Relevance of Biofilms in the Pathogenesis of Shiga-Toxin-Producing<i>Escherichia coli</i>Infection

Villegas, Natalia Ángel; Baronetti, José L.; Albesa, Inés; Polifroni, Rosana; Parma, A; Etcheverría, Analía Inés; Becerra, María Cecilia; Padola, Nora Lía; Paraje, María Gabriela

doi:10.1155/2013/607258

Cited by 26 publications

(23 citation statements)

References 29 publications

(48 reference statements)

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“…A study using viable but nonculturable O157 STEC cells showed stresses can induce Shigatoxin production by qRT-PCR and Vero-cytotoxicity assay (Liu et al, 2010). Another study showed that stresses could promote Shiga toxin release as well as biofilm formation (Villegas et al, 2013). In our study, stressed STEC had higher cytotoxicity than non-stressed STEC, and the increased release of toxin may also increase their survival under stressed environments.…”

Section: Influence Of Stresses On the Cytotoxicity Of Stec Grown In Gsupporting

confidence: 53%

Effects of Stresses on the Growth and Cytotoxicity of Shiga-Toxin Producing Escherichia coli in Ground Beef and Spinach

2017

SDRP-JFST

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†Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer. Abstract:The objectives of this study were to examine the effect of stresses on the growth and cytotoxicity of pathogenic Escherichia coli in beef and spinach. A mixture of three strains of Shiga toxin-producing E. coli (STEC) O157:H7 or 4 strains of non-O157 STEC, O26:H11, O103:H1, O104:H4, and O145:NM, was subjected to stress of 2 ppm chlorine, aw 0.97, pH 5, or 15-day starvation. Stressed or non-stressed STEC was inoculated into 5 g of irradiated ground beef or spinach. The cell populations during storage at 8, 12, or 16C for 4 weeks were compared to evaluate the growth variation between O157 and non-O157 STEC. Supernatant from each sample after 24-h incubation at 22C was used to determine Vero-cytotoxicity using [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, MTS] or lactate dehydrogenase (LDH) assay to evaluate the effects of stresses on the cytotoxicity exhibited by STEC. After one week at 8C, the population of non-stressed non-O157 (3.1 log CFU/g) was significantly (p<0.05) higher than O157 (1.9 log CFU/g) in ground beef, and the difference in populations (3.9 vs. 1.7 log CFU/g, p<0.05) was also observed after 4 weeks. However, in spinach, the populations after 4 weeks at 8C were not significant (3.9 vs. 3.3 log CFU/g). Starvation or chlorine stress induced higher growth in non-O157 than O157 in ground beef (4.5 vs. 1.2 log CFU/g) and spinach (4.7 vs. 2.5 log CFU/g). At 12 and 16C, cell populations of stressed and nonstressed O157 or non-O157 STEC were not significantly (p>0.05) different in beef and spinach. MTS assay showed that stressed O157 and non-O157 STEC exhibited significantly (p<0.05) higher cytotoxicity than the non-stressed controls. The numbers of surviving Vero cells were 47-52% (stressed) vs. 65% (control) in beef and 20-30% (stressed) vs. 52-53% (non-stressed) in spinach. Similarly, LDH assay also indicated an increased cytotoxicity (p<0.05) in stressed O157 and non-O157 STEC than non-stressed controls in spinach. There was no significant difference among the four stresses in inducing the levels of cytotoxicity in O157 or non-O157 STEC. Results showed that STEC cells exposed to sub-lethal stresses might have increased cytotoxicity during subsequent growth in ground beef or spinach. The findings illustrate the importance of applying suitable control measures to eliminate the presence of stressed STEC in beef and spinach processing environment or their subsequent contamination in the products.

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Section: Influence Of Stresses On the Cytotoxicity Of Stec Grown In Gsupporting

confidence: 53%

Effects of Stresses on the Growth and Cytotoxicity of Shiga-Toxin Producing Escherichia coli in Ground Beef and Spinach

2017

SDRP-JFST

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“…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). Indeed, bacteria within a biofilm are protected against several stresses, such as a nutrient-limited environment and sanitizers (13).…”

mentioning

confidence: 99%

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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“…However, one could also combine both the explanations, because there has been a significant decrease in an overall antioxidant protection in planktonic cells during the stationary phase, and a strong reduction in the level of DCF-DA oxidation to its fluorescent form in the stationary phase of biofilm. Several authors have previously proposed a protective mechanisms for biofilm formed by the microorganisms other thanE.coli (Albesa et al 2004;Singer et al 2009;Arce Miranda et al 2011;Villegas et al 2013). The results have shown an interesting relationship -cells of biofilm have a higher resistance to the mediators that produce hydroxyl radical, but in the case of exposure to the superoxide anion, the nature of this relationship is reversed -which means that they are more resistant than the planktonic forms.…”

Section: Resultsmentioning

confidence: 99%

Resistance of oxidative stress in biofilm and planktonic cells

Jakubowski

Walkowiak

2015

Braz. arch. biol. technol.

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Relevance of Biofilms in the Pathogenesis of Shiga-Toxin-ProducingEscherichia coliInfection

Cited by 26 publications

References 29 publications

Effects of Stresses on the Growth and Cytotoxicity of Shiga-Toxin Producing Escherichia coli in Ground Beef and Spinach

Effects of Stresses on the Growth and Cytotoxicity of Shiga-Toxin Producing Escherichia coli in Ground Beef and Spinach

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

Resistance of oxidative stress in biofilm and planktonic cells

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