Clarithromycin-resistant Strains Research Articles

Impact of mixed-infection rate of clarithromycin-susceptible and clarithromycin-resistant Helicobacter pylori strains on the success rate of clarithromycin-based eradication treatment.

Clarithromycin (CAM) resistance is a major contributor to the failure to eradicate Helicobacter pylori (H. pylori). The mixed-infection ratio of CAM-susceptible and CAM-resistant H. pylori strains differs among individuals. Pyrosequencing analysis can be used to quantify gene mutations at position each 2142 and 2143 of the H. pylori 23S rRNA gene in intragastric fluid samples. Herein, we aimed to clarify the impact of the rate of mixed infection with CAM-susceptible and CAM-resistant H. pylori strains on the success rate of CAM-containing eradication therapy. Sixty-four H. pylori-positive participants who received CAM-based eradication therapy, also comprising vonoprazan and amoxicillin, were enrolled in this prospective cohort study. Biopsy and intragastric fluid samples were collected during esophagogastroduodenoscopy. H. pylori culture and CAM-susceptibility tests were performed on the biopsy samples, and real-time PCR and pyrosequencing analyses were performed on the intragastric fluid samples. The mutation rates and eradication success rates were compared. The overall CAM-based eradication success rate was 84% (54/64): 62% (13/21) for CAM-resistant strains, and 95% (39/41) for CAM-sensitive strains. When the mutation rate of the 23S rRNA gene was 20% or lower for both positions (2142 and 2143), the eradication success rate was 90% or more. However, when the mutation rate was 20% or higher, the eradication success rate was lower (60%). The mutation rate of the CAM-resistance gene was related to the success of eradication therapy, as determined via pyrosequencing analysis.

Prevalence of Clarithromycin-Resistant Helicobacter pylori Strains in Zambia: A Sub-Saharan African Country

Introduction: Helicobacter pylori (H. pylori) is one of the most important infections globally, affecting more than 50% of the human population. Clarithromycin (CLA)-containing regimens are recommended for empirical eradication of H. pylori in populations with less than 15% resistance. The aim of this study was to estimate the prevalence of CLA resistance in samples collected from Zambian patients to determine if CLA is suitable for first-line H. pylori empirical treatment. Methodology: We used archival biopsy samples collected from dyspeptic patients undergoing endoscopy. The samples had been snap-frozen immediately after collection and stored at −80°C. We performed multiplex real-time PCR using Bosphore Helicobacter pylori Genotyping Kits v1, Istanbul, Turkey, to determine the presence of wild-type H. pylori and three mutations, A2142G, A2142C, and A2143G, of domain V in 23s rRNA gene. Results: We tested 259 gastric biopsy samples from patients with dyspepsia, of which 136 (53%) were from females. The median age was 48 years (IQR 40–61 years). Endoscopically, most of the patients, 164 (63%), had a normal gastric mucosa. CLA resistance was found in 48 (28%) samples, with A2142G mutation in 23 (13%), A2143G mutation in 32 (18%), and double mutations A2142C and A2143G in 6 (3%). Conclusions: The presence of significant levels of CLA resistance in Zambia suggests that it should not be used as first-line empirical treatment for H. pylori infection. However, with a limitation of suitable alternatives, there is an urgent need to formulate new treatment approaches.

Independent Risk Factors Predicting Eradication Failure of Hybrid Therapy for the First-Line Treatment of Helicobacter pylori Infection.

Hybrid therapy is a recommended first-line anti-H. pylori treatment option in the American College of Gastroenterology guidelines, the Bangkok Consensus Report on H. pylori management, and the Taiwan H. pylori Consensus Report. However, the cure rates of eradication therapy in some countries are suboptimal, and the factors affecting the treatment efficacy of hybrid therapy remain unclear. The aim of this study is to identify the independent risk factors predicting eradication failure of hybrid therapy in the first-line treatment of H. pylori infection. A retrospective cohort study was conducted on 589 H. pylori-infected patients who received 14-day hybrid therapy between September 2008 and December 2021 in ten hospitals in Taiwan. The patients received a hybrid therapy containing a dual regimen with a proton pump inhibitor (PPI) plus amoxicillin for an initial 7 days and a quadruple regimen with a PPI plus amoxicillin, metronidazole and clarithromycin for a final 7 days. Post-treatment H. pylori status was assessed at least 4 weeks after completion of treatment. The relationships between eradication rate and 13 host and bacterial factors were investigated via univariate and multivariate analyses. In total, 589 patients infected with H. pylori infection were included in the study. The eradication rates of hybrid therapy were determined as 93.0% (95% confidence interval (CI): 90.9-95.1%), 94.4% (95% CI: 93.8-97.2%) and 95.5%% (95% CI: 93.8-97.2%) by intention-to-treat, modified intention-to-treat and per-protocol analyses, respectively. Univariate analysis showed that the eradication rate of clarithromycin-resistant strains was lower than that of clarithromcyin-susceptible strains (83.3% (45/54) vs. 97.6%% (280/287); p < 0.001). Subjects with poor drug adherence had a lower cure rate than those with good adherence (73.3% (11/15) vs. 95.5% (534/559); p = 0.005). Other factors such as smoking, alcohol drinking, coffee consumption, tea consumption and type of PPI were not significantly associated with cure rate. Multivariate analysis revealed that clarithromcyin resistance of H. pylori and poor drug adherence were independent risk factors related to eradication failure of hybrid therapy with odds ratios of 4.8 (95% CI: 1.5 to 16.1; p = 0.009) and 8.2 (95% CI: 1.5 to 43.5; p = 0.013), respectively. A 14-day hybrid therapy has a high eradication rate for H. pylori infection in Taiwan, while clarithromycin resistance of H. pylori and poor drug adherence are independent risk factors predicting eradication failure of hybrid therapy.

