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Background: While gastric cancer is generally declining globally, the temporal trend of young-onset (< 40 years) gastric cancer remains uncertain. We performed this analysis to determine the temporal trends of young-onset gastric cancer compared to late-onset cancer (≥ 40 years). Methods: We extracted cross-sectional data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. The burden of gastric cancer from 1990 to 2019 was assessed through indicators including incidence and mortality rates, which were classified at global, national, and regional levels, and according to socio-demographic indexes (SDI) and age or sex groups. Joinpoint regression analysis was used to identify specific years with significant changes. The correlation between AAPC with countries' average SDI was tested by Pearson's Test. Results: The global incidence rate of young-onset gastric cancer decreased from 2.20 (per 100,000) in 1990 to 1.65 in 2019 (AAPC: − 0.95; 95% confidence interval [CI] − 1.25 to − 0.65; P < 0.001). Late-onset cancer incidence also decreased from 59.53 (per 100,000) in 1990 to 41.26 in 2019 (AAPC: − 1.23; 95% CI − 1.39 to − 1.06, P < 0.001). Despite an overall decreasing trend, the incidence rate of young-onset cancer demonstrated a significant increase from 2015 to 2019 (annual percentage change [APC]: 1.39; 95% CI 0.06 to 2.74; P = 0.041), whereas no upward trend was observed in late-onset cancer. Mortality rates of young- and late-onset cancer both exhibited a significant decline during this period (AAPC: − 1.82; 95% CI − 2.15 to − 1.56; P < 0.001 and AAPC: − 1.69, 95% CI − 1.79 to − 1.59; P < 0.001). The male-to-female rate ratio for incidence and mortality in both age groups have been increasing since 1990. While countries with high SDI have had a greater decline in the incidence of late-onset gastric cancer (slope of AAPC change: − 0.20, P = 0.004), it was not observed in young-onset cancer (slope of AAPC change: − 0.11, P = 0.13). Conclusions: The global incidence and mortality rates of both young- and late-onset gastric cancer have decreased since 1990. However, the incidence rate of young-onset cancer has demonstrated a small but significant upward trend since 2015. There was disparity in the decline in young-onset gastric cancer among male and high SDI countries. These findings could help to inform future strategies in preventing gastric cancer in younger individuals. [ABSTRACT FROM AUTHOR]

Transient gut microbiota alterations have been reported after antibiotic therapy for Helicobacter pylori. However, alteration in the gut virome after H. pylori eradication remains uncertain. Here, we apply metagenomic sequencing to fecal samples of 44 H. pylori-infected patients at baseline, 6-week (N = 44), and 6-month (N = 33) after treatment. Following H. pylori eradication, we discover contraction of the gut virome diversity, separation of virome community with increased community difference, and shifting towards a higher proportion of core virus. While the gut microbiota is altered at 6-week and restored at 6-month, the virome community shows contraction till 6-month after the treatment with enhanced phage-bacteria interactions at 6-week. Multiple courses of antibiotic treatments further lead to lower virus community diversity when compared with treatment naive patients. Our results demonstrate that H. pylori eradication therapies not only result in transient alteration in gut microbiota but also significantly alter the previously less known gut virome community. Here, Wang et al. use metagenomic sequencing to explore the impact of antibiotic treatment for Helicobacter pylori on the gut virome community in infected patients, showing that recurrent treatment leads to a lower virus community diversity and altered virus-bacteria interactions, compared with treatment naive patients. [ABSTRACT FROM AUTHOR]

Methylated septin 9 (SEPT9) has been approved for non-invasive screening of colorectal cancer (CRC), but data on monitoring of CRC is sparse. Droplet digital polymerase chain reaction (ddPCR), with higher detection precision and simpler quantification than conventional PCR, has not been applied in SEPT9 detection. We explored the role of SEPT9 ddPCR for CRC detection and to measure serial SEPT9 levels in blood samples of CRC patients before and 3-month after surgery. SEPT9 methylated ratio, methylated abundance, and CEA levels were all higher in CRC patients than normal controls (all P < 0.05). The area under the curve (AUC) for methylated ratio and abundance to detect CRC was 0.707 and 0.710, respectively. There was an increasing trend for SEPT9 methylated abundance from proximal to distal cancers (P = 0.017). At 3-month after surgery, both methylated abundance and ratio decreased (P = 0.005 and 0.053, respectively), especially methylated abundance in stage III and distal cancer (both P < 0.01). We have developed a ddPCR platform for the quantitative detection of plasma SEPT9 in CRC patients. SEPT9 methylated abundance had an early post-operative decline, which may be useful in monitoring of treatment response. [ABSTRACT FROM AUTHOR]

