Virulence profile comparison between LEE-negative Shiga toxin-producing Escherichia coli (STEC) strains isolated from cattle and humans

Galli, Lucía; Miliwebsky, Elizabeth; Irino, Kinue; Leotta, Gerardo Aníbal; Rivas, Marta

doi:10.1016/j.vetmic.2009.11.028

Cited by 77 publications

(93 citation statements)

References 32 publications

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“…However, 95% of the O91:H21strains, including the HUS-associated strains B2F1 and TW01674, had stx 2 , and all were stx 2a , stx 2c , stx 2d , or combinations of these subtypes. These results are consistent with data obtained from the analysis of clinical O91 strains (14,17,20,27).…”

Section: Discussionsupporting

confidence: 91%

“…However, some studies tested for some of these genes in a few O91 strains. The results that we obtained were mostly consistent with data obtained for two O91:H21 strains isolated from minced meat and raw milk in France (19), four O91:H21 strains isolated from human and bovine sources in Argentina (20), an O91:H21 strain isolated from cattle feces-polluted wastewater in Spain (25), and clinical O91 strains isolated in the European Union (27). From these genotypic studies, we can surmise that the STEC O91 serogroup strains do not have many of the genes that are common in other STEC strains and even differed in the prevalence of genes that are common in other LEE-negative STEC strains, such as serotype O113:H21 strains.…”

Section: Discussionsupporting

confidence: 90%

“…Surveys of nonclinical sources have shown that STEC serogroup O91 strains are also present in foods. These strains have been isolated from raw milk and cheeses in France (17) and Switzerland (18), from minced beef in France (19), and from cattle feces in Argentina (20), and they are the second most common STEC serogroup found in various types of meats and dairy products in Germany (16). In the United States, STEC O91 strains have been isolated from ground beef (21), from the production environments of other food animals, and also from fresh produce (22).…”

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confidence: 99%

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

Feng

Delannoy

Lacher

et al. 2017

Appl Environ Microbiol

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Shiga toxin-producing Escherichia coli (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. Most of the isolates were identified to be strains of the O91:H21 and O91:H14 serotypes, with a few O91:H10 strains and one O91:H9 strain being identified. None of the strains had the eae gene, which codes for the intimin adherence protein, and many did not have some of the genetic markers that are common in other STEC strains. The genetic profiles of the strains within each serotype were similar but differed greatly between strains of different serotypes. The genetic profiles of the O91:H21 strains that we tested were identical or nearly identical to those of the clinical O91:H21 strains that have caused severe diseases. Multilocus sequence typing and clustered regularly interspaced short palindromic repeat analyses showed that the O91:H21 strains clustered within the STEC 1 clonal group but the other O91 serotype strains were phylogenetically diverse.IMPORTANCE This study showed that food and environmental O91:H21 strains have similar genotypic profiles and Shiga toxin subtypes and are phylogenetically related to the O91:H21 strains that have caused hemolytic-uremic syndrome, suggesting that these strains may also have the potential to cause severe illness.KEYWORDS STEC, O91, virulence, diversity S higa toxin (Stx) is the main virulence factor of Shiga toxin-producing Escherichia coli (STEC). There are two main Stx types, designated Stx1 and Stx2, and each has many subtypes. However, STEC pathogenesis is complex, and Stx alone, without an adherence factor, is deemed to be insufficient to cause severe diseases like hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS) (1, 2). The most common STEC adherence factor is the eae-encoded intimin adhesin, which resides on the locus of enterocyte effacement (LEE) pathogenicity island. However, some STEC strains, such as those of serotypes O91:H21, O113:H21, and others, lack eae but have still caused severe disease (3-5) and so are postulated to have other means for adherence. Genes such as saa, which codes for STEC agglutinating adhesin (6), and sab, which codes for an outer membrane autotransporter protein that enhances biofilm formation (7), have been found in LEE-negative STEC strains and are thought to play a role in adherence.STEC serotype O91:H21 strains are LEE negative but have caused HUS (8, 9). The

