Evolution of STEC virulence: Insights from the antipredator activities of Shiga toxin producing E. coli

Koudelka, Gerald B.; Arnold, Jason W.; Chakraborty, Dolonchapa

doi:10.1016/j.ijmm.2018.07.001

Cited by 18 publications

(23 citation statements)

References 56 publications

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“…Indeed, even commensal bacteria can rapidly acquire toxic genes, transforming them into human pathogens. Most exotoxins supplied by temperate phages are only expressed when lytic growth is induced, for instance during DNA-damaging antibiotic treatments, although some exceptions exist 34,35 . The best known phage-encoded exotoxin, the cholera toxin, was discovered in 1996 26,36 .…”

Section: Prophages Contribute To the Secretion Of Toxinsmentioning

confidence: 99%

“…Exposure to the toxins can lead to neuronal paralysis in humans 37,38 . In another example, lysogenisation of E. coli cells by Stx-encoding lambdoid phages results in the development of the Shiga toxin producing E. coli (STEC) pathogen, with the toxin inhibiting the eukaryotic protein synthesis 35 . Furthermore, the toxic-shock-syndrome toxin-1 (Staphylococcus aureus) and diphtheria toxin (Corynebacterium diphtheria) are also phagederived 24,[39][40][41] .…”

Section: Prophages Contribute To the Secretion Of Toxinsmentioning

confidence: 99%

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Bacteriophages as drivers of bacterial virulence and their potential for biotechnological exploitation

Schroven

Aertsen

Lavigne

2020

FEMS Microbiology Reviews

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Bacteria-infecting viruses (phages) and their hosts maintain an ancient and complex relationship. Bacterial predation by lytic phages drives an ongoing phage-host arms race, whereas temperate phages initiate mutualistic relationships with their hosts upon lysogenisation as prophages. In human pathogens, these prophages impact bacterial virulence in distinct ways: by secretion of phage-encoded toxins, modulation of the bacterial envelope, mediation of bacterial infectivity and the control of bacterial cell regulation. This review builds the argument that virulence-influencing prophages hold extensive, unexplored potential for biotechnology. More specifically, it highlights the development potential of novel therapies against infectious diseases, to address the current antibiotic resistance crisis. First, designer bacteriophages may serve to deliver genes encoding cargo proteins which repress bacterial virulence. Secondly, one may develop small molecules mimicking phage-derived proteins targeting central regulators of bacterial virulence. Thirdly, bacteria equipped with phage-derived synthetic circuits which modulate key virulence factors could serve as vaccine candidates to prevent bacterial infections. The development and exploitation of such antibacterial strategies will depend on the discovery of other prophage-derived, virulence control mechanisms and, more generally, on the dissection of the mutualistic relationship between temperate phages and bacteria, as well as on continuing developments in the synthetic biology field.

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Section: Prophages Contribute To the Secretion Of Toxinsmentioning

confidence: 99%

Section: Prophages Contribute To the Secretion Of Toxinsmentioning

confidence: 99%

Bacteriophages as drivers of bacterial virulence and their potential for biotechnological exploitation

Schroven

Aertsen

Lavigne

2020

FEMS Microbiology Reviews

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“…For this reason, exotoxin-mediated killing of protists represents a basic principle of bacterial defense against unicellular eukaryotic predators. The unexpected high frequency of exotoxin-coding genes in regions lacking the presumed mammalian hosts suggest that (1) mammals are not their primary targets and (2) exotoxins such as Stx may have evolved for the purpose of bacterial antipredator defense [ 206 , 207 ]. The bacterivorous predator Tetrahymena thermophila is killed in cocultures with STEC for which the Stx-encoding bacteria enhance survival in the face of protist predation over those bacteria that are negative for Stx expression [ 208 ].…”

Section: Ehec-caused Diseases and Damage Of Human Target Cellsmentioning

confidence: 99%

Valid Presumption of Shiga Toxin-Mediated Damage of Developing Erythrocytes in EHEC-Associated Hemolytic Uremic Syndrome