Background: A histamine-2 receptor antagonist (H2RA) is one of the common gastroprotective co-therapies used with non-steroidal anti-inflammatory drugs (NSAIDs) for the prevention or treatment of peptic ulcers (PUs). To date, no study has directly compared the prophylactic effectiveness between high-dose and low-dose H2RA.Objective: Our objective was to compare the effectiveness of high-dose versus low-dose H2RAs in the primary prophylaxis of PUs among short-term NSAID users.Methods: A retrospective cohort study was conducted using the Clinical Data Analysis and Reporting System (CDARS) in Hong Kong. Patients aged 18 years or above who received a single prescription of oral NSAID with oral H2RA were identified within the study period (1 January 2009-31 December 2012). Patients with a history of or risk factors for PU in the corresponding 2 years prior to the index date (of the first NSAID prescription) were excluded. Log binomial regression analysis was used to calculate the relative risk of PU among NSAID users with high-dose H2RA versus low-dose H2RA exposure.Results: Among the NSAID cohort (n = 102,042), 77,509 (76 %) were on low-dose H2RA and 24,533 (24 %) were on high-dose H2RA. Of the total 69 PU cases identified during the drug exposure period, 64 (0.08 %) received low-dose-H2RA and five (0.02 %) received high-dose H2RA. The overall absolute risk of PUs for NSAID users whilst on H2RA was approximately 1 per 1,479 patients. The adjusted relative risk for NSAID users receiving high-dose H2RA versus low-dose H2RA was 0.32 (95 % confidence interval [CI] 0.13-0.79). Patients aged ≥65 years, receiving a longer duration of treatment, or with concomitant use of antiplatelet agents were found to be at higher risk of PU.Conclusion: High-dose H2RA showed greater effectiveness than low-dose H2RA in the primary prophylaxis of NSAID-associated PUs in short-term new users. [ABSTRACT FROM AUTHOR]

OBJECTIVES:The benefits of narrow band imaging (NBI) on enhancing colorectal adenoma detection remain questionable. We tested whether the new generation of NBI (190-NBI), which is twice as bright as the previous version, would improve adenoma detection when compared with high-definition white light (HD-WL) colonoscopy.METHODS:It was a randomized controlled trial with tandem colonoscopy. We recruited patients who underwent colonoscopy for symptoms, screening, or surveillance. Patients were randomized for the use of either 190-NBI or HD-WL on withdrawal. Tandem colonoscopy was performed by using the same assigned colonoscope and withdrawal method. Lesions detected on first-pass and second-pass examination were used for adenoma detection and miss rates, respectively. The primary outcomes were adenoma and polyp detection rates.RESULTS:A total of 360 patients were randomized to undergo either 190-NBI or HD-WL colonoscopy. Both the adenoma and polyp detection rates were significantly higher in the 190-NBI group compared with the HD-WL group (adenoma: 48.3% vs. 34.4%, P=0.01; polyps: 61.1% vs. 48.3%, P=0.02). The mean number of polyps detected per patient was higher in the 190-NBI group (1.49% vs. 1.13, P=0.07). There was no significant difference in the adenoma miss rates between the two groups (21.8% vs. 21.2%). Multivariate analysis showed that the use of 190-NBI (odds ratio (OR) 1.85; 95% confidence interval (CI) 1.10-3.12), withdrawal time (OR 1.29; CI 1.19-1.38), patient's age (OR 1.04; CI 1.01-1.06), and male gender (OR 2.38; CI 1.42-3.99) were associated with adenoma detection.CONCLUSIONS:190-NBI colonoscopy was superior to the conventional HD-WL in detecting colorectal adenomas or polyps, but there was no significant difference in adenoma miss rates. [ABSTRACT FROM AUTHOR]