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 90%

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confidence: 99%

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

Feng

Delannoy

Lacher

et al. 2017

Appl Environ Microbiol

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“…However, the presence of the LEE island does not seem to be essential for full virulence, as a wide number of STEC LEE-negative strains have been associated with sporadic cases and small outbreaks of hemorrhagic colitis and the HUS (9). The increasing number of LEEnegative STEC strains associated with human infection (31,32), and the identification of novel adhesins in STEC O157:H7 (91,97), which are also present in other STEC strains, lead to further characterization of other non-LEE-encoded adhesion factors (Table 1). The following sections describe recent progress in the investigation of those novel adhesion/colonization factors in different STEC strains.…”

Section: Intimin As the Key Colonization Factor Of Stec Strainsmentioning

confidence: 99%

Molecular Mechanisms That Mediate Colonization of Shiga Toxin-Producing Escherichia coli Strains

2012

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Shiga toxin-producing Escherichia coli (STEC) is a group of pathogens which cause gastrointestinal disease in humans and have been associated with numerous food-borne outbreaks worldwide. The intimin adhesin has been considered for many years to be the only colonization factor in these strains. However, the rapid progress in whole-genome sequencing of different STEC serotypes has accelerated the discovery of other adhesins (fimbrial and afimbrial), which have emerged as important contributors to the intestinal colonization occurring during STEC infection. This review summarizes recent progress to identify and characterize, at the molecular level, novel adhesion and colonization factors in STEC strains, with an emphasis on their contribution to virulence traits, their host-pathogen interactions, the regulatory mechanisms controlling their expression, and their role as targets eliciting immune responses in the host. STEC O157:H7 AND NON-O157 STEC Shiga-toxigenic Escherichia coli (STEC) O157:H7 is an important cause of human gastrointestinal disease and the beststudied STEC associated with large outbreaks worldwide (43, 74). STEC O157:H7 strains cause diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS) (59). Disease-associated human isolates of E. coli O157:H7 are characterized for the presence of specific sets of virulence genes, including those encoding Shigatoxins (stx 1 , stx 2 ), intimin (eae), hemolysin (hlyA), and long polar fimbriae (lpf1 and lpf2) (45, 97). The production of Stx is the main virulence feature of STEC associated with the development of HUS (82) but cannot be solely responsible for full pathogenicity. STEC associated with severe human disease is usually capable of colonizing the intestinal mucosa and possesses mobile genetic elements carrying virulence genes, such as plasmids, transposons, phages, and pathogenicity islands (79,92,97). Several important colonization properties are carried by the locus of enterocyte effacement (LEE) pathogenicity island (92), which governs the ability of STEC to colonize the intestinal mucosa of the host and produces a peculiar pathogenic process known as the attachingand-effacing (A/E) lesion (for a review, see reference 59).Most virulence/colonization factors have been described for STEC O157:H7 isolates; however, it is important to identify and determine the virulence traits of other STECs important for disease in humans, the so-called "non-O157 STEC" strains. In addition to diarrhea, these isolates are also associated with severe disease. Several serogroups of non-O157 STEC have been described; however, the serogroups O26, O45, O103, O111, and O145 have been identified as the "big six" non-O157 STEC O serogroups, because they have been associated with increasing frequency in patients with bloody diarrhea and HUS (12,29,41,55). Because the U.S. Food and Drug Administration recognizes that non-O157 STEC serogroups are emerging as an important cause of food-borne disease, these isolates impact both the imported and domestic food supply. Therefor...

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“…The mechanism used by LEE negative STEC strains to adhere and colonize to epithelial cells is poorly understood, although the Protein Sea has been involved in the cells adherence [4]. In a recent study in STEC LEE negatives, Montero, Velasco [5] identified a member of the Heat-resistant agglutinin family and characterized this antigen named Hem agglutinin from Shiga toxin-producing E. coli (Hes).…”

Section: Introductionmentioning

confidence: 99%

Understanding the Detection of Shiga Toxin Producing Escherichia Coli: Virulence Factors, Pathogenicity Islands or Serotypes?

Colello¹

2018

BJSTR

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Virulence profile comparison between LEE-negative Shiga toxin-producing Escherichia coli (STEC) strains isolated from cattle and humans

Cited by 77 publications

References 32 publications

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

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

Molecular Mechanisms That Mediate Colonization of Shiga Toxin-Producing Escherichia coli Strains

Understanding the Detection of Shiga Toxin Producing Escherichia Coli: Virulence Factors, Pathogenicity Islands or Serotypes?

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