Efficacy and safety of Lacticaseibacillus rhamnosus R0011 and Lactobacillus helveticus R0052 as an adjuvant for Helicobacter pylori eradication: a double-blind, randomized, placebo-controlled study

BackgroundHelicobacter pylori eradication is recommended as a way of providing symptomatic relief for dyspepsia. The limited efficacy of triple therapy is a major problem in many countries, including Thailand. Some probiotics have been shown to improve the H. pylori eradication rate and reduce side effects. This study aimed at evaluating the efficacy of probiotic (Lacidofil® STRONG) as adjuvant to standard triple therapy.MethodsThis randomized, double-blind, placebo-controlled study was conducted between July 2020 and June 2022. Eligible patients with H. pylori gastritis (i.e., n=90 out of the 160 patients screened) were randomized to receive 14-day standard triple therapy either with probiotics or with a placebo (N=45/group). The treatment regimen entailed 30 mg lansoprazole administered twice daily, 1,000 mg amoxicillin administered twice daily, and 1 g clarithromycin modified-release formulation administered once daily. A probiotic capsule containing Lacticaseibacillus rhamnosus R0011 and Lactobacillus helveticus R0052 (Lacidofil® STRONG) or placebo were given twice daily during the eradication therapy and for an additional 4 weeks. Successful H. pylori eradication was defined as a negative 13C-urea breath test at least 4 weeks after complete eradication.ResultsAs per-protocol analysis, eradication rates after the 14-day regimen with probiotic or placebo were 90.9% and 75.0% (p=0.047), respectively. Antibiotic susceptibility testing demonstrated high clarithromycin resistance (24%). For clarithromycin-resistant strains, there was no statistical difference in eradication rates between the probiotic and placebo groups. Furthermore, probiotic supplementation significantly reduced treatment side effects, including bloating (OR 0.27 [95% CI 0.10 to 0.75], p=0.012), diarrhea (OR 0.23 [95% CI 0.28 to 0.65], p=0.006), nausea (OR 0.05 [95% CI 0.01 to 0.36], p=0.003), and bitter taste (OR 0.14 [95% CI 0.03 to 0.69], p=0.015). In addition, the probiotic group had lower gastrointestinal symptom rating scale (GSRS) scores (1.46 ± 0.36 vs. 2.65 ± 0.66, p&amp;lt;0.001) and higher SF-36 health-related quality-of-life scores (63.3 ± 10.2 vs. 57.3 ± 13.4, p=0.020) after treatment than the placebo group.ConclusionThe probiotic adjuvant with 14-day standard triple therapy improved the H. pylori eradication rate. Supplementation with Lacidofil® STRONG during the 2-week eradication treatment and 4-week follow-up phase can help to reduce the gastrointestinal side effects of eradication therapy and increase patients’ general health-related quality of life.

Efficacy and Safety of Vonoprazan and Amoxicillin Dual Therapy for Helicobacter pylori Eradication: A Systematic Review and Meta-Analysis