OBJECTIVES:Both capsule endoscopy (CE) and angiography have been recommended as first investigation for patients with acute overt obscure gastrointestinal bleeding (OGIB). However, no studies have directly compared the two modalities in patients with overt OGIB. We compared the diagnostic yield and long-term outcomes of patients with overt OGIB randomized to CE or angiogram.METHODS:Consecutive patients presented with acute melena or hematochezia, but nondiagnostic upper and lower endoscopy, were immediately randomized to receive small-bowel CE or angiography. All patients were monitored for rebleeding and anemia for up to 5 years. Primary end point was the diagnostic yield of the assigned investigation. Secondary end points included rebleeding, further transfusion, readmission for bleeding or anemia, and mortality.RESULTS:A total of 60 patients with overt OGIB were randomized. The mean follow-up was 48.5 months. The diagnostic yield of immediate CE was significantly higher than angiography (53.3% vs. 20.0%, P=0.016). The cumulative risk of rebleeding in the angiography and CE group was 33.3% and 16.7%, respectively (P=0.10, log-rank test). There was no significant difference in the long-term outcomes between the two groups including further transfusion, hospitalization for rebleeding, and mortality.CONCLUSIONS:In patients with overt OGIB, immediate CE has higher diagnostic yield and comparable long-term outcomes when compared with angiography. [ABSTRACT FROM AUTHOR]

OBJECTIVES:Although colonoscopy is considered the most accurate screening tool for colorectal neoplasm, the optimal interval of repeating a screening colonoscopy, particularly in average-risk subjects after a negative colonoscopy, is poorly defined. We determine the 5-year risk of advanced neoplasia on rescreening colonoscopy in a cohort of average-risk Chinese subjects.METHODS:We invited a cohort of asymptomatic average-risk Chinese subjects (aged 55–75 years) who were recruited in our previous screening colonoscopy studies to undergo a repeat colonoscopy at the end of 5 years. The rates of advanced colorectal neoplasia at the end of 5 years in these subjects were determined according to their baseline colonoscopy findings.RESULTS:A total of 511 of the 620 eligible subjects underwent repeat-screening colonoscopy at the end of 5 years. Among them, 401 subjects had no baseline neoplasia (370 with no baseline polyps and 31 with hyperplastic polyps). In subjects with no baseline polyp, 24.6% were found to have at least one adenoma and 1.4% had advanced neoplasia on rescreening. The number needed to rescreen for one advanced neoplasia in subjects with no baseline polyp was 74 (95% confidence interval (CI), 32–168). The prevalence of advanced neoplasia at 5 years in subjects with baseline-advanced neoplasia was 20.7% (relative risk 19.6; 95% CI, 5.2–74.1; vs. subjects with no baseline polyp). The presence of baseline-advanced neoplasia (odds ratio (OR) 13.1; 95% CI, 4.1–41.7) and age in years (OR 1.11; 95% CI, 1.01–1.22) are two independent factors for development of advanced neoplasia at 5 years.CONCLUSIONS:The risk of advanced neoplasia is sufficiently low 5 years after a normal screening colonoscopy in Chinese subjects.Am J Gastroenterol 2009; 104:2028–2034; doi:10.1038/ajg.2009.202; published online 19 May 2009 [ABSTRACT FROM AUTHOR]

INTRODUCTION: Although empirical antisecretory drug therapy is recommended to young dyspeptic patients without alarming features, the effectiveness of this approach remains undetermined. We evaluated the long-term effects of an initial 12-wk course of lansoprazole in young dyspeptic patients without Helicobacter pylori ( H. pylori) infection. METHODS: Patients who were less than 45 yr and presented with at least 3 months of dyspepsia in the absence of alarming features were eligible. They were offered 13C-urea breath test (UBT) to determine H. pylori status and all symptomatic patients with negative UBT were randomized to receive lansoprazole 30 mg daily or placebo for 12 wk. Those who had previous endoscopy or positive UBT were excluded. Primary end point was the proportion of patients with treatment failure, defined as worsening of global dyspeptic symptom, while on study medication. Patients were followed up for 26 wk for global dyspeptic symptom as determined by 7-point Likert scale. Quality-of-life assessment (SF-36), need of endoscopy, and utilization of other health-care services were monitored for 52 wk. RESULTS: A total of 157 dyspeptic patients were randomized. At the end of 12-wk treatment, the proportion of patients with treatment failure was similar in the lansoprazole (33.3%) and placebo (30.3%) groups ( P= 0.74). Patients' global assessment of their dyspeptic symptom was comparable at all time points measured. There was also no significant difference in the SF-36 mental and physical summary scales. At the end of 52 wk, there was no difference in the proportion of patients who underwent endoscopy, had additional medical consultations, or used other nonstudy medications between the two groups. CONCLUSION: Lansoprazole is not effective in the initial management of young dyspeptic patients without H. pylori infection. [ABSTRACT FROM AUTHOR]

