Certaines bactéries de la flore commensale exacerberaient-elles la carcinogenèse colorectale ?

Raisch, Jennifer; Dalmasso, Guillaume; Bonnet, Richard; Barnich, Nicolas; Bonnet, Mathilde; Bringer, Marie-Agnès

doi:10.1051/medsci/20163202011

Cited by 14 publications

(5 citation statements)

References 36 publications

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“…Most CRCs (~90%) are sporadic and therefore influenced by external factors such as diet and microbiota [ 70 , 71 , 72 , 73 ]. E. coli is highly suspected of being involved in CRC development.…”

Section: Roles Of Colibactinmentioning

confidence: 99%

Colibactin: More Than a New Bacterial Toxin

Faïs

Delmas

Barnich

et al. 2018

Toxins

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185

177

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Cyclomodulins are bacterial toxins that interfere with the eukaryotic cell cycle. A new cyclomodulin called colibactin, which is synthetized by the pks genomic island, was discovered in 2006. Despite many efforts, colibactin has not yet been purified, and its structure remains elusive. Interestingly, the pks island is found in members of the family Enterobacteriaceae (mainly Escherichia coli and Klebsiella pneumoniae) isolated from different origins, including from intestinal microbiota, septicaemia, newborn meningitis, and urinary tract infections. Colibactin-producing bacteria induce chromosomal instability and DNA damage in eukaryotic cells, which leads to senescence of epithelial cells and apoptosis of immune cells. The pks island is mainly observed in B2 phylogroup E. coli strains, which include extra-intestinal pathogenic E. coli strains, and pks E. coli are over-represented in biopsies isolated from colorectal cancer. In addition, pks E. coli bacteria increase the number of tumours in diverse colorectal cancer mouse models. Thus, colibactin could have a major impact on human health. In the present review, we will focus on the biological effects of colibactin, the distribution of the pks island, and summarize what is currently known about its synthesis and its structure.

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Section: Roles Of Colibactinmentioning

confidence: 99%

Colibactin: More Than a New Bacterial Toxin

Faïs

Delmas

Barnich

et al. 2018

Toxins

Self Cite

185

177

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“…The widespread application of antibiotics and presence of immunodeficiencies increase the risk of anaerobic bacteremia caused by opportunistic pathogens invading the bloodstream, and anaerobic bacteremia is becoming a primary cause of death in patients with chronic diseases. 25 Thus, the early prevention and control of primary diseases can reduce the occurrence and development of anaerobic-bacteria bloodstream infection.…”

Section: Discussionmentioning

confidence: 99%

Bloodstream infection caused by Bacteroides caccae in a patient with renal hypertension: a case report

Yang

Zhang

et al. 2021

J Int Med Res

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Bacteroides caccae is an anaerobic bacterium with a reportedly high isolation rate; however, it rarely causes bloodstream infections. Patients with hypertension are at increased risk of developing anaerobic bacterial infection. In this study, we report a case of bacteremia caused by B. caccae in a patient with renal hypertension and gastrointestinal hemorrhage. This study describes the clinical manifestations of bloodstream infection involving B. caccae to provide guidance for laboratory technicians and clinicians. A 42-year-old Chinese man was admitted for gastrointestinal hemorrhage and subsequently diagnosed with anaerobic blood infection. The pathogenic bacteria isolated from anaerobic blood culture bottles were identified as B. caccae by using an automatic bacterial identification instrument and mass spectrometry (MS). B. caccae is an intestinal opportunistic pathogen that can invade the intestinal mucosa and cause anaerobic bloodstream infection. Two or more sets of blood cultures and MS identification can greatly improve the positive detection rate of blood cultures of anaerobic bacteria. Furthermore, the increased drug resistance of anaerobic bacteria necessitates drug sensitivity tests for anaerobic bacteria in many hospitals. Thus, the early prevention and control of primary diseases with appropriate diagnoses and timely anti-infection therapies are necessary to reduce B. caccae bloodstream infection.

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“…NTBF have a direct effect on colonic epithelial cells, enhancing barrier effects, reducing membrane permeability, inhibiting colonization by other pathogenic bacteria, and preferentially occupying colonic ecological niches to maintain intestinal flora homeostasis 16 . It also promotes the development of the immune system by secreting polysaccharide A (PSA), which regulates the immune response and maintains the immune homeostasis of the body 17 , 18 . In addition, NTBF also can alleviate colonic inflammation and inhibit tumorigenesis in the colon, but the exact mechanism is not yet clear 19 .…”

Section: Introductionmentioning

confidence: 99%

Protective effects of a new generation of probiotic Bacteroides fragilis against colitis in vivo and in vitro

He,

Niu,

et al. 2023

Sci Rep

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Bacteroides fragilis, one of the potential next-generation probiotics, but its protective mechanism is not yet known. We aimed to characterize the anti-inflammatory effect of B. fragilisATCC25285 and to elucidate its mechanism through in vivo and in vitro experiments. An in vitro model of inflammation by induction of colonic cells with TNF-a, and co-cultured with B. fragilis to detect cell viability, apoptosis and invasive capacity. Furthermore, critical proteins of the TLR/NF-κB pathway and the inflammatory cytokines were measured. For animal trials, C57BL/6 J male mice were orally administered B. fragilis or PBS once daily for 21 days. Colitis was induced by drinking 2.5% DSS from days 0 to 7. The mice were weighed daily and rectal bleeding, stool condition and blood in the stool were recorded. We found that B. fragilis treatment alone was harmless and had no effect on cell viability or apoptosis. While predictably TNF-α decreased cell viability and increased apoptosis, B. fragilis attenuated this deterioration. The NF-κB pathway and inflammatory cytokines IL-6 and IL-1β activated by TNF-α were also blocked by B. fragilis. Notably, the metabolic supernatant of B. fragilis also has an anti-inflammatory effect. Animal studies showed that live B. fragilis rather than dead strain ameliorated DSS-induced colitis, as evidenced by weight loss, shortened colon length and enhanced barrier function. The colonic tissue levels of inflammatory cytokines (TNF-α, IL-1β, IL-6) were decreased and IL-10 was increased as a result of B. fragilis administration. In conclusion, B. fragilis ATCC25285 exhibited anti-inflammatory effects whether in vivo or in vitro, and it may be a potential probiotic agent for improving colitis.

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Certaines bactéries de la flore commensale exacerberaient-elles la carcinogenèse colorectale ?

Cited by 14 publications

References 36 publications

Colibactin: More Than a New Bacterial Toxin

Colibactin: More Than a New Bacterial Toxin

Bloodstream infection caused by Bacteroides caccae in a patient with renal hypertension: a case report

Protective effects of a new generation of probiotic Bacteroides fragilis against colitis in vivo and in vitro

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