Helicobacter pylori antimicrobial resistance and antibiotic consumption in the low-resource Central America setting

Control of Helicobacter pylori with engineered probiotics secreting selective guided antimicrobial peptides

Helicobacter pylori is the primary cause of 78% of gastric cancer cases, providing an opportunity to prevent cancer by controlling a single bacterial pathogen within the complex gastric microbiota. We developed highly selective antimicrobial agents against H. pylori by fusing an H. pylori-binding guide peptide (MM1) to broad-spectrum antimicrobial peptides. The common dairy probiotic Lactococcus lactis was then engineered to secrete these guided antimicrobial peptides (gAMPs). When co-cultured in vitro with H. pylori, the gAMP probiotics lost no toxicity compared to unguided AMP probiotics against the target, H. pylori, while losing >90% of their toxicity against two tested off-target bacteria. To test binding to H. pylori, the MM1 guide was fused to green fluorescent protein (GFP), resulting in enhanced binding compared to unguided GFP as measured by flow cytometry. In contrast, MM1-GFP showed no increased binding over GFP against five different off-target bacteria. These highly selective gAMP probiotics were then tested by oral gavage in mice infected with H. pylori. As a therapy, the probiotics outperformed antibiotic treatment, effectively eliminating H. pylori in just 5 days, and also protected mice from challenge infection as a prophylactic. As expected, the gAMP probiotics were as toxic against H. pylori as the unguided AMP probiotics. However, a strong rebound in gastric species diversity was found with both the selective gAMP probiotics and the non-selective AMP probiotics. Eliminating the extreme microbial dysbiosis caused by H. pylori appeared to be the major factor in diversity recovery. IMPORTANCE Alternatives to antibiotics in the control of Helicobacter pylori and the prevention of gastric cancer are needed. The high prevalence of H. pylori in the human population, the induction of microbial dysbiosis by antibiotics, and increasing antibiotic resistance call for a more sustainable approach. By selectively eliminating the pathogen and retaining the commensal community, H. pylori control may be achieved without adverse health outcomes. Antibiotics are typically used as a therapeutic post-infection, but a more targeted, less disruptive approach could be used as a long-term prophylactic against H. pylori or, by extension, against other gastrointestinal pathogens. Furthermore, the modular nature of the guided antimicrobial peptide (gAMP) technology allows for the substitution of different guides for different pathogens and the use of a cocktail of gAMPs to avoid the development of pathogen resistance.

The global prevalence of gastric cancer in Helicobacter pylori-infected individuals: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is a gastrointestinal pathogen that infects around half of the world's population. H. pylori infection is the most severe known risk factor for gastric cancer (GC), which is the second highest cause of cancer-related deaths globally. We conducted a systematic review and meta-analysis to assess the global prevalence of GC in H. pylori-infected individuals.

METHODS

We performed a systematic search of the PubMed, Web of Science, and Embase databases for studies of the prevalence of GC in H. pylori-infected individuals published from 1 January 2011 to 20 April 2021. Metaprop package were used to calculate the pooled prevalence with 95% confidence interval. Random-effects model was applied to estimate the pooled prevalence. We also quantified it with the I2 index. Based on the Higgins classification approach, I2 values above 0.7 were determined as high heterogeneity.

RESULTS

Among 17,438 reports screened, we assessed 1053 full-text articles for eligibility; 149 were included in the final analysis, comprising data from 32 countries. The highest and lowest prevalence was observed in America (pooled prevalence: 18.06%; 95% CI: 16.48 - 19.63; I2: 98.84%) and Africa (pooled prevalence: 9.52%; 95% CI: 5.92 - 13.12; I2: 88.39%). Among individual countries, Japan had the highest pooled prevalence of GC in H. pylori positive patients (Prevalence: 90.90%:95% CI: 83.61-95.14), whereas Sweden had the lowest prevalence (Prevalence: 0.07%; 95% CI: 0.06-0.09). The highest and lowest prevalence was observed in prospective case series (pooled prevalence: 23.13%; 95% CI: 20.41 - 25.85; I2: 97.70%) and retrospective cohort (pooled prevalence: 1.17%; 95% CI: 0.55 - 1.78; I 2: 0.10%).

CONCLUSIONS

H. pylori infection in GC patients varied between regions in this systematic review and meta-analysis. We observed that large amounts of GCs in developed countries are associated with H. pylori. Using these data, regional initiatives can be taken to prevent and eradicate H. pylori worldwide, thus reducing its complications.

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.

Prevalence of antibiotic resistance of Helicobacter pylori isolates in Shanghai, China

OBJECTIVE

This study aimed to evaluate the resistance of Helicobacter pylori (H. pylori) to common antibiotics in Shanghai.

