The problem of Helicobacter pylori resistance to antibiotics: a systematic review in Latin America

Probiotic Lactobacillus fermentum UCO-979C biofilm formation on AGS and Caco-2 cells and Helicobacter pylori inhibition

The ability of the human isolate Lactobacillus fermentum UCO-979C to form biofilm and synthesize exopolysaccharide on abiotic and biotic models is described. These properties were compared with the well-known Lactobacillus casei Shirota to better understand their anti-Helicobacter pylori probiotic activities. The two strains of lactobacilli synthesized exopolysaccharide as detected by the Dubois method and formed biofilm on abiotic and biotic surfaces visualized by crystal violet staining and scanning electron microscopy. Concomitantly, these strains inhibited H. pylori urease activity by up to 80.4% (strain UCO-979C) and 66.8% (strain Shirota) in gastric adenocarcinoma (AGS) cells, but the two species showed equal levels of inhibition (~84%) in colorectal adenocarcinoma (Caco-2) cells. The results suggest that L. fermentum UCO-979C has probiotic potential against H. pylori infections. However, further analyses are needed to explain the increased activity observed against the pathogen in AGS cells as compared to L. casei Shirota.

Stomach cancer burden in Central and South America

RATIONALE AND OBJECTIVE

Stomach cancer mortality rates in Central and South America (CSA) are among the highest in the world. We describe the current burden of stomach cancer in CSA.

METHODS

We obtained regional and national-level cancer incidence data from 48 population-based registries (13 countries) and nation-wide cancer deaths from WHO's mortality database (18 countries). We estimated world population age-standardized incidence (ASR) and mortality (ASMR) rates per 100,000 and estimated annual percent change to describe time trends.

RESULTS

Stomach cancer was among the 5 most frequently diagnosed cancers and a leading cause of cancer mortality. Between CSA countries, incidence varied by 6-fold and mortality by 5-6-fold. Males had up to 3-times higher rates than females. From 2003 to 2007, the highest ASRs were in Chile, Costa Rica, Colombia, Ecuador, Brazil and Peru (males: 19.2-29.1, females: 9.7-15.1). The highest ASMRs were in Chilean, Costa Rican, Colombian and Guatemalan males (17.4-24.6) and in Guatemalan, Ecuadorian and Peruvian females (10.5-17.1). From 1997 to 2008, incidence declined by 4% per year in Brazil, Chile and Costa Rica; mortality declined by 3-4% in Costa Rica and Chile. 60-96% of all the cancer cases were unspecified in relation to gastric sub-site but, among those specified, non-cardia cancers occurred 2-13-times more frequently than cardia cancers.

CONCLUSION

The variation in rates may reflect differences in the prevalence of Helicobacter pylori infection and other risk factors. High mortality may additionally reflect deficiencies in healthcare access. The high proportion of unspecified cases calls for improving cancer registration processes.

Surveillance of Levofloxacin Resistance in Helicobacter pylori Isolates in Bogotá-Colombia (2009-2014)

Increased resistance of Helicobacter pylori to clarithromycin and metronidazole has resulted in recommendation to substitute fluoroquinolones for eradication therapy. The aims of the study were to determine the prevalence and changes in primary levofloxacin resistance related to H. pylori gyrA sequences. The study utilized H. pylori strains isolated from patients undergoing gastroscopy in Bogotá, Colombia from 2009 to 2014. Levofloxacin susceptibility was assessed by agar dilution. Mutations in gyrA sequences affecting the quinolone resistance-determining region (QRDR) were evaluated by direct sequencing. Overall, the mean prevalence of primary levofloxacin resistance was 18.2% (80 of 439 samples). Resistance increased from 11.8% (12/102) in 2009 to 27.3% (21/77) in 2014 (p = 0.001). gyrA mutations in levofloxacin resistant strains were present in QRDR positions 87 and 91. The most common mutation was N87I (43.8%, 35/80) followed by D91N (28.8%, 23/80) and N87K (11.3%, 9/80). Levofloxacin resistance increased markedly in Colombia during the six-year study period. Primary levofloxacin resistance was most often mediated by point mutations in gyrA, with N87I being the most common QRDR mutation related to levofloxacin resistance.

