scholarly journals The Short-Chain Fatty Acids Propionate and Butyrate Augment Adherent-Invasive Escherichia coli Virulence but Repress Inflammation in a Human Intestinal Enteroid Model of Infection

2021 ◽  
Author(s):  
Fernanda Pace ◽  
Sara E. Rudolph ◽  
Ying Chen ◽  
Bin Bao ◽  
David L. Kaplan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Terminal Ileum ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Intestinal Environment ◽  
Chain Fatty Acids

The human terminal ileum and colon are colonized by a community of microbes known as the microbiota. Short-chain fatty acids (SCFAs) excreted by bacterial members of the microbiota define the intestinal environment.

scholarly journals In vitro contractile effects of short chain fatty acids in the rat terminal ileum.

Gut ◽  
1996 ◽  
Vol 38 (1) ◽  
pp. 53-58 ◽  
Author(s):  
C Cherbut ◽  
A C Aube ◽  
H M Blottiere ◽  
P Pacaud ◽  
C Scarpignato ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Terminal Ileum ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Chain Fatty Acids

scholarly journals Differential effects of short-chain fatty acids and iron on expression of iha in Shiga-toxigenic Escherichia coli

Microbiology ◽  
2009 ◽  
Vol 155 (11) ◽  
pp. 3554-3563 ◽  
Author(s):  
Sylvia Herold ◽  
James C. Paton ◽  
Potjanee Srimanote ◽  
Adrienne W. Paton
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Human Colon ◽  
Short Chain Fatty Acids ◽  
Iron Chelator ◽  
Short Chain ◽  
Human Gut ◽  
E Coli ◽  
Total Concentrations ◽  
Chain Fatty Acids

Shiga-toxigenic Escherichia coli (STEC) colonizing the bowel are exposed to a variety of short-chain fatty acids (SCFAs), including acetate, propionate and butyrate, produced by gut microflora. However, the total concentrations and relative amounts of SCFAs in the lumen vary with intestinal niche. Here we report that conditions simulating SCFA concentrations present in the human gut trigger expression of the iha gene, which encodes an adherence-conferring outer-membrane protein of pathogenic E. coli. We show that growth under conditions simulating colonic, but not ileal, SCFA concentrations increases iha expression in three tested STEC strains, with the strongest expression detected in LEE-negative STEC O113:H21 strain 98NK2. Expression of iha is known to be subject to Fur-mediated iron repression in O157:H7 STEC, and the same occurs in 98NK2. However, exogenous iron did not repress iha expression in the presence of colonic SCFAs in either 98NK2 or the O157:H7 strain EDL933. Moreover, exposure to the iron chelator 2,2′-dipyridyl caused no further enhancement of iha expression over that induced by colonic SCFAs. These findings indicate that SCFAs regulate iha expression in STEC independently of iron. Increased expression of iha under colonic but not ileal SCFA conditions possibly may contribute to preferential colonization of the human colon by STEC.

scholarly journals Virulence response of escherichia coli O157:H7 to bile salts and short chain fatty acids

2021 ◽  
Author(s):  
Mihaela Anca Serbanescu
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Epithelial Cells ◽  
Bile Salts ◽  
Short Chain Fatty Acids ◽  
Enterohemorrhagic Escherichia Coli ◽  
Short Chain ◽  
Human Epithelial Cells ◽  
Virulence Properties ◽  
Chain Fatty Acids

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a gastrointestinal pathogen which causes hemorrhagic colitis and can lead to neurological damage, acute kidney failure (hemolytic uremic syndrome and vascular lesions. During intestinal colonization EHEC is exposed to a variety of stresses including bile salts (BS) in the small intestine and short chain fatty acids (SCFA) in the large intestine; little is known about how these stresses affect this pathogen's virulence properties. The goal of this study was to investigate the impact of exposure of E. coli O157:H7 to physiologically relevant concentrations of BS and SCFA alone and in mixtures on bacterial survival, verotoxin production and adhesion to human epithelial cells. The results indicated that BS treatments significantly enhanced several virulence properties including survival and adhesion to human epthelial cell lines including colonic epithelial cells. Verotoxin production was not affected by any of the BS treatments. Bacterial pretreatment with erythromycin at a sub-minimal inhibitory concentration eliminated the adhesion enhancement after BS treatment, suggesting that protein synthesis was required for enhanced adhesion of BS treated organisms. Using the isogenci mutant of the known adhesions, intimin and iha it was established that there was no role for intimin or iha in the BS-induced adhesion enhancement. SCFA treatments reduced bacterial viability but significantly enhanced both adhesion to human epithelial cells and verotoxin production. The results of this research indicate that ingestion stresses such as BS and SCFA, which are part of the host's natural chemical assault on foreign organisms, may actually enhance the viulence properties of this pathogen and contribute to, rather than, prevent infection. Furthermore, they suggest that this pathogen may use these ingestion stresses to cue the expression of numerous virulence factors for successful infection of local microenvironments.

scholarly journals Evaluation of the intestinal microbiota and short-chain fatty acids content in patients with chronic inflammatory bowel diseases

2021 ◽  
Vol 55 (2) ◽  
pp. 98-103
Author(s):  
M.V. Stoykevich ◽  
N.S. Fedorova ◽  
N.V. Nedzvetskaya ◽  
I.A. Klenina ◽  
O.M. Tatarchuk
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Intestinal Microbiota ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Control Group ◽  
Microbiological Study ◽  
Inflammatory Bowel ◽  
Chronic Inflammatory Bowel ◽  
Chain Fatty Acids

