A Single Nucleotide Polymorphism in Increases Tolerance to Bile Salts, Acid, and Staining of Calcofluor-Binding Polysaccharides in Serovar Typhimurium E40.

The outer membrane of plays an important role in combating stress encountered in the environment and hosts. The transport and insertion of lipopolysaccharides (LPS) into the outer membrane involves lipopolysaccharide transport proteins (LptA-F) and mutations in the genes encoding for these proteins are often lethal or result in the transport of atypical LPS that can alter stress tolerance in bacteria. During studies of heterogeneity in bile salts tolerance, serovar Typhimurium E40 was segregated into bile salts tolerant and sensitive cells by screening for growth in TSB with 10% bile salts.

Chronological set of E. coli O157:H7 bovine strains establishes a role for repeat sequences and mobile genetic elements in genome diversification.

Background: Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a significant foodborne pathogen that resides asymptomatically within cattle and other ruminants. The EHEC genome harbors an extensive collection of mobile genetic elements (MGE), including multiple prophage, prophage-like elements, plasmids, and insertion sequence (IS) elements.

Results: A chronological collection of EHEC strains (FRIK804, FRIK1275, and FRIK1625) isolated from a Wisconsin dairy farm (farm X) comprised a closely related clade genetically differentiated by structural alterations to the chromosome.

Genome Sequences of 14 Escherichia coli O157:H7 Strains Isolated before and during the Time Frame of the 2018 Multistate Outbreak Associated with Romaine Lettuce.

Several outbreaks of O157:H7 associated with contaminated leafy green vegetables have been documented. Here, we report the draft genome sequences of 14 strains isolated from human patients in the state of Wisconsin during a multistate outbreak in early 2018 that was linked to consumption of romaine lettuce.

Phylogenetic characterization of Escherichia coli O157 : H7 based on IS629 distribution and Shiga toxin genotype.

Shiga toxin (stx)-producing Escherichia coli O157 : H7 is a prominent food-borne pathogen. Symptoms in human infections range from asymptomatic to haemorrhagic colitis and haemolytic uraemic syndrome, and there is a need for methods that yield information that can be used to better predict clinical and epidemiological outcomes. IS629 is an insertion sequence notable for its prevalence and variable distribution in the chromosome of E.

Evolution of the Stx2-encoding prophage in persistent bovine Escherichia coli O157:H7 strains.

Escherichia coli O157:H7 is a human pathogen that resides asymptomatically in its bovine host. The level of Shiga toxin (Stx) produced is variable in bovine-derived strains in contrast to human isolates that mostly produce high levels of Stx. To understand the genetic basis for varied Stx production, chronological collections of bovine isolates from Wisconsin dairy farms, R and X, were analyzed for multilocus prophage polymorphisms, stx(2) subtypes, and the levels of stx(2) transcript and toxin.