scholarly journals Molecular Evolution of the Intimin Gene in O111 Clones of Pathogenic Escherichia coli

2002 ◽  
Vol 184 (2) ◽  
pp. 479-487 ◽  
Author(s):  
Cheryl L. Tarr ◽  
Thomas S. Whittam
Keyword(s):  
Escherichia Coli ◽  
Developed Countries ◽  
The United States ◽  
Food Borne ◽  
Pathogenic Escherichia Coli ◽  
Close Relationship ◽  
Important Virulence Factor ◽  
Enterocyte Effacement ◽  
Close Relatives ◽  
Random Substitution

ABSTRACT Intimin is an important virulence factor in two groups of enteric pathogens: enteropathogenic Escherichia coli (EPEC), which is a major cause of infant diarrhea in the developing world, and enterohemorrhagic E. coli (EHEC), which has caused large food-borne outbreaks of hemorrhagic colitis in the United States and other developed countries. Intimin is encoded on a 35-kb pathogenicity island called the locus of enterocyte effacement (LEE). At least five antigenic types have been described for the highly variable gene, and each type is generally characteristic of particular evolutionary lineages. We determined the nucleotide sequences of intimin and other LEE genes in two O111 clones that have not been amenable to typing. The sequences from both O111:H8 and O111:H9 differed from the Int-β that is typical of other clones in the same evolutionary lineage. The sequence from the O111:H8 strains was a mosaic of divergent segments that alternately clustered with Int-α, Int-β, or Int-γ. The sequence from the O111:H9 clone consistently showed a close relationship with that from E2348/69, a distantly related strain that expresses Int-α. The results suggest that there have been multiple acquisitions of the LEE in the EHEC 2/EPEC 2 clonal lineage, with a recent turnover in either O111:H8 or its close relatives. Amino acid substitutions that alter residue charge occurred more frequently than would be expected under random substitution in the extracellular domains of intimin, suggesting that diversifying selection has promoted divergence in this region of the protein. An N-terminal domain that presumably functions in the periplasm may also be under positive selection.

scholarly journals Potentially Human-Pathogenic Escherichia coli O26 in Norwegian Sheep Flocks

2011 ◽  
Vol 77 (14) ◽  
pp. 4949-4958 ◽  
Author(s):  
C. Sekse ◽  
M. Sunde ◽  
B.-A. Lindstedt ◽  
P. Hopp ◽  
T. Bruheim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Human Pathogens ◽  
Content Type ◽  
Representative Sampling ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Close Relationship ◽  
Large Survey

ABSTRACTA national survey ofEscherichia coliO26 in Norwegian sheep flocks was conducted, using fecal samples to determine the prevalence. In total, 491 flocks were tested, andE. coliO26 was detected in 17.9% of the flocks. One hundred forty-twoE. coliO26 isolates were examined for flagellar antigens (H typing) and four virulence genes, includingstxandeae, to identify possible Shiga toxin-producingE. coli(STEC) and enteropathogenicE. coli(EPEC). Most isolates (129 out of 142) were identified asE. coliO26:H11. They possessedeaeand may have potential as human pathogens, although only a small fraction were identified as STEC O26:H11, giving a prevalence in sheep flocks of only 0.8%. Correspondingly, the sheep flock prevalence of atypical EPEC (aEPEC) O26:H11 was surprisingly high (15.9%). The genetic relationship between theE. coliO26:H11 isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus variable number tandem repeat analysis (MLVA), identifying 63 distinct PFGE profiles and 22 MLVA profiles. Although the MLVA protocol was less discriminatory than PFGE and a few cases of disagreement were observed, comparison by partition mapping showed an overall good accordance between the two methods. A close relationship between a few isolates of aEPEC O26:H11 and STEC O26:H11 was identified, but all theE. coliO26:H11 isolates should be considered potentially pathogenic to humans. The present study consisted of a representative sampling of sheep flocks from all parts of Norway. This is the first large survey of sheep flocks focusing onE. coliO26 in general, including results of STEC, aEPEC, and nonpathogenic isolates.

Introduction to the Food Safety Concerns of Verotoxin-Producing Escherichia coli

2003 ◽  
Vol 228 (4) ◽  
pp. 331-332 ◽  
Author(s):  
Hussein S. Hussein ◽  
Stanley T. Omaye
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Safety Concern ◽  
Critical Evaluation ◽  
The United States ◽  
Global Perspective ◽  
E Coli ◽  
The Past ◽  
Food Borne Pathogens ◽  
Food Borne

