Introduction
Helicobacter pylori (
H. pylori) is an important human pathogen that is associated with gastric cancer, mucosa-associated lymphoid tissue (MALT) lymphoma, peptic ulcer disease, and various other conditions [
1‐
3]. Domestic and foreign guidelines have indicated that regardless of symptoms or complications,
H. pylori-infected patients should receive eradication treatment [
4,
5].
The proposal to eliminate
H. pylori has given rise to concerns about the disruption of the gut microbiota caused by
H. pylori eradication. A previous study demonstrated that there were substantial differences in the extent and severity of perturbations among different
H. pylori eradication regimens [
6,
7]. The gut microbiota plays a crucial role in human health, and dysbiosis is associated with various diseases [
8,
9]. Consequently, when selecting eradication regimens for patients infected with
H. pylori, it is essential to take into account the impact of these regimens on the gut microbiota.
In recent years, high-dose dual therapy (HDDT), comprising a potent acid suppressant such as esomeprazole or vonoprazan and amoxicillin, has been emerging rapidly. This is due to its benefits of high eradication efficacy and a relatively lower incidence of adverse side effects [
10‐
13]. In the latest Chinese national clinical practice guideline, HDDT has been recommended for initial eradication treatment in individuals with
H. pylori infection [
14]. Nevertheless, at present, there are few studies exploring the impact of HDDT on the gut microbiota. Thus, the aim of this study was to evaluate the impact of HDDT on the gut microbiota, and to compare the alterations in the gut microbiota following
H. pylori eradication using HDDT and BQT.
Materials and methods
Study design and participants
This research was carried out in Hainan Province, China, spanning from September 2023 to April 2024. The inclusion criteria were established as follows: (1) both genders within the age range of 18 to 70 years; (2) diagnosis of H. pylori infection via the carbon-13/14 urea breath test (13C/14C-UBT). Patients meeting any of the following exclusion criteria were excluded: (1) patients who had previously undergone H. pylori eradication treatment; (2) individuals with a history of gastrointestinal surgery or the presence of severe gastrointestinal conditions, such as peptic ulcers, gastrointestinal bleeding, or malignant tumors; (3) presence of severe systemic diseases; (4) use of antibiotics, acid suppressants, probiotics, or or non-steroidal anti-inflammatory drugs (NSAIDs) within the previous month; (5) allergy to penicillin or other medications employed in this study; (6) pregnant or lactating women; (7) participating in other clinical trials; and (8) patients who were deemed unqualified for enrollment following assessment by the researchers. All patients provided informed consent and the study protocol was approved by the Institutional Ethics Board of Wenchang People’s Hospital ([2021]-1) and registered in the China Clinical Trials Registry (ChiCTR2100053268).
Interventions and follow-up
All participants were randomly assigned to either the HDDT or BQT group in a 1:1 ratio using a computer- generated randomization list. The HDDT regimen comprised esomeprazole (Zhengda Tianqing Pharmaceutical Co., Ltd, Jiangsu, China) at a dosage of 20 mg and amoxicillin (Gener-sanyang Pharmaceutical Co., Ltd., Hainan, China) at 750 mg, both to be taken four times daily for 14 days. Subjects were instructed to consume esomeprazole half an hour prior to breakfast, lunch, dinner, and bedtime, while amoxicillin was to be taken after breakfast, lunch, dinner, and bedtime. The BQT regimen consisted of esomeprazole (Zhengda Tianqing Pharmaceutical Co., Ltd, Jiangsu, China) 20 mg, amoxicillin (Gener-sanyang Pharmaceutical Co., Ltd, Hainan, China) 1000 mg, clarithromycin (Shandong Xinhua Pharmaceutical Co., Ltd, Shandong, China) 500 mg, and bismuth potassium citrate (Youcare Pharmaceutical Group Co., Ltd, Beijing, China) 600 mg, all to be taken twice daily for 14 days. Esomeprazole and bismuth potassium citrate were taken half an hour before breakfast and dinner, and amoxicillin and clarithromycin were administered after breakfast and dinner. Throughout the course of this study, with the exception of the above 14 days of medication, the use of other medications such as antibiotics, gastric acid-suppressing agents, or probiotics was prohibited. 14CUBT was used to determine the H. pylori status 6 weeks after the completion of treatment.
