Eradication of Helicobacter pylori according to 23S ribosomal RNA point mutations associated with clarithromycin resistance

Systematic review: third-line susceptibility-guided treatment for Helicobacter pylori infection

BACKGROUND

Susceptibility-guided therapies (SGTs) have been proposed as preferable to empirical rescue treatments after two treatment failures. The aim of this study was to perform a systematic review and meta-analysis evaluating the effectiveness and efficacy of SGT as third-line therapy.

METHODS

A systematic search was performed in multiple databases. Studies reporting cure rates of Helicobacter pylori with SGT in third-line therapy were selected. A qualitative analysis describing the current evidence and a pooled mean analysis summarizing the cure rates of SGT in third-line therapy was performed.

RESULTS

No randomized controlled trials or comparative studies were found. Four observational studies reported cure rates with SGT in third-line treatment, and three studies which mixed patients with second- and third-line treatment also reported cure rates with SGT. The majority of the studies included the patients when culture had been already obtained, and so the effectiveness of SGT and empirical therapy has never been compared. A pooled mean analysis including four observational studies (283 patients) showed intention-to-treat and per-protocol eradication rates with SGT of 72% (95% confidence interval 56-87%; I(2) : 92%) and 80% (95% confidence interval 71-90%; I(2) : 80%), respectively.

CONCLUSIONS

SGT may be an acceptable option as rescue treatment. However, cure rates are, at best, moderate and this approach has never been compared with a well-devised empirical therapy. The evidence in favor of SGT as rescue therapy is currently insufficient to recommend its use.

Antimicrobial susceptibility and clarithromycin resistance patterns of Helicobacter pylori clinical isolates in Vietnam

Helicobacter pylori is a gastric pathogen that causes several gastroduodenal disorders such as peptic ulcer disease and gastric cancer.  Eradication efforts of H. pylori are often hampered by antimicrobial resistance in many countries, including Vietnam.  Here, the study aimed to investigate the occurrence of antimicrobial resistance among H. pylori clinical isolates across 13 hospitals in Vietnam.  The study further evaluated the clarithromycin resistance patterns of H. pylori strains.  In order to address the study interests, antimicrobial susceptibility testing, epsilometer test and PCR-based sequencing were performed on a total of 193 strains isolated from patients, including 136 children (3–15 years of age) and 57 adults (19–69 years of age).  Antimicrobial susceptibility testing showed that the overall resistance to amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline was 10.4%, 85.5%, 24.4%, 37.8%, and 23.8% respectively.  The distribution of minimum inhibitory concentrations (MICs) of clarithromycin-resistant strains was 85.5% with MIC >0.5 μg/mL.  The majority of the clarithromycin resistant isolates (135 of 165 subjects) have MICs ranging from 2 μg/mL to 16 μg/mL.  Furthermore, sequencing detection of mutations in 23S rRNA gene revealed that strains resistant and susceptible to clarithromycin contained both A2143G and T2182C mutations.  Of all isolates, eight clarithromycin-resistant isolates (MIC >0.5 μg/mL) had no mutations in the 23S rRNA gene.  Collectively, these results demonstrated that a proportion of clarithromycin-resistant H. pylori strains, which are not related to the 23S rRNA gene mutations, could be potentially related to other mechanisms such as the presence of an efflux pump or polymorphisms in the CYP2C19 gene.  Therefore, the present study suggests that providing susceptibility testing prior to treatment or alternative screening strategies for antimicrobial resistance is important for future clinical practice.  Further studies on clinical guidelines and treatment efficacy are pivotal for successful eradication of H. pylori infection.

Comparison of the efficacy of culture-based tailored therapy for Helicobacter pylori eradication with that of the traditional second-line rescue therapy in Korean patients: a prospective single tertiary center study

OBJECTIVE

The effectiveness of Helicobacter pylori therapies has declined with an increase in antibiotic resistance. To overcome this problem, the efficacy of tailored H. pylori eradication therapy based on antimicrobial susceptibility testing was compared with that of empirical second-line rescue regimens.