Occurrence of Mutations in the Antimicrobial Target Genes Related to Levofloxacin, Clarithromycin, and Amoxicillin Resistance in Helicobacter pylori Isolates from Buenos Aires City

Domain V of 23S rRNA, gyrA and gyrB Quinolones Resistance-Determining Region (QRDR), and pbp-1A gene point mutations were investigated in Helicobacter pylori-resistant isolates from three centres of Buenos Aires. Minimal inhibitory concentrations (MICs) were performed in 197 isolates from 52 H. pylori-positive naive patients by agar dilution method. Point mutations were achieved by amplification and sequencing of the target genes, and their association with resistance was determined by natural transformation assays. Resistance rates were as follows: metronidazole 28.8%, clarithromycin (CLA) 26.9%, levofloxacin (LEV) 32.7%, and amoxicillin (AMX) 7.6%. Nearly one-third of patients carried multidrug-resistant isolates. A2143G or A2142G in domain V of 23S-rRNA was found in all isolates showing high level of resistance to CLA (MIC >2 mg/L), accounting for 76.0% (38/50) of those with the resistant phenotype. The mutations A2267G or T1861C carried by 8/12 isolates with MIC 1-2 mg/L (low level) did not confer resistance by transformation. Substitutions at GyrA position 87 or 91, mainly N87K and D91G, were found in 92.8% (52/56) of the LEV-resistant isolates: 48 isolates with MIC 4-64 mg/L and 4/8 isolates with MIC 2 mg/L. The remaining four harboured K133N, also present in susceptible isolates. None of the substitutions in GyrB demonstrated to confer resistance. Transformation proved that PBP-1A N562Y and/or T556S substitutions confer the AMX resistance in our isolates, showing an additive effect. In conclusion, the usually reported mutations related to CLA, LEV, and AMX resistance were found in our isolates. However, low-level CLA resistance seems not to be due to mutations in Domain V of 23S rRNA gene.

Levofloxacin Sequential Therapy vs Levofloxacin Triple Therapy in the Second-Line Treatment of Helicobacter pylori: A Randomized Trial

OBJECTIVES

The efficacy of levofloxacin triple therapy has fallen below 80% in the second-line treatment of Helicobacter pylori (H. pylori). We aimed to assess whether the levofloxacin sequential therapy is more effective than levofloxacin triple therapy in the second-line treatment.

METHODS

This open-label, randomized, multicenter trial was conducted between 2012 and 2015. H. pylori-infected subjects who failed from clarithromycin-based regimens (N=600) were randomized (1:1) to receive levofloxacin sequential therapy (LS: lansoprazole and amoxicillin for the first 5 days, followed by lansoprazole, levofloxacin, and metronidazole for another 5 days) or levofloxacin triple therapy (LT: lansoprazole, amoxicillin, and levofloxacin for 10 days). Successful eradication was defined as negative (13)C-urea breath test at least 6 weeks after treatment. Our primary outcome was the eradication rate by intention-to-treat (ITT) and per-protocol (PP) analyses. Antibiotic resistance was determined by agar dilution test.

RESULTS

The prevalence of clarithromycin, levofloxacin, and metronidazole resistance was 60, 17.6, and 36.9%, respectively. The eradication rates of LS and LT were 84.3% (253/300) and 75.3% (226/300), respectively, in the ITT analysis (P=0.006) and 86.3% (253/293) and 78.8% (223/283), respectively, in the PP analysis (P=0.021). The efficacies of both LS and LT were affected by levofloxacin resistance. The secondary resistance of levofloxacin was 66.7 and 73.9% after LS and LT, respectively. The efficacies of LS and LT were not affected by the CYP2C19 polymorphism.

