In vitro effects of sub‐inhibitory concentrations of amoxicillin on physiological responses and virulence determinants in a commensal strain of Escherichia coli

2021 ◽  
Author(s):  
Jatin Chadha
Keyword(s):  
Escherichia Coli ◽  
Physiological Responses ◽  
Virulence Determinants ◽  
Commensal Strain ◽  
In Vitro Effects

In vitro effects of photobiomodulation applied to gingival fibroblasts cultured on titanium and zirconia surfaces and exposed to LPS from Escherichia coli

2020 ◽  
Vol 35 (9) ◽  
pp. 2031-2038
Author(s):  
Taisa Nogueira Pansani ◽  
Fernanda Gonçalves Basso ◽  
Carlos Alberto de Souza Costa
Keyword(s):  
Escherichia Coli ◽  
Gingival Fibroblasts ◽  
In Vitro Effects

In Vitro Effects of Thymol-β-d-Glucopyranoside on Salmonella enterica Serovar Typhimurium and Escherichia coli K88†

2016 ◽  
Vol 79 (2) ◽  
pp. 299-303 ◽  
Author(s):  
G. LEVENT ◽  
R. B. HARVEY ◽  
G. CIFTCIOGLU ◽  
R. C. BEIER ◽  
K. J. GENOVESE ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Pure Culture ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Lower Gastrointestinal Tract ◽  
Serovar Typhimurium ◽  
In Vitro Effects ◽  
Porcine Feces

ABSTRACT Although thymol is bactericidal against many pathogens in vitro, its in vivo effectiveness against pathogens in the lower gastrointestinal tract is limited because of its rapid absorption in the proximal gut. Thymol-β-d-glucopyranoside (β-thymol), a conjugated form of thymol, can deliver thymol to the lower gastrointestinal tract and has shown antibacterial effects. In the present study, we examined the in vitro effects of β-thymol on Salmonella enterica serovar Typhimurium (ST) and Escherichia coli K88 (K88). We inoculated one-half strength Mueller-Hinton broth with 5.8 ± 0.09 log CFU/ml novobiocin- and naladixic acid–resistant (NN) ST (NVSL 95-1776) and 5.1 ± 0.09 log CFU ml−1 NN-resistant K88, with or without porcine feces (0.1% [wt/vol]) (fecal incubations). The resultant bacterial suspensions were distributed under N2 to triplicate sets of tubes to achieve initial concentrations of 0, 3, 6, and 12 mM for ST treatments and 0, 3, 12, and 30 mM for K88 treatments. Samples were incubated at 39°C and then plated onto NN-containing brilliant green agar and NN-containing MacConkey agar; ST and K88 CFU concentrations were determined via 10-fold dilutions, and viable cell counts were performed at 0, 6, and 24 h. No differences in ST CFU counts were observed in β-thymol–treated tubes without the added porcine feces (i.e., pure culture) at 6 or 24 h. However, in tubes that contained fecal incubations, ST CFU counts were reduced (P < 0.05) from controls at 6 h in tubes treated with 6 and 12 mM β-thymol, whereas in tubes treated with 3, 6, and 12 mM β-thymol the CFU counts were reduced (P < 0.05) at 24 h. No differences were observed in K88 CFU counts in pure culture or in fecal incubations at 6 h, but K88 CFU counts were reduced (P < 0.05) in both pure and fecal incubations at 24 h. The results from this study demonstrate that β-thymol, in the presence of fecal suspensions, has anti-Salmonella and anti–E. coli effects, suggesting a role of β-glycoside–hydrolyzing microbes for the release of bactericidal thymol from β-thymol.

cGMP modulation of ileal ion transport: in vitro effects of Escherichia coli heat-stable enterotoxin

1982 ◽  
Vol 243 (1) ◽  
pp. G36-G41 ◽  
Author(s):  
S. Guandalini ◽  
M. C. Rao ◽  
P. L. Smith ◽  
M. Field
Keyword(s):  
Escherichia Coli ◽  
Ion Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Rabbit Ileum ◽  
Heat Stable ◽  
Transport Effects ◽  
In Vitro Effects ◽  
Nonadditive Effects

