Determination of Adhesin Gene Sequences in, and Biofilm Formation by, O157 and Non-O157 Shiga Toxin-Producing<i>Escherichia coli</i>Strains Isolated from Different Sources

Biscola, Franciele Tafarello; Abe, Cecília M.; Guth, Beatriz E. C.

doi:10.1128/aem.01920-10

Cited by 55 publications

(62 citation statements)

References 38 publications

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“…The first set of primers amplified the passengerencoding domain sequence (named eha ␣ ) where nucleotide divergences have been described. The other set of primers amplified the translocationencoding domain sequence (named eha ␤ ), which is highly conserved (8,18,28).…”

Section: Methodsmentioning

confidence: 99%

“…The biofilm-forming ability of STEC has been investigated under different conditions, using different STEC isolates representing different serotypes and origins (6)(7)(8). Biofilm formation by STEC may be regarded as a survival strategy for this bacterium (9)(10)(11)(12).…”

mentioning

confidence: 99%

“…Moreover, non-O157 isolates continue to gain importance as pathogens of concern (15). Their biofilm-forming abilities were shown to be different from those of O157 isolates (8). This gives importance to characterizing STEC biofilms and to understanding how these bacteria travel through the food supply chain from preharvest to consumer goods.…”

mentioning

confidence: 99%

“…Fimbriae such as type 1 fimbriae, curli, long polar fimbriae, and F9 fimbriae have been hypothesized to be required largely during the attachment step (16). The maturation step of STEC biofilm is thought to involve mostly autotransporters such as EhaA, EhaB, Agn43, Cah, and EspP (8,(17)(18)(19)(20) and exopolysaccharides such as poly-N-acetylglucosamine (PGA), cellulose, and colanic acid (21). We hypothesize that its ability to form biofilms contributes to STEC persistence and that this consequently could influence their incidence.…”

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confidence: 99%

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Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections

Vogeleer

Tremblay

Jubelin³

et al. 2016

Appl Environ Microbiol

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bForming biofilms may be a survival strategy of Shiga toxin-producing Escherichia coli to enable it to persist in the environment and the food industry. Here, we evaluate and characterize the biofilm-forming ability of 39 isolates of Shiga toxin-producing Escherichia coli isolates recovered from human infection and belonging to seropathotypes A, B, or C. The presence and/or production of biofilm factors such as curli, cellulose, autotransporter, and fimbriae were investigated. The polymeric matrix of these biofilms was analyzed by confocal microscopy and by enzymatic digestion. Cell viability and matrix integrity were examined after sanitizer treatments. Isolates of the seropathotype A (O157:H7 and O157:NM), which have the highest relative incidence of human infection, had a greater ability to form biofilms than isolates of seropathotype B or C. Seropathotype A isolates were unique in their ability to produce cellulose and poly-N-acetylglucosamine. The integrity of the biofilms was dependent on proteins. Two autotransporter genes, ehaB and espP, and two fimbrial genes, z1538 and lpf2, were identified as potential genetic determinants for biofilm formation. Interestingly, the ability of several isolates from seropathotype A to form biofilms was associated with their ability to agglutinate yeast in a mannose-independent manner. We consider this an unidentified biofilmassociated factor produced by those isolates. Treatment with sanitizers reduced the viability of Shiga toxin-producing Escherichia coli but did not completely remove the biofilm matrix. Overall, our data indicate that biofilm formation could contribute to the persistence of Shiga toxin-producing Escherichia coli and specifically seropathotype A isolates in the environment. Shiga toxin-producing Escherichia coli (STEC) strains, including enterohemorrhagic E. coli (EHEC), are food-borne and waterborne human enteric pathogens responsible for infections. They are associated with important public health concerns in developed countries. Symptoms associated with STEC infections range from abdominal cramps and bloody diarrhea to postinfectious complications, such as hemolytic-uremic syndrome (HUS). HUS, a life-threatening complication of STEC infections, is a consequence of Shiga toxin production. According to the Public Health Agency of Canada (PHAC), more than 30,000 cases of STEC infections occur each year in Canada (1). Environmentally, the main reservoir for STEC is cattle. Transmission of STEC to humans typically is associated with the consumption of contaminated food such as undercooked beef, fresh produce, unpasteurized milk, or contaminated drinking water (2), but these pathogens also can be transmitted from person to person or via direct contact with animals or their feces.The 2003 Karmali seropathotype model classifies STEC into seropathotypes based on their reported incidence in human disease, outbreaks, and/or association with the development of severe symptoms in humans (3). Serotypes frequently responsible for hemorrhagic colitis (HC) and HUS, ...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections

Vogeleer

Tremblay

Jubelin³

et al. 2016

Appl Environ Microbiol

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“…This observation has led to naming the proteins calcium-binding antigen 43 homologous or Cah. The recent evaluation of cah genes in a STEC collection found that the cah gene was present in 17 of 18 STEC O157:H7 strains (94%) and 6 of 33 STEC non-O157 strains (18%) (10). Expression of Cah on E. coli DH5␣ produced an autoaggregation phenotype, absent when the cah gene is inactivated, indicating that Cah promotes bacterium-to-bacterium interaction (95).…”

Section: Stec Autotransportersmentioning

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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Human pathogens in plant biofilms: Formation, physiology, and detection

Ximenes

Hoagland

et al. 2017

Biotech & Bioengineering

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Fresh produce, viewed as an essential part of a healthy life style is usually consumed in the form of raw or minimally processed fruits and vegetables, and is a potentially important source of food-borne human pathogenic bacteria and viruses. These are passed on to the consumer since the bacteria can form biofilms or otherwise populate plant tissues, thereby using plants as vectors to infect animal hosts. The life cycle of the bacteria in plants differs from those in animals or humans and results in altered physiochemical and biological properties (e.g., physiology, immunity, native microflora, physical barriers, mobility, and temperature). Mechanisms by which healthy plants may become contaminated by microorganisms, develop biofilms, and then pass on their pathogenic burden to people are explored in the context of hollow fiber microfiltration by which plant-derived microorganisms may be recovered and rapidly concentrated to facilitate study of their properties. Enzymes, when added to macerated plant tissues, hydrolyze or alter macromolecules that would otherwise foul hollow-fiber microfiltration membranes. Hence, microfiltration may be used to quickly increase the concentration of microorganisms to detectable levels. This review discusses microbial colonization of vegetables, formation and properties of biofilms, and how hollow fiber microfiltration may be used to concentrate microbial targets to detectable levels. The use of added enzymes helps to disintegrate biofilms and minimize hollow fiber membrane fouling, thereby providing a new tool for more time effectively elucidating mechanisms by which biofilms develop and plant tissue becomes contaminated with human pathogens. Biotechnol. Bioeng. 2017;114: 1403-1418. © 2017 Wiley Periodicals, Inc.

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Determination of Adhesin Gene Sequences in, and Biofilm Formation by, O157 and Non-O157 Shiga Toxin-ProducingEscherichia coliStrains Isolated from Different Sources

Cited by 55 publications

References 38 publications

Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections

Biofilm-Forming Abilities of Shiga Toxin-Producing Escherichia coli Isolates Associated with Human Infections

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

Human pathogens in plant biofilms: Formation, physiology, and detection

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