La salmonelosis es considerada una de las zoonosis de origen alimentario de mayor prevalencia y actualmente supone uno de los mayores problemas de seguridad alimentaria. El objetivo del estudio fue detectar la presencia de especies de Salmonella spp. en carcasas porcinas destinadas al consumo humano, mediante técnicas de aislamiento. Se utilizaron 300 carcasas porcinas procedentes de dos camales de Lima. Las muestras fueron tomadas mediante hisopados sobre la piel de la carcasa, en cuatro zonas distintas: cabeza, vientre, lomo y pierna, representando en total 1200 submuestras. Las submuestras tomadas, fueron recogidas en tubos Falcon con Agua Peptonada Tamponada y llevadas al Laboratorio de Microbiología y Parasitología de la FMV – UNMSM. Después del pre-enriquecimiento no selectivo en APT, se utilizó el caldo Rappaport Vassiliadis como enriquecimiento selectivo. Posteriormente, para la siembra se usaron medios selectivos: Agar Xilosa Lisina Desoxicolato (XLD) y Agar Salmonella – Shigella (SS). Se realizaron pruebas bioquímicas y serotipificación para su identificación final. De las 300 carcasas examinadas, en 19 de ellas se obtuvieron aislamientos de Salmonella spp. lo que representa un porcentaje de positividad de 6.3% ± 2.4(19/300). Según la zona de muestreo, el resultado fue 21 aislados compatibles con Salmonella spp. de un total de 1200 submuestras analizadas, esto debido a que dos carcasas fueron positivas en dos submuestras. El mayor porcentaje de aislamientos se obtuvo de la piel de la cabeza 33.33% (7/21), y vientre 33.33% (7/21), seguida por el lomo 23.81% (5/21) y finalmente de la pierna 9.52% (2/21) Los aislados fueron serotipificados, e identificados como Salmonella Derby. Conocer los niveles de contaminación de las carcasas porcinas permite determinar la necesidad de implementar medidas de control contra salmonelosis y ayuda a evaluar si su implementación permite reducir el porcentaje de carne de cerdo contaminada que llega al consumidor. / Salmonellosis is considered one of the most prevalent foodborne zoonotic diseases. In developed countries, is now one of the biggest problems of food security. The aim of the study was to detect the presence of Salmonella spp. on pig carcasses intended for human consumption, by isolation techniques. Three hundred pig carcasses from two slaughterhouses in Lima were used. Samples were taken by swab on the skin of the carcasses, in four different areas: head, stomach, back and leg, representing a total 1200 subsamples. The subsamples were collected in Falcon tubes with Buffered Peptone Water and taken to the Laboratory of Microbiology and Parasitology, FMV - UNMSM. After the non-selective pre - enrichment in BPW, Rappaport Vassiliadis broth was used as selective enrichment. Subsequently, Xylose Lysine Deoxycholate Agar (XLD) and Salmonella - Shigella Agar (SS) selective medias, were used. Biochemical and serological tests for final identification were performed. Of the 300 cases examined, 19 isolates of Salmonella spp were obtained, representing 6.3% ± 2.4(19/300). According to the sampling area, the result was 21 isolates compatible with Salmonella spp. From a total of 1200 sub-samples analyzed, because two carcasses were positive in two subsamples. The highest percentage of isolates were obtained from the skin of the head, 33.33 % (7/ 21), and 33.33 % belonged to the belly (7/21), followed by the back with 23.81 % (5 /21) and finally 9.52 % from the leg (2/21). Isolates were serotyped and identified as Salmonella Derby. Knowing the levels of contamination of pig carcasses helps to determine the need to implement control measures against Salmonella and helps to assess whether implementation can reduce the percentage of contaminated pork that reaches the consumer. Key words: Salmonella spp., salmonellosis, pig carcasses, slaughterhouses, public health / Tesis