Introduction: Vonoprazan, a novel potassium-competitive acid blocker, has a strong acid suppression effect and potent efficacy in acid-associated diseases, including Helicobacter pylori eradication. We performed a systematic review and meta-analysis to investigate the efficacy and safety of vonoprazan/amoxicillin dual therapy for H. pylori eradication. Methods: We conducted a systematic literature search through PubMed, Web of Science, EMBASE, and the Cochrane Library up to June 2022, to identify randomized controlled trials and cohort studies comparing vonoprazan/amoxicillin dual therapy and triple therapies for H. pylori eradication. Primary outcomes were cure rates and relative efficacy. Secondary outcomes included adverse events, dropout rate, and subgroup analysis. Results: Five studies with 1,852 patients were included in the analysis. The cure rates of vonoprazan/amoxicillin dual therapy were 85.6% with 95% confidence interval (CI) of 79.7–91.5% and 88.5% (95% CI: 83.2–93.8%) in the intention-to-treat and per-protocol analyses. The efficacy of vonoprazan/amoxicillin dual therapy was not inferior to that of triple therapy with pooled risk ratio (RR) of 1.03 (95% CI: 0.97–1.10) and 1.02 (95% CI: 0.98–1.08) in intention-to-treat and per-protocol analyses; while it was significantly superior to the omeprazole or lansoprazole-based triple therapy (RR = 1.15, 95% CI: 1.05–1.25, p = 0.001). For clarithromycin-resistant strains, vonoprazan/amoxicillin dual therapy showed superiority to vonoprazan-based triple therapy (86.7% vs. 71.4%, RR = 1.20, 95% CI: 1.03–1.39, p = 0.02); however, vonoprazan/amoxicillin dual therapy was significant inferior to vonoprazan-based triple therapy for clarithromycin-sensitive strains (83.0% vs. 92.8%, RR = 0.90, 95% CI: 0.85–0.95, p = 0.0002). The adverse effects of vonoprazan/amoxicillin dual therapy were lower than those of triple therapy (21.2% vs. 26.5%, RR = 0.86, 95% CI: 0.73–1.01, p = 0.06), especially the incidence of diarrhea (p = 0.01). Conclusions: The efficacy of vonoprazan/amoxicillin dual therapy is noninferior to vonoprazan-based triple therapy but superior to the omeprazole or lansoprazole-based triple therapy and has less side effects. Patients with clarithromycin-resistant strains are particularly expected to benefit from vonoprazan/amoxicillin dual therapy.

A Rapid Screening Assay for Clarithromycin-Resistant Mycobacterium avium Complex Using Melting Curve Analysis with Nonfluorescent Labeled Probes.

Mycobacterium avium complex (MAC) thrives in various environments and mainly causes lung disease in humans. Because macrolide antibiotics such as clarithromycin or azithromycin are key drugs for MAC lung disease, the emergence of macrolide-resistant strains prevents the treatment of MAC. More than 95% of macrolide-resistant MAC strains are reported to have a point mutation in 23S rRNA domain V. This study successfully developed a melting curve assay using nonfluorescent labeled probes to detect the MAC mutation at positions 2058 to 2059 of the 23S rRNA gene (AA genotype, clarithromycin susceptible; TA, GA, AG, CA, AC, and AT genotypes, clarithromycin resistant). In the AA-specific probe assay, the melting peak of the DNA fragment of the AA genotype was higher than that of DNA fragments of other genotypes. Melting temperature (Tm) values of the AA genotype and the other genotypes were about 80°C and 77°C, respectively. DNA fragments of each genotype were identified correctly in six other genotype-specific probes (TA, GA, AG, CA, AC, and AT) assays. Using genomic DNA from six genotype strains of M. avium and four genotype strains of M. intracellulare, we confirmed that all genomic DNAs could be correctly identified as individual genotypes according to the highest Tm values among the same probe assays. These results indicate that this melting curve-based assay is able to determine MAC genotypes at positions 2058 to 2059 of the 23S rRNA gene. This simple method could contribute to the rapid detection of clarithromycin-resistant MAC strains and help to provide accurate drug therapy for MAC lung disease. IMPORTANCE Since macrolide antibiotics such as clarithromycin or azithromycin are key drugs in multidrug therapy for Mycobacterium avium complex (MAC) lung diseases, the rapid detection of macrolide-resistant MAC strains has important implications for the treatment of MAC. Previous studies have reported a correlation between drug susceptibility testing and the mutation of macrolide resistance genes. In this study, we developed a novel melting curve-based assay using nonfluorescent labeled probes to identify both clarithromycin-resistant M. avium and M. intracellulare with mutations in the 23S rRNA gene, which is the clarithromycin or azithromycin resistance gene. This assay contributed to not only the detection of MAC mutations but also the determination of all genotypes at positions 2058 to 2059 of the 23S rRNA gene. Furthermore, because nonfluorescent labeled probes are used, this assay is more easily and more immediately available than other methods.

