Antibiotic-resistant Helicobacter pylori strains in Portuguese children

Global prevalence of Helicobacter pylori antibiotic resistance among children in the world health organization regions between 2000 and 2023: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori infection causes gastritis, peptic ulcers, and gastric cancer. The infection is typically acquired in childhood and persists throughout life. The major impediment to successful therapy is antibiotic resistance. This systematic review and meta-analysis aimed to comprehensively assess the global prevalence of antibiotic resistance in pediatric H. pylori infection.

METHODS

We performed a systematic search of publication databases that assessed H. pylori resistance rates to clarithromycin, metronidazole, levofloxacin, amoxicillin, and tetracycline in children. The WHO region classification was used to group pooled primary and secondary resistance estimates along with 95% confidence interval (CI). H. pylori antibiotic resistance rates were retrieved and combined with odds ratios (95% CI) to investigate the global prevalence and temporal trends. Subgroup analysis of the prevalence of antibiotic resistance was conducted by country, age groups, and susceptibility testing methods.

RESULTS

Among 1417 records obtained initially, 152 studies were selected for eligibility assessment after applying exclusion criteria in multiple steps. Ultimately, 63 studies involving 15,953 individuals were included comprising data from 28 countries in 5 WHO regions. The primary resistance rates were metronidazole 35.3% (5482/15,529, 95% CI: 28.7-42.6), clarithromycin 32.6% (5071/15,555, 95% CI: 27.7-37.9), tetracycline 2.1% (148/7033, 95% CI: 1.3-3.6), levofloxacin 13.2% (1091/8271, 95% CI: 9.3-18.4), and amoxicillin 4.8% (495/10305, 95% CI: 2.5-8.8). Raising antibiotic resistance was detected in most WHO regions.

CONCLUSIONS

The escalating trend of H. pylori antibiotic resistance in children warrants urgent attention globally. National and regional surveillance networks are required for antibiotic stewardship in children infected with H. pylori.

Antibiotic resistance of Helicobacter pylori in Chinese children: A multicenter study from 2016 to 2023

BACKGROUND

To investigate the antibiotic resistance of Helicobacter pylori (H. pylori) strains to clarithromycin, metronidazole, amoxicillin, levofloxacin, furazolidone, and tetracycline in Chinese children.

MATERIALS AND METHODS

This multicenter, retrospective study was conducted from January 2016 through May 2023. Gastric mucosa biopsies were obtained from pediatric participants who underwent upper gastrointestinal endoscopy at 96 hospitals in northern, southwestern, and southeastern China. The susceptibility of H. pylori to six commonly used antibiotics was determined by agar dilution method.

RESULTS

Among the 3074 H. pylori isolates, 36.7% were resistant to clarithromycin, 77.3% to metronidazole, 16.6% to levofloxacin, and 0.3% to amoxicillin. No strains were detected to be resistant to furazolidone or tetracycline. During the 8-year study period, resistance to clarithromycin and metronidazole showed a significant upward trend, while the resistance pattern of the other antibiotics demonstrated a slight but nonsignificant fluctuation. Significant regional differences were found in the distribution of clarithromycin resistance among the northern (66.0%), southwestern (48.2%), and southeastern (34.6%) regions. The metronidazole resistance rate was significantly lower in the southeastern coastal region (76.3%) than in the other two regions (88.2% in the north and 87.7% in the southwest). Multi-drug resistance for two or more antibiotics was detected in 36.3% of the H. pylori strains, and the predominant multi-resistance pattern was the dual resistance to clarithromycin and metronidazole.

CONCLUSIