scholarly journals Identification and Characterization of a Novel Genomic Island Integrated at selC in Locus of Enterocyte Effacement-Negative, Shiga Toxin-Producing Escherichia coli

2001 ◽  
Vol 69 (11) ◽  
pp. 6863-6873 ◽  
Author(s):  
H. Schmidt ◽  
W.-L. Zhang ◽  
U. Hemmrich ◽  
S. Jelacic ◽  
W. Brunder ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Serine Protease ◽  
Shiga Toxin ◽  
Genomic Island ◽  
Immunoblot Analysis ◽  
Pcr Analysis ◽  
Integrase Gene ◽  
Human Apolipoprotein ◽  
Genes Encoding ◽  
Enterocyte Effacement

ABSTRACT The selC tRNA gene is a common site for the insertion of pathogenicity islands in a variety of bacterial enteric pathogens. We demonstrate here that Escherichia colithat produces Shiga toxin 2d and does not harbor the locus of enterocyte effacement (LEE) contains, instead, a novel genomic island. In one representative strain (E. coliO91:H− strain 4797/97), this island is 33,014 bp long and, like LEE in E. coli O157:H7, is integrated 15 bp downstream of selC. ThisE. coli O91:H− island contains genes encoding a novel serine protease, termed EspI; an adherence-associated locus, similar to iha ofE. coli O157:H7; an E.coli vitamin B12 receptor (BtuB); an AraC-type regulatory module; and four homologues of E.coli phosphotransferase proteins. The remaining sequence consists largely of complete and incomplete insertion sequences, prophage sequences, and an intact phage integrase gene that is located directly downstream of the chromosomal selC. Recombinant EspI demonstrates serine protease activity using pepsin A and human apolipoprotein A-I as substrates. We also detected Iha-reactive protein in outer membranes of a recombinant clone and 10 LEE-negative, Shiga toxin-producing E. coli (STEC) strains by immunoblot analysis. Using PCR analysis of various STEC, enteropathogenic E. coli, enterotoxigenicE. coli, enteroaggregativeE. coli, uropathogenic E.coli, and enteroinvasive E.coli strains, we detected the ihahomologue in 59 (62%) of 95 strains tested. In contrast,espI and btuB were present in only two (2%) and none of these strains, respectively. We conclude that the newly described island occurs exclusively in a subgroup of STEC strains that are eae negative and contain the variantstx 2d gene.

scholarly journals A Genomic Island, Termed High-Pathogenicity Island, Is Present in Certain Non-O157 Shiga Toxin-Producing Escherichia coli Clonal Lineages

1999 ◽  
Vol 67 (11) ◽  
pp. 5994-6001 ◽  
Author(s):  
H. Karch ◽  
S. Schubert ◽  
D. Zhang ◽  
W. Zhang ◽  
H. Schmidt ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Wide Spectrum ◽  
Pathogenicity Island ◽  
Immunoblot Analysis ◽  
Ecological Niches ◽  
Pathogenic Potential ◽  
Integrase Gene ◽  
E Coli ◽  
High Pathogenicity

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) strains cause a wide spectrum of diseases in humans. In this study, we tested 206 STEC strains isolated from patients for potential virulence genes including stx, eae, and enterohemorrhagicE. coli hly. In addition, all strains were examined for the presence of another genetic element, the high-pathogenicity island (HPI). The HPI was first described in pathogenic Yersiniaspecies and encodes the pesticin receptor FyuA and the siderophore yersiniabactin. The HPI was found in the genome of distinct clonal lineages of STEC, including all 31 eae-positive O26:H11/H− strains and 7 of 12 eae-negative O128:H2/H− strains. In total, the HPI was found in 56 (27.2%) of 206 STEC strains. However, it was absent from the genome of all 37 O157:H7/H−, 14 O111:H−, 13 O103:H2, and 13 O145:H− STEC isolates, all of which were positive for eae. Polypeptides encoded by the fyuA gene located on the HPI could be detected by using immunoblot analysis in most of the HPI-positive STEC strains, suggesting the presence of a functional yersiniabactin system. The HPI in STEC was located next to the tRNA gene asnT. In contrast to the HPI of other pathogenic enterobacteria, the HPI of O26 STEC strains shows a deletion at its left junction, leading to a truncated integrase geneint. We conclude from this study that theYersinia HPI is disseminated among certain clonal subgroups of STEC strains. The hypothesis that the HPI in STEC contributes to the fitness of the strains in certain ecological niches rather than to their pathogenic potential is discussed.