Verotoxin-producing Escherichia coli (VTEC) have emerged in the past two decades as food-borne pathogens that can cause major outbreaks of human illnesses worldwide. The number of outbreaks has increased in recent years due to changes in food production and processing systems, eating habits, microbial adaptation, and methods of VTEC transmission. The human illnesses range from mild diarrhea to hemolytic uremic syndrome (HUS) that can lead to death. The VTEC outbreaks have been attributed to O157:H7 and non-O157:H7 serotypes of E. coli. These E. coli serotypes include motile (e.g., O26:H11 and O104:H21) and nonmotile (e.g., O111:H–,0145:H–, and O157:H–) strains. In the United States, E. coli O157:H7 has been the major cause of VTEC outbreaks. Worldwide, however, non-O157:H7 VTEC (e.g., members of the 026, O103, O111, O118, O145, and O166 serogroups) have caused approximately 30% of the HUS cases in the past decade. Because large numbers of the VTEC outbreaks have been attributed to consumption of ruminant products (e.g., ground beef), cattle and sheep are considered reservoirs of these food-borne pathogens. Because of the food safety concern of VTEC, a global perspective on this problem is addressed (Exp Biol Med Vol. 228, No. 4). The first objective was to evaluate the known non-O157:H7 VTEC strains and the limitations associated with their detection and characterization. The second objective was to identify the VTEC serotypes associated with outbreaks of human illnesses and to provide critical evaluation of their virulence. The third objective was to determine the rumen effect on survival of E. coli O157:H7 as a VTEC model. The fourth objective was to explore the role of intimins in promoting attaching and effacing lesions in humans. Finally, the ability of VTEC to cause persistent infections in cattle was evaluated.

scholarly journals Escherichia coli and Salmonella spp. in meat in Jeddah, Saudi Arabia

2013 ◽  
Vol 7 (11) ◽  
pp. 812-818 ◽  
Author(s):  
Archana Iyer ◽  
Taha Kumosani ◽  
Soonham Yaghmoor ◽  
Elie Barbour ◽  
Esam Azhar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Diseases ◽  
Developed Countries ◽  
Salmonella Spp ◽  
E Coli ◽  
Food Borne Pathogens ◽  
Food Borne ◽  
Microbiological Methods ◽  
Meat Samples ◽  
Butcher Shops

Introduction: Food-borne pathogens are the leading cause of illness and death in developing countries, killing approximately 1.8 million people annually. In developed countries, food-borne pathogens are responsible for millions of cases of infectious gastrointestinal diseases each year, costing billions of dollars. The objective of this study was to screen for two major food-borne pathogens, Escherichia coli and Salmonella spp., from meat samples obtained from different strata of the consumer market in Jeddah. Methodology: A total of 60 meat samples, 20 each from large hypermarkets, groceries and small butcher shops were used in the study. Samples were transported to the laboratory in a cooler. They were macerated in peptone water and then seeded on selective media appropriate for each organism. Colonies were identified using conventional microbiological methods and suspected colonies were confirmed as E. coli and Salmonella spp. by polymerase chain reaction (PCR) using specific primers. Results: The results indicated a high degree of contamination in samples from butcher shops as compared to those from groceries or hypermarkets (high scale supermarkets). Both pathogens E. coli and Salmonella spp. were found in higher rates in the samples from butcher shops. In small butcher shops, E. coli was found at an incidence of 65%, and Salmonella at 45%. Conclusion: The results indicate an urgent need for applying proper food hygienic practices in food outlets, especially in small ones, to reduce the incidence of food-borne diseases. Vigilance by the right agencies must be implemented in order to prevent future food-borne outbreaks.

scholarly journals Genomic Diversity and Virulence Profiles of Historical Escherichia coli O157 Strains Isolated from Clinical and Environmental Sources

2014 ◽  
Vol 81 (2) ◽  
pp. 569-577 ◽  
Author(s):  
Lydia V. Rump ◽  
Narjol Gonzalez-Escalona ◽  
Wenting Ju ◽  
Fei Wang ◽  
Guojie Cao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
The United States ◽  
Genomic Diversity ◽  
Severe Illness ◽  
Pathogenic Potential ◽  
Content Type ◽  
E Coli ◽  
Virulence Markers ◽  
Virulence Potential ◽  
Food Borne

ABSTRACTEscherichia coliO157:H7 is, to date, the majorE. coliserotype causing food-borne human disease worldwide. Strains of O157 with other H antigens also have been recovered. We analyzed a collection of historic O157 strains (n= 400) isolated in the late 1980s to early 1990s in the United States. Strains were predominantly serotype O157:H7 (55%), and various O157:non-H7 (41%) serotypes were not previously reported regarding their pathogenic potential. Although lacking Shiga toxin (stx) andeaegenes, serotypes O157:H1, O157:H2, O157:H11, O157:H42, and O157:H43 carried several virulence factors (iha,terD, andhlyA) also found in virulent serotypeE. coliO157:H7. Pulsed-field gel electrophoresis (PFGE) showed the O157 serogroup was diverse, with strains with the same H type clustering together closely. Among non-H7 isolates, serotype O157:H43 was highly prevalent (65%) and carried important enterohemorrhagicE. coli(EHEC) virulence markers (iha,terD,hlyA, andespP). Isolates from two particular H types, H2 and H11, among the most commonly found non-O157 EHEC serotypes (O26:H11, O111:H11, O103:H2/H11, and O45:H2), unexpectedly clustered more closely with O157:H7 than other H types and carried several virulence genes. This suggests an early divergence of the O157 serogroup to clades with different pathogenic potentials. The appearance of important EHEC virulence markers in closely related H types suggests their virulence potential and suggests further monitoring of those serotypes not implicated in severe illness thus far.

