Salmonella é uma das principais causas de Doenças Transmitidas por Alimentos em todo o mundo, sendo que no Estado do Rio Grande do Sul (RS) esse microrganismo tem sido apontado como um dos principais agentes de toxinfecções alimentares nos últimos anos. Neste trabalho foram caracterizados isolados de Salmonella envolvidas em salmoneloses ocorridas no RS, no período de 2007 a 2013. Entre os 163 isolados investigados, 138 (84,7%) foram sorotipificados com S. Enteritidis, enquanto os outros isolados foram S. Schwarzengrund (n = 9 – 5,5 %), S. Typhimurium (n = 6 – 3,7%), S. Infantis (n = 1 – 0,6 %), S. Agona (n = 1 – 0,6 %), S. Derby (n = 1 – 0,6 %), S. London (n = 1 – 0,6 %), S. Give (n = 1 – 0,6 %), S. Panama (n = 1 – 0,6 %) e S. enterica (n = 4 – 2,5 %). Os principais alimentos envolvidos nos surtos foram maionese caseira (17,39%), seguido dos produtos de confeitaria (15,94 %) e carnes (12,32 %). A resistência da S. Enteritidis a 12 agentes antimicrobianos também foi investigada. As maiores porcentagens de resistência foram encontradas em relação à nitrofurantoína (94,2 %) e ao ácido nalidíxico (89,1 %). A resistência para duas drogas foi verificada em 80,43 % dos isolados. Sendo que a multirresistência para três ou cinco antimicrobianos foi verificada em quatro e dois isolados, respectivamente. Quando os isolados foram submetidos à PCR-Ribotipificação, apenas um perfil de bandas foi identificado. Os resultados de PCR-Ribotipificação sugerem que uma mesma cepa de S. Enteritidis foi isolada a partir de alimentos envolvidos em salmoneloses ocorridas em diferentes municípios do Estado do RS no período de 2007 a 2013. Uma vez que o mesmo perfil de bandas foi identificado em S. Enteritidis causadoras de salmoneloses, durante 1999 a 2006, os resultados indicam que a mesma cepa de S. Enteritidis tem causado surtos alimentares no RS, durante o período de 1999 a 2013. / Salmonella is a major cause of Foodborne Diseases worldwide, and in the State of Rio Grande do Sul (RS) this microorganism has been identified as the main agent of foodborne diseases in last years. In this work, Salmonella isolates responsible for salmonellosis occurred in the State of RS, in the period 2007 to 2013 were characterized. Among the 163 isolates investigated, 138 (84.7 %) were serotyped as S. Enteritidis, whereas the other isolates were S. Schwarzengrund (n = 9 – 5.5 %), S. Typhimurium (n = 6 – 3.7 %), S. Infantis (n = 1 – 0.6 %), S. Agona (n = 1 – 0.6 %), S. Derby (n = 1 – 0.6%), S. London (n = 1 – 0.6 %), S. Give (n = 1 – 0.6 %), S. Panama (n = 1 – 0.6 %) and S. enterica (n = 4 – 2.5 %). The main food vehicles identified were homemade mayonnaise (17.39 %), followed by pastry products (15.94 %) and beef (12.32 %). The S. Enteritidis resistance to 12 antimicrobial agents was investigated. The highest percentages of resistance were found to nitrofurantoin (94.2 %) and nalidixic acid (89.1 %). The resistance to two different drugs was observed in 80.43 % of the isolates. Multidrug-resistance for three to five antimicrobials was observed in four and two isolates, respectively. When the isolates were analysed by PCR-Ribotyping, only one banding profile was identified. The results of PCR-Ribotyping suggest that the same strain of S. Enteritidis was isolated from foods involved in salmonelloses occurred in different municipalities of the State of RS in the period 2007-2013. Since the same banding pattern was found in strains involved in salmonellosis outbreaks of 1999 to 2006, results indicated that the same strain of S. Enteritidis has caused salmonellosis outbreaks in RS, during the period of 1999 to 2013.