CONCLUSIONS

Levofloxacin sequential therapy was more effective than levofloxacin triple therapy, and it is recommended in the second-line treatment for H. pylori (

TRIAL REGISTRATION NUMBER

NCT01537055).

Antimicrobial resistance of Helicobacter pylori strains to five antibiotics, including levofloxacin, in Northwestern Turkey

INTRODUCTION

Antibiotic resistance is the main factor that affects the efficacy of current therapeutic regimens against Helicobacter pylori. This study aimed to determine the rates of resistance to efficacy clarithromycin, amoxicillin, tetracycline, levofloxacin and metronidazole among H. pylori strains isolated from Turkish patients with dyspepsia.

METHODS

H. pylori was cultured from corpus and antrum biopsies that were collected from patients with dyspeptic symptoms, and the antimicrobial susceptibility of H. pylori was determined using the E-test (clarithromycin, amoxicillin, tetracycline, metronidazole and levofloxacin) according to the EUCAST breakpoints. Point mutations in the 23S rRNA gene of clarithromycin-resistant strains were investigated using real-time PCR.

RESULTS

A total of 98 H. pylori strains were isolated, all of which were susceptible to amoxicillin and tetracycline. Of these strains, 36.7% (36/98) were resistant to clarithromycin, 35.5% (34/98) were resistant to metronidazole, and 29.5% (29/98) were resistant to levofloxacin. Multiple resistance was detected in 19.3% of the isolates. The A2143G and A2144G point mutations in the 23S rRNA-encoding gene were found in all 36 (100%) of the clarithromycin-resistant strains. Additionally, the levofloxacin MIC values increased to 32 mg/L in our H. pylori strains. Finally, among the clarithromycin-resistant strains, 27.2% were resistant to levofloxacin, and 45.4% were resistant to metronidazole.

CONCLUSIONS

We conclude that treatment failure after clarithromycin- or levofloxacin-based triple therapy is not surprising and that metronidazole is not a reliable agent for the eradication of H. pylori infection in Turkey.

Efficacy of 7-Day and 14-Day Triple Therapy Regimens for the Eradication of Helicobacter pylori: A Comparative Study in a Cohort of Romanian Patients

Objective. This study compared the eradication rates of of Helicobacter pylori (HP) infection by a 7-day and 14-day anti-HP regimen. Materials and Methods. An open, randomized, prospective study was performed to evaluate the response to anti-HP treatment in adult HP-positive patients following a 7-day course (Regimen A) of a proton pump inhibitor in association with clarithromycin and amoxicillin compared to a 14-day course (Regimen B). Gastric biopsies were performed at baseline and two months after anti-HP treatment. Results. Seventy-eight patients aged 18–64 years (28 males, 50 females) diagnosed with HP infection were included. Fifty-two (66.7%) patients received Regimen B and 26 (33.3%) Regimen A. The overall eradication rate was 70.5%. Better treatment response (p < 0.01) was seen in Regimen B (44/52, 84.2% versus 11/26, 42.3%). Significant improvement in histological features was seen in regimen B. There has been significant overall reduction in endoscopic aspects of gastric and duodenal lesions in both regimens. Younger patients ≤35 years had a better response to Regimen B. Better treatment response was seen in women, urban residents, and those with tertiary level of education in both groups. Conclusion. 14-day anti-HP regimen offered a significant better overall eradication of HP in study population.

Treatment of Helicobacter pylori Infection 2015

Many interesting articles have been published from many parts of the world over the last year assessing different issues around Helicobacter pylori eradication therapy. This article will address the published literature over the last year pertaining to the topic of treatment of H. pylori infection. The main themes that emerge are assessing the efficacy of standard triple therapy, as well as exploring new first-line treatments, mainly optimized nonbismuth- and bismuth-containing quadruple therapies with some promising data also emerging on dual therapy. There was also considerable progress in investigating antibiotic resistance rates with much more data emerging from varied parts of the world compared to recent years. There have also been advances in the use of adjunctive therapies, especially probiotic therapies. Undoubtedly, the eradication of H. pylori remains a worthwhile goal to alleviate the burden of diseases caused by the complications of this infection, including dyspepsia, peptic ulcer disease, and gastric cancer.