MATERIAL AND METHODS

Patients who had persistent H. pylori infection after the first eradication were recommended to undergo culture for determining the minimal inhibitory concentration (MIC) via gastroscopy, which increased the cost by 300%. Fourteen-day esomeprazole, tripotassium dicitrate bismuthate, metronidazole and tetracycline (EBMT) therapy or esomeprazole, moxifloxacin and amoxicillin (MEA) therapy was performed according to the results of antibiotic susceptibility testing. In case of refusal to undergo culture, the participants were treated with either 14-day empirical EBMT or MEA regimen for second eradication after explaining the complexity, side effects and costs associated with each regimen. This trial was registered at ClinicalTrials.Gov (NCT 02349685).

RESULTS

In the 219 patients included, the intention to treat (ITT) and per protocol (PP) eradication rates was 75.3% and 79.8% in the 14-day EBMT group (n = 89), 70.8% and 72.4% in the 14-day MEA group (n = 89) and 87.8% and 100.0% in the 14-day tailored therapy group (n = 41), respectively. Based on the PP analysis, the 14-day tailored therapy group showed a significantly higher eradication rate than the 14-day EBMT or MEA group (both p ≤ 0.001).

CONCLUSIONS

Tailored therapy based on H. pylori culture and MIC test could be an option as a second-line eradication regimen in the presence of high level of antimicrobial resistance.

Tailored Therapy Versus Empiric Chosen Treatment for Helicobacter pylori Eradication: A Meta-Analysis

Although various regimens are empirically accepted for Helicobacter pylori eradication, the efficacy might be declined by multiple individual factors. The necessity of a personalized eradication therapy still remains controversial. The aim of the study was to compare tailored therapy with empiric chosen regimens. Databases of PUBMED, EMBASE, and MEDLINE were searched for eligible studies, published up to October 2015. All relevant controlled clinical trials were included. A random-effect model was applied to compare pooled relative risk (RR) with related 95% confidence intervals (CIs).Thirteen controlled clinical trials integrating 3512 participants were assessed. Overall, the pooled eradication rates of tailored groups were higher than those of empiric ones (intention-to-treat: RR = 1.16, 95% CI 1.10-1.22; preprotocol: RR = 1.14, 95% CI 1.08-1.21). In subgroup analysis, tailored therapy was superior to 7-day standard triple therapy (RR = 1.22, 95% CI 1.16-1.29) and bismuth-quadruple therapy (RR = 1.14, 95% CI 1.07-1.22) on eradication rates; first-line tailored therapy achieved higher eradication rates than first-line empirical regimens (pooled RR = 1.18, 95%CI 1.14-1.22), whereas tailored rescue regimen showed no difference with empirical ones (pooled RR = 1.16, 95% CI 0.96-1.39). Moreover, among different tailored designs, susceptibility-guided tailored therapy obtained higher eradication rates than empiric groups, independent of CYP2C19 genotype detection (with CYP: RR = 1.16, 95% CI 1.09-1.23; without CYP: RR = 1.14, 95% CI 1.01-1.28). Both molecular test-based and culture-based tailored groups were better on eradication rates than empiric groups (molecular: RR = 1.23, 95% CI 1.11-1.35; culture: RR = 1.13, 95% CI 1.06-1.20). Compared with empiric chosen treatments, tailored therapy is a better alternative for H pylori eradication.

Antibiotic treatment for Helicobacter pylori: Is the end coming?

Infection with the Gram-negative pathogen Helicobacter pylori (H. pylori) has been associated with gastro-duodenal disease and the importance of H. pylori eradication is underscored by its designation as a group I carcinogen. The standard triple therapy consists of a proton pump inhibitor, amoxicillin and clarithromycin, although many other regimens are used, including quadruple, sequential and concomitant therapy regimens supplemented with metronidazole, clarithromycin and levofloxacin. Despite these efforts, current therapeutic regimens lack efficacy in eradication due to antibiotic resistance, drug compliance and antibiotic degradation by the acidic stomach environment. Antibiotic resistance to clarithromycin and metronidazole is particularly problematic and several approaches have been proposed to overcome this issue, such as complementary probiotic therapy with Lactobacillus. Other studies have identified novel molecules with an anti-H. pylori effect, as well as tailored therapy and nanotechnology as viable alternative eradication strategies. This review discusses current antibiotic therapy for H. pylori infections, limitations of this type of therapy and predicts the availability of newly developed therapies for H. pylori eradication.

