Shiga Toxin-Producing Serogroup O91 Escherichia coli Strains Isolated from Food and Environmental Samples.

Shiga toxin-producing (STEC) strains of the O91:H21 serotype have caused severe infections, including hemolytic-uremic syndrome. Strains of the O91 serogroup have been isolated from food, animals, and the environment worldwide but are not well characterized. We used a microarray and other molecular assays to examine 49 serogroup O91 strains (environmental, food, and clinical strains) for their virulence potential and phylogenetic relationships.

The Serogroup O1 and O2 Lipopolysaccharides Are Encoded by Multiple O-antigen Gene Clusters.

strains belonging to serogroups O1 and O2 are frequently associated with human infections, especially extra-intestinal infections such as bloodstream infections or urinary tract infections. These strains can be associated with a large array of flagellar antigens. Because of their frequency and clinical importance, a reliable detection of O1 and O2 strains and also the frequently associated K1 capsule is important for diagnosis and source attribution of infections in humans and animals.

Variable tellurite resistance profiles of clinically-relevant Shiga toxin-producing Escherichia coli (STEC) influence their recovery from foodstuffs.

Tellurite (Tel)-amended selective media and resistance (Tel-R) are widely used for detecting Shiga toxin-producing Escherichia coli (STEC) from foodstuffs. Tel-R of 81 O157 and non-O157 STEC strains isolated from animal, food and human was thus investigated. Variations of STEC tellurite minimal inhibitory concentration (MIC) values have been observed and suggest a multifactorial and variable tellurite resistome between strains.

Genetic Analysis and Detection of fliC H1 and fliC H12 Genes Coding for Serologically Closely Related Flagellar Antigens in Human and Animal Pathogenic Escherichia coli.

The E. coli flagellar types H1 and H12 show a high serological cross-reactivity and molecular serotyping appears an advantageous method to establish a clear discrimination between these flagellar types. Analysis of fliC H1 and fliC H12 gene sequences showed that they were 97.

Revisiting the STEC Testing Approach: Using espK and espV to Make Enterohemorrhagic Escherichia coli (EHEC) Detection More Reliable in Beef.

Current methods for screening Enterohemorrhagic Escherichia coli (EHEC) O157 and non-O157 in beef enrichments typically rely on the molecular detection of stx, eae, and serogroup-specific wzx or wzy gene fragments. As these genetic markers can also be found in some non-EHEC strains, a number of "false positive" results are obtained. Here, we explore the suitability of five novel molecular markers, espK, espV, ureD, Z2098, and CRISPRO26:H11 as candidates for a more accurate screening of EHEC strains of greater clinical significance in industrialized countries.

Defining the Genome Features of Escherichia albertii, an Emerging Enteropathogen Closely Related to Escherichia coli.

Escherichia albertii is a recently recognized close relative of Escherichia coli. This emerging enteropathogen possesses a type III secretion system (T3SS) encoded by the locus of enterocyte effacement, similar to enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC).

Improved traceability of Shiga-toxin-producing Escherichia coli using CRISPRs for detection and typing.

Among strains of Shiga-toxin-producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are frequently associated with severe clinical illness in humans. The development of methods for their reliable detection from complex samples such as food has been challenging thus far, and is currently based on the PCR detection of the major virulence genes stx1, stx2, and eae, and O-serogroup-specific genes. However, this approach lacks resolution.

Detection of Shiga Toxin-Producing Escherichia coli from Nonhuman Sources and Strain Typing.

Shiga toxin-producing Escherichia coli (STEC) strains are commonly found in the intestine of ruminant species of wild and domestic animals. Excretion of STEC with animal feces results in a broad contamination of food and the environment. Humans get infected with STEC through ingestion of contaminated food, by contact with the environment, and from STEC-excreting animals and humans.

Sequence Variations in the Flagellar Antigen Genes fliCH25 and fliCH28 of Escherichia coli and Their Use in Identification and Characterization of Enterohemorrhagic E. coli (EHEC) O145:H25 and O145:H28.