Effect of bacterial and host factors on Helicobacter pylori eradication therapy

INTRODUCTION

A clearer understanding of the factors affecting the cure rate of Helicobacter pylori infection might lead to the development of novel prevention strategies and therapeutic targets.

AREAS COVERED

This review covers two important issues that affect the eradication of H. pylori: bacterial and host factors. Several virulence factors have been shown to be predictors for gastroduodenal diseases. Successful treatment of H. pylori infection also depends on host genetic factors such as CYP2C19 and IL-1B. The latest evidence on host genetic factors is discussed.

EXPERT OPINION

The authors identify three main targets for achieving effective eradication therapy. The first therapeutic target is to identify counter measures for antibiotic-resistant H. pylori strains. Thus, antibiotic susceptibility should be checked in all patients, ideally, before the start of eradication treatment. The second therapeutic target is the inhibition of acid suppression. Maintaining a high intragastric pH for 24 h increases the effectiveness of some antibiotics and the eradication effects for H. pylori. The third therapeutic target is to identify high-risk groups; the CYP2C19 and IL-1B polymorphisms are candidates for significant risk factors. A personalized medical approach will likely increase the cure rate of H. pylori infection.

Dietary amelioration of Helicobacter infection

We review herein the basis for using dietary components to treat and/or prevent Helicobacter pylori infection, with emphasis on (a) work reported in the last decade, (b) dietary components for which there is mechanism-based plausibility, and (c) components for which clinical results on H pylori amelioration are available. There is evidence that a diet-based treatment may reduce the levels and/or the virulence of H pylori colonization without completely eradicating the organism in treated individuals. This concept was endorsed a decade ago by the participants in a small international consensus conference held in Honolulu, Hawaii, USA, and interest in such a diet-based approach has increased dramatically since then. This approach is attractive in terms of cost, treatment, tolerability, and cultural acceptability. This review, therefore, highlights specific foods, food components, and food products, grouped as follows: bee products (eg, honey and propolis); probiotics; dairy products; vegetables; fruits; oils; essential oils; and herbs, spices, and other plants. A discussion of the small number of clinical studies that are available is supplemented by supportive in vitro and animal studies. This very large body of in vitro and preclinical evidence must now be followed up with rationally designed, unambiguous human trials.

The Primary Resistance of Helicobacter pylori in Taiwan after the National Policy to Restrict Antibiotic Consumption and Its Relation to Virulence Factors-A Nationwide Study

Objective

The Taiwan Government issued a policy to restrict antimicrobial usage since 2001. We aimed to assess the changes in the antibiotic consumption and the primary resistance of H. pylori after this policy and the impact of virulence factors on resistance.

Methods

The defined daily dose (DDD) of antibiotics was analyzed using the Taiwan National Health Insurance (NHI) research database. H. pylori strains isolated from treatment naïve (N=1395) and failure from prior eradication therapies (N=360) from 9 hospitals between 2000 and 2012 were used for analysis. The minimum inhibitory concentration was determined by agar dilution test. Genotyping for CagA and VacA was determined by PCR method.

Results

The DDD per 1000 persons per day of macrolides reduced from 1.12 in 1997 to 0.19 in 2008, whereas that of fluoroquinolones increased from 0.12 in 1997 to 0.35 in 2008. The primary resistance of amoxicillin, clarithromycin, metronidazole, and tetracycline remained as low as 2.2%, 7.9%, 23.7%, and 1.9% respectively. However, the primary levofloxacin resistance rose from 4.9% in 2000–2007 to 8.3% in 2008–2010 and 13.4% in 2011–2012 (p=0.001). The primary resistance of metronidazole was higher in females than males (33.1% vs. 18.8%, p<0.001), which was probably attributed to the higher consumption of nitroimidazole. Neither CagA nor VacA was associated with antibiotic resistance.