FREQUENCY AND ANTIMICROBIAL RESISTANCE PROFILE OF SALMONELLA TYPHI ISOLATED FROM DISTRICT BUNER

Objective: The objective of this study was to investigate the frequency and drug resistance of Salmonella typhi in district Buner, Khyber Pakhtunkhwa. Methodology: This cross-section study was conducted at District Head Quarter Hospital Buner and private diagnostic centers from Jan 2020 to May 2021. A total of 460 blood samples were collected from OPD patients reported with signs and symptoms of Typhoid fever. Samples were cultured on blood and MacConkey agar and incubated at 37? for 24 hours. Bacterial identification was done on colony morphology, gram staining, and polyvalent antisera for strain identification. Finally, antibiotic susceptibility testing was done for the isolated bacteria. All commonly prescribed first-line and second-option antibiotics were tested on Mueller Hinton agar by Kirby Bauer disk diffusion method following CLSI guidelines 2020. Result: A total of 240 out of 460 samples showed bacterial growth where Salmonella typhi was found in 98 (40.8%) cases. Among them, 28(28.6%) were reported as MDR while 1 (17.4%) were XDR. Out of the XDR, 4 strains were found resistant to Vancomycin and clarithromycin as well. The isolated S. typhi was 100% sensitive to Meropenem, and Azithromycin, however showed 100% resistance to Aztreonam, Ampicillin, and Cotrimoxazole. Prevalence of S. typhi was more (50%) in females while resistance was reported more in age group 20-40 years. Conclusion: The frequency of Salmonella typhi at district Buner was 41% in patients reported with high-grade fever where 28% of the strains reported were multidrug resistant. Some extended spectrum drug-resistant S. typhi and Vancomycin and Clarithromycin resistant strains were also reported which is alarming. Meropenem, and Azithromycin were the only drugs effective against most of the strains. However, resistance to these drugs may develop soon if we do not stop the empirical excessive use of antibiotics. Keywords: Multidrug-resistant, Salmonella typhi, Typhoid fever, Extended spectrum drug-resistant

Efficacy of bismuth for antibiotic-resistant Helicobacter pylori strains eradication: A systematic review and meta-analysis.

Antibiotic resistance of Helicobacter pylori (H.pylori) is increasing worldwide, and bismuth quadruple therapy has been recommended as a first-line regimen in many areas. This study aimed to investigate whether bismuth would improve the eradication rate (ER) of clarithromycin-/metronidazole-/levofloxacin-resistant H.pylori strains and how much additional efficacy bismuth could achieve. PubMed, EMBASE, Web of Science, and Cochrane Central databases for randomized controlled trials were systematically searched by two independent reviewers until 15 January 2022. Pooled ERs of clarithromycin-/metronidazole-/levofloxacin-resistant H.pylori strains were compared between bismuth-containing and non-bismuth therapies. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Eight studies enrolling 340 individuals were included. The RRs of pooled ERs compared between bismuth-containing and non-bismuth therapies were 1.83 for clarithromycin-resistant strains (95% CI 1.16-2.89, pooled ER: 76.9% vs. 36.6%, p=.009, I2 =0%), 1.39 for metronidazole-resistant strains (95% CI 1.09-1.78, pooled ER: 86.8% vs. 60.9%, p=.008, I2 =37%), 2.75 for dual clarithromycin/metronidazole-resistant strains (95% CI 1.01-7.52, pooled ER: 76.9% vs. 18.2%, p=.05, I2 =0%), and 1.04 for levofloxacin-resistant strains (95% CI 0.56-1.93, pooled ER: 63.4% vs. 54.3%, p=.90; I2 =60%). Bismuth significantly increased the ERs of clarithromycin-, metronidazole-, and dual-resistant strains by 40%, 26%, and 59%, respectively. Subgroup analysis of treatment duration showed that the significantly higher eradication rate for antibiotic-resistant strains in bismuth-containing therapy than non-bismuth therapy was only observed in 14-day treatment regimens and not in 7-day regimens (p=.02 and .17, respectively). Bismuth was most effective in improving the ERs of dual-resistant H.pylori strains, followed by clarithromycin- and metronidazole-resistant strains. Prolonged treatment duration might effectively improve the efficacy of bismuth in overcoming antibiotic resistance.

Vonoprazan Triple and Dual Therapy for Helicobacter pylori Infection in the United States and Europe: Randomized Clinical Trial

Background & aimsNovel, effective treatments for Helicobacter pylori infection are needed. This study evaluated the efficacy of vonoprazan, a potassium-competitive acid blocker, vs standard treatment on H pylori eradication in the United States and Europe. MethodsIn a randomized, controlled, phase 3 trial, treatment-naïve adults with H pylori infection were randomized 1:1:1 to open-label vonoprazan dual therapy (20 mg vonoprazan twice daily; 1 g amoxicillin 3 times daily), or double-blind triple therapy twice a day (vonoprazan 20 mg or lansoprazole 30 mg; amoxicillin 1 g; clarithromycin 500 mg) for 14 days. The primary outcome was noninferiority in eradication rates in patients without clarithromycin- and amoxicillin-resistant strains (noninferiority margin = 10%). Secondary outcomes assessed superiority in eradication rates in clarithromycin-resistant infections, and in all patients. ResultsA total of 1046 patients were randomized. Primary outcome eradication rates (nonresistant strains): vonoprazan triple therapy 84.7%, dual therapy 78.5%, vs lansoprazole triple therapy 78.8% (both noninferior; difference 5.9%; 95% confidence interval [CI], −0.8 to 12.6; P < .001; difference –0.3%; 95% CI, −7.4 to 6.8; P = .007, respectively). Eradication rates in clarithromycin-resistant infections: vonoprazan triple therapy 65.8%, dual therapy 69.6%, vs lansoprazole triple therapy 31.9% (both superior; difference 33.9%; 95% CI, 17.7–48.1; P < .001; difference 37.7%; 95% CI, 20.5–52.6; P < .001, respectively). In all patients, vonoprazan triple and dual therapy were superior to lansoprazole triple therapy (80.8% and 77.2%, respectively, vs 68.5%, difference 12.3%; 95% CI, 5.7–18.8; P < .001; difference 8.7%; 95% CI, 1.9–15.4; P = .013). Overall frequency of treatment-emergent adverse events was similar between vonoprazan and lansoprazole regimens (P > .05). ConclusionBoth vonoprazan-based regimens were superior to proton pump inhibitor–based triple therapy in clarithromycin-resistant strains and in the overall study population. ClinicalTrials.gov; NCT04167670.