Editorial--Avoiding Unethical Helicobacter pylori Clinical Trials: Susceptibility-Based Studies and Probiotics as Adjuvants

As a general rule, any clinical study where the result is already known or when the investigator(s) compares an assigned treatment against another assigned treatment known to be ineffective in the study population (e.g., in a population with known clarithromycin resistance) is unethical. As susceptibility-based therapy will always be superior to empiric therapy in any population with a prevalence of antimicrobial resistance >0%, any trial that randomizes susceptibility-based therapy with empiric therapy would be unethical. The journal Helicobacter welcomes susceptibility or culture-guided studies, studies of new therapies, and studies of adjuvants and probiotics. However, the journal will not accept for review any study we judge to be lacking clinical equipoise or which assign subjects to a treatment known to be ineffective, such as a susceptibility-based clinical trial with an empiric therapy comparator. To assist authors, we provide examples and suggestions regarding trial design for comparative studies, for susceptibility-based studies, and for studies testing adjuvants or probiotics.

High Helicobacter pylori cure rate with sitafloxacin-based triple therapy

BACKGROUND

Bacterial resistance of Helicobacter pylori to antibiotics is increasing and it often leads to failure of antibiotic treatment. A new sitafloxacin-based triple therapy was developed to counter this situation; the fluoroquinolone sitafloxacin has a low minimum inhibitory concentration for H. pylori.

AIM

To investigate the efficacy in Japanese patients of sitafloxacin-based triple therapy and document its efficacy in relation to anti-microbial susceptibility.

METHODS

We investigated the efficacy of a 1-week sitafloxicin-based regimen of rabeprazole 10 mg four times daily (q.d.s.), metronidazole 250 mg twice daily (b.d.) and sitafloxacin 100 mg b.d. in 180 H. pylori-positive Japanese patients (first-line treatment: n = 45, second-line; n = 41, third-line: n = 94). At 8 weeks, patients were given the (13) C-urea breath test to assess eradication status.

RESULTS

Eradication rate was 92.2% [95% confidence interval (CI): 87.3-95.7%, 166/180] in intention-to-treat analysis. Although the eradication rate was higher in patients treated with first-line therapy [45/45 (100%, 95% CI: 83.4-100%)] than in those with second- [38/41 (92.7%, 80.1-98.5%)] or third-line therapy [83/94 (88.3%, 80.0-94.0%)], no significant differences were noted with respect to the number of previous therapy attempts (P = 0.054). Eradication rates in patients infected with sensitive- and resistant strains to metronidazole were 96.6% (28/29) and 96.3% (77/80) (P = 0.941), respectively, while rates were 98.4% (60/61) in sitafloxacin-sensitive and 50.0% (1/2) in sitafloxacin resistant strains (P < 0.001).

CONCLUSION

Sitofloxacin-based triple therapy with metronidazole b.d. and rabeprazole q.d.s. achieved an eradication rate exceeding 88%, irrespective of eradication history, CYP2C19 genotype, or metronidazole resistance status.

Systematic review and meta-analysis: susceptibility-guided versus empirical antibiotic treatment for Helicobacter pylori infection

BACKGROUND

The cure rate of standard triple therapy for Helicobacter pylori infection is unacceptably low. Susceptibility-guided therapies (SGTs) have been proposed as an alternative to standard empirical treatments. The aim of this study was to perform a systematic review and meta-analysis evaluating the efficacy of SGTs.

METHODS

A systematic search was performed in multiple databases. Randomized controlled trials comparing cure rates of SGTs versus those of empirical therapy were selected and analysed separately for first- and second-line treatments. A meta-analysis was performed using risk ratio (RR) and number needed to treat (NNT) to measure the effect.

