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In Vitro Framework to Assess the Anti-Helicobacter pylori Potential of Lactic Acid Bacteria Secretions as Alternatives to Antibiotics.

ABSTRACT: Helicobacter pylori is a prevalent bacterium that can cause gastric ulcers and cancers. Lactic acid bacteria (LAB) ameliorate treatment outcomes against H. pylori, suggesting that they could be a source of bioactive molecules usable as alternatives to current antibiotics for which resistance is mounting. We developed an in vitro framework to compare the anti-H. pylori properties of 25 LAB and their secretions against H. pylori. All studies were done at acidic and neutralized pH, with or without urea to mimic various gastric compartments. Eighteen LAB strains secreted molecules that curtailed the growth of H. pylori and the activity was urea-resistant in five LAB. Several LAB supernatants also reduced the urease activity of H. pylori. Pre-treatment of H. pylori with acidic LAB supernatants abrogated its flagella-mediated motility and decreased its ability to elicit pro-inflammatory IL-8 cytokine from human gastric cells, without reverting the H. pylori-induced repression of other pro-inflammatory cytokines. This study identified the LAB that have the most anti-H. pylori effects, decreasing its viability, its production of virulence factors, its motility and/or its ability to elicit pro-inflammatory IL-8 from gastric cells. Once identified, these molecules can be used as alternatives or complements to current antibiotics to fight H. pylori infections.

SUBMITTER: Whiteside SA

PROVIDER: S-EPMC8198849 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

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In Vitro Framework to Assess the Anti-Helicobacter pylori Potential of Lactic Acid Bacteria Secretions as Alternatives to Antibiotics.

Whiteside Samantha A SA Mohiuddin Mahi M MM Shlimon Sargon S Chahal Jaspreet J MacPherson Chad W CW Jass Jana J Tompkins Thomas A TA Creuzenet Carole C

International journal of molecular sciences 20210526 11

Helicobacter pylori is a prevalent bacterium that can cause gastric ulcers and cancers. Lactic acid bacteria (LAB) ameliorate treatment outcomes against H. pylori, suggesting that they could be a source of bioactive molecules usable as alternatives to current antibiotics for which resistance is mounting. We developed an in vitro framework to compare the anti-H. pylori properties of 25 LAB and their secretions against H. pylori. All studies were done at acidic and neut ...[more]

PMID: 34073352

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Project description:We previously demonstrated (M. M. Exner, P. Doig, T. J. Trust, and R. E. W. Hancock, Infect. Immun. 63:1567-1572, 1995) that Helicobacter pylori has at least one nonspecific porin, HopE, which has a low abundance in the outer membrane but forms large channels. H. pylori is relatively susceptible to most antimicrobial agents but less susceptible to the polycationic antibiotic polymyxin B. We demonstrate here that H. pylori is able to take up higher basal levels of the hydrophobic fluorescent probe 1-N-phenylnaphthylamine (NPN) than Pseudomonas aeruginosa or Escherichia coli, consistent with its enhanced susceptibility to hydrophobic agents. Addition of polymyxin B led to a further increase in NPN uptake, indicative of a self-promoted uptake pathway, but it required a much higher amount of polymyxin B to yield a 50% increase in NPN uptake in H. pylori (6 to 8 microg/ml) than in P. aeruginosa or E. coli (0.3 to 0.5 microg/ml), suggesting that H. pylori has a less efficient self-promoted uptake pathway. Since intrinsic resistance involves the collaboration of restricted outer membrane permeability and secondary defense mechanisms, such as periplasmic beta-lactamase (which H. pylori lacks) or efflux, we examined the possible role of efflux in antibiotic susceptibility. We had previously identified in H. pylori 11637 the presence of portions of three genes with homology to potential restriction-nodulation-division (RND) efflux systems. It was confirmed that H. pylori contained only these three putative RND efflux systems, named here hefABC, hefDEF, and hefGHI, and that the hefGHI system was expressed only in vivo while the two other RND systems were expressed both in vivo and in vitro. In uptake studies, there was no observable energy-dependent tetracycline, chloramphenicol, or NPN efflux activity in H. pylori. Independent mutagenesis of the three putative RND efflux operons in the chromosome of H. pylori had no effect on the in vitro susceptibility of H. pylori to 19 antibiotics. These results, in contrast to what is observed in E. coli, P. aeruginosa, and other clinically important gram-negative bacteria, suggest that active efflux does not play a role in the intrinsic resistance of H. pylori to antibiotics.

Project description:BackgroundIncreasing prevalence of antibiotic resistance especially to clarithromycin and metronidazole has been observed in Helicobacter pylori (H. pylori).AimTo characterize the antimicrobial resistance pattern of H. pylori before and after treatment in a cohort of patients accumulated over a period of 15 years after an unsuccessful eradication treatment had been given comparing sensitivity data from patients with newly diagnosed H. pylori infection. A specific objective was to look for resistance to levofloxacin.Material and methodsTotal of 50 patients newly diagnosed for H. pylori infection treated with omeprazole and amoxicillin/clarithromycin and 42 H pylori treatment-resistant patients treated with omeprazole and amoxicillin/levofloxacin were enrolled in this study. Cultures including antibiotic sensitivity testing were conducted according to standard laboratory routines and thus also in keeping with a European study protocol using E-test gradient strips or disc diffusion methods.ResultsClarithromycin resistance was more frequently observed in the H. pylori resistant group than in newly diagnosed H. pylori group (39% versus 11%). Regarding metronidazole the distribution was 70% versus 38%, and 8% versus 12% were resistant to tetracycline. No resistance was observed for amoxicillin. After re-treatment of patients belonging to the H. pylori treatment-resistant group, just two patient strains were recovered of which one harbored metronidazole resistance. In the group of newly diagnosed H. pylori, seven patients were culture positive by control after treatment. Two and three patient strains showing resistance to clarithromycin and metronidazole, respectively. None of the strains in our material was classified as resistant to amoxicillin and levofloxacin. Whereas 12% was resistant to tetracycline in the newly diagnosed before treatment.ConclusionClarithromycin resistance was more frequent in the H. pylori treatment-resistant group than strains from patients with newly diagnosed H. pylori infection. No resistance was observed to amoxicillin and levofloxacin. In such cases Therefore levofloxacin may be used provided in vitro sensitivity testing confirms applicability.Trial registrationClinicalTrials.gov identifier: NCT05019586.

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In Vitro Framework to Assess the Anti-Helicobacter pylori Potential of Lactic Acid Bacteria Secretions as Alternatives to Antibiotics.

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In Vitro Framework to Assess the Anti-<i>Helicobacter pylori</i> Potential of Lactic Acid Bacteria Secretions as Alternatives to Antibiotics.

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