scholarly journals Modelling Growth and Decline in a Two-Species Model System: Pathogenic Escherichia coli O157:H7 and Psychrotrophic Spoilage Bacteria in Milk

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 331 ◽  
Author(s):  
Emiliano J. Quinto ◽  
Juan M. Marín ◽  
Irma Caro ◽  
Javier Mateo ◽  
Donald W. Schaffner
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Food Borne ◽  
Pathogenic Escherichia Coli ◽  
Spoilage Bacteria ◽  
Processing And Storage ◽  
And Storage ◽  
Natural Microbiota

Shiga toxin-producing Escherichia coli O157:H7 is a food-borne pathogen and the major cause of hemorrhagic colitis. Pseudomonas is the genus most frequent psychrotrophic spoilage microorganisms present in milk. Two-species bacterial systems with E. coli O157:H7, non-pathogenic E. coli, and P. fluorescens in skimmed milk at 7, 13, 19, or 25 °C were studied. Bacterial interactions were modelled after applying a Bayesian approach. No direct correlation between P. fluorescens’s growth rate and its effect on the maximum population densities of E. coli species was found. The results show the complexity of the interactions between two species in a food model. The use of natural microbiota members to control foodborne pathogens could be useful to improve food safety during the processing and storage of refrigerated foods.

scholarly journals The Genome Sequence of Avian Pathogenic Escherichia coli Strain O1:K1:H7 Shares Strong Similarities with Human Extraintestinal Pathogenic E. coli Genomes

2007 ◽  
Vol 189 (8) ◽  
pp. 3228-3236 ◽  
Author(s):  
Timothy J. Johnson ◽  
Subhashinie Kariyawasam ◽  
Yvonne Wannemuehler ◽  
Paul Mangiamele ◽  
Sara J. Johnson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genomic Sequence ◽  
Epidemiological Studies ◽  
Coli Strain ◽  
Avian Pathogenic Escherichia Coli ◽  
Future Studies ◽  
E Coli ◽  
Food Borne ◽  
Pathogenic Escherichia Coli ◽  
Complete Genomic

ABSTRACT Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include human uropathogenic E. coli (UPEC) and avian pathogenic E. coli (APEC). Regardless of host of origin, ExPEC strains share many traits. It has been suggested that these commonalities may enable APEC to cause disease in humans. Here, we begin to test the hypothesis that certain APEC strains possess potential to cause human urinary tract infection through virulence genotyping of 1,000 APEC and UPEC strains, generation of the first complete genomic sequence of an APEC (APEC O1:K1:H7) strain, and comparison of this genome to all available human ExPEC genomic sequences. The genomes of APEC O1 and three human UPEC strains were found to be remarkably similar, with only 4.5% of APEC O1's genome not found in other sequenced ExPEC genomes. Also, use of multilocus sequence typing showed that some of the sequenced human ExPEC strains were more like APEC O1 than other human ExPEC strains. This work provides evidence that at least some human and avian ExPEC strains are highly similar to one another, and it supports the possibility that a food-borne link between some APEC and UPEC strains exists. Future studies are necessary to assess the ability of APEC to overcome the hurdles necessary for such a food-borne transmission, and epidemiological studies are required to confirm that such a phenomenon actually occurs.

scholarly journals The Citrobacter rodentium Genome Sequence Reveals Convergent Evolution with Human Pathogenic Escherichia coli

2009 ◽  
Vol 192 (2) ◽  
pp. 525-538 ◽  
Author(s):  
Nicola K. Petty ◽  
Richard Bulgin ◽  
Valerie F. Crepin ◽  
Ana M. Cerdeño-Tárraga ◽  
Gunnar N. Schroeder ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Effector Proteins ◽  
Genomic Islands ◽  
Citrobacter Rodentium ◽  
Mobile Dna ◽  
Secretion Systems ◽  
Pathogenic Escherichia Coli ◽  
Enterocyte Effacement ◽  
Host Infection

ABSTRACT Citrobacter rodentium (formally C itrobacter freundii biotype 4280) is a highly infectious pathogen that causes colitis and transmissible colonic hyperplasia in mice. In common with enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively), C. rodentium exploits a type III secretion system (T3SS) to induce attaching and effacing (A/E) lesions that are essential for virulence. Here, we report the fully annotated genome sequence of the 5.3-Mb chromosome and four plasmids harbored by C. rodentium strain ICC168. The genome sequence revealed key information about the phylogeny of C. rodentium and identified 1,585 C. rodentium-specific (without orthologues in EPEC or EHEC) coding sequences, 10 prophage-like regions, and 17 genomic islands, including the locus for enterocyte effacement (LEE) region, which encodes a T3SS and effector proteins. Among the 29 T3SS effectors found in C. rodentium are all 22 of the core effectors of EPEC strain E2348/69. In addition, we identified a novel C. rodentium effector, named EspS. C. rodentium harbors two type VI secretion systems (T6SS) (CTS1 and CTS2), while EHEC contains only one T6SS (EHS). Our analysis suggests that C. rodentium and EPEC/EHEC have converged on a common host infection strategy through access to a common pool of mobile DNA and that C. rodentium has lost gene functions associated with a previous pathogenic niche.

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