Project description:Comparative genomic hybridization of a temporally and locally diverse set of S. enterica ssp I serovar Enteritidis isolates, and some closely related serovar Dublin and Gallinarum strains, to the sequenced Enteritidis PT4
Project description:Even though the incidence of salmonellosis in humans has decreased over the last years, Salmonella spp. are still a leading cause of foodborne outbreaks in Europe (Anon., 2014). Of more than 2500 different serovars of Salmonella enterica, S. enterica serovar Enteritidis (S. Enteritidis) is the most frequently reported serovar in relation to food borne disease, and egg and egg products are the most important vehicles (Anon., 2014). It has recently been shown that S. Enteritidis is superior to other serovars tested regarding survival in egg white, which may explain why many egg borne outbreaks are caused by this serovar (De Vylder et al., 2013). The genetic background for this apparent better adaptation to survival in egg is only partially known. The aim of this work was to carry out gene expression analysis in order to understand how S. Enteritidis adapts to growth in the hostile environment of egg. This study analyzed gene expression of this bacterium during growth in whole egg, and whether highly expressed genes were essential for the growth. High quality RNA was extracted from S. Enteritidis using an improved modified RNA-extraction protocol. Global gene expression during growth in whole egg was compared to growth in LB-medium using DNA array method. Twenty-six genes were significantly upregulated during growth in egg; these belonged to amino acids biosynthesis, di/oligopeptide transport system, biotin synthesis, ferrous iron transport system, and type III secretion system. Significant downregulation of 15 genes related to formate hydrogenlyase (FHL) and trehalose metabolism was observed. The results suggested that S. Enteritidis is starved for amino-acids, biotin and iron when growing in egg.
Project description:Screen for differences in gene expression between a parental Salmonella enterica serovar Enteritidis strain (ATCC4931) and an adapted strain with increased resistance to the widely used antimicrobial sanitizer dodecyltrimethylammonium chloride (DTAC) Time course of comparative gene expression changes between log phase parental and adapted Enteritidis strains after 0, 10, 30 and 150 min of exposure to 50% of the respective MIC of DTAC.
Project description:Investigation of whole genome gene expression level changes in Salmonella enterica serova Enteritidis and Typhimurium under chlorine treatment Overall design: An eighteen chip study using total RNA isolated from three separate cultures of (1) S. Enteritidis in BHI broth (2) S. Typhimurium in BHI broth (3) S. Enteritidis in BHI broth w/ 130 ppm chlorine (4) S. Typhimurium in BHI w/ 130 ppm chlorine (5) S. Enteritidis in BHI broth w/ 390 ppm (6) S. Typhimurium in BHI broth w/ 390 ppm. Each chip measures the expression level of 5,027 ORFs covering the whole genome of S. Enteritidis and S. Typhimurium.
Project description:Microarray based CGH was conducted over a group of 29 strains of S. Enteritidis spanning different epidemiological periods in Uruguay, plus 6 other S. Enteritidis strains isolated from distant geographical regions. We also included 9 Salmonella enterica strains of other serovars isolated in Uruguay. A S. Enteritidis dispensable genome of 233 chromosomal genes and high extent of variation in virulence plasmid was found. Strains isolated before the epidemic show the highest genomic differences as compared with the PT4 reference strain. Comparison with the gene content of other serovars demonstrate extensive horizontal gene transfer between circulating strains beyond serovar definition. Our results show that the epidemic of S Enteritidis in Uruguay was produced by the introduction of strains closely related to PT4, and corroborate the extensive genetic homogeneity among S. Enteritidis isolates worldwide. Phage SE14 emerges as the only specific region for S. Enteritidis. Genetic differences detected in pre-epidemic strains, mainly associated with the absence of phage SE20, suggest that genetic features encoded in this phage may be related to particular epidemiological behavior.
Project description:Investigation of whole genome gene expression level changes in Salmonella enterica serova Enteritidis and Typhimurium under chlorine treatment An eighteen chip study using total RNA isolated from three separate cultures of (1) S. Enteritidis in BHI broth (2) S. Typhimurium in BHI broth (3) S. Enteritidis in BHI broth w/ 130 ppm chlorine (4) S. Typhimurium in BHI w/ 130 ppm chlorine (5) S. Enteritidis in BHI broth w/ 390 ppm (6) S. Typhimurium in BHI broth w/ 390 ppm. Each chip measures the expression level of 5,027 ORFs covering the whole genome of S. Enteritidis and S. Typhimurium.