected by PCR in three macrophyte rhizos... more Five subgroups of sulfate-reducing bacteria (SRB) were detected by PCR in three macrophyte rhizospheres (Polygonum densiflorum, Hymenachne donacifolia, and Ludwigia helminthorriza) and three subgroups in Eichhornia crassipes from La Granja, a floodplain lake from the upper Madeira basin. The SRB community varied according to the macrophyte species but with different degrees of association with their roots. The rhizosphere of the C 4 plant Polygonum densiflorum had higher frequencies of SRB subgroups as well as higher mercury methylation potentials (27.5 to 36.1%) and carbon (16.06 ؎ 5.40%), nitrogen (2.03 ؎ 0.64%), Hg (94.50 ؎ 6.86 ng Hg g ؊1), and methylmercury (8.25 ؎ 1.45 ng Hg g ؊1) contents than the rhizosphere of the C 3 plant Eichhornia crassipes. Mercury methylation in Polygonum densiflorum and Eichhornia crassipes was reduced when SRB metabolism was inhibited by sodium molybdate.