In vitro antagonistic activity of Lactobacillus casei against Helicobacter pylori

Dynamic variations of the gastric microbiota: Key therapeutic points in the reversal of Correa's cascade

Correa's cascade is a dynamic process in the development of intestinal-type gastric cancer (GC), and its pathological features, gastric microbiota and interactions between microorganisms and their hosts vary at different developmental stages. The characteristics of cells, tissues and gastric microbiota before or after key therapeutic points are critical for monitoring malignant transformation and early tumour reversal. This review summarises the pathological features of gastric mucosa, characteristics of gastric microbiota, specific microbial markers, microbe-microbe interactions and microbe-host interactions at different stages in Correa's cascade. The markers related to each Correa's cascade point were analysed in detail. We attempted to identify key therapeutic points for early cancer reversal and provide a novel approach to reduce the incidence of GC and improve precise treatment.

The prevalence of clarithromycin-resistant Helicobacter pylori isolates: a systematic review and meta-analysis

Background

Knowledge of global clarithromycin (CLA)-resistant rates of Helicobacter pylori (H. pylori) is crucial for decision of the most appropriate eradication therapies with good clinical outcomes. Therefore, this review and meta-analysis aimed to evaluate the global prevalence of the CLA resistance in H. pylori to provide some guidance for selecting the first-line antibiotics.

Method

A comprehensive search was performed for relevant literature until April 2021 in PubMed, Embase, and Web of Science databases. Freeman-Tukey double arcsine transformation was performed to estimate the weighted pooled prevalence of resistance.

Results

The meta-analysis included 248 articles. The prevalence of CLA-resistant H. pylori was 27.53% (95% CI [25.41-29.69]). The heterogeneity between reports was significant (I² = 97.80%, P < 0.01). The resistance rate increased from 24.28% in 2010-2017 to 32.14% in 2018-2021 (P < 0.01). Iran, with 38 articles, has the most report. Nevertheless, Switzerland, Portugal, and Israel had the highest resistance rates (67.16%, 48.11%, and 46.12%, respectively). The heterogeneity between the continents and the antimicrobial susceptibility methods also interpreted standard guidelines and breakpoints was insignificant (P > 0.05).

Conclusion

Overall CLA resistance rate was 27.53%, worldwide. The difference in CLA resistance rate among the included studies can be due to several reasons such as differences in antibiotic prescription rates in various geographic areas, use of different breakpoints or inaccurate criteria in performed studies, and the emergence of multidrug-resistant (MDR) strains.

Probiotics as the live microscopic fighters against Helicobacter pylori gastric infections

Background

Helicobacter pylori (H. pylori) is the causative agent of stomach diseases such as duodenal ulcer and gastric cancer, in this regard incomplete eradication of this bacterium has become to a serious concern. Probiotics are a group of the beneficial bacteria which increase the cure rate of H. pylori infections through various mechanisms such as competitive inhibition, co-aggregation ability, enhancing mucus production, production of bacteriocins, and modulating immune response.

Result

In this study, according to the received articles, the anti-H. pylori activities of probiotics were reviewed. Based on studies, administration of standard antibiotic therapy combined with probiotics plays an important role in the effective treatment of H. pylori infection. According to the literature, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus rhamnosus GG, and Saccharomyces boulardii can effectively eradicate H. pylori infection. Our results showed that in addition to decrease gastrointestinal symptoms, probiotics can reduce the side effects of antibiotics (especially diarrhea) by altering the intestinal microbiome.

Conclusion

Nevertheless, antagonist activities of probiotics are H. pylori strain-specific. In general, these bacteria can be used for therapeutic purposes such as adjuvant therapy, drug-delivery system, as well as enhancing immune system against H. pylori infection.

Antimicrobial Efficacy of Five Probiotic Strains Against Helicobacter pylori

Treatment of Helicobacter pylori (H. pylori) infection is a challenge for clinicians. The large increase in drug-resistant strains makes the formulation of new therapeutic strategies fundamental. The frequent onset of side effects during antibiotic treatment (mainly due to intestinal dysbiosis) should not be underestimated as it may cause the interruption of treatment, failure of H. pylori eradication and clonal selection of resistant bacteria. Probiotic integration during antibiotic treatment can exert a dual function: a direct antagonistic effect on H. pylori and a balancing effect on dysbiosis. Therefore, it fulfills the definition of a new therapeutic strategy to successfully treat H. pylori infection. Data reported in literature give promising but discrepant results. Aim: To assess in vitro bacteriostatic and bactericidal activity of probiotic strains against H. pylori. Materials and methods: L. casei, L. paracasei, L. acidophilus, B. lactis and S. thermophilus strains were used. Agar well diffusion and time-kill curves were carried out to detect bacteriostatic and bactericidal activity, respectively. Results: All probiotic strains showed both bacteriostatic and bactericidal activity vs. H. pylori. Conclusions: Such findings prompted us to plan a protocol of treatment in which probiotics are given to infected patients in association with antibiotic therapy.