Conclusions

The low primary clarithromycin and metronidazole resistance of H. pylori in Taiwan might be attributed to the reduced consumption of macrolides and nitroimidazole after the national policy to restrict antimicrobial usage. Yet, further strategies are needed to restrict the consumption of fluoroquinolones in the face of rising levofloxacin resistance.

The nuclease activities of both the Smr domain and an additional LDLK motif are required for an efficient anti-recombination function of Helicobacter pylori MutS2

Helicobacter pylori, a human pathogen, is a naturally and constitutively competent bacteria, displaying a high rate of intergenomic recombination. While recombination events are essential for evolution and adaptation of H. pylori to dynamic gastric niches and new hosts, such events should be regulated tightly to maintain genomic integrity. Here, we analyze the role of the nuclease activity of MutS2, a protein that limits recombination during transformation in H. pylori. In previously studied MutS2 proteins, the C-terminal Smr domain was mapped as the region responsible for its nuclease activity. We report here that deletion of Smr domain does not completely abolish the nuclease activity of HpMutS2. Using bioinformatics analysis and mutagenesis, we identified an additional and novel nuclease motif (LDLK) at the N-terminus of HpMutS2 unique to Helicobacter and related ε-proteobacterial species. A single point mutation (D30A) in the LDLK motif and the deletion of Smr domain resulted in ∼ 5-10-fold loss of DNA cleavage ability of HpMutS2. Interestingly, the mutant forms of HpMutS2 wherein the LDLK motif was mutated or the Smr domain was deleted were unable to complement the hyper-recombination phenotype of a mutS2(-) strain, suggesting that both nuclease sites are indispensable for an efficient anti-recombinase activity of HpMutS2.

Early or late antibiotic intervention prevents Helicobacter pylori-induced gastric cancer in a mouse model

H. pylori infection causes gastritis, peptic ulcers and gastric cancer. Eradicating H. pylori prevents ulcers, but to what extent this prevents cancer remains unknown, especially if given after intestinal metaplasia has developed. H. pylori infected wild-type (WT) mice do not develop cancer, but mice lacking the tumor suppressor p27 do so, thus providing an experimental model of H. pylori-induced cancer. We infected p27-deficient mice with H. pylori strain SS1 at 6-8 weeks of age. Persistently H. pylori-infected WT C57BL/6 mice served as controls. Mice in the eradication arms received antimicrobial therapy (omeprazole, metronidazole and clarithromycin) either "early" (at 15 weeks post infection, WPI) or "late" at 45 WPI. At 70 WPI, mice were euthanized for H. pylori determination, histopathology and cytokine/chemokine expression. Persistently infected mice developed premalignant lesions including high-grade dysplasia, whereas those given antibiotics did not. Histologic activity scores in the eradication groups were similar to each other, and were significantly decreased compared with controls for inflammation, epithelial defects, hyperplasia, metaplasia, atrophy and dysplasia. IP-10 and MIG levels in groups that received antibiotics were significantly lower than controls. There were no significant differences in expression of IFN-γ, TNF-α, IL-1β, RANTES, MCP-1, MIP-1α or MIP-1β among the three groups. Thus, H. pylori eradication given either early or late after infection significantly attenuated gastric inflammation, gastric atrophy, hyperplasia, and dysplasia in the p27-deficient mice model of H. pylori-induced gastric cancer, irrespective of the timing of antibiotic administration. This was associated with reduced expression of IP-10 and MIG.