scholarly journals Shiga Toxins, and the Genes Encoding Them, in Fecal Samples from Native Idaho Ungulates

2008 ◽  
Vol 75 (3) ◽  
pp. 862-865 ◽  
Author(s):  
Jeremy J. Gilbreath ◽  
Malcolm S. Shields ◽  
Rebekah L. Smith ◽  
Larry D. Farrell ◽  
Peter P. Sheridan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Wild Ungulates ◽  
Fecal Samples ◽  
Shiga Toxins ◽  
Toxin Genes ◽  
Genes Encoding ◽  
Shiga Toxin Genes

ABSTRACT Cattle are a known reservoir of Shiga toxin-producing Escherichia coli. The prevalence and stability of Shiga toxin and/or Shiga toxin genes among native wild ungulates in Idaho were investigated. The frequency of both Shiga genes and toxin was similar to that reported for Idaho cattle (∼19%).

Characteristics of Shiga Toxin–Producing Escherichia coli Isolated from Swiss Raw Milk Cheese within a 3-Year Monitoring Program

2010 ◽  
Vol 73 (1) ◽  
pp. 88-91 ◽  
Author(s):  
C. ZWEIFEL ◽  
N. GIEZENDANNER ◽  
S. CORTI ◽  
G. KRAUSE ◽  
L. BEUTIN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Monitoring Program ◽  
Raw Milk ◽  
Health Impact ◽  
Toxin Gene ◽  
Genes Encoding ◽  
Raw Milk Cheese ◽  
Human Infections ◽  
Hard Cheese

Food is an important vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx1 was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx2 group, mainly stx2 and stx2vh-a/b. Production of Stx2 and Stx2vh-a/b subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

Outbreak of Shiga Toxin–Producing Escherichia coli (STEC) O104:H4 Infection in Germany Causes a Paradigm Shift with Regard to Human Pathogenicity of STEC Strains

2012 ◽  
Vol 75 (2) ◽  
pp. 408-418 ◽  
Author(s):  
LOTHAR BEUTIN ◽  
ANNETT MARTIN
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Outbreak Strain ◽  
Fenugreek Seeds ◽  
E Coli ◽  
Aggregative Adherence ◽  
Uremic Syndrome ◽  
Enterocyte Effacement ◽  
The Way

An outbreak that comprised 3,842 cases of human infections with enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104:H4 occurred in Germany in May 2011. The high proportion of adults affected in this outbreak and the unusually high number of patients that developed hemolytic uremic syndrome makes this outbreak the most dramatic since enterohemorrhagic E. coli (EHEC) strains were first identified as agents of human disease. The characteristics of the outbreak strain, the way it spread among humans, and the clinical signs resulting from EAHEC infections have changed the way Shiga toxin–producing E. coli strains are regarded as human pathogens in general. EAHEC O104:H4 is an emerging E. coli pathotype that is endemic in Central Africa and has spread to Europe and Asia. EAHEC strains have evolved from enteroaggregative E. coli by uptake of a Shiga toxin 2a (Stx2a)–encoding bacteriophage. Except for Stx2a, no other EHEC-specific virulence markers including the locus of enterocyte effacement are present in EAHEC strains. EAHEC O104:H4 colonizes humans through aggregative adherence fimbrial pili encoded by the enteroaggregative E. coli plasmid. The aggregative adherence fimbrial colonization mechanism substitutes for the locus of enterocyte effacement functions for bacterial adherence and delivery of Stx2a into the human intestine, resulting clinically in hemolytic uremic syndrome. Humans are the only known natural reservoir known for EAHEC. In contrast, Shiga toxin–producing E. coli and EHEC are associated with animals as natural hosts. Contaminated sprouted fenugreek seeds were suspected as the primary vehicle of transmission of the EAHEC O104:H4 outbreak strain in Germany. During the outbreak, secondary transmission (human to human and human to food) was important. Epidemiological investigations revealed fenugreek seeds as the source of entry of EAHEC O104:H4 into the food chain; however, microbiological analysis of seeds for this pathogen produced negative results. The survival of EAHEC in seeds and the frequency of human carriers of EAHEC should be investigated for a better understanding of EAHEC transmission routes.