Enterohemorrhagic E. coli (EHEC) serogroup O145 is regarded as one of the major EHEC serogroups involved in severe infections in humans. EHEC O145 encompasses motile and non-motile strains of serotypes O145:H25 and O145:H28.

Genetic Diversity of the fliC Genes Encoding the Flagellar Antigen H19 of Escherichia coli and Application to the Specific Identification of Enterohemorrhagic E. coli O121:H19.

Enterohemorrhagic Escherichia coli (EHEC) O121:H19 belong to a specific clonal type distinct from other classical EHEC and major enteropathogenic E. coli groups and is regarded as one of the major EHEC serogroups involved in severe infections in humans. Sequencing of the fliC genes associated with the flagellar antigen H19 (fliCH19) revealed the genetic diversity of the fliCH19 gene sequences in E.

Can apoptosis and necrosis coexist in ejaculated human spermatozoa during in vitro semen bacterial infection?

Purpose: To evaluate whether ejaculated human spermatozoa undergo complete apoptosis or necrosis during experimental semen bacterial infection in vitro.

Methods: Apoptotic markers, including mitochondrial transmembrane potential (ΔΨm), phosphatidylserine (PS) externalization, and DNA fragmentation, have been detected simultaneously in ejaculated human sperm after their incubation with a known pathogenic (Escherichia coli), as well as with conditionally pathogenic bacterial strains (Staphylococcus haemolyticus, Bacteroides ureolyticus) and/or leukocytes. The ΔΨm and translocation of PS was evaluated using the JC-1 and Annexin V binding tests, respectively.

blaCTX-M-₁₅-carrying Escherichia coli and Salmonella isolates from livestock and food in Germany.

Objectives: The characterization of CTX-M-₁₅ β-lactamase-producing Escherichia coli and Salmonella isolates originating mainly from German livestock and food.

Methods: E. coli (526, mainly commensals) and Salmonella (151) non-human isolates resistant to third-generation cephalosporins, originating from routine and monitoring submissions (2003-12) to the Federal Institute for Risk Assessment and different national targeted studies (2011-12), were examined for the presence of blaCTX-M-₁₅ genes by PCR amplification/sequencing.

Exploiting the explosion of information associated with whole genome sequencing to tackle Shiga toxin-producing Escherichia coli (STEC) in global food production systems.

The rates of foodborne disease caused by gastrointestinal pathogens continue to be a concern in both the developed and developing worlds. The growing world population, the increasing complexity of agri-food networks and the wide range of foods now associated with STEC are potential drivers for increased risk of human disease. It is vital that new developments in technology, such as whole genome sequencing (WGS), are effectively utilized to help address the issues associated with these pathogenic microorganisms.

Fertilizing potential of ejaculated human spermatozoa during in vitro semen bacterial infection.

Objective: To assess the in vitro effect of three bacterial isolates (Escherichia coli, serotype O75:HNT, Staphylococcus haemolyticus, and Bacteroides ureolyticus) and/or leukocytes on sperm motility, subcellular changes in sperm plasma membranes, and sperm fertilizing potential.

Design: An in vitro model of semen bacterial infection.

Setting: Basic research laboratory.

Emerging types of Shiga toxin-producing E. coli (STEC) O178 present in cattle, deer, and humans from Argentina and Germany.

More than 400 serotypes of Shiga toxin-producing Escherichia coli (STEC) have been implicated in outbreaks and sporadic human diseases. In recent years STEC strains belonging to serogroup O178 have been commonly isolated from cattle and food of bovine origin in South America and Europe. In order to explore the significance of these STEC strains as potential human pathogens, 74 German and Argentinean E.

Novel morphological findings of human sperm removal by leukocytes in in vivo and in vitro conditions: preliminary study.