RESULTS

Twelve studies were included in the meta-analysis. In first-line treatment, SGT was more efficacious than empirical 7-10 day triple therapy (RR 1.16, 95% CI 1.10-1.23, I (2) = 33%; NNT = 8). Most studies used a 7-10 day triple therapy and randomized the patients after endoscopy and/or culture, thus precluding the comparison of SGT versus non-invasive testing and empirical treatment in clinical practice. For second-line therapy, only four studies were found. Results were highly heterogeneous and no significant differences were found (RR 1.11, 95% CI 0.82-1.51, I (2) = 87%).

CONCLUSIONS

Once endoscopy and culture have been performed, SGT is superior to empirical 7 or 10 day triple therapy for first-line treatment. Further studies are needed to evaluate the effectiveness of SGT in clinical practice, especially when compared with currently recommended first-line quadruple therapies.

Treatment of Helicobacter pylori infection: Past, present and future

Helicobacter pylori (H. pylori) is a major human pathogen associated with significant morbidity and mortality. However, after decades of efforts, treatment of H. pylori remains a challenge for physicians, as there is no universally effective regimen. Due to the rising prevalence of antimicrobial resistance, mainly to clarithromycin, efficacy of standard triple therapies has declined to unacceptably low levels in most parts of the world. Novel regimens, specifically experimented to improve the therapeutic outcome against antibiotic-resistant H. pylori strains, are now recommended as first-line empirical treatment options providing high efficacy (reportedly > 90% in intention to treat analysis) even in high clarithromycin resistance settings. These include the bismuth quadruple, concomitant, sequential and hybrid therapies. Due to the rapid development of quinolone resistance, levofloxacin-based regimens should be reserved as second-line/rescue options. Adjunct use of probiotics has been proposed in order to boost eradication rates and decrease occurrence of treatment-related side effects. Molecular testing methods are currently available for the characterization of H. pylori therapeutic susceptibility, including genotypic detection of macrolide resistance and evaluation of the cytochrome P450 2C19 status known to affect the metabolism of proton pump inhibitors. In the future, use of these techniques may allow for culture-free, non-invasive tailoring of therapy for H. pylori infection.

Acrylate-tethering drug carrier: covalently linking carrier to biological surface and application in the treatment of Helicobacter pylori infection

The development of carriers to sustain drugs at stomach surface is an attractive strategy to increase drug bioavailability locally and systematically. So far, the only reported carrier that can form a covalent bond with mucus, the thiolated carrier, relies on a reversible disulfide exchange reaction between thiols on the carrier and disulfide bridges on the mucus. Here we show the design and fabrication of a cellulose carrier with tethering acrylate groups (denoted here as clickable carrier) that, under a nontoxic condition, can efficiently react with thiols on biomaterials in situ through the thermodynamically driven and kinetically probable Michael thiol-ene click reaction. Here we show the attachments of the clickable carriers to a mucin protein, a surface of human laryngeal carcinoma cells, and a surface of a fresh porcine stomach. We also show that the required thiol moieties can be generated in situ by reducing existing cystine disulfide bridges with either the edible vitamin C or the relatively nontoxic tris(2-carboxyethyl) phosphine. Comparing to a control carrier, the clickable carrier can increase some drug concentrations in an ex vivo stomach tissue, and improve the Helicobacter pylori treatment in infected C57BL/6 mice.

[Future trends of Helicobacter pylori eradication therapy in Korea]

The prevalence of Helicobacter pylori infection in Korea shows a decreasing trend and has changed to that of developed country, especially for those below 30 years old. However, the primary antibiotic resistance rates are higher than those of developed countries. The reason for the decrease in the efficacy of standard triple therapy is mainly due to the increase in the resistance against clarithromycin. Sequential therapy seems to be more effective than the standard triple therapy, but the intention-to-treat eradication rate of sequential therapy in Korea, which is mostly under 80.0%, is still not satisfactory. Therefore, a promising regimen is needed. Recently, the Japanese health insurance system admitted 'H. pylori-infected gastritis'as an indication of eradication. Furthermore, the Kyoto Consensus Meeting on H. pylori Gastritis held from January 30th to February 1st, 2014, proposed that 'all H. pylori positive patients should be offered to receive H. pylori eradication'. This suggests that the concept of eradication has been changed from 'treatment' to 'prevention'. Various individualized tailored therapy based on the polymorphism, age and other demographic factors and antibiotic resistance has been attempted to maximize H. pylori eradication therapy. The aim of this article is to review the current epidemiology, H. pylori resistance state, treatment guideline, and to assess the possible future strategy and treatment for H. pylori infection in Korea.