Updates on Management of Helicobacter pylori Infection and Antibiotic Resistant Helicobacter Infection Management

H. pylori is a common human pathogen and it is estimated that approximately 50% of the world's population are infected. Furthermore it's prevalence infection in Indonesia is 20% but much higher among several ethnic groups (Papuans 42.9%, Batak 40.0%, and Bugis 36.7%). H. pylori’s growth and survival has been shown to be sensitive to a variety of antimicrobial agents. The success of the treatment depends on susceptibility, dosage, formulation, dose frequency, the use of adjuvants such as anti-secretory drugs, antacids or probiotics, and duration of treatment. The treatment for H. pylori infection keep evolving and the triple therapy, levofloxacin, was replaced by CLR in triple therapy for 14-day with eradication rates over 90%. Sequential therapy, also achieved a higher cure rate against clarithromycin-resistant strains than a 7 and 10 day triple therapy. Triple bismuth therapy and quadruple bismuth therapy are used less frequently due to their inherent complexity, the large number of tablets four times a day, side effects, and lack of support from pharmaceutical companies. Inclusively, vonoprazan is also a good choice that is fully effective from day one. The role of the probiotics is unclear and is not recommended in consensus groups. Two mucolytic agents, erdosteine and N-acetylcysteine (NAC), were found to increase it's eradication efficiency clinical trials when administered in supplementation with triple therapy but are not commonly used because of the need for high doses, and increased medical costs. therefore, H. pylori resistant management should be adapted to the results of the the culture of resistance and the guidelines of existing resistance patterns.

Antibiotic resistance of Helicobacter pylori isolated from children in Chongqing, China.

The resistance of Helicobacter pylori (H. pylori) to antibiotics has been increasing worldwide and varies across different geographic areas and times. Limited studies reported the prevalence of antibiotic resistance and its related gene mutations in children in Chongqing, a city located in southwest China. We collected 112 H. pylori strains isolated from gastric biopsies of 156 children at Children's Hospital of Chongqing Medical University and calculated resistance rates of these strains to six antibiotics. The A2143G and A2142G mutations in 23S rRNA gene, which are related to clarithromycin resistance, and Asn87 and Asp91 mutations in gyrA gene, which are related to levofloxacin resistance, were investigated in 102 strains. The resistance rates to clarithromycin, metronidazole, and levofloxacin were 47.3% (53/112), 88.4% (99/112), and 18.8% (21/112), respectively. No resistance to amoxicillin, tetracycline, and furazolidone was observed. Dual and triple resistance percentages were 37.5% (42/112) and 10.7% (12/112), respectively. The detection rate of A2143G mutation in 23S rRNA gene was 83.3% (40/48). The detection rates of mutations of Asn87 and Asp91 in gyrA gene were 52.6% (10/19) and 36.8% (7/19), respectively. Conclusion:The prevalence of H. pylori resistance to clarithromycin, metronidazole, and levofloxacin was high in children in Chongqing, China. The A2143G mutation was detected in most clarithromycin-resistant strains, and Asn87 and Asp91 of gyrA mutation points were common in levofloxacin-resistant strains. In clinical practice, anti-H. pylori therapy should be individualized based on a susceptibility test. What is Known: •The resistance of H. pylori to antibiotics changes with the geographic areas and that in Asia the resistance rate is high. • Mutation plays a vital role in antibiotics resistance of H. pylori. What is New: •High resistance rates to single and multiple antibiotics in children of Chongqing, a city located in southwest China, were observed. • Molecular assays showed good conformance with susceptibility test results to direct antibiotic resistance of H. pylori.

Update on the first-line treatment of Helicobacter pylori infection in areas with high and low clarithromycin resistances.