O presente trabalho objetivou identificar os fatores de risco para a presença de S. Enteritidis no sistema de produção de frangos de corte, avaliar, qualificar e quantificar as variáveis encontradas e elaborar um modelo teórico de estimativa de risco deste sorovar em frangos criados em sistema de integração. Os dados foram obtidos de trabalhos recentes realizados por alguns autores e deram subsídios à realização de uma análise de riscos microbiológicos. Para caracterização molecular foram utilizadas 42 cepas de Salmonella isoladas de frangos e rações inoculados experimentalmente com uma cepa de S. Typhimurium. A inoculação da bactéria foi realizada na ração e a mesma tratada com diferentes concentrações dos ácidos propílico, fórmico e acético sendo, então, fornecida para consumo ad libitum até os 21 dias de idade, quando as aves foram sacrificadas. Foram obtidos diferentes perfis genéticos com o uso do ERIC e BOX-PCR, que se mostraram eficientes para discriminação das cepas em estudo. / The aim of this work was identify the risk factors for S. Enteritidis in the production system of broiler chickens, to evaluate, qualify and quantify the variables studied and to make a theoretical model of risk assessment of this serovar in broilers in integration system. Therefore, the data was obtain from works of some authors and supported the proposed model of microbiological risk analysis. For molecular characterization were included 42 Salmonella spp. strains isolated from chicks and feed experimentally inoculated with S. Tiphimurium. After inoculation of feed with the specific dose of strain, it was submitted to treatment with propilic, formic and acetic acids in several concentrations and it was given to birds ad libitum until 21 days old, when they were sacrificed. It was obtained different patterns through the ERIC and BOX-PCR techniques, which showed good discrimination power for the strains analyzed.

Call number: LD2668 .T4 1963 K57 / Master of Science

Call number: LD2668 .T4 1965 A31 / Master of Science

Master of Science / Department of Animal Sciences and Industry / J. Ernest Minton / Previous research evaluated a laboratory strain of Bacillus licheniformis (BL) in a model swine epithelium and found it exerted anti-inflammatory effects on Salmonella enterica serovar Typhimurium (S)-induced secretion of interleukin-8 (IL-8). The current investigation evaluated the anti-inflammatory actions of Bacillus bacteria available commercially as feed additives for the swine industry. Three isolates were obtained from the product, two Bacillus subtilis (BS1 and BS3) and one Bacillus licheniformis (BL2). Swine jejunal epithelial IPEC-J2 cells were seeded into wells on permeable membrane supports and allowed to form confluent monolayers. Treatments included apical pretreatment with BL, BS1, BL2, or BS3 for 17 h without S, and the same Bacillus treatments but with 10[superscript]8 CFU S added in the final 1 h of Bacillus incubation. Two additional treatments included negative control wells receiving no bacteria (C) and positive control wells receiving only S. Following bacterial incubation, wells were washed and fresh media containing gentamicin was added. Cells were incubated for an additional 5 h, after which apical and basolateral media were recovered for quantitation of IL-8 and bacitracin. In addition, inserts with epithelial cells that had received S were lysed and lysates cultured to determine treatment effects on S invasion. Exposure to S alone provoked an increase in IL-8 secretion from IPEC-J2 cells compared to C wells (P < 0.001 for both the apical and basolateral directions). Pre-treatment with each Bacillus isolate followed by challenge with S reduced S-induced IL-8 secretion in both apical and basolateral compartments compared to the wells receiving only S (P < 0.001; except for BS3 apical, P < 0.01). Secretion of bacitracin could only be detected in BL2 and BL2+S. Fewer S colonies could be cultured from lysates of BL2+S than S, BS1+S, and BS3+S treatments (P < 0.001). Results suggest that Bacillus subtilis and Bacillus licheniformis have the ability to intervene in secretion of the neutrophil chemoattractant IL-8 from swine intestinal epithelial cells. This effect on chemokine secretion by gastrointestinal epithelial cells in vitro could not be explained solely by production of bacitracin or reduced invasion of epithelial cells by S.

Salmonella is one of the most important pathogens of mankind and animals alike, causing several billion pounds worth of damage worldwide each year. We have sequenced, annotated and published 4 genomes of Salmonella of well-defined virulence in farm animals. This provides valuable measures of intraserovar diversity and opportunities to formally link genotypes to phenotypes in target animals. Specifically, we have examined pathway detrition and mutagenesis and linked this to host specificity of the serovars. With the advent of next generation sequencing there has been a boom in genomic sequence submission, and an onslaught of -omics data has ensued. Integrating these different data types is complex and there is little available to visualise this data in the context of its genome. We present GeneBook, a web-based tool that synchronously integrates disparate datasets, displaying a fully annotated genome, enriched with publicly available data and the user's private experiments. It is accessed through a user-friendly interface that allows scientists to interrogate genomic features across multiple, heterogeneous, experiments.