Problem: Biological significance of increased number of leukocytes in ejaculate remains a subject of controversy. The aim of this research was to describe the morphological characteristics of the sperm elimination by leukocytes in in vivo and in vitro conditions using natural stimulator of the immune system--uropathogenic Escherichia coli, O75:HNT, isolated from semen.

Method Of Study: The study was performed on ejaculated spermatozoa from normozoospermic men with leukocytospermia (n=10, in vivo experiment) or without leukocytospermia (n=15, in vitro experiment).

Genetic diversity and virulence potential of shiga toxin-producing Escherichia coli O113:H21 strains isolated from clinical, environmental, and food sources.

Shiga toxin-producing Escherichia coli strains of serotype O113:H21 have caused severe human diseases, but they are unusual in that they do not produce adherence factors coded by the locus of enterocyte effacement. Here, a PCR microarray was used to characterize 65 O113:H21 strains isolated from the environment, food, and clinical infections from various countries. In comparison to the pathogenic strains that were implicated in hemolytic-uremic syndrome in Australia, there were no clear differences between the pathogens and the environmental strains with respect to the 41 genetic markers tested.

α-Haemolysin of Escherichia coli in IBD: a potentiator of inflammatory activity in the colon.

Objective: α-Haemolysin (HlyA) influences host cell ionic homeostasis and causes concentration-dependent cell lysis. As a consequence, HlyA-producing Escherichia coli is capable of inducing 'focal leaks' in colon epithelia, through which bacteria and antigens translocate. This study addressed the role of HlyA as a virulence factor in the pathogenesis of colitis according to the 'leaky gut' concept.

Shiga toxin-producing Escherichia coli strains from cattle as a source of the Stx2a bacteriophages present in enteroaggregative Escherichia coli O104:H4 strains.

Enteroaggregative, Shiga toxin-producing E. coli (EAEC-STEC) O104:H4 strains are emerging pathogens causing life threatening diseases in humans. EAEC-STEC O104:H4 strains isolated between 2001 and 2011 were found to harbor a distinct type of Shiga toxin 2a- (Stx2a) encoding prophage.

Characteristics of enteroaggregative Escherichia coli isolated from healthy carriers and from patients with diarrhoea.

The aim of this study was to compare the virulence characteristics and phylogenetic features of enteroaggregative Escherichia coli (EAEC) strains from adults with and without diarrhoea and to search for associations between the analysed genes and carrier or diarrhoeagenic strains, respectively. Faecal samples of 487 healthy humans were screened for EAEC strains and compared with isolates from diarrhoeal patients. Virulence and virulence-associated gene typing, serotyping, multilocus sequence typing and antibiotic susceptibility testing were performed for characterization of the isolates.

Molecular and phenotypic characterization of Escherichia coli O26:H8 among diarrheagenic E. coli O26 strains isolated in Brazil.

Escherichia coli strains of serogroup O26 comprise two distinct groups of pathogens, characterized as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC).

Discrimination of enterohemorrhagic Escherichia coli (EHEC) from non-EHEC strains based on detection of various combinations of type III effector genes.

Enterohemorrhagic Escherichia coli (EHEC) strains comprise a subgroup of Shiga-toxin (Stx)-producing E. coli (STEC) and are characterized by a few serotypes. Among these, seven priority STEC serotypes (O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, O145:H28, and O157:H7) are most frequently implicated in severe clinical illness worldwide.

Genotypes and virulence characteristics of Shiga toxin-producing Escherichia coli O104 strains from different origins and sources.

Sixty-two Escherichia coli strains carrying the wzxO104-gene from different sources, origins and time periods were analyzed for their serotypes, virulence genes and compared for genomic similarity by pulsed-field gel-electrophoresis (PFGE). The O104 antigen was present in 55 strains and the structurally and genetically related capsular antigen K9 in five strains. The presence of 49 genes associated with enteropathogenic E.

Towards a molecular definition of enterohemorrhagic Escherichia coli (EHEC): detection of genes located on O island 57 as markers to distinguish EHEC from closely related enteropathogenic E. coli strains.

Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far.