BACKGROUND: Detection of fecal DNA is a promising approach to colorectal cancer screening. However, the sensitivity of current fecal DNA tests for colorectal polyps is low. We evaluated the feasibility of detecting aberrantly methylated DNA or cyclooxygenase-2 (COX-2) mRNA in feces of patients with colorectal cancer or polyps. METHODS: Fecal samples were collected prior to colonoscopy from 20 patients with colorectal cancer, 30 patients with colorectal polyps, and 30 subjects with normal colonic examination. Presence of hypermethylated DNA in 7 tumor-related genes ( APC, ATM, hMLH1, sFRP2, HLTF, MGMT, and GSTP1) in stool was analyzed by methylation-specific PCR. COX-2 mRNA in fecal samples was detected by RT-PCR. RESULTS: With the use of this panel of methylation markers, the sensitivity of detecting colorectal cancer and adenoma was 75% (95% CI 50.9–91.3%) and 68% (95% CI 46.5–85.1%), respectively. Three normal subjects also had methylated DNA detected in stool, which gives a specificity of 90% (95% CI 73.5–97.9%). The mean number of genes methylated in DNA from the stool of patients with colorectal cancer and adenoma was 1.4 and 0.9, respectively. In contrast, COX-2 mRNA was detected in the stool samples of 10 (50%) cancer patients and one (4%) patient with advanced adenoma only. Two (6.7%) stool samples from normal subjects also had COX-2 mRNA detected. CONCLUSION: Detection of aberrantly methylated DNA in fecal samples is more sensitive than COX-2 mRNA for detection of colorectal cancer and adenoma. [ABSTRACT FROM AUTHOR]

BACKGROUND: As there is no effective treatment for irritable bowel syndrome (IBS), many patients turn to traditional Chinese medicine (TCM) for possible cure. We investigated the therapeutic efficacy of an ancient herbal Chinese formula in patients with diarrhea-predominant IBS. METHODS: This was a randomized double-blinded placebo-controlled trial. Chinese IBS patients with predominant diarrhea symptoms that fulfilled Rome II criteria were recruited. The diagnosis was verified by a TCM herbalist using TCM criteria. Eligible patients were randomized to receive a standard preparation of TCM extracts that contained 11 herbs or placebo with similar appearance and taste for 8 wk after a 2-wk run-in period. Patients were followed up for an additional 8 wk post-treatment. Primary outcome was patient's global symptom assessment. Other outcome measures included individual IBS symptom scores and health-related quality of life (short form 36). RESULTS: One hundred nineteen patients were randomized: 60 to receive TCM and 59 to receive placebo. There was no significant difference in the proportion of patients with global symptom improvement between the TCM and placebo groups at week 8 (35% vs 44.1%, p= 0.38) and at week 16 (31.7% vs 33.9%, p= 0.62). Moreover, there was no difference in individual symptom scores and the quality-of-life assessment between the two groups at all time points. BACKGROUND: The use of this herbal formulation for diarrhea-predominant IBS did not lead to global symptom improvement. Further controlled clinical studies may be necessary to characterize the role of TCM in the management of IBS. [ABSTRACT FROM AUTHOR]