Current international consensuses on Helicobacter pylori eradication therapy recommend that only regimens that reliably produce eradication rates of ⩾90% should be used for empirical treatment. The Real-world Practice & Expectation of Asia-Pacific Physicians and Patients in Helicobacter Pylori Eradication Survey also showed that the accepted minimal eradication rate in H. pylori-infected patients was 91%. According to efficacy prediction model, the per-protocol eradication rates of 7-day and 14-day standard triple therapies fall below 90% when clarithromycin resistance rate ⩾5%. Several strategies including bismuth-containing, non-bismuth-containing quadruple therapies (including sequential, concomitant, hybrid and reverse hybrid therapies), high-dose dual therapy and vonoprazan-based triple therapy have been proposed to increase the eradication rate of H. pylori infection. According to efficacy prediction model, the eradication rate of 14-day concomitant therapy, 14-day hybrid therapy and 7-day vonoprazan-based triple therapy is less than 90% if the frequency of clarithromycin-resistant strains is higher than 90%, 58% and 23%, respectively. To meet the recommendation of the consensus report and patients' expectation, local surveillance networks for resistance of H. pylori to clarithromycin are required to select appropriate eradication regimens in each geographic region. In areas with low (<5%) clarithromycin resistance (e.g. Sweden, Philippine, Myanmar and Bhutan), 7-day and 14-day standard triple therapies can be adopted for the first-line treatment of H. pylori infection with eradication rates of ⩾90%. In areas with high (⩾5%) clarithromycin resistance (most other countries worldwide) or unknown clarithromycin resistance, 14-day hybrid, 14-day reverse hybrid, 14-day concomitant and 10- to 14-day bismuth quadruple therapy can be used to treat H. pylori infection.

Molecular detection of genotypic clarithromycin‐resistant strains and its effect on the eradication rate of concomitant therapy in Helicobacter pylori infection

Antimicrobial eradication rates for Helicobacter pylori have been decreasing and the reason for treatment failure was found to be resistance to one or more of the antibiotics. Clarithromycin resistance to H pylori was associated with point mutations in the 23S rRNA gene and the PCR-RFLP method can detect these point mutations. The aim of this study was to determine the molecular detection of genotypic clarithromycin-resistant strains and its effect on the eradication rate of concomitant therapy in H pylori infection. The presence of H pylori DNA was confirmed by amplifying the UreC gene by polymerase chain reaction (PCR) and point mutations on 23S rRNA (A2142G and A2143G) were detected by PCR-RFLP. A total of 98 H pylori-infected patients were involved and among them, genotypic clarithromycin-sensitive strain was 93.9% and clarithromycin-resistant strain was 6.1%. All patients were found to have the A2143G point mutation but A2142G was not detected. Successful eradication rate of concomitant therapy was found to be 89.8% and unsuccessful rate was 10.2%. Among patients with the clarithromycin-resistant gene, only 16.7% had successful eradication and 83.3% had unsuccessful eradication. There was a statistically significant association between failure rate of concomitant therapy and detection of clarithromycin-resistant genes (P < 0.01). The presence of A2143G point mutation in the clarithromycin-resistant strain has a negative effect on the eradication rate of H pylori infection.

Anti-Helicobacter pylori Effects of Propolis Ethanol Extract on Clarithromycin and Metronidazole Resistant Strains

Antimicrobial resistance for Helicobacter pylori infection still become problem in Indonesia especially for metronidazole and clarithromycin resistance that is commonly used in the national regiment therapy. Finding a new antimicrobial agent against this bacterium is still a challenge to face. Propolis extract is well known substance which has antimicrobial effect against some gram-negative bacteria. However, the effect against H. pylori remain unknown. We analysed the antimicrobial effect of propolis extract against H. pylori in clarithromycin and metronidazole Resistant Strains. Anti-H. pylori effect of ethanol propolis extract was tested on 10 types of H. pylori strains isolated from dyspeptic patients in Indonesia. Ethanol propolis extracts (PRO) show inhibitory activity at concentrations of 5% and 10% on all strains H. pylori. Determination minimum inhibitory concentration (MIC) value of propolis extract used microdilution method, the MIC values were in the range of 1024-8192 µg/mL. Determination of the minimum bactericidal concentration (MBC) value is performed by scratch method based on the results of the microdilution test and produces an MBC value in the range of 1024 - 16348 µg/mL. The required concentration of propolis extract for the bactericidal effect against H. pylori was the same or eight-fold higher than the corresponding value. The combination of propolis extract and metronidazole based through paper tape method showed an additive effect, as well as the combination of propolis extract and clarithromycin. This extract might be can become alternative treatment against H. pylori infection that resistance for metronidazole and clarithromycin treatment

Efficacy of bismuth added to standard triple therapy as the first-line eradication regimen for Helicobacter pylori infection.