La producción de cobayos es una actividad que cada vez cobra más importancia en nuestro país, debido al aumento de la demanda de la carne de esta especie en el mercado nacional e internacional. Sin embargo, los conocimientos en sanidad de cobayos son aún escasos, haciéndola vulnerable a las diversas enfermedades. En este contexto sobresale la salmonelosis enfermedad que causa altos porcentajes de mortalidad y morbilidad en producción de cobayos. El presente estudio identificó las lesiones anatomopatológicas más frecuentes que predominaron en órganos de cobayos infectados con Salmonella spp. Para ello se realizó el estudio retrospectivo de 125 protocolos de necropsia de cobayos, obtenidos del Laboratorio de Histología, Embriología y Patología Veterinaria de la Facultad de Medicina Veterinaria de la Universidad Nacional Mayor de San Marcos, en un período comprendido entre el 2001 al 2007, el diagnóstico de la salmonelosis fue confirmada por el Laboratorio de Microbiología Veterinaria de dicha Universidad, resultando 81 cobayos positivos a Salmonella spp. y 44 negativos. Los resultados muestran que la mayoría de órganos se encontraron lesionados, con una mediana de 5 órganos por animal, siendo el hígado el órgano que frecuentemente presentó lesiones patológicas con un 87.7 % ± 0.07 (71/81), siendo la imagen patomorfológica que predominó la hepatitis necrótica con un 44.4 % (36/81). Así mismo, se realizó la clasificación de las lesiones anatomopatológicas en procesos inflamatorios, trastornos circulatorios, degenerativos y de adaptación siendo la inflamación el trastorno patológico más frecuente, representando el 43.4 % ± 4.8 (177/408) del total de órganos lesionados encontrados en los 81 cobayos infectados con Salmonella spp. Palabras Claves: Cobayos, Salmonella spp., Lesiones anatomopatológicas / The guinea pig production is an activity that becomes increasingly more important in our country due to increased demand for the meat of this species in domestic and international markets. However, health knowledge in guinea pigs are still scarce, making it vulnerable to various diseases. In this context stands salmonellosis, disease that causes high mortality and morbidity rates of production of guinea pigs. This study identified the most common pathologic lesions predominated in organs of guinea pigs infected with Salmonella spp. This retrospective study was conducted on necropsy of 125 guinea pigs, obtained from the Laboratory of Histology, Embryology and Veterinary Pathology, College of Veterinary Medicine of the Universidad Nacional Mayor de San Marcos, in a period between 2001 to 2007, the diagnosis of salmonellosis was confirmed by the Veterinary Microbiology Laboratory of the University, resulting in 81 guinea pigs positive for Salmonella spp. and 44 negatives. The results show that most organs were injured, with a median of 5 organs per animal, the liver being the organ that pathological lesions often presented with a 87.7% ± 0.07 (71/81) being the prevailing pathomorphological image necrotic hepatitis in 44.4% (36/81). Likewise, it was made the classification of pathological lesions in inflammatory processes, circulatory disorders, degenerative and adaptive, inflammation being the most common pathological disorder, accounting for 43.3% ± 4.8 (177/408) of total injured organs found in the 81 guinea pigs infected with Salmonella spp. Key Words: Guinea pigs, Salmonella spp., anatomopathological lesions.