Master of Science / Department of Grain Science and Industry / Cassandra Jones / Salmonella contamination in animal food production facilities is a growing concern. The bacteria has been the cause of 40% of pet food recalls in the past 5 years, and there are potential human health implications because pet food is a direct human contact food. A potential method to reduce Salmonella contamination in pet food is through the use of acidifiers and desiccants to destroy and inhibit growth of bacteria. The objective of this thesis was to quantify Salmonella contamination in livestock feed and pet food manufacturing facilities, and propose mitigation measures to mitigate the presence of pathogens in animal food. Therefore, the objective of Experiment 1 was to investigate sources of Salmonella contamination throughout livestock feed (n = 2) and pet food (n = 2) manufacturing facilities on a specific sampling day. Salmonella was present in all four facilities. However, one of the livestock feed manufacturing facilities had more than double the Salmonella-positive locations than all other facilities. This experiment demonstrated that surface type and location should be taken into consideration when controlling Salmonella contamination. In Experiments 2 and 3, the use of a commercial powdered dry acidulant, sodium bisulfate, was studied as a coating of dog kibble to reduce and prevent Salmonella growth over time. The coating reduced Salmonella concentration, and its efficacy was not impacted by altering the bulk density or surface area of the kibble. Experiment 4 was conducted to determine the efficacy of sodium bisulfate added to poultry mash to reduce or prevent Salmonella growth over time. The inclusion of the dry acidulant did not reduce Salmonella concentration; however, storage time reduced Salmonella contamination in poultry feed. In summary, Salmonella contamination exists in manufacturing facilities, but the location and magnitude of contamination differs. Furthermore, sodium bisulfate effectively reduces Salmonella contamination when applied as a pet food coating, but not in poultry feed.

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

Although dialkylnitrosamines are environmentally significant carcinogens, the use of short-term bioassays to assess the mutagenic potential of these compounds remains problematic. The Ames test, a mutagenicity assay based on the reversion of Salmonella typhimurium histidine auxotrophs, is the most widely used bioassay in genetic toxicology, but the traditional Ames tester strains are largely insensitive to dialkylnitrosamine mutagenicity. I have constructed several mutagenicity tester strains that co-express combinations of full-length human cytochrome P450 2E1, rat cytochrome P450 reductase, and human cytochrome b5 in S. typhimurium lacking ogt and ada methyltransferases (YG7104ER, ogt-; and YG7108ER, ogt-, ada-). These new strains are susceptible to dialkylnitrosamine mutagenicity in the absence of an exogenous metabolic activating system (S9 fraction). Mutagenicity is dependent upon the coexpression of P450 2E1 with P450 reductase and is similar or greater than that obtained with the parental strains in the presence of S9 fraction from ethanol-induced rat liver. Coexpressing human cytochrome b5 with cytochrome P450 2E1 and cytochrome P450 reductase potentiates the mutagenicity observed with dialkylnitrosamines. These strains were sensitive to nitrosamines with varying alkyl side chains, including dimethylnitrosamine, diethylnitrosamine, dipropylnitrosamine, and dibutylnitrosamine. Mutagenicity decreased with alkyl chain length, consistent with the stringency of the ada-encoded enzyme for methyl and ethyl DNA adducts. These new strains may prove useful in the evaluation of nitrosamine contamination of food and environmental samples, and may serve as useful tools in investigating the molecular properties of proteins in the cytochrome P450 monooxygenase system.

Salmonellosis is a foodborne disease, poultry and poultry products are the main source of the disease. Many countries including Iraq still use antibiotics to control Salmonella. The increase in antibiotic resistant bacteria putatively caused by the overuse of antibiotics in agriculture has provided the incentive to look for alterna-tives to antibiotic to control diseases in livestock. Lactic acid bacteria with probiotic characteristics have the potential to beneficially affect the gut microflora of chick-ens and help reduce the incidence of Salmonella infection. In this study, Lactobacillus plantarum NCIMB 41607 was examined in vitro for in-hibitory effects against Salmonella and in vivo for its effects on the gut microflora and on the incidence of Salmonella infection. In separate studies Lb. plantarum was administered to chicks as fermented moist feed (containing 175 mmol/L lactic acid and 1x109 CFU/g of Lb. plantarum), in drinking water or applied to dry feed. Rifampicin resistance was used as a biomarker for the Lb. plantarum NCIMB 41607. Traditional and molecular microbiology including DGGE, RISA, and FISH were used with electron microscopy to assess the effect of Lb. plantarum on bac-terial population in the digestive system of chicks. Lactobacillus plantarum (NCIMB 41607) was found to reduce the growth of Salmonella Typhimurium and Salmonella Enteritidis by 4 Log CFU/g in a chicken simulated digestive system in vitro. The presence of rifampicine resistant Lactobacillus plantarum in the gut was con-firmed by replica plating and fluorescent in situ hybridisation with a strain specific probe. In general, the bacterial population in the guts of chicks fed Lactobacillus plantarum was more diverse in the guts of chicks fed control feed. There was no significant effect on Salmonella infection in Ross chicks compared with control. However, with specific pathogen free chicks the Salmonella infection was reduced. The intestinal villi lengths in FMF group were increased. These studies demonstrate that probiotics can affect the microflora in the chicken gut. Lactobacillus plantarum NCIMB 41607 may have the potential to control of Salmonella Typhimurium infection in chicken and continued research is advised.