Addressing the increasing antibiotic resistance, including clarithromycin resistance, which affects Helicobacter pylori eradication therapy, is a challenge for clinicians. The objective of this study was to determine the efficacy of bismuth added to standard triple therapy as a first-line treatment regimen for Helicobacter pylori infection. The secondary outcome was the treatment efficacy for clarithromycin-resistant strains. A prospective study was undertaken from January to December 2019. A total of 107 patients with Helicobacter pylori infection were enrolled and received Helicobacter pylori eradication therapy with bismuth added to standard triple therapy for 14days. We also evaluated the clarithromycin resistance rate by dual-priming oligonucleotide-based multiplex PCR and treatment efficacy. A total of 104 patients completed standard triple therapy with bismuth added for Helicobacter pylori eradication. The eradication rates in the intention to treat and per-protocol analyses were 87.9% and 90.4%, respectively. The frequency of clarithromycin resistance was 33.6% (35/104), and the eradication rate was 77.1% in resistant strains (27/35). Bismuth added to standard triple therapy could be acceptable as a first-line treatment regimen for Helicobacter pylori eradication in patients with clarithromycin-resistant strains. In particular, in areas with high clarithromycin tolerance, it is advisable to consider bismuth add-on therapy as the first-line treatment regimen.

Antimicrobial activity and additive effect of the modified Gingyo-san with antimicrobials against Helicobacter pylori

IntroductionHelicobacter pylori is an important factor in the development of gastroduodenal ulcers and gastric cancer. Although H. pylori eradication therapy has been employed, the eradication rate has decreased in recent years owing to an increase in clarithromycin-resistant strains. We previously reported the anti-infective effect of herbal medicines against several bacterial species. Here, we evaluated the growth inhibitory activity of herbal medicines alone and in combination with antimicrobials against H. pylori. Methods and resultsNine of 37 herbal medicines inhibited the growth of H. pylori ATCC700392. In particular, modified Gingyo-san showed the strongest growth inhibitory activity with a minimum inhibitory concentration (MIC) of 512 μg/ml for not only ATCC700392 but also clarithromycin-resistant strains having a 23 S rRNA mutation. Results of Time-Kill Kinetics Assay showed that 1 mg/mL modified Gingyo-san treatment for one hour killed 50% of the H. pylori population. Furthermore, modified Gingyo-san showed additive effects with clarithromycin, amoxicillin, and metronidazole against H. pylori ATCC700392 and clarithromycin-resistant strains. ConclusionsOur findings showed that modified Gingyo-san inhibits the growth of H. pylori and improves antimicrobial susceptibility when used in combination. Therefore, modified Gingyo-san has the potential to enhance the eradication rate of clarithromycin-resistant H. pylori.

The efficacies of non-bismuth containing quadruple therapies in the treatment of first-line anti-Helicobacter pylori across 4-year time interval with changing antibiotics resistance

BackgroundNon-bismuth containing quadruple therapy (concomitant therapy) is an alternative treatment for Helicobacter pylori (H. pylori) eradication with increasing clarithromycin-resistant strains over times. This study compared the efficacies of non-bismuth containing quadruple therapy (concomitant therapy) in the treatment of first-line anti-Helicobacter Pylori between two time intervals (January 2013 to June 2014 and June 2016 to December 2017). MethodsH. pylori-infected patients were recruited in the intention-to-treat (ITT analysis) and divided into EACM-A group (enrolled from January 2013 to June 2014, N = 98) and EACM-B group (enrolled from June 2016 to December 2017, N = 99). Patients were prescribed with 7-day esomeprazole 40 mg bid., clarithromycin 500 mg bid., amoxicillin 1 g bid. and metronidazole 500 mg bid. Ninety patients and 93 patients were analyzed in the per protocol (PP) analysis (8 and 6 patients lost follow-up in each group). Urea breath tests were performed 4–8 weeks thereafter. ResultsThe eradication rates for EACM-A and EACM-B groups were 87.8% (95% confidence interval [CI] = 79.7%–93.5%) and 84.8% (95% CI = 76.2%–91.2%) (p = 0.55) in intention-to-treat (ITT) analysis; 95.6% (95% CI = 89.1%–98.8%) and 90.3% (95% CI = 82.4%–95.5%) (p = 0.17) in per protocol (PP) analysis. The adverse event rates were 16.7% vs. 10.8% in the 2 groups (p = 0. 0.24). The antibiotic resistance rates between the 2 groups were amoxicillin (0%), tetracycline (0%); clarithromycin (11.8% vs. 17.8%, p = 0.46); metronidazole (32.4% vs. 33.3%, p = 0.93) and levofloxacin (14.7% vs. 37.8%, p = 0.02). ConclusionThe success rate of 7-days concomitant therapy encountered an approximately 5% decrease across 4-year time interval (2013–2017) with the changes of clarithromycin resistance from 11.8% to 17.8% in Taiwan.