BACKGROUND AND AIMS: Capsule endoscopy (CE) is one of the widely accepted investigations for obscure gastrointestinal bleeding (OGIB), but little is known about the impact of CE on the long-term outcome of patients with OGIB. We studied the long-term outcome of patients with OGIB after CE examination. PATIENTS AND METHODS: Forty-nine consecutive patients (45% men, mean age 58.3 yr) who underwent CE for OGIB were studied. The most clinically relevant finding that was related to bleeding was identified by CE. All patients were followed up for at least 12 months for clinical overt and occult bleeding. RESULTS: The median follow-up was 19 months (range 12 to 31). Possible bleeding lesions were detected by CE in 31 (63.3%) patients, and 15 (30.6%) patients, underwent further interventions including laparotomy and push enteroscopy. The overall long-term rebleeding rate in this cohort was 32.7%. The cumulative rebleeding rate was significantly lower in patients with a negative CE (5.6%) than in patients with a positive CE (48.4%, p= 0.03 log-rank test). The sensitivity and negative predictive value of CE in predicting rebleeding were 93.8% and 94.4%, respectively. CONCLUSIONS: Patients with OGIB and negative CE had a very low rebleeding rate, and further invasive investigations can be deferred. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Crohn's disease (CD) is a heterogenous disease characterized by variable manifestations and outcomes, and increasing in incidence in China. Phenotypic classification has been proposed to assist in subtyping of disease. Non-caseating intestinal granulomas are a hallmark of CD, but whether intestinal granulomas help predict Chinese CD phenotypes or determine severity, is not known. AIMS: To determine the association between intestinal granulomas with CD phenotype, severity, risk factors, and serological markers. METHODS: This was a single-centre study of consecutive definite Chinese CD cases. Granulomas were diagnosed by an experienced GI pathologist. Correlation with the Vienna Classification and other parameters was performed. RESULTS: Eighty Chinese CD patients were recruited, 40 (50%) of whom had intestinal granulomas. Intestinal granulomas were independently associated with the stricturing behavior (OR: 4.71; 95% CI: 1.41–15.72), colonic location of disease (OR: 26.96; 95% CI: 2.68–271.14), but not with age of CD diagnosis. Current or previous smoking protected against the development of granulomas (OR: 0.16; 95% CI: 0.04–0.59). Granulomas were not associated with peri-anal involvement, extra-intestinal manifestations, anti-neutrophil cytoplasmic antibody or anti- Saccharomyces cerevisiae antibody serology, or severity of CD gauged by the requirement of major intestinal surgery or immunomodulating therapy. CONCLUSIONS: Intestinal granulomas in the setting of CD may be helpful in determining phenotypic subtypes of CD, but is unhelpful in predicting disease severity. Smoking impairs the formation of granulomas in CD. [ABSTRACT FROM AUTHOR]

OBJECTIVES: While promoter hypermethylation is a common molecular alteration of human colorectal cancer that could be detected in the bloodstream, we tested the feasibility of quantitative detection of aberrant DNA methylation in multiple genes in the serum samples of colorectal cancer patients. METHODS: The pre-therapeutic serum samples of 49 colorectal cancer patients and 41 age-matched controls with normal colonoscopy were examined. The presence of methylated DNA in APC (adenomatous polyposis coli), hMLH1 (human MutL homolog 1), and HLTF (helicase-like transcription factor) was detected by quantitative methylation-specific PCR (MethyLight). RESULTS: There was a significant difference in the concentration of methylated serum DNA between cancer patients and controls for HLTF ( p= 0.015) and hMLH1 ( p= 0.0001) genes, but not for APC gene ( p= 0.21). In total, 28 patients with colorectal cancer and 4 controls had methylated DNA detected in at least one marker, which gave a sensitivity of 57% and specificity of 90%. All patients with methylation in two methylation markers had advanced (stage III/IV) cancer ( p= 0.006) and patients with methylation in at least one marker tended to have a lower probability of survival ( p= 0.08). CONCLUSION: The quantitative detection of aberrant DNA methylation in serum may be a promising high-throughput approach for the noninvasive screening and monitoring of colorectal cancer. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Magnetic resonance colonography (MRC) is a new noninvasive diagnostic modality for colorectal cancer. However, the use of MRC in the detection of colorectal neoplasm in average-risk individuals remains unknown. This study determined the performance and the patient's preference of MRC in the detection of colorectal neoplasm.METHODS: Both high-risk (i.e., symptoms suggestive of colorectal neoplasm, positive fecal occult blood test, history of colorectal cancer in one or more first-degree relatives) and average-risk (i.e., asymptomatic individuals>50 yr) individuals were recruited. MRC was performed immediately prior to conventional colonoscopy (CC) by using air inflation without contrast. The finding on CC together with histology was used as a gold standard. Patients' pain and discomfort score were recorded immediately and 24 h after the procedure. They were also asked about their preferences for the two procedures.RESULTS: A total of 165 patients (79 average risk and 86 high risk) were recruited. Eight patients had incomplete MRC and one patient had failed CC. Of the remaining 156 patients, 4 were found to have colonic cancer and 31 were found to have 67 polyps. MRC correctly identified 3 cancers (sensitivity 75%, specificity 99.3%) and 4 patients with colonic polyps (sensitivity 12.9% and specificity 97.6%). Sensitivity of MRC tended to be lower in polyps<10 mm in size and in average-risk individuals. The mean procedure time of CC was significantly shorter than MRC (13.6± 6.7vs20.6± 2.7 min,p<0.001). Although there was no significant difference in the pain and discomfort scores of the 2 procedures, 75% of patients preferred CC to MRC.CONCLUSIONS: The performance of MRC when used in the detection of colonic neoplasm in average-risk individuals is unsatisfactory. [ABSTRACT FROM AUTHOR]