Fecal sampling
Fresh stool samples were collected at three time points: at the baseline (before treatment), at week 2 (following the completion of 14 days of treatment), and at week 8 (6 weeks after 14 days of treatment). Subjects were instructed to collect their stool using a pre-prepared standard sterile specimen collection receptacle and then required to transport the collected stools to the hospital within a 2-hour time frame. Once at the hospital, the stool specimens were promptly transferred to a -80℃ refrigerator immediately and stored there until the time of DNA extraction.
Microbial DNA from stool samples was extracted using the OMEGA Soil DNA Kit (Omega Bio-Tek, Norcross, GA, USA) following the manufacturer’s instructions and stored at -20 °C prior to analysis. DNA purity and concentration were determined using a NanoDrop NC2000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) and agarose gel electrophoresis. PCR amplification of the 16 S rRNA gene V3–V4 hyper-variable regions was conducted using the forward primer 338 F (5’-ACTCCTACGGGAGGCAGCA-3’) and reverse primer 806R (5’-GGACTACHVGGGTWTCTAAT-3’). All amplifications were performed in the PCR component containing 5 µl of buffer (5×), 0.25 µl of Fast pfu DNA polymerase (5 U/µl), 2 µl (2.5 mM) of dNTPs, 1 µl (10 µM) of each forward and reverse primer, 1 µl of DNA template, and 14.75 µl of dd H2O. The PCR conditions were as follows: 98 °C for 5 min; 25 cycles of 98 °C for 30 s, 53 °C for 30 s, and 72 °C for 45 s; and a final extension step at 72 °C for 5 min. PCR amplicons were purified using Vazyme VAHTSTM DNA Clean Beads (Vazyme, Nanjing, China) and quantified using a Quant-iT PicoGreen dsDNA Assay Kit (Invitrogen, Carlsbad, CA, USA). After purification and quantification, amplicons were standardized to equimolar levels and pair-end sequencing was performed using the Illumina MiSeq platform with the MiSeq Reagent Kit v3 at Bioyi Biotechnology Co., Ltd., Wuhan, China.
Microbiota sequencing data analysis
Microbiota sequencing data were processed by Quantitative Insights into Microbial Ecology (QIIME). Raw sequence data were demultiplexed using the demux plugin following by primers cutting with cutadapt plugin. Sequences were then quality-filtered, denoised, merged, and chimeras removed using the DADA2 plugin [
15]. Amplicon sequence variants (ASVs) were aligned with multiple alignment using fast Fourier transform (MAFFT) and used to construct a phylogeny using fasttree2 [
16]. The diversity plugin was used to estimate alpha diversity indices and beta diversity metrics. Taxonomy was assigned to the OTUs using the classify-sklearn naïve Bayes taxonomy classifier in the feature-classifier plugin against the SILVA Release 132 database [
17].
QIIME and R packages (version 3.2.0) were employed for the analysis of microbiome bioinformatics [
18]. Alpha diversity (Chao1, Shannon, and Simpson indices) and beta diversity were calculated using the phyloseq package [
19]. The statistical significance of the Chao1, Shannon, and Simpson indices among the groups was assessed using Wilcoxon rank- sum test or Kruskal–Wallis test, and visualized as box plots. Beta diversity was evaluated through principal coordinate analysis (PCoA) based on weighted UniFrac distance metrics and analysis of similarities (ANOSIM). The Wilcoxon rank- sum test and Kruskal–Wallis test were used to compare the differences in the relative abundance of bacterial taxa both within and between groups. The linear discriminant analysis effect size (LEfSe) analysis was adopted to identify the differential taxa between groups. The functional profiles of the gut microbiota were estimated using Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Moreover, Welch’s t test was carried out to compare the abundances of metabolic pathways between two groups.
Continuous clinical parameters are expressed as mean ± standard deviation (SD), and categorical variables are shown as frequencies and percentages. For the comparison of continuous variables between the two groups, Student’s t-test was utilized. Categorical variables were compared using Pearson’s chi-square test or Fisher’s exact test.