Clarithromycin vs. Gemifloxacin in Quadruple Therapy Regimens for Empiric Primary Treatment of Helicobacter pylori Infection: A Randomized Clinical Trial

BACKGROUND Eradication of Helicobacter pylori infection plays a crucial role in the treatment of peptic ulcer. Clarithromycin resistance is a major cause of treatment failure. This randomized clinical trial aimed at evaluating the efficacy of a clarithromycin versus gemifloxacin containing quadruple therapy regimen in eradication of H.pylori infection. METHODS In this randomized double blind clinical trial (RCT 2012102011054N2), a total of 120 patients were randomized to two groups of 60 patients each. Patients with proven H.pylori infection were consecutively assigned into two groups to receive OBAG or OBAC in gastroenterology clinic in Rasoul-e- Akram General Hospital in Tehran, Iran. The patients in the OBAG group received omeprazole (20 mg) twice daily, bismuth subcitrate (240 mg) twice daily, amoxicillin (1 gr) twice daily, and gemifloxacin (320 mg) once daily, and those in the OBAC group received omeprazole (20 mg) twice daily, 240 mg of bismuth subcitrate twice daily, amoxicillin (1 gr) twice daily, and clarithromycin (500 mg) twice daily for 10 days. RESULTS Five patients from each group were excluded from the study because of poor compliance, so 110 patients completed the study. The intention-to-treat eradication rate was 61.6% and 66.6% for the OBAC and OBAG groups, respectively. According to the per protocol analysis, the success rates of eradication of H.pylori infection were 67.2% and 72.7% for OBAC and OBAG groups, respectively (p=0.568). CONCLUSION The results of this study suggest that gemifloxacin containing regimen is at least as effective as clarithromycin regimen; hence, this new treatment could be considered as an alternative for the patients who cannot tolerate clarithromycin.

Epidemiology of Helicobacter pylori infection among the healthy population in Iran and countries of the Eastern Mediterranean Region: A systematic review of prevalence and risk factors

AIM: To investigate the epidemiology of Helicobacter pylori (H. pylori) infection among the healthy asymptomatic population in Iran and countries of the Eastern Mediterranean Region.

METHODS: A computerized English language literature search of PubMed, ISI Web of Science, Scopus, and Google Scholar was performed in September 2013. The terms, “Eastern Mediterranean Regional Office (EMRO)” and “Helicobacter pylori”, “H. pylori” and “prevalence” were used as key words in titles and/or abstracts. A complementary literature search was also performed in the following countries: Afghanistan, Bahrain, Djibouti, Egypt, Iran, Iraq, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Pakistan, Palestine, Qatar, Saudi Arabia, Somalia, Sudan, Syria, Tunisia, The United Arab Emirates, and Yemen.

RESULTS: In the electronic search, a total of 308 articles were initially identified. Of these articles, 26 relevant articles were identified and included in the study. There were 10 studies from Iran, 5 studies from the Kingdom of Saudi Arabia, 4 studies from Egypt, 2 from the United Arab Emirates, and one study from Libya, Oman, Tunisia, and Lebanon, respectively. The overall prevalence of H. pylori infection in Iran, irrespective of time and age group, ranged from 30.6% to 82%. The overall prevalence of H. pylori infection, irrespective of time and age group, in other EMRO countries ranged from 22% to 87.6%.

CONCLUSION: The prevalence of H. pylori in EMRO countries is still high in the healthy asymptomatic population. Strategies to improve sanitary facilities, educational status, and socioeconomic status should be implemented to minimize H. pylori infection.

Early or late antibiotic intervention prevents Helicobacter pylori-induced gastric cancer in a mouse model

H. pylori infection causes gastritis, peptic ulcers and gastric cancer. Eradicating H. pylori prevents ulcers, but to what extent this prevents cancer remains unknown, especially if given after intestinal metaplasia has developed. H. pylori infected wild-type (WT) mice do not develop cancer, but mice lacking the tumor suppressor p27 do so, thus providing an experimental model of H. pylori-induced cancer. We infected p27-deficient mice with H. pylori strain SS1 at 6-8 weeks of age. Persistently H. pylori-infected WT C57BL/6 mice served as controls. Mice in the eradication arms received antimicrobial therapy (omeprazole, metronidazole and clarithromycin) either "early" (at 15 weeks post infection, WPI) or "late" at 45 WPI. At 70 WPI, mice were euthanized for H. pylori determination, histopathology and cytokine/chemokine expression. Persistently infected mice developed premalignant lesions including high-grade dysplasia, whereas those given antibiotics did not. Histologic activity scores in the eradication groups were similar to each other, and were significantly decreased compared with controls for inflammation, epithelial defects, hyperplasia, metaplasia, atrophy and dysplasia. IP-10 and MIG levels in groups that received antibiotics were significantly lower than controls. There were no significant differences in expression of IFN-γ, TNF-α, IL-1β, RANTES, MCP-1, MIP-1α or MIP-1β among the three groups. Thus, H. pylori eradication given either early or late after infection significantly attenuated gastric inflammation, gastric atrophy, hyperplasia, and dysplasia in the p27-deficient mice model of H. pylori-induced gastric cancer, irrespective of the timing of antibiotic administration. This was associated with reduced expression of IP-10 and MIG.