Detzner

Pohlentz

Müthing

2020

Toxins

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The global emergence of clinical diseases caused by enterohemorrhagic Escherichia coli (EHEC) is an issue of great concern. EHEC release Shiga toxins (Stxs) as their key virulence factors, and investigations on the cell-damaging mechanisms toward target cells are inevitable for the development of novel mitigation strategies. Stx-mediated hemolytic uremic syndrome (HUS), characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal injury, is the most severe outcome of an EHEC infection. Hemolytic anemia during HUS is defined as the loss of erythrocytes by mechanical disruption when passing through narrowed microvessels. The formation of thrombi in the microvasculature is considered an indirect effect of Stx-mediated injury mainly of the renal microvascular endothelial cells, resulting in obstructions of vessels. In this review, we summarize and discuss recent data providing evidence that HUS-associated hemolytic anemia may arise not only from intravascular rupture of erythrocytes, but also from the extravascular impairment of erythropoiesis, the development of red blood cells in the bone marrow, via direct Stx-mediated damage of maturing erythrocytes, leading to “non-hemolytic” anemia.

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“…Shigatoxigenic Escherichia coli (STEC) are major zoonotic foodborne pathogens capable of causing severe gastrointestinal diseases and complications such as haemorrhagic colitis (HC) and haemolytic uremic syndrome (HUS) [1,2]. The main virulence factors of STEC are the phage-encoded cytotoxins called Shiga toxins (Stx family), with several toxin subtypes [3]. Stx phages can be present, either integrated in the STEC chromosome as temperate bacteriophage or as free particles in the environment [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Causes of Shigatoxigenic Escherichia coli PCR Positive and Culture Negative Samples

et al. 2020

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Molecular methods may reveal the presence of pathogens in samples through the detection of specific target gene(s) associated with microorganisms, but often, the subsequent cultural isolation of the pathogen is not possible. This discrepancy may be related to low concentration of the cells, presence of dead cells, competitive microflora, injured cells and cells in a viable but non-culturable state, free DNA and the presence of free bacteriophages which can carry the target gene causing the PCR-positive/culture-negative results. Shiga-toxigenic Escherichia coli (STEC) was used as a model for studying this phenomenon, based on the phage-encoded cytotoxins genes (Stx family) as the detection target in samples through real-time qPCR. Stx phages can be integrated in the STEC chromosome or can be isolated as free particles in the environment. In this study, a combination of PCR with culturing was used for investigating the presence of the stx1 and stx2 genes in 155 ovine recto-anal junction swab samples (method (a)-PCR). Samples which were PCR-positive and culture-negative were subjected to additional analyses including detection of dead STEC cells (method (b)-PCR-PMA dye assay), presence of Stx phages (method (c)-plaque assays) and inducible integrated phages (method (d)-phage induction). Method (a) showed that even though 121 samples gave a PCR-positive result (78%), only 68 samples yielded a culturable isolate (43.9%). Among the 53 (34.2%) PCR-positive/culture-negative samples, 21 (39.6%) samples were shown to have STEC dead cells only, eight (15.1%) had a combination of dead cells and inducible stx phage, while two samples (3.8%) had a combination of dead cells, inducible phage and free stx phage, and a further two samples had Stx1 free phages only (3.8%). It was thus possible to reduce the samples with no explanation to 20 (37.7% of 53 samples), representing a further step towards an improved understanding of the STEC PCR-positive/culture-negative phenomenon.

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Evolution of STEC virulence: Insights from the antipredator activities of Shiga toxin producing E. coli

Cited by 18 publications

References 56 publications

Bacteriophages as drivers of bacterial virulence and their potential for biotechnological exploitation

Bacteriophages as drivers of bacterial virulence and their potential for biotechnological exploitation

Valid Presumption of Shiga Toxin-Mediated Damage of Developing Erythrocytes in EHEC-Associated Hemolytic Uremic Syndrome

Investigation of the Causes of Shigatoxigenic Escherichia coli PCR Positive and Culture Negative Samples

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