METHODS

A total of 1171 eligible subjects participated in the study. Antibiotic susceptibility to six common antibiotics was examined with the disk diffusion method. Mutations in resistant-related genes were identified via Sanger sequencing analysis.

RESULTS

Overall, the resistance rates of strains to amoxicillin, clarithromycin, levofloxacin, metronidazole, tetracycline, and furazolidone were 0.1%, 27.8%, 31.1%, 79.9%, 0.1%, and 0.5%, respectively. Compared with untreated patients, resistance rates of clarithromycin (P < 0.01), levofloxacin (P < 0.01), and metronidazole were significantly higher in re-treated patients (P < 0.05). The total multiple resistance rate was 40.5%. Age (levofloxacin), gender (clarithromycin, levofloxacin, and metronidazole) and endoscopic findings (clarithromycin and levofloxacin) were independent factors influencing antibiotic resistance. High correlation was observed between the drug susceptibility test and molecular test for the resistance to clarithromycin and levofloxacin.

CONCLUSIONS

The resistance rates of H. pylori to amoxicillin, tetracycline, and furazolidone were low, whereas the resistance rates of H. pylori to clarithromycin, levofloxacin, and metronidazole were high, especially in re-treated patients. Our results indicate that the clinical resistance patterns of clarithromycin and levofloxacin could be guided by relevant gene mutations.

Emergence of amoxicillin resistance and identification of novel mutations of the pbp1A gene in Helicobacter pylori in Vietnam

Background

Amoxicillin-resistant Helicobacter pylori (H. pylori) strains seem to have increased over time in Vietnam. This threatens the effectiveness of H. pylori eradication therapies with this antibiotic. This study aimed to investigate the prevalence of primary resistance of H. pylori to amoxicillin and to assess its association with pbp1A point mutations in Vietnamese patients.

Materials and methods

Naive patients who presented with dyspepsia undergoing upper gastrointestinal endoscopy were recruited. Rapid urease tests and PCR assays were used to diagnose H. pylori infection. Amoxicillin susceptibility was examined by E-tests. Molecular detection of the mutant pbp1A gene conferring amoxicillin resistance was carried out by real-time PCR followed by direct sequencing of the PCR products. Phylogenetic analyses were performed using the Tamura-Nei genetic distance model and the neighbor-joining tree building method.

Results

There were 308 patients (46.1% men and 53.9% women, p = 0.190) with H. pylori infection. The mean age of the patients was 40.5 ± 11.4 years, ranging from 18 to 74 years old. The E-test was used to determine the susceptibility to amoxicillin (minimum inhibitory concentration (MIC) ≤ 0.125 μg/ml) in 101 isolates, among which the rate of primarily resistant strains to amoxicillin was 25.7%. Then, 270 sequences of pbp1A gene fragments were analysed. There were 77 amino acid substitution positions investigated, spanning amino acids 310–596, with the proportion varying from 0.4 to 100%. Seven amino acid changes were significantly different between amoxicillin-sensitive (Amox^S) and amoxicillin-resistant (Amox^R) samples, including Phe₃₆₆ to Leu (p <  0.001), Ser₄₁₄ to Arg (p <  0.001), Glu/Asn_464–465 (p = 0.009), Val₄₆₉ to Met (p = 0.021), Phe₄₇₃ to Val (p <  0.001), Asp₄₇₉ to Glu (p = 0.044), and Ser/Ala/Gly_595–596 (p = 0.001). Phylogenetic analyses suggested that other molecular mechanisms might contribute to amoxicillin resistance in H. pylori in addition to the alterations in PBP1A.

Conclusions

We reported the emergence of amoxicillin-resistant Helicobacter pylori strains in Vietnam and new mutations statistically associated with this antimicrobial resistance. Additional studies are necessary to identify the mechanisms contributing to this resistance in Vietnam.

First Chemical Investigation of Korean Wild Mushroom, Amanita hemibapha subsp. javanica and the Identification of Anti-Helicobacter pylori Compounds