[New therapeutic strategies against Helicobacter pylori]

The standard therapy for Helicobacter pylori infection in Korea is a triple-drug regimen consisting of a proton pump inhibitor with two antibiotics such as clarithromycin, amoxicillin, and metronidazole. However, as the eradication rate of this regimen has declined over the past decade, this prompted the formulation of new therapeutic regimens. New therapeutic strategies against H. pylori infection that had been tried all over the world include sequential therapy, concomitant therapy, and tailored therapy This article will review the basic concepts and the results of previous clinical trials on the aforementioned new therapeutic regiments.

Treatment of Helicobacter pylori infection 2014

This review summarizes important studies regarding H.pylori therapy published from April 2013 to April 2014. The main themes that emerge are assessing the efficacy of standard triple therapy, as well as exploring new first-line treatments, predominantly optimized triple therapies and non-bismuth quadruple schemes. Regarding newer non-bismuth quadruple regimens, the compliance and tolerance seem to be similar for sequential and concomitant regimens. Notably, no study yet has demonstrated a clear statistical superiority for either, and a systematic review and meta-analysis may be warranted. Other studies examined the role of levofloxacin and bismuth based therapies in H. pylori eradication. The efficacy of bismuth as a second-line after sequential therapy was particularly noteworthy. Levofloxacin-based therapies also appear to be useful and versatile as part of different antibiotic combinations and in first-, second-, and third-line therapies. The emerging problem of quinolone resistance remains a worry. Individualized therapy, based on factors such as antimicrobial information, resistance data, and CYP2C19 metabolism, may well be the most notable future trend to emerge this year.

Treatment of Helicobacter pylori infection: meeting the challenge of antimicrobial resistance

Treatment of Helicobacter pylori (H. pylori) infection is paramount for the management of prevalent gastrointestinal disorders including peptic ulcer disease and gastric cancer. Due to the wide increase in prevalence of H. pylori resistance to antibiotics, clarithromycin-based triple therapies are not any more suitable for unconditional empiric use, and should not be recommended, unless local resistance to this antibiotic is low (< 20%). Alternative strategies have been proposed to overcome the issue of increasing clarithromycin resistance, and some of them are already implemented in clinical practice. These comprise: (1) adoption of novel, more effective, empirical treatments: bismuth quadruple, sequential, non-bismuth quadruple (concomitant), dual-concomitant (hybrid), and levofloxacin-based regimens, the latter mainly designated as second-line/rescue options; (2) perspectives for a susceptibility-guided (tailored) therapeutic approach based on culture-free molecular testing methods; and (3) adjunct use of probiotics to improve eradication rates. The present article is aimed to provide a comprehensive overview of current and emerging strategies in the treatment of H. pylori infection, focusing on the challenge of antimicrobial resistance.

Efficacy of tailored Helicobacter pylori eradication treatment based on clarithromycin susceptibility and maintenance of acid secretion

BACKGROUND

Insufficient acid inhibition during Helicobacter pylori eradication treatment and bacterial resistance to antibiotics often causes eradication failure. Four times daily dosing (q.i.d.) of a proton-pump inhibitor (PPI) achieves potent acid inhibition, suggesting its potential usefulness as a regimen for eradicating H. pylori infection. Therefore, a tailored eradication regimen based on antibiotic susceptibility and maintenance of acid inhibition should have a high success rate. We investigated the efficacy of such treatment based on clarithromycin (CAM) susceptibility.

METHODS

Using 153 H. pylori-positive Japanese patients, we investigated the efficacy of tailored eradication strategy: (1) Patients infected with CAM-sensitive H. pylori were treated with a PPI (rabeprazole 10 mg q.i.d.), amoxicillin 500 mg q.i.d., and CAM 200 mg b.i.d. (n = 89), and (2) patients infected with CAM-resistant were given the same doses of rabeprazole and amoxicillin and metronidazole 250 mg b.i.d. (n = 64) for 1 week.