Diarrheagenic strains of Escherichia coli have been shown to produce a heat-stable enterotoxin (ST) that simulates guanylate cyclase, increases short-circuit current (Isc), and inhibits active Cl absorption in the intestine. In rabbit ileum, the ion transport effects are smaller than those produced by cAMP-related agonists. Because ST may be a selective cGMP agonist, we further explored its mode of action in rabbit ileum. ST inhibits net Na and net Cl absorption. ST also inhibits the same fraction of Cl influx across the brush border that theophylline inhibits. At maximal doses, ST and 8-bromo-cGMP (8-Br-cGMP) had nearly equal, nonadditive effects of Isc that were about 66% of that produced by 8-Br-cAMP. ST increased mucosal cGMP concentration 16-fold, whereas epinephrine, an inhibitor of secretion, increased cGMP concentration by only 30%. This is insufficient to alter ion transport because doses of ST that increased cGMP concentration by 100% failed to alter Cl fluxes. Furthermore, epinephrine did not increase cGMP concentration in isolated enterocytes. We conclude that 1) cGMP mediates ST effects on ion transport, and 2) although ST and cAMP-related agonists have the same antiabsorptive effects, ST is less effective in stimulating electrogenic Cl secretion.

In Vitro Effects of Homeopathic Drugs on Cultured Escherichia coli

Homeopathy ◽  
2018 ◽  
Vol 107 (02) ◽  
pp. 150-154 ◽  
Author(s):  
Carmen Kurmann ◽  
Esther Imbach ◽  
Felix Amsler ◽  
Susanne Pannek-Rademacher ◽  
Jürgen Pannek
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Antibiotic Treatment ◽  
Resistance Testing ◽  
E Coli ◽  
Homeopathic Treatment ◽  
In Vitro Effects ◽  
Tract Infections ◽  
Homeopathic Drugs

Background Recurrent urinary tract infections (UTIs) are one of the most common morbidities in persons with neurogenic lower urinary tract dysfunction (NLUTD). Repetitive antibiotic treatment increases the risk of selecting multi-resistant bacteria. Homeopathic treatment has been reported to be effective in these patients. The mechanism of action, however, has not been clarified. Recently, a direct bactericidal effect of homeopathic remedies was shown. Such an effect is not in accordance with the general principles of homeopathy. To test this paradigm, we assessed the in vitro effects of homeopathic drugs on Escherichia coli derived from patients with NLUTD. Methods E. coli bacteria were harvested from 28 consecutive urine cultures. Standard antibiotic resistance testing and simultaneous resistance testing to homeopathic drugs (Apis mellifica, Cantharis, Causticum hahnemanni, Staphysagria, Nux vomica, Berberis vulgaris, and Lycopodium clavatum) in high (C30) potency were performed. Results No significant inhibitory effect of any of the tested homeopathic drugs on any E. coli population could be found, irrespective of their sensitivity to antibiotic treatment. Conclusion Based on our results, effects of homeopathic treatment of UTI are not based on direct bactericidal or bacteriostatic effects. These findings are in concordance with the hypothesis that homeopathy is based on host effects: for example, activation of the immune system, rather than effects on pathogens.

scholarly journals l-Fucose Stimulates Utilization of d-Ribose by Escherichia coli MG1655 ΔfucAO and E. coli Nissle 1917 ΔfucAO Mutants in the Mouse Intestine and in M9 Minimal Medium

2007 ◽  
Vol 75 (11) ◽  
pp. 5465-5475 ◽  
Author(s):  
Steven M. Autieri ◽  
Jeremy J. Lins ◽  
Mary P. Leatham ◽  
David C. Laux ◽  
Tyrrell Conway ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Minimal Medium ◽  
Wild Type ◽  
E Coli ◽  
Commensal Strain ◽  
Mouse Intestine ◽  
Level 2 ◽  
Growth Experiments

