Transcriptional analysis reveals specific niche factors and response to environmental stresses of enterohemorrhagic Escherichia coli O157:H7 in bovine digestive contents.

Background: Enterohemorrhagic Escherichia coli (EHEC) are responsible for severe diseases in humans, and the ruminant digestive tract is considered as their main reservoir. Their excretion in bovine feces leads to the contamination of foods and the environment. Thus, providing knowledge of processes used by EHEC to survive and/or develop all along the bovine gut represents a major step for strategies implementation.

Transcriptomic analysis reveals specific metabolic pathways of enterohemorrhagic Escherichia coli O157:H7 in bovine digestive contents.

Background: The cattle gastrointestinal tract (GIT) is the main enterohemorrhagic Escherichia coli (EHEC) reservoir. In order to identify nutrients required for the survival or multiplication of EHEC in the bovine GIT, we compared the transcriptomes of the EHEC O157:H7 reference strain EDL933 cultured in vitro in bovine digestive contents (DCs) (rumen, small intestine and rectum) using RNA-sequencing.

Results: Gene expression profiles showed that EHEC EDL933 activated common but also specific metabolic pathways to survive in the different bovine DCs.

Aspartate metabolism is involved in the maintenance of enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content.

The gastrointestinal tract (GIT) of healthy cattle is the main reservoir of enterohaemorrhagic Escherichia coli (EHEC). Therefore, it is crucial to better understand the physiology of EHEC in the bovine GIT. In this study, we demonstrate that aspartate present in bovine small intestine content (BSIC), was exhausted after incubation of the reference EHEC strain EDL933 but was poorly assimilated by the endogenous microbiota.

Factors Involved in the Persistence of a Shiga Toxin-Producing O157:H7 Strain in Bovine Feces and Gastro-Intestinal Content.

Healthy cattle are the primary reservoir for O157:H7 Shiga toxin-producing responsible for human food-borne infections. Because farm environment acts as a source of cattle contamination, it is important to better understand the factors controlling the persistence of O157:H7 outside the bovine gut. The O157:H7 strain MC2, identified as a persistent strain in French farms, possessed the characteristics required to cause human infections and genetic markers associated with clinical O157:H7 isolates.

Lactobacillus reuteri suppresses E. coli O157:H7 in bovine ruminal fluid: Toward a pre-slaughter strategy to improve food safety?

The bovine gastrointestinal tract (GIT) is the main reservoir for enterohaemorrhagic Escherichia coli (EHEC) responsible for food-borne infections. Therefore, it is crucial to develop strategies, such as EHEC suppression by antagonistic microorganisms, to reduce EHEC survival in the GIT of cattle and to limit shedding and food contamination. Most human-derived Lactobacillus reuteri strains produce hydroxypropionaldehyde (HPA), an antimicrobial compound, during anaerobic reduction of glycerol.

Draft genome sequence and characterization of commensal strain BG1 isolated from bovine gastro-intestinal tract.

is the most abundant facultative anaerobic bacteria in the gastro-intestinal tract of mammals but can be responsible for intestinal infection due to acquisition of virulence factors. Genomes of pathogenic strains are widely described whereas those of bovine commensal strains are very scarce. Here, we report the genome sequence, annotation, and features of the commensal BG1 isolated from the gastro-intestinal tract of cattle.

Draft Genome Sequence of Enterohemorrhagic O157:H7 Strain MC2 Isolated from Cattle in France.

Enterohemorrhagic (EHEC) with serotype O157:H7 is a major foodborne pathogen. Here, we report the draft genome sequence of EHEC O157:H7 strain MC2 isolated from cattle in France. The assembly contains 5,400,376 bp that encoded 5,914 predicted genes (5,805 protein-encoding genes and 109 RNA genes).

A secretome view of colonisation factors in Shiga toxin-encoding Escherichia coli (STEC): from enterohaemorrhagic E. coli (EHEC) to related enteropathotypes.

Shiga toxin-encoding Escherichia coli (STEC) regroup strains that carry genes encoding Shiga toxin (Stx). Among intestinal pathogenic E. coli, enterohaemorrhagic E.

Colonization of the meat extracellular matrix proteins by O157 and non-O157 enterohemorrhagic Escherichia coli.

Enterohemorrhagic Escherichia coli (EHEC) are anthropozoonotic agents that range third among food-borne pathogens respective to their incidence and dangerousness in the European Union. EHEC are Shiga-toxin producing E. coli (STEC) responsible for foodborne poisoning mainly incriminated to the consumption of contaminated beef meat.

The gluconeogenesis pathway is involved in maintenance of enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content.