In this article, patterns of information flows are examined for three commodity futures traded in both the developed U.S. market and the emerging China market using a bivariate GARCH model. There are established but dynamic patterns of information flows across markets, and it is important to understand them. Government policies on capital flows across borders and regulation of financial markets may alter patterns of information flows. In this paper, three important futures contracts are used that are similarly listed in both the U.S. and China markets, namely copper, soybeans and wheat to examine the pattern of information flows across the two countries.

The transmission mechanism between the Asian dollar and Eurodollar markets is investigated for the period 1981-1989 using a cointegration analysis and error correction model. Results indicate the absence of reverse causality in the Asian dollar market throughout the 1980s. In the Eurodollar market, reverse causality exists in the first half, but disappears in the second half of the decade. Both markets are evolving into rapid incorporation of prior interest rate information into current rates. These results are likely to be due to reduced market regulation, expansion of futures trading, more sophisticated telecommunications and 24-hour trading practices. [ABSTRACT FROM AUTHOR]

With the increasing incidence and mortality of colorectal cancer (CRC), early and accurate diagnosis is of paramount priority to combat this cancer. Epigenetic alterations such as DNA methylation are innovative biomarkers for CRC, due to their stability, frequency, and accessibility in bodily fluids. In this study, blood samples were prospectively collected from patients before and after operation for CRC for determination of methylated septin 9 (mSEPT9) and compared to carcinoembryonic antigen (CEA). The sensitivity of using mSEPT9 methylation status for diagnosing CRC was significantly higher than using elevated CEA levels (73.2% vs 48.2%; p value < 0.001). The sensitivities of both tests increased with higher tumor staging (P = 0.004 and 0.04 respectively). Combined mSEPT9 and CEA had higher accuracy than single CEA or mSEPT9 (P = 0.009 and 0.532 separately). An increase in the methylation level of mSEPT9 detected in the post-operative samples was associated with a higher mortality rate (15.2% vs 1.8%; P = 0.024) and the presence of metastasis (27.3% vs 7.0%; P = 0.013). mSEPT9 was more sensitive than CEA for diagnosing CRC, and combined mSEPT9 and CEA was more accurate. After curative resection, detection of increased mSEPT9 methylation level may indicate adverse outcomes. [ABSTRACT FROM AUTHOR]

The role of bacteria other than Helicobacter pylori (HP) in the stomach remains elusive. We characterized the gastric microbiota in individuals with different histological stages of gastric carcinogenesis and after receiving HP eradication therapy. Endoscopic gastric biopsies were obtained from subjects with HP gastritis, gastric intestinal metaplasia (IM), gastric cancer (GC) and HP negative controls. Gastric microbiota was characterized by Illumina MiSeq platform targeting the 16 S rDNA. Apart from dominant H. pylori, we observed other Proteobacteria including Haemophilus, Serratia, Neisseria and Stenotrophomonas as the major components of the human gastric microbiota. Although samples were largely converged according to the relative abundance of HP, a clear separation of GC and other samples was recovered. Whilst there was a strong inverse association between HP relative abundance and bacterial diversity, this association was weak in GC samples which tended to have lower bacterial diversity compared with other samples with similar HP levels. Eradication of HP resulted in an increase in bacterial diversity and restoration of the relative abundance of other bacteria to levels similar to individuals without HP. In conclusion, HP colonization results in alterations of gastric microbiota and reduction in bacterial diversity, which could be restored by antibiotic treatment. [ABSTRACT FROM AUTHOR]