Background. The pathogenesis of chronic inflammatory bowel disease (IBD) is still not fully clarified. It is known that disorders of the intestinal microbiota lead to an increased intestinal permeability, activation of mucous and adaptive immunity, impaired production and intestinal absorption of short-chain fatty acids (SCFA). The ratio of acetic, propionic, butyric acids is an important indicator of the integrity of the intestinal microbial community. Thus, the study of the composition of the intestinal microbiota and the concentrations of fecal SCFA is a very promi­sing approach to broadening the understanding of IBD pathoge­nesis. The purpose of our study was to determine the features of the production of fecal SCFA and the composition of colon microbiota in patients with IBD. Materials and methods. The study, which was carried out at the Department of Intestinal Diseases of the Institute of Gastroenterology of the National Academy of Medical Sciences of Ukraine, involved 74 patients with IBD with an average age of (43.2 ± 1.8) years, who according to nosology were divided into 2 groups: group I — those with ulcerative colitis (UC) (n = 66), group II — individuals with Crohn’s disease (CD) (n = 8). The diagnoses of CD and UC were established accor­ding to generally accepted diagnostic standards in gastroenterology. Determination of fecal SCFA was carried out by chromatographic method with the use of hardware-software complex for medical researches on the basis of the gas chromatographer Chromateс Crystal 5000. The intestinal microflora was evaluated using a microbiological study of the colon content. Results. Patients with IBD had significant changes in the spectrum of SCFA, which were similar in both UC and CD: a decrease in acetic acid in the UC group by 5.7 times, in the CD group by 10.5 times (p < 0.05), butyric acid in the UC group by 1.6 times, in the CD group by 1.5 times (p < 0.05), and an increase in propionic acid in the UC group by 4 times and in the CD group by 3.3 times (p < 0.05) compared with the control group. There was also a significant increase in the anaerobic index in patients with IBD. Microbiological study of feces showed a significant decrease in Lactobacillus, which was observed in all patients with IBD, as well as a decrease in Bifidobacterium in 19.7 % of those with UC and in 37.5 % with CD. There was a decrease of other representatives of the normal microflora: Enterococci (in 15.2 % in the UC group and 25 % in the CD group) and Escherichia coli (in 15.2 % in the UC group and 12.5 % in the CD group). Excessive growth of opportunistic flora was also detected: hemolytic Escherichia coli was increased in 19.7 % of patients with UC and in 12.5 % of those with CD; Proteus was detected in 12.1 % of people with UC and in 37.5 % with CD. The excessive growth of Candida was found in 43.9 % of patients in the UC group and in 87.5 % of indivi­duals with CD. Conclusions. Quantitative and qualitative deviations of the intestinal microbiota, such as a decrease in the number of major symbionts and an increase in the number of opportunistic pathogens, were observed in all examined patients with IBD. The obtained results showed that changes in SCFA concentrations in both nosologies of IBD differed significantly from those in the control group, which in combination with primary genetic defects of the barrier function of the epithelium and its regenerative abi­lity can lead to deterioration in the course and prognosis of IBD. Evalua­tion of the ratio of SCFA fractions with the calculation of the anaerobic index may be useful for the diagnosis of intestinal dysbiosis in patients with IBD.

scholarly journals Integrating the extracellular, intracellular, and intercellular metabolic processes of Escherichia coli through glucose saturation, inhibition of the acetyl-CoA carboxylase subunit accA with asRNA, and through quantifying cell to cell quorum-sensing

2019 ◽  
Author(s):  
Tatiana Hillman ◽  
Cory Tobin
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Quorum Sensing ◽  
Bacterial Cell ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Acetyl Coa Carboxylase ◽  
Metabolic Processes ◽  
Acetyl Coa ◽  
Chain Fatty Acids

The study aims to demonstrate the link between bacterial cell metabolism and virulence through integrating the environmental, genetic, and cell to cell signaling molecular processes. Dietary fiber metabolized into glucose, increases the proliferation of intestinal microflora, which augments the outputof the Short Chain Fatty Acids. Bacteria ferment the glucose, from fiber, into Short Chain Fatty Acids, which help regulate many biochemical processes and pathways. Each SCFA maintains colonic pH, promotes cell differentiation, and the apoptosis of colonocytes. To model a high-fiber diet, increasing the synthesis of Acetyl-CoA carboxylase, an enzyme that catabolizes glucose into SCFAs, Escherichia coli was cultured in Luria Broth enhanced with a high to low concentration of glucose. The 15mM, a high concentration of glucose, yielded qPCR products measured, for the target gene accA, which was 4,210ng/µL. The 7.5mM sample produced a concentration equaled to 375 ng/µL, and the 0µM sample measured an accA concentration of 196 ng/µL. The gene accA, 1 of 4 subunits for the Acetyl-CoA Carboxylase enzyme, was suppressed by asRNA, producing a qPCR concentration of 63ng/µL. Antisense RNA for accA reduced the amount of Lux-S, a vital gene needed for propagating quorum-sensing signal molecules. The Lux-S gene, responsible for releasing autoinducer 2 for cell to cell quorum sensing, was reduced by the gene inhibition of accA with asRNA. The increase in Lux-S transcription increases biofilm production for spreading virulence. The further implications of the study propose designing antibiotics that target bacterial cell metabolic processes to block bacterial antibiotic resistance.

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