ABSTRACT Escherichia coli MG1655 uses several sugars for growth in the mouse intestine. To determine the roles of l-fucose and d-ribose, an E. coli MG1655 ΔfucAO mutant and an E. coli MG1655 ΔrbsK mutant were fed separately to mice along with wild-type E. coli MG1655. The E. coli MG1655 ΔfucAO mutant colonized the intestine at a level 2 orders of magnitude lower than that of the wild type, but the E. coli MG1655 ΔrbsK mutant and the wild type colonized at nearly identical levels. Surprisingly, an E. coli MG1655 ΔfucAO ΔrbsK mutant was eliminated from the intestine by either wild-type E. coli MG1655 or E. coli MG1655 ΔfucAO, suggesting that the ΔfucAO mutant switches to ribose in vivo. Indeed, in vitro growth experiments showed that l-fucose stimulated utilization of d-ribose by the E. coli MG1655 ΔfucAO mutant but not by an E. coli MG1655 ΔfucK mutant. Since the ΔfucK mutant cannot convert l-fuculose to l-fuculose-1-phosphate, whereas the ΔfucAO mutant accumulates l-fuculose-1-phosphate, the data suggest that l-fuculose-1-phosphate stimulates growth on ribose both in the intestine and in vitro. An E. coli Nissle 1917 ΔfucAO mutant, derived from a human probiotic commensal strain, acted in a manner identical to that of E. coli MG1655 ΔfucAO in vivo and in vitro. Furthermore, l-fucose at a concentration too low to support growth stimulated the utilization of ribose by the wild-type E. coli strains in vitro. Collectively, the data suggest that l-fuculose-1-phosphate plays a role in the regulation of ribose usage as a carbon source by E. coli MG1655 and E. coli Nissle 1917 in the mouse intestine.

Studies on the interaction of Escherichia coli endotoxin with erythrocyte membranes

1982 ◽  
Vol 60 (7) ◽  
pp. 977-985 ◽  
Author(s):  
David V. Godin ◽  
John M. Tuchek ◽  
Maureen E. Garnett
Keyword(s):  
Escherichia Coli ◽  
Membrane Lipids ◽  
Effect Of Temperature ◽  
Erythrocyte Membranes ◽  
Simple Relationship ◽  
In Vitro Effects ◽  
The Stability ◽  
Erythrocyte Stability

Escherichia coli lipopolysaccharide (endotoxin) alters the stability of erythrocytes to hypotonic lysis although the nature and magnitude of the effect varied with temperature and with the type of red blood cell examined. Evidence has been obtained suggesting a possible modulatory role of membrane lipids in governing the molecular consequences of membrane–endotoxin interaction. The marked effect of temperature on the stabilization of red cells by endotoxin was not attributable to variations in toxin binding and was not observed with more conventional structurally unrelated antihemolytic agents. Although chemical modifications which alter the toxicity of endotoxin in vivo also modify its ability to stabilize erythrocytes in vitro, no simple relationship between in vivo endotoxin toxicity and in vitro effects on erythrocyte stability was apparent. The critical dependence of endotoxin antihemolytic effects in vitro on molecular structure may offer a convenient means of assessing the homogeneity of these preparations before performing experiments in vivo.

In Vivo and In Vitro Effects of Tea Extracts on Enterotoxigenic Escherichia coli-induced Intestinal Fluid Loss in Animal Models

2006 ◽  
Vol 43 (4) ◽  
pp. 459-469 ◽  
Author(s):  
M.J. Bruins ◽  
R. Cermak ◽  
J.L. Kiers ◽  
J. van der Meulen ◽  
J.M.M. van Amelsvoort ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Animal Models ◽  
Enterotoxigenic Escherichia Coli ◽  
Fluid Loss ◽  
Intestinal Fluid ◽  
In Vitro Effects
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