scholarly journals Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Toxins ◽  
2018 ◽  
Vol 10 (6) ◽  
pp. 241 ◽  
Author(s):  
Maike Krause ◽  
Holger Barth ◽  
Herbert Schmidt
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Enterocyte Effacement

scholarly journals Whole-Genome Analysis of a Shiga Toxin-Producing Escherichia coli O103:H2 Strain Isolated from Cattle Feces

2020 ◽  
Vol 9 (45) ◽  
Author(s):  
Yujie Zhang ◽  
Yen-Te Liao ◽  
Vivian C. H. Wu
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Whole Genome Analysis ◽  
Content Type ◽  
Cattle Feces ◽  
Beef Products ◽  
Foodborne Outbreaks ◽  
Enterocyte Effacement

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) serotype O103 is one of the primary pathogenic contaminants of beef products, contributing to several foodborne outbreaks in recent years. Here, we report the whole-genome sequence of a STEC O103:H2 strain isolated from cattle feces that contains a locus of enterocyte effacement (LEE) pathogenicity island.

scholarly journals Use of the espZ Gene Encoded in the Locus of Enterocyte Effacement for Molecular Typing of Shiga Toxin-Producing Escherichia coli

2006 ◽  
Vol 44 (2) ◽  
pp. 449-458 ◽  
Author(s):  
M. W. Gilmour ◽  
D. M. Tracz ◽  
A. K. Andrysiak ◽  
C. G. Clark ◽  
S. Tyson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Molecular Typing ◽  
Enterocyte Effacement

scholarly journals The Locus of Enterocyte Effacement-Encoded Effector Proteins All Promote Enterohemorrhagic Escherichia coli Pathogenicity in Infant Rabbits

2005 ◽  
Vol 73 (3) ◽  
pp. 1466-1474 ◽  
Author(s):  
Jennifer M. Ritchie ◽  
Matthew K. Waldor
Keyword(s):  
Escherichia Coli ◽  
Effector Proteins ◽  
Enterohemorrhagic Escherichia Coli ◽  
Lesion Formation ◽  
Specific Effects ◽  
Genes Encoding ◽  
Organ Specific ◽  
Rabbit Intestine ◽  
Enterocyte Effacement

ABSTRACT The genes encoding the enterohemorrhagic Escherichia coli (EHEC) type III secretion system (TTSS) and five effector proteins secreted by the TTSS are located on the locus of enterocyte effacement (LEE) pathogenicity island. Deletion of tir, which encodes one of these effector proteins, results in a profound reduction (∼10,000-fold) in EHEC colonization of the infant rabbit intestine, but the in vivo phenotypes of other LEE genes are unknown. Here, we constructed in-frame deletions in escN, the putative ATPase component of the TTSS, and the genes encoding the four other LEE-encoded effector proteins, EspH, Map, EspF, and EspG, to investigate the contributions of the TTSS and the translocated effector proteins to EHEC pathogenicity in infant rabbits. We found that the TTSS is required for EHEC colonization and attaching and effacing (A/E) lesion formation in the rabbit intestine. Deletion of escN reduced EHEC recovery from the rabbit intestine by ∼10,000-fold. Although EspH, Map, EspF, and EspG were not required for A/E lesion formation in the rabbit intestine or in HeLa cells, these effector proteins promote EHEC colonization. Colonization by the espH and espF mutants was reduced throughout the intestine. In contrast, colonization by the map and espG mutants was reduced only in the small intestine, indicating that Map and EspG have organ-specific effects. EspF appears to down-regulate the host response to EHEC, since we observed increased accumulation of polymorphonuclear leukocytes in the colonic mucosa of rabbits infected with the EHEC espF mutant. Thus, all the known LEE-encoded effector proteins influence EHEC pathogenicity.