RESULTS

In the tailored regimen group, the overall eradication rate was 96.7% (95% CI: 92.5-98.9%, 148/153) in the intention-to-treat (ITT) analysis and 97.4% (93.4-99.3%, 148/152) in the PP analysis. The eradication rates for the CAM- and metronidazole-based treatments were similar (95.5% and 98.4%, respectively, p = .400). The tailored treatment achieved a high eradication rate in CYP2C19 rapid metabolizers who were a resistance genotype for PPI treatment (94.3% (86.0-98.4%, 66/70)).

DISCUSSION

A tailored H. pylori eradication regimen based on CAM susceptibility and maintaining acid secretion (rabeprazole 10 mg q.i.d.) is useful because it can achieve an eradication rate exceeding 95%, irrespective of eradication history, thus overcoming differences among CYP2C19 genotypes.

Dual-priming oligonucleotide-based multiplex PCR using tissue samples in rapid urease test in the detection of Helicobacter pylori infection

AIM: To investigate whether tissue samples processed by the rapid urease test (RUT) kit are suitable for dual-priming oligonucleotide-based multiplex polymerase chain reaction (DPO-PCR) to detect Helicobacter pylori (H. pylori).

METHODS: A total of 54 patients with specific gastrointestinal symptom were enrolled in this study. During endoscopy, gastric biopsy specimens were taken for histology, RUT, and DPO-PCR. DPO-PCR was performed on gastric biopsy samples and tissue samples that were analyzed by RUT at 2 separate institutes. In detecting H. pylori, the concordance rate of the DPO-PCR tests between the tissue samples that had been submitted to RUT and the gastric biopsy samples was investigated.

RESULTS: H. pylori co-occurred with 76.0% (19/25) of gastric ulcers, 64.3% (9/14) of duodenal ulcers, and 33.3% (4/12) of gastritis cases. H. pylori infection was found in 100% (3/3) of the patients with both gastric and duodenal ulcers. Overall, H. pylori was detected in 35 of 54 (64.8%) patients. The diagnostic sensitivities of histology, RUT, and DPO-PCR were 85.7% (30/35), 74.3% (26/35), and 97.1% (34/35), respectively (P = 0.02). The positive predictive value (PPV) of DPO-PCR was 94.4%, whereas the negative predictive value (NPV) was 94.7%. In the rapid urease test (CLOtest)-negative cases, the frequency of positive DPO-PCR and histologic results was 20.0% (7/35). The concordance rate of the DPO-PCR tests between the tissue samples from the RUT kit and the gastric biopsy samples was 94.4% (51/54). The rate of DPO-PCR and silver stain positivity in the RUT-negative cases was 20.0% (7/35).

CONCLUSION: In diagnosing H. pylori infection, DPO-PCR can be performed on tissue samples that have been processed by the RUT kit. Particularly, in patients with RUT-negative results, DPO-PCR on these tissue samples could be helpful in detecting of H. pylori infection.

Meta-analysis of first-line triple therapy for helicobacter pylori eradication in Korea: is it time to change?

Proton pump inhibitor (PPI)-based triple therapy consisting of PPI, amoxicillin, and clarithromycin, is the recommended first-line treatment for Helicobacter pylori infection. However, the eradication rate of triple therapy has declined over the past few decades. We analyzed the eradication rate and adverse events of triple therapy to evaluate current practices in Korea. A comprehensive literature search was performed up to August 2013 of 104 relevant studies comprising 42,124 patients. The overall eradication rate was 74.6% (95% confidence interval [CI], 72.1%-77.2%) by intention-to-treat analysis and 82.0% (95% CI, 80.8%-83.2%) by per-protocol analysis. The eradication rate decreased significantly from 1998 to 2013 (P < 0.001 for both intention-to-treat and per-protocol analyses). Adverse events were reported in 41 studies with 8,018 subjects with an overall incidence rate of 20.4% (95% CI, 19.6%-21.3%). The available data suggest that the effectiveness of standard triple therapy for H. pylori eradication has decreased to an unacceptable level. A novel therapeutic strategy is warranted to improve the effectiveness of first-line treatment for H. pylori infection in Korea.