Discussion
As public health awareness has been steadily growing, an increasing number of people are choosing to proactively undergo testing or eradication treatment for
H. pylori. Currently, there are numerous regimens available for
H. pylori eradication. PPI-based triple therapy was formerly the predominant prescribed treatment option, boasting an eradication success rate of around 90% [
20,
21]. However, with the increasing antibiotic resistance, the eradication rate of triple therapy has gradually decreased to below 80% in some regions, and is no longer recommended as a first-line eradication regimen in China [
22‐
24]. At present, BQT, which demonstrates a relatively high eradication rate, is the most recommended and commonly utilized first-line eradication regimen in China [
25]. In several regions where bismuth is unavailable, non-bismuth quadruple therapies, including sequential therapy, concomitant therapy, and hybrid therapy, can also achieve satisfactory eradication effectiveness and have been recommended as first-line regimens [
26]. Nevertheless, these quadruple regimens tend to have a relatively high incidence of side effects and poor patient compliance. Moreover, the long-term use of multiple antibiotics can exacerbate
H. pylori’s resistance. Consequently, researchers have been constantly searching for new effective regimens with fewer adverse events and less use of antibiotics. In this context, HDDT, which typically consists of only a single antibiotic (usually amoxicillin), was proposed and attracted much attention [
27]. It has been reported that higher doses or more potent acid-inhibiting drugs can maintain the gastric pH above 6 [
28]. When the gastric pH ranges from 6 to 8,
H. pylori could develop into the replication state, and became more sensitive to amoxicillin [
29,
30]. Additionally, frequent dosing of amoxicillin ensures that its concentration remains higher than the minimum inhibitory concentration for an extended period [
31,
32]. Furthermore, the primary resistance rate to amoxicillin is less than 5% in most regions, and even after an unsuccessful eradication attempt, the secondary resistance rate remains relatively low [
33]. Hence, this simple dual-drug regimen could achieve high eradication efficacy and good safety [
10,
11,
34].
Accumulating evidence has proven the beneficial effects of
H. pylori eradication on on gastric cancer prevention and peptic ulcer treatment [
35‐
37]. However, the disruption of the gut microbiota caused by PPIs and antibiotics has been a significant concern. Previous studies have demonstrated that
H. pylori eradication could significantly alter the composition and diversity of the gut microbiota [
6,
7,
38]. Liou et al. compared the impacts of BQT, concomitant therapy, and triple therapy on the gut microbiota, and found that the alpha diversity indices and beta diversity of all three groups changed significantly at week 2, the diversity of patients in the triple therapy group returned to baseline levels at week 8, whereas the disruption of the gut microbiota in the concomitant therapy and BQT groups was not completely restored even after a year [
6]. Another study also indicated that the eradication of
H. pylori infection could lead to gut microbiota dysbiosis, and the changes induced by BQT, concomitant therapy, and sequential therapy nearly returned to the baseline level one year after treatment [
7]. In the current study, a comparison was made between the impacts of HDDT and BQT on the gut microbiota. It was found that HDDT caused minimal disruption to the diversity, while BQT significantly altered the diversity at week 2 and these changes persisted at week 8. These results were consistent with previous findings. Horii et al. analyzed the impact of vonoprazan-amoxicillin (VA) dual therapy on the gut microbiota and found that, compared to the baseline, there was no significant difference in the diversity at week 1 and at week 8 [
39]. Another study from China compared the changes in the gut microbiota before and after treatment in the VA dual therapy group and the BQT group. It was discovered that the alpha diversity and the relative abundance of phyla in both groups did not change significantly one month after treatment, but the relative abundance of some dominant genera changed markedly in the BQT group [
40]. A recent study conducted among servicemen also showed that the disruption caused by HDDT was less than that of BQT [
41].
It has been reported that short-term exposure to amoxicillin exerted a relatively minor impact on the diversity of the gut microbiota [
42]. In another study, it was demonstrated that after subjects received 500 mg/day of amoxicillin for 7 consecutive days, the composition of the gut microbiota remained similar to that of the placebo group, and the Simpson index did not undergo significant changes before and after the intervention [
43]. However, macrolides were found to have a potent effect on the gut microbiota and were capable of inhibiting numerous microorganisms. A previous study indicated that macrolides might have a more persistent effect on the gut microbiota compared to amoxicillin, even the changes of some bacteria persisted for 1–2 years after completing a macrolide course [
44]. Results from Nobel et al. also revealed that macrolides had greater effect on the gut microbiota than amoxicillin [
45]. Maier et al. found that macrolides could not only inhibit many gut bacteria but also kill several species [
46]. They believed that this could partly explain the strong effect of macrolides on gut microbiota. A study further demonstrated that sequential treatments involving two antibiotics led to more severe disruptions in the gut microbiota than exposure to a single antibiotic [
45]. In addition, a study showed that simultaneous administration of PPI, amoxicillin and clarithromycin increases the serum concentrations of PPI and the active 14-OH-clarithromycin metabolite significantly [
47]. Hence, BQT, which contains both amoxicillin and clarithromycin, might induce a more substantial impact on the gut microbiota than HDDT, which only contained amoxicillin.