scholarly journals Localization of the Insertion Site and Pathotype Determination of the Locus of Enterocyte Effacement of Shiga Toxin-Producing Escherichia coli Strains

2004 ◽  
Vol 70 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Yolande Bertin ◽  
Karima Boukhors ◽  
Valerie Livrelli ◽  
Christine Martin
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Insertion Site ◽  
Pcr Amplification ◽  
Food Samples ◽  
Asymptomatic Children ◽  
Healthy Cattle ◽  
Sporadic Cases ◽  
Enterocyte Effacement ◽  
Great Genetic Diversity

ABSTRACT 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 espAβv variant. As previously observed, the O157 serogroup is associated with eaeγ, O26 is associated with eaeβ, and O103 is associated with eaeε. However, the unexpected eaeζ allele was detected in 5 of the 12 isolates. PCR amplification and pulsed-field gel electrophoresis using the I-CeuI endonuclease followed by Southern hybridization indicated that the LEE was inserted in the vicinity of the selC (three isolates), pheU (two isolates), or pheV (six isolates) tRNA gene. Six isolates harbored two or three of these tRNA loci altered by the insertion of integrase genes (CP4-int and/or int-phe), suggesting the insertion of additional foreign DNA fragments at these sites. In spite of great genetic diversity of LEE pathotypes and LEE insertion sites, bovine strains harbor alleles of LEE genes that are frequently found in clinical STEC strains isolated from outbreaks and sporadic cases around the world, underscoring the potential risk of the bovine strains on human health.

scholarly journals Contribution of the Twin Arginine Translocation System to the Virulence of Enterohemorrhagic Escherichia coli O157:H7

2003 ◽  
Vol 71 (9) ◽  
pp. 4908-4916 ◽  
Author(s):  
Nathalie Pradel ◽  
Changyun Ye ◽  
Valérie Livrelli ◽  
Jianguo Xu ◽  
Bernard Joly ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Immunoblot Analysis ◽  
Vero Cells ◽  
Soft Agar ◽  
Enterohemorrhagic Escherichia Coli ◽  
E Coli ◽  
Twin Arginine Translocation ◽  
Tat System ◽  
K 12

ABSTRACT Shiga toxin-producing Escherichia coli O157:H7 is a major food-borne infectious pathogen. In order to analyze the contribution of the twin arginine translocation (TAT) system to the virulence of E. coli O157:H7, we deleted the tatABC genes of the O157:H7 EDL933 reference strain. The mutant displayed attenuated toxicity on Vero cells and completely lost motility on soft agar plates. Further analyses revealed that the ΔtatABC mutation impaired the secretion of the Shiga toxin 1 (Stx1) and abolished the synthesis of H7 flagellin, which are two major known virulence factors of enterohemorrhagic E. coli O157:H7. Expression of the EDL933 stxAB 1 genes in E. coli K-12 conferred verotoxicity on this nonpathogenic strain. Remarkably, cytotoxicity assay and immunoblot analysis showed, for the first time, an accumulation of the holotoxin complex in the periplasm of the wild-type strain and that a much smaller amount of StxA1 and reduced verotoxicity were detected in the ΔtatC mutant cells. Together, these results establish that the TAT system of E. coli O157:H7 is an important virulence determinant of this enterohemorrhagic pathogen.

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