Virulence Gene Profiles and Clonal Relationships of Escherichia coli O26:H11 Isolates from Feedlot Cattle as Determined by Whole-Genome Sequencing.

Unlabelled: Escherichia coli O26 is the second most important enterohemorrhagic E. coli (EHEC) serogroup worldwide. Serogroup O26 strains are categorized mainly into two groups: enteropathogenic (EPEC) O26, carrying a locus of enterocyte effacement (LEE) and mostly causing mild diarrhea, and Shiga-toxigenic (STEC) O26, which carries the Shiga toxin (STX) gene (stx), responsible for more severe outcomes.

Genome Sequences of 64 Non-O157:H7 Shiga Toxin-Producing Escherichia coli Strains.

Shiga toxin-producing Escherichia coli (STEC) strains are human pathogens. Although >400 non-O157 serotypes have been involved in human disease, whole-genome sequencing information is missing for many serotypes. We sequenced 64 STEC strains comprising 38 serotypes, isolated from clinical sources, animals, and environmental samples, to improve the phylogenetic understanding of these important foodborne pathogens.

Virulence characterization of non-O157 Shiga toxin-producing Escherichia coli isolates from food, humans and animals.

A total of 359 non-O157 STEC isolates from food, humans and animals were examined for serotypes, Shiga toxin subtypes and intimin subtypes. Isolates solely harboring stx2 from the three sources were selected for Vero cell cytotoxicity test. stx subtypes in eae negative isolates were more diverse than in eae positive isolates primarily carrying stx2a.

Complete Sequences of Six IncA/C Plasmids of Multidrug-Resistant Salmonella enterica subsp. enterica Serotype Newport.

Multidrug-resistant (MDR) Salmonella enterica subsp. enterica serotype Newport has been a long-standing public health concern in the United States. We present the complete sequences of six IncA/C plasmids from animal-derived MDR S.

Genomic diversity and virulence profiles of historical Escherichia coli O157 strains isolated from clinical and environmental sources.

Escherichia coli O157:H7 is, to date, the major E. coli serotype causing food-borne human disease worldwide. Strains of O157 with other H antigens also have been recovered.

Pathogenicity islands in Shiga toxin-producing Escherichia coli O26, O103, and O111 isolates from humans and animals.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) are increasingly recognized as foodborne pathogens worldwide. Serogroups O26, O111, and O103 cause most known outbreaks related to non-O157 STEC. Pathogenicity islands (PAIs) play a major role in the evolution of STEC pathogenicity.

Draft Genome Sequences of Two O104:H21 Escherichia coli Isolates Causing Hemorrhagic Colitis during a 1994 Montana Outbreak Provide Insight into Their Pathogenicity.

We sequenced the genomes of two strains of O104:H21 enterohemorrhagic Escherichia coli (EHEC) isolated during an outbreak of hemorrhagic colitis in Montana in 1994. These strains carried a plasmid that contains several virulence genes not present in pO157. The genome sequences will improve phylogenetic analysis of other non-O157 E.

Genome Sequences of Two Emerging Non-O157 Shiga Toxin-Producing Escherichia coli Strains.

Shiga toxin-producing Escherichia coli (STEC) causes severe illness in humans, including hemorrhagic colitis and hemolytic uremic syndrome. A parallel evolutionary model was proposed in which E. coli strains of distinct phylogenies independently integrate Shiga toxin-encoding genes and evolve into STEC.

Molecular subtyping and virulence gene analysis of Listeria monocytogenes isolates from food.

A total of 67 Listeria monocytogenes isolates from 698 raw meat samples were characterized for molecular serogroup identification and antimicrobial susceptibility. Approximately one third (32.8%) of the isolates belonged to molecular serogroup 1/2a, 3a, followed by 1/2c, 3c (26.

Phylogenetic analysis of non-O157 Shiga toxin-producing Escherichia coli strains by whole-genome sequencing.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains are emerging food-borne pathogens causing life-threatening diseases and food-borne outbreaks. A better understanding of their evolution provides a framework for developing tools to control food safety. We obtained 15 genomes of non-O157 STEC strains, including O26, O111, and O103 strains.

Genetic characterization of Escherichia coli O104 isolates from different sources in the United States.

Escherichia coli O104 isolates collected from different sources in the United States were examined for virulence genes typical of enterohemorrhagic E. coli and those identified in the O104:H4 isolate associated with the 2011 German outbreak. The unexpected presence of virulence markers in these isolates highlights the importance of screening unusual and potentially pathogenic Shiga toxin-producing E.

Prevalence, distribution and evolutionary significance of the IS629 insertion element in the stepwise emergence of Escherichia coli O157:H7.

Background: Insertion elements (IS) are known to play an important role in the evolution and genomic diversification of Escherichia coli O157:H7 lineages. In particular, IS629 has been found in multiple copies in the E. coli O157:H7 genome and is one of the most prevalent IS in this serotype.

Different IS629 transposition frequencies exhibited by Escherichia coli O157:H7 strains in the stepwise evolutionary model.

The insertion sequence IS629, which is highly prevalent in Escherichia coli O157:H7 genomes, was found to be absent in O157:H- strains, which are on a divergent pathway in the emergence of O157:H7. Although O157:H- is deficient in IS629, it permits IS629 transposition, with an excision frequency higher than that of ancestral O55:H7 strains but significantly lower than that of pathogenic O157:H7 strains.

Comparison of commercial RNA extraction kits for preparation of DNA-free total RNA from Salmonella cells.

Background: The isolation of DNA-free RNA is a crucial step in the reverse transcription PCR (RT-PCR). Every RNA extraction procedure results in RNA samples contaminated with genomic DNA, which can cause false-positive outcomes in highly sensitive applications, including a recently developed quantitative real-time PCR (RT-qPCR) assay that targets invA mRNA for the detection of live Salmonella cells. The assay of this specific mRNA can be used to indicate the presence of live, as opposed to dead, cells of Salmonella enterica in a food matrix.

Characterization of a gne::IS629 O rough:H7 Escherichia coli strain from a hemorrhagic colitis patient.

Shiga-toxigenic Escherichia coli strains that are O rough:H7 due to gne::IS629 were thought to be rare and to have unknown pathogenic potential. Recently, an O rough:H7 strain caused by gne::IS629 was isolated from a hemorrhagic colitis patient, suggesting that these strains are pathogenic and may not be as rare as anticipated.

Genetic analysis for the lack of expression of the O157 antigen in an O Rough:H7 Escherichia coli strain.

The O-antigen (rfb) operon and related genes of MA6, an O rough:H7 Shiga-toxigenic Escherichia coli strain, were examined to determine the cause of the lack of O157 expression. A 1,310-bp insertion, homologous to IS629, was observed within its gne gene. trans complementation with a functional gne gene from O157:H7 restored O157 antigen expression in MA6.

Use of multitoxin immunoaffinity columns for determination of aflatoxins and ochratoxin A in ginseng and ginger.

Conditions were optimized for the simultaneous, alkaline, aqueous methanol extraction of aflatoxins (AFL), i.e., B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2), and ochratoxin A (OTA) with subsequent purification, isolation, and determination of the toxins in ginseng and ginger.