Enterohaemorrhagic Escherichia coli (EHEC) are responsible for outbreaks of food- and water-borne illness. The bovine gastrointestinal tract (GIT) is thought to be the principle reservoir of EHEC. Knowledge of the nutrients essential for EHEC growth and survival in the bovine intestine may help in developing strategies to limit their shedding in bovine faeces thus reducing the risk of human illnesses.

[EHEC carriage in ruminants and probiotic effects].

Enterohaemorrhagic Escherichia coli (EHEC) are Shiga-Toxin producing E. coli (STEC) that cause human outbreaks which can lead to a severe illness such as haemolytic-uraemic syndrome (HUS), particularly in young children. The gastrointestinal tract of cattle and other ruminants is the principal reservoir of EHEC strains and outbreaks have been associated with direct contact with the farm environment, and with the consumption of meat, dairy products, water and fruit or vegetable contaminated with ruminant manure.

Carbohydrate utilization by enterohaemorrhagic Escherichia coli O157:H7 in bovine intestinal content.

The bovine gastrointestinal (GI) tract is the main reservoir for enterohaemorrhagic Escherichia coli (EHEC) responsible for food-borne infections. Characterization of nutrients preferentially used by EHEC in the bovine intestine would help to develop ecological strategies to reduce EHEC carriage. However, the carbon sources that support the growth of EHEC in the bovine intestine are poorly documented.

Enterohaemorrhagic Escherichia coli gains a competitive advantage by using ethanolamine as a nitrogen source in the bovine intestinal content.

The bovine gastrointestinal tract is the main reservoir for enterohaemorrhagic Escherichia coli (EHEC) responsible for food-borne infections. Characterization of nutrients that promote the carriage of these pathogens by the ruminant would help to develop ecological strategies to reduce their survival in the bovine gastrointestinal tract. In this study, we show for the first time that free ethanolamine (EA) constitutes a nitrogen source for the O157:H7 EHEC strain EDL933 in the bovine intestinal content because of induction of the eut (ethanolamine utilization) gene cluster.

Genomic analysis of the PAI ICL3 locus in pathogenic LEE-negative Shiga toxin-producing Escherichia coli and Citrobacter rodentium.

Shiga toxin-producing Escherichia coli (STEC) causes a spectrum of human illnesses such as haemorrhagic colitis and haemolytic-uraemic syndrome. Although the locus of enterocyte effacement (LEE) seems to confer enhanced virulence, LEE-negative STEC strains are also associated with severe human disease, suggesting that other unknown factors enhance the virulence potential of STEC strains. A novel hybrid pathogenicity island, termed PAI I(CL3), has been previously characterized in the LEE-negative O113 : H21 STEC strain CL3.

Molecular analysis of shiga toxin-producing Escherichia coli strains isolated from hemolytic-uremic syndrome patients and dairy samples in France.

Shiga toxin-producing Escherichia coli (STEC) has been associated with food-borne diseases ranging from uncomplicated diarrhea to hemolytic-uremic syndrome (HUS). While most outbreaks are associated with E. coli O157:H7, about half of the sporadic cases may be due to non-O157:H7 serotypes.

Differential expression of stx2 variants in Shiga toxin-producing Escherichia coli belonging to seropathotypes A and C.

Only a subset of Shiga toxin (Stx)-producing Escherichia coli (STEC) are human pathogens, but the characteristics that account for differences in pathogenicity are not well understood. In this study, we investigated the distribution of the stx variants coding for Stx2 and its variants in highly virulent STEC of seropathotype A and low-pathogenic STEC of seropathotype C. We analysed and compared transcription of the corresponding genes, production of Shiga toxins, and stx-phage release in basal as well as in induced conditions.

Association of virulence genotype with phylogenetic background in comparison to different seropathotypes of Shiga toxin-producing Escherichia coli isolates.

The distribution of virulent factors (VFs) in 287 Shiga toxin-producing Escherichia coli (STEC) strains that were classified according to Karmali et al. into five seropathotypes (M. A.

Localization of the insertion site and pathotype determination of the locus of enterocyte effacement of shiga toxin-producing Escherichia coli strains.

Of 220 Shiga toxin-producing Escherichia coli (STEC) strains collected in central France from healthy cattle, food samples, and asymptomatic children, 12 possessed the eae gene included in the locus of enterocyte effacement (LEE) pathogenicity island. Based on gene typing, we observed 7 different eae espA espB tir pathotypes among the 12 STEC strains and described the new espAbetav variant. As previously observed, the O157 serogroup is associated with eaegamma, O26 is associated with eaebeta, and O103 is associated with eaeepsilon.