Amanita hemibapha subsp. javanica (Amanitaceae) is an edible Korean wild mushroom. A. hemibapha subsp. javanica is often confused with A. subjunquillea, known as the East Asian death cap, which is potentially fatal when ingested. This study aimed to conduct the first chemical investigation of A. hemibapha subsp. javanica, which resulted in the isolation of seven fatty acid derivatives (1–7) and three steroids (8–10) from the MeOH extract of its fruiting bodies, and their structures were determined by comparing their NMR spectroscopic data with those previously reported, along with the data from LC/MS. Compound 1 was reported previously without the identification of its absolute configuration; its structure, including the absolute configuration was confirmed for the first time, in this study, by using ¹H NMR and its fragmentation patterns in MS/MS data, and LC/MS analysis. A recently developed method using competing enantioselective acylation (CEA) coupled with LC/MS analysis was applied for determining the absolute configuration of compound 1, which revealed the 11S-configuration. In the anti-Helicobacter pylori activity test, compound 3 showed antibacterial activity against H. pylori strain 51 with 38.0% inhibition, comparable to that of quercetin (34.4% inhibition) as a positive control. Specifically, compound 4 displayed the most potent antibacterial activity against H. pylori strain 51 with 80.5% inhibition at the final concentration of 100 μm with a MIC₅₀ value of 72 μm. These findings suggested that the active compound 4 is a natural antibiotic that may be used in the development of novel antibiotics against H. pylori. In addition, the first chemical investigation of A. hemibapha subsp. javanica revealed that this mushroom can serve as a promising natural source for the bioactive natural products.

Antimicrobial Resistance of Helicobacter pylori in Gastric Biopsy Samples from Lima/Peru

Background: Helicobacter pylori prevalence and gastric cancer rates are remarkably high in Peru. Effective antimicrobial regimens are essential for successful H. pylori eradication. We aimed at assessing antimicrobial resistance rates to first- and second-line therapeutic agents in H. pylori strains detected in gastric biopsy samples. Materials and Methods: Gastric biopsy samples (antrum and corpus) were collected from therapy-naive patients (n = 154). H. pylori presence in the samples was confirmed by histopathology. Genotypic resistance to clarithromycin and quinolones was determined by real-time PCR. Results: Histology results were 100% concordant with PCR results (97/154; 63% H. pylori-positive in both). In 6% (6/97) of the patients, we found discordant results of H. pylori infection in antrum and corpus samples from the same patient. Resistance rates to clarithromycin and quinolone were 34% (33/97) and 68% (56/82), respectively. Antimicrobial resistance to both antimicrobials was 30% (25/82). Conclusion: Antimicrobial resistance rates of H. pylori to clarithromycin and quinolones are very high in Lima, Peru. Many first- and second-line, empiric eradication regimens may not be recommended for Peruvian patients.

Review - Treatment of Helicobacter pylori infection 2020

This review summarizes important studies regarding Helicobacter pylori therapy published from April 2019 to April 2020. The main themes that emerge involve studies assessing antibiotic resistance, and there is also growing momentum behind the utility of vonoprazan as an alternative to proton pump inhibitor (PPI) therapy and also bismuth-based regimens as a first-line regimen. Antibiotic resistance is rising wherever it is being assessed, and clarithromycin resistance in particular has reached a point where it may no longer be a viable therapy without previous testing in many regions of the world. The evidence for the efficacy of a bismuth-based quadruple therapy as a first-line therapy is now very clearly established, and there is substantial evidence that it is the best performing first-line therapy. The utility of vonoprazan as an alternative to PPI therapy, especially in resistant and difficult-to-treat groups, has also been considered in great detail this year, and it may offer an opportunity in the near future to reduce the problem of antibiotic resistance.

Impact of previous metronidazole exposure on metronidazole-based second-line quadruple therapy for Helicobacter pylori infection

BACKGROUND/AIMS

The negative effects on the eradication success of Helicobacter pylori infection after previous exposure to macrolides, including clarithromycin on clarithromycin-based first-line therapy have been demonstrated. However, whether this is true for metronidazole-based second-line quadruple therapy remains unclear. We investigated the relationship between past administration of metronidazole and the failure of metronidazole-based second-line quadruple therapy in patients with H. pylori infection.

METHODS

Patients over 20 years of age who were diagnosed with H. pylori infection between January 1998 and March 2016 were enrolled in this study. The relationship between the clinical parameters and the results of a C13-urea breath test after metronidazole-based second-line quadruple therapy was analyzed in patients for whom clarithromycin-based triple therapy failed to eradicate H. pylori.

RESULTS

The H. pylori eradication failure rate was significantly higher in patients with a history of metronidazole use than in patients without a history of metronidazole use (p = 0.011). Multivariable analysis showed that the odds ratio of previous metronidazole use for eradication failure was 3.468 (95% confidence interval, 1.391 to 8.649; p = 0.008). In the subgroup analysis of patients with a history of metronidazole use, the duration of metronidazole use and interval between its use and eradication therapy did not significantly affect H. pylori eradication failure.

CONCLUSION

Previous exposure to metronidazole was a significant risk factor for treatment failure of metronidazole-based second-line quadruple therapy; therefore, this should be considered when establishing a treatment strategy for patients with H. pylori infection.