Helicobacter pylori infection in pediatrics

This review concerns important pediatric studies published from April 2013 to March 2014. New data on pathogenesis have demonstrated that Th1 type cytokine secretion at the gastric level is less intense in children compared with adults. They have also shown that the most significant risk factor for Helicobacter pylori infection is the parents' origin and frequency of childcare in settings with a high prevalence of infection. A new hypothesis on the positive relationship between childhood H. pylori infection and the risk of gastric cancer in adults has been suggested which calls for an implementation of preventive programs to reduce the burden of childhood H. pylori infection in endemic areas. Several studies have investigated the role of H. pylori infection in iron-deficiency anemia, and results support the role of the bacterium in this condition. Antibiotic resistance is an area of intense research with data confirming an increase in antibiotic resistance, and the effect of CYP2C19 genetic polymorphism on proton-pump inhibitor metabolism should be further investigated as cure rates are lower in extensive metabolizers. Studies confirmed that probiotic supplementation may have beneficial effects on eradication and therapy-related side effects, particularly diarrhea in children.

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.

Management of Helicobacter pylori infection in Latin America: a Delphi technique-based consensus

AIM

To optimize diagnosis and treatment guidelines for this geographic region, a panel of gastroenterologists, epidemiologists, and basic scientists carried out a structured evaluation of available literature.

METHODS

Relevant questions were distributed among the experts, who generated draft statements for consideration by the entire panel. A modified three-round Delphi technique method was used to reach consensus. Critical input was also obtained from representatives of the concerned medical community. The quality of the evidence and level of recommendation supporting each statement was graded according to United States Preventive Services Task Force criteria.

RESULTS

A group of ten experts was established. The survey included 15 open-ended questions that were distributed among the experts, who assessed the articles associated with each question. The levels of agreement achieved by the panel were 50% in the first round, 73.3% in the second round and 100% in the third round. Main consensus recommendations included: (1) when available, urea breath and stool antigen test (HpSA) should be used for non-invasive diagnosis; (2) detect and eradicate Helicobacter pylori (H. pylori) in all gastroscopy patients to decrease risk of peptic ulcer disease, prevent o retard progression in patients with preneoplastic lesions, and to prevent recurrence in patients treated for gastric cancer; (3) further investigate implementation issues and health outcomes of H. pylori eradication for primary prevention of gastric cancer in high-risk populations; (4) prescribe standard 14-d triple therapy or sequential therapy for first-line treatment; (5) routinely assess eradication success post-treatment in clinical settings; and (6) select second- and third-line therapies according to antibiotic susceptibility testing.

CONCLUSION

These achievable steps toward better region-specific management can be expected to improve clinical health outcomes.

Mechanisms underlying resistance of Helicobacter pylori to metronidazole

Many diseases of the digestive system are related to Helicobacter pylori (H. pylori), which is an microaerophilic bacterium and has the highest infection rate in humans around the world. Metronidazole is an effective drug to kill H. pylori. The resistance to metronidazole in H. pylori has increased in recent years. The precise mechanism underlying the resistance of H. pylori to metronidazole is still unknown. This article reviews the latest progress in understanding the resistance to metronidazole in H. pylori.