El objetivo del presente estudio fue detectar la presencia de Salmonella spp. en el total (n igual a 30) de la población de tortugas motelo (Geochelone denticulata) de un criadero de 25 m2 de área, construido con materiales de la misma zona y piso de tierra; la alimentación de los animales a base de frutas y verduras, agua Ad libitum y se observó presencia de roedores, la crianza se realizo en condiciones de cautiverio en la ciudad de Iquitos, Región Loreto. Las muestras de heces se obtuvieron por hisopado rectal, luego llevadas al laboratorio de la Estación Experimental IVITA-Iquitos y se colocaron en un medio de enriquecimiento Agar Soya Tripticasa para luego ser remitidas en condiciones de refrigeración a la Sección de Bacteriología y Micología del Laboratorio de Microbiología y Parasitología, de la Facultad de Medicina Veterinaria de la Universidad Nacional Mayor de San Marcos; para su aislamiento e identificación mediante pruebas de cultivo bacteriológico y bioquímicas. El 6.7% (2/30) de las muestras fueron positivas a Salmonella spp. Adicionalmente se encontraron otras bacterias como Escherichia coli y Pseudomona aeruginosa en un 80% (24/30), Proteus vulgaris en un 26.6% (8/30), Proteus mirabilis en 6.7% (2/30) y Citrobacter spp. 16.7% (5/30). La Salmonella spp se detectó en tortugas sanas y enfermas, además se realizó la tipificación por el método Who Global Salm Surv, obteniendo como resultado Salmonella enterica subespecie enterica serotipo typhimurium en las dos muestras positivas a dicha bacteria. Se concluye que existe presencia de Salmonella spp. (Salmonella typhimurium) en muestras de hisopados cloacales de tortugas motelo criadas en cautiverio, y que los demás microorganismos hallados forman parte de la familia enterobacteriaceae propio del tracto intestinal de éstos animales. / The objective of the present study was to detect the presence of Salmonella spp. in the total (n same 30) of the population of turtles motelo (Geochelone denticulata) of a hatchery of 25 m2 of area, built with materials of the same area and earth floor; the feeding of the animals with the help of fruits and vegetables, dilutes Ad libitum and presence of rodents, the upbringing one was observed I carry out under captivity conditions in the city of Iquitos, Región Loreto. The samples of grounds were obtained by rectal hisopado and then taken to the laboratory of the Experimental Station IVITA-Iquitos and they were placed in a means of enrichment Agar Soya Tripticasa for then to be remitted under refrigeration conditions to the Section of Bacteriology and Micología of the Laboratory of Microbiology and Parasitología, of the Faculty of Veterinary Medicine of the University National Major of than San Marcos; for their isolation and identification by means of bacteriological and biochemical cultivation tests. The 6. 7% (2/30) of the samples they went positive to Salmonella spp. Additionally they were other bacterias like Escherichia coli and Pseudomona aeruginosa in 80% (24/30), Proteus vulgaris in a 26. 6% (8/30), Proteus mirabilis in 6. 7% (2/30) and Citrobacter spp. 16. 7% (5/30). The Salmonella spp was detected in healthy and sick turtles, she was also carried out the tipificación for the method Who Global Salm Surv, obtaining Salmonella enterica subspecies enterica serotipo typhimurium in the two positive samples to this bacteria. You concludes that presence of Salmonella spp exists. (Salmonella typhimurium) in samples of hisopados cloacales of turtles motelo raised in captivity, and that the other found microorganisms are part of the family enterobacteriaceae characteristic of the intestinal tract of these animals.

Thèse d'exercice : Pharmacie : Nancy 1 : 2008. / Titre provenant de l'écran-titre.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 105-118).

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 88-102).

Salmonella infections remain one of the most common food borne diseases worldwide. Gastroenteritis, which can be caused by many non-typhoidal Salmonella (NTS) serovars, is relatively common in North America. One of the main risk factors of NTS gastroenteritis is travel to endemic areas in the developing world. The current treatment of NTS infections with antibiotics is reserved for severe cases. A growing concern with antibiotic use is that clinical isolates are becoming drug resistant. Although most NTS infections are self-limiting in nature, the burden on the body and recovery can take several months. Thus, it is vital to prevent NTS infections rather than solely rely on treatment. We have previously discovered two novel surface associated polysaccharides in Salmonella: O-Antigen capsule and X-factor. Not only O-Antigen Capsule is considered a common surface antigen, but its’ genes were found to be expressed during in vivo infections in mice. Such an antigen would be a suitable candidate in developing a vaccine against Salmonella induced gastroenteritis. The goal of this research was to evaluate the use of O-Antigen capsule to develop a traveler’s vaccine for NTS associated gastroenteritis. Results and Conclusions: We have developed a purification protocol and purified the capsule and X-factor from Salmonella Typhimurium, Enteritidis, and Heidelberg. Lipopolysaccharide (LPS) was co-isolated with O-Antigen capsule, but removed using Triton extraction. Salmonella LPS is strain-specific and an adaptive immune response against LPS will not provide cross-protection. We generated specific immune sera in rabbits to recognize O-Antigen capsule and X-factor produced by Salmonella Typhimurium and Enteritidis. We used a mouse model to determine the immunization dose of O-Antigen capsule and showed that conjugation is necessary to enhance the immune response in mice. To boost capsule production, we analyzed PyihUTSRQPO activity using a luciferase-based reporter system. Deletion of a putative transcriptional repressor (YihW) resulted in over 100-fold increase in PyihUTSRQPO confirming YihW as a repressor. We have also looked at the effect of growth media, temperature, and sugar precursors on PyihUTSRQPO activity, and were able to show that PyihUTSRQPO has highest activity in Tryptone broth at 30oC in the absence of any additional sugars.