When analyzing the gut microbiota composition after receiving HDDT and BQT, we observed that a greater number of species had alterations in their abundances in the BQT group compared to the HDDT group at week 2. Among these species, several play crucial roles in the health and diseases. For instance,
Faecalibacterium_prausnitzii,
Roseburia_inulinivorans,
Agathobacter_rectalis,
and Anaerostipes_hadrus are involved in gut butyrate production [
48‐
52]. Butyrate is significant as it can impact colonic motility, contribute to immunity maintenance, and possess anti-inflammatory properties [
53,
54].
Bifidobacterium_longum is one of the most abundant members in the gut, and can protect the intestinal epithelial barrier and tissue structure, balance the gut microbiota to alleviate the symptoms of colitis and maintain the host in a healthy state [
55].
Bacteroides_uniformi and
Bacteroides_thetaiotaomicron are capable of degrading and utilizing glycans for capsular polysaccharide synthesis, which is essential for maintaining intestinal health [
56]. Moreover, it has been demonstrated that
Parabacteroides_distasonis could exert protective effects against certain diseases, including colorectal cancer, multiple sclerosis, and inflammatory bowel disease [
57]. Consequently, the reduction in the abundances of these beneficial bacterial species can have a negative impact on intestinal health and may promote inflammation and disease development. In addition, after receiving BQT,
Pantoea_piersonii,
Streptococcus_parasanguinis and
Streptococcus_vestibularis tend to overgrow in the gut, which may lead to invasive diseases, such as peritonitis and subacute endocarditis [
58‐
60]. However, in the HDDT group at week 2, the relative abundances of these potential pathogens did not show an increase. These observed changes collectively suggested that the impact of HDDT on the gut microbiota is milder than that of BQT. Chen et al. also demonstrated that BQT had a greater effect on the relative abundance of butyrate-producing bacteria compared to HDDT [
41].
Our prior study indicated that patients who received BQT experienced more abdominal discomfort, particularly diarrhea than patients in the HDDT group (4.6% vs. 1.4%,
P = 0.014) [
12]. In the current study, we analyzed the association between specific bacteria and diarrhea, and found that patients experiencing diarrhea had a relatively higher abundance of
Veillonella.
Veillonella is a Gram-negative anaerobic coccus that has the capacity to produce lipopolysaccharide, stimulate the release of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6, and commonly seen in upper respiratory and intestinal infections [
61]. A study that aimed to explore the association of fecal bacteria composition and subtypes and symptoms of irritable bowel syndrome showed that an increased abundance of
Veillonella was associated with loose stools, while a reduced abundance was linked to constipation [
62]. Another study involving 992 children from four low-income countries demonstrated that
Veillonella exhibited a significant increase in young children with moderate-to-severe diarrhea [
63]. Gomez et al. also found that diarrheic calves had a higher abundance of
Veillonella than control group [
64]. Hence, the increased abundance of
Veillonella might be the underlying cause of the occurrence of diarrhea after receiving BQT, and it’s worth of further study.
However, there were some deficiencies in our study. Firstly, the sample size was relatively small in our study, and we could not conduct more stratified analysis. Secondly, this study did not collect gastric samples to analyze the gastric microbiota before and after treatment. Thirdly, analysis of 16 S rRNA can only provide information on the presence of bacteria, information including the changes of antibiotic resistance gene cannot be obtained, and need to be analyzed in our further study. Lastly, HDDT cannot be used for patients who have an allergy to amoxicillin or those with amoxicillin-resistant
H. pylori. For these infected patients, vonoprazan-tetracycline dual therapy has been suggested as a potentially viable option [
65], but still need to be further validated.
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