Effect of Antibiotic Susceptibility and CYP3A4/5 and CYP2C19 Genotype on the Outcome of Vonoprazan-Containing Helicobacter pylori Eradication Therapy

Background: Helicobacter pylori eradication containing the potassium-competitive acid blocker, vonoprazan, achieves a higher eradication rate than therapy with proton pump inhibitors (PPIs). Because vonoprazan is mainly metabolized by CYP3A4/5, CYP genotype may affect the eradication rate. We investigated the influence of antibiotic susceptibility and CYP3A4/5 and CYP2C19 genotypes on the eradication rates. Methods: A total of 307 Japanese who were genotyped for CYP3A4 *1/*22, CYP3A5 *1/*3 and CYP2C19 *1/*2/*3/*17, and investigated for susceptibility to antimicrobial agents, received vonoprazan-containing regimens: (1) With amoxicillin and clarithromycin as the first-line treatment; (2) with amoxicillin and metronidazole as the second-line treatment; or (3) with amoxicillin and sitafloxacin as the third-line treatment. Results: The eradication rate was 84.5% (95% confidence interval [CI]: 78.9–89.1%) using first-line, 92.6% (95% CI: 82.1–97.9%) using second-line and 87.5% (95% CI: 73.1–95.8%) using third-line treatment. Infection with clarithromycin-resistant strains was a predictive factor for failed eradication (odds ratio: 5.788, 95% CI: 1.916–17.485, p = 0.002) in multivariate analysis. No significant differences were observed in the eradication rate of regimens among CYP3A4, CYP3A5 and CYP2C19 genotypes. Conclusions: Genotyping for CYP3A4 *1/*22, CYP3A5 *1/*3 and CYP2C19 *1/*2/*3/*17 before vonoprazan-containing eradication treatment may not be useful for predicting clinical outcomes.

Mutations of Helicobacter pylori RdxA are mainly related to the phylogenetic origin of the strain and not to metronidazole resistance.

Drug resistance of Helicobacter pylori is a major clinical problem worldwide. The objective of the present study was to investigate the prevalence of antibiotic-resistant H. pylori in the city of Shenzhen in China, as well as to identify the genetic mutations specifically associated with drug resistance rather than unrelated phylogenetic signals. Antibiotic susceptibility testing was performed on 238 clinical strains successfully isolated from H. pylori-positive dyspeptic patients who underwent gastroscopy at the Department of Gastroenterology in Shenzhen People's Second Hospital. Following WGS of all strains using Illumina technology, mutation and phylogenetic analyses were performed. The resistance rates were 84.9%, 35.3%, 25.2% and 2.1% for metronidazole, clarithromycin, ciprofloxacin and rifampicin, respectively. An A2143G conversion in the 23S rRNA gene was the primary mutation observed in clarithromycin-resistant strains, whilst N87K/I and D91G/N/Y in GyrA were detected in ciprofloxacin-resistant strains. In RdxA, our results demonstrated that only R16H/C and M21A are significant contributors to metronidazole resistance; there were 15 other sites, but these are phylogenetically related and thus unrelated to metronidazole resistance. There is a high prevalence of metronidazole, clarithromycin and ciprofloxacin resistance and a low prevalence of rifampicin resistance in H. pylori from Shenzhen, China. Omission of phylogenetically related sites will help to improve identification of sites genuinely related to antibiotic resistance in H. pylori and, we believe, other species.

Genotypic and Phenotypic Resistance to Clarithromycin in Helicobacter pylori Strains.

Background: The increasing prevalence of antimicrobial resistance, together with the lack of novel treatment options, negatively affects successful eradication of Helicobacter pylori. The aim of this study was to investigate genetic mutations in the 23S rRNA genes, which is associated with clarithromycin resistance, and to determine the clinical impact of genotype on phenotypic antimicrobial resistance. Methods: A total of 46 H. pylori strains were obtained from 13 patients, before and after unsuccessful eradication with clarithromycin-based triple therapy. The phenotypic resistance of each H. pylori strain was determined by minimum inhibitory concentration against clarithromycin using the serial two-fold agar dilution method. The genomic sequences of 23S rRNA genes were identified through next-generation sequencing, and nucleotide variants were determined based on comparison with genome sequences of the reference strain H. pylori 26695. Results: Clarithromycin resistance was found in 9 of 13 subjects before treatment and all subjects after unsuccessful eradication. Whole-genome sequencing of the 23S rRNA genes detected 42 mutations on 40 nonidentical loci, including 2147A>G (formerly 2143A>G) and 2146A>G (formerly 2142A>G). All strains with clarithromycin-resistant phenotype had either 2147A>G or 2146A>G mutation. When comparing genotype and phenotype for clarithromycin resistance, there was a significant association between 2147A>G mutation and clarithromycin-resistant phenotype. Conclusions: All clarithromycin-resistant strains had either 2146A>G or 2147A>G mutation, suggesting that tests targeting these two mutations may be enough for the prediction of clarithromycin resistance in this population.