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

In recent decades salmonellosis has been on the rise as a food related illness worldwide. Causing over 24% of all non-typhoidal Salmonellosis cases, SE is the most frequently isolated serovar of Salmonella. Increased isolation of SE from eggs has paralleled an increase in the number of transovarian infections associated with laying hens in the poultry industry. This route of infection is a fairly new line of study when compared to the more traditional path where SE originates from fecal contamination through the shell. Salmonella Typhimurium (ST) is another concern for the egg industry. ST has caused 23.5% of all non-typhoidal salmonellosis cases. Understanding these two egg pathogens requires an in depth look at the mechanisms by which an egg may support infection and bacterial growth. Eggs were inoculated with both SE and ST onto the vitelline membrane and incubated for 24 hours. It was hoped that by gathering samples from the interior of the egg membrane, the albumen of the egg, and the membrane itself, some clarification as to when Salmonella is allowed to grow within the egg could be gathered. Albumen and membrane were found to be more hospitable environments to bacterial growth with increased storage times. In order to better understand the movement of bacteria into pre-ovulatory tissues, samples were gathered from mature laying hens. Follicular tissues were separated into divisions based on maturity, and bacteria were added to an in vitro cell culture broth containing the follicles. The point of this experiment was to determine if either species of Salmonella preferentially moved into follicles of different maturity when inoculated in vitro. A third experiment looked into the role of developmental stages of the vitelline membrane in exclusion of bacteria from the nutrient rich yolk. Tissues were gathered in the method described above. The follicular sack was removed from half of these samples and left intact for the other half. Another treatment group included was the yolks of eggs which had been laid by the same flock of birds. Results showed that follicles with intact follicular sacks were more susceptible to bacterial colonization than other treatment groups.

La salmonelosis es una de las enfermedades transmitidas por alimentos más frecuente en el mundo. El Código Alimentario Argentino establece para carne molida la ausencia de Salmonella spp. y para su análisis recomienda la norma BAM. Esta metodología requiere tiempo hasta obtener el resultado final. La PCR se utiliza como método rápido para la detección de patógenos. El objetivo de este trabajo fue prevenir la presencia de Salmonella spp. en la carne molida destinada a consumo minorista. Se desarrolló una técnica de PCR en tiempo real (RT- PCR) con agentes intercalantes para la detección de Salmonella spp. y se realizó una validación intra-laboratorio. El límite de detección fue 104 UFC/20 μl de mezcla de reacción. En esta etapa la técnica presentó 100% de inclusividad y exclusividad. Se comparó el desempeño de esta técnica contra una PCR de punto final y una RT-PCR comercial mediante el análisis de 92 muestras de carne molida obtenidas de carnicerías de la ciudad de Berisso. Durante el muestreo se realizó una encuesta al responsable del comercio. Se obtuvieron 13 (14%) muestras positivas por aislamiento y por RT-PCR comercial y ocho (8,7%) muestras positivas al utilizar PCR de punto final y la técnica desarrollada. Se aislaron 5 serotipos de Salmonella. El desempeño de la RT-PCR desarrollada se puede mejorar mediante el rediseño de los oligonucleótidos cebadores en base a los clones circulantes aislados en la carne molida. En las encuestas se identificaron problemas como: falta de trazabilidad de la carne, falta de procedimientos de sanitización estandarizado y carencias edilicias. El Programa “Carnicerías Saludables” permitió detectar los puntos críticos en las etapas de triturado y envasado de la carne molida y de esta forma implementar estrategias de prevención y control de salmonelosis por medio de la capacitación de 167 manipuladores.