Potential of selected lactic acid bacteria from Theobroma cacao fermented fruit juice and cell-free supernatants from cultures as inhibitors of Helicobacter pylori and as good probiotic

OBJECTIVE

The present study was designed to evaluate the inhibitory effect of lactic acid bacteria (LAB) isolates from the fermented cocoa juice and their cell-free culture supernatants (CFS) against Helicobacter pylori strains and their potential as good probiotic. Isolation of lactic acid bacteria (LAB) was performed by culture and subculture of sample on MRS agar. Morphological characteristics, Gram staining and catalase reaction were used to identify the isolates. The antagonistic activity of LAB was tested using the agar spot-on-lawn method and the inhibitory effect of CFS using well diffusion assay. Acid tolerance and resistance to antibiotics tests were used to evaluate the probiotic potential of LAB isolates.

RESULTS

Antagonistic effect was observed in 65.52% of isolated LAB. Isolate LAB19 showed the broader spectrum of antagonistic effect. The overall inhibitory activity was two to three folds reduced when CFSs were used instead of LAB isolates themselves. Our data showed that LAB19 controlled H. pylori growth using bacteriocins and that LAB4', LAB8, LAB11', LAB12, LAB13', LAB15, LAB16 and LAB17 were through organic acids. LAB9, LAB11' and LAB12 showed properties of probiotic tested. In this study, nine LAB isolates were found to possess anti-Helicobacter activity and some preliminary probiotic properties.

Efficacy and safety of probiotics in eradicating Helicobacter pylori: A network meta-analysis

BACKGROUND

Due to decreasing eradication rate and increasing side effects, probiotics have gradually become an important supplement to standard eradication regimens for Helicobacter pylori.

OBJECTIVE

To evaluate the effectiveness and safety of probiotics in facilitating the eradication of H pylori and to explore the best timing and duration of probiotic supplementation, use of eradication regimens, strains, locations, and common side effects.

METHODS

Eligible studies were retrieved from the PubMed, EMBASE, Cochrane Library, Web of Science, and CNKI databases, and we applied the Stata 12.0 software for the standard meta-analysis and network meta-analysis.

RESULTS

Forty eligible studies with 8924 patients were included in the analysis. We used a random-effects model (I = 52.1% and I = 81.4%) to analyze the eradication rate and the incidence of total side effects by intention to treat (ITT). Compared with the control group, a higher eradication rate (relative risk [RR] 1.140, 95% confidence interval (CI) 1.101-1.180, P < .001) and lower incidence of total side effects (RR 0.470, 95% CI 0.391-0.565, P < .001) were observed in the probiotic group. In the subgroup analysis, we evaluated the surface under the cumulative ranking curve scores for the before + same (75.2%), >2 weeks (92.6%), probiotic + quadruple regimen (99.9%), Lactobacillus (73.6%), multiple strains (72.1%), China (98.5%) groups. The rankings of common side effects are shown in Table 6. SUCRA scores for diarrhea (39.7%), abdominal pain (43.9%), nausea (78.8%), taste disturbance (99.6%), vomiting (7.1%), and constipation (30.9%) were reported. The consistency of all comparison groups was good.

CONCLUSIONS

Probiotics improved the eradication rate and reduced side effects when added to the treatments designed to eradicate H pylori. The use of probiotics before the eradication treatment and throughout the eradication treatment, and also the use of probiotics for more than 2 weeks, exerted better eradication effects. Probiotics combined with the bismuth quadruple regimen was the best combination. Lactobacillus and multiple strains were better choices of probiotic strains. The eradication effect observed in China was better than the effect observed in other countries.

Characterization and assessment of two biocontrol bacteria against Pseudomonas syringae wilt in Solanum lycopersicum and its genetic responses

Pseudomonas and Bacillus species are attractive due to their potential bio-control application against plant bacterial pathogens. Pseudomonas aeruginosa strain D4 and Bacillus stratosphericus strain FW3 were isolated from mine tailings in South Korea. In these potent bacterial strains, we observed improved antagonistic activity against Pseudomonas syringae DC3000. These strains produced biocatalysts for plant growth promotion, and in vivo examination of Solanum lycopersicum included analysis of disease severity, ion leakage, chlorophyll content, and H₂O₂ detection. In addition, regulation of the defense genes pathogen-related protein 1a (PR1a) and phenylalanine ammonia lyase (PAL) was compared with treated plants and untreated control plants. The results suggest that these two bacterial strains provide protection against plant pathogens via direct and indirect modes of action and could be used as a bio-control agent.

Fermented Foods: Are They Tasty Medicines for Helicobacter pylori Associated Peptic Ulcer and Gastric Cancer?

More than a million people die every year due to gastric cancer and peptic ulcer. Helicobacter pylori infection in stomach is the most important reason for these diseases. Interestingly, only 10-20% of the H. pylori infected individuals suffer from these gastric diseases and rest of the infected individuals remain asymptomatic. The genotypes of H. pylori, host genetic background, lifestyle including smoking and diet may determine clinical outcomes. People from different geographical regions have different food habits, which also include several unique fermented products of plant and animal origins. When consumed raw, the fermented foods bring in fresh inocula of microbes to gastrointestinal tract and several strains of these microbes, like Lactobacillus and Saccharomyces are known probiotics. In vitro and in vivo experiments as well as clinical trials suggest that several probiotics have anti-H. pylori effects. Here we discuss the possibility of using natural probiotics present in traditional fermented food and beverages to obtain protection against H. pylori induced gastric diseases.