Helicobacter pylori isolates from ethnic minority patients in Guangxi: Resistance rates, mechanisms, and genotype

AIM: To investigate the rate of Helicobacter pylori (H. pylori) resistance to clarithromycin among ethnic minority patients in Guangxi, explore the underlying mechanisms, and analyze factors influencing genotype distribution of H. pylori isolates.

METHODS: H. pylori strains were isolated, cultured and subjected to drug sensitivity testing. The 23S rRNA gene of H. pylori isolates was amplified by PCR and analyzed by PCR-RFLP and direct sequencing to detect point mutations. REP-PCR was used for genotyping of H. pylori isolates, and NTsys_2 software was used for clustering analysis based on REP-PCR DNA fingerprints. Factors potentially influencing genotype distribution of H. pylori isolates were analyzed.

RESULTS: The rate of clarithromycin resistance was 31.3%. A2143G and A2144G mutations were detected in the 23S rRNA gene of all clarithromycin-resistant H. pylori isolates. At a genetic distance of 78%, clarithromycin-resistant H. pylori isolates could be divided into six groups. Significant clustering was noted among H. pylori isolates from patients with peptic ulcer or gastritis.

CONCLUSION: The rate of clarithromycin resistance is relatively high in ethnic minority patients in Guangxi. Main mechanisms of clarithromycin resistance are A2143G and A2144G mutations in the 23S rRNA gene. Clarithromycin-resistant H. pylori isolates can be divided into six groups based on REP-PCR DNA fingerprints. Several factors such as disease type may influence the genotype distribution of H. pylori isolates.

Effects of emodin and other herbal extracts on resistance of Helicobacter pylori to clarithromycin

AIM: To evaluate the effects of emodin and other herbal extracts on resistance of Helicobacter pylori (H. pylori) to clarithromycin, and to explore the methods for effectively inhibiting H. pylori antibiotic resistance.

METHODS: The MIC of herbal extracts against clarithromycin resistance of H. pylori was detected by double dilution method. Clarithromycin resistant H. pylori was cultured in medium containing herbal extracts at a concentration of half MIC and passaged once every 5 d for 6 times. The MIC of clarithromycin against antibiotic resistance of H. pylori was assessed before and after stress culture. The DNA of H. pylori was extracted to detect drug resistant-related gene mutations.

RESULTS: The MIC of clarithromycin against H. pylori was reduced by herbal extracts. The gene mutations of 23s rRNA A2143G and A2144G were detected in clarithromycin-resistant H. pylori. No back mutations were discovered after treatment with herbal extracts for 30 d.

CONCLUSION: Herbal extracts have a synergistic effect in inhibiting the clarithromycin resistance of H. pylori. The synergistic action is not associated with the back mutations of 23s rRNA gene mutations related to clarithromycin resistance of H. pylori.

Helicobacter pylori: Future perspectives in therapy reflecting three decades of experience

The rising prevalence of antibiotic resistance has created a need to reassess the established Helicobacter pylori (H. pylori) eradication protocols, and to develop new ones. Various bacterial and host factors are evaluated, and their contribution to eradication failure is estimated. For a long time being considered the cornerstone eradication scheme, the standard triple therapy has been replaced with novel, more efficient regimens, namely sequential and concomitant, along with the emergence of a new design of bismuth quadruple therapy. A rescue levofloxacin based regimen has overcome the fear of therapy failure due to higher prevalence of dual resistant (clarithromycin and metronidazole) H. pylori. Culture-free and efficient susceptibility test are reestablishing the concept of tailored therapy, making eradication success close to originally desirable rates. Alleviating therapy side effects and improving patient compliance are as important as choosing appropriate eradication schemes, so various probiotic compound supplements are taken into consideration. Finally, we summarize the emerging efforts and obstacles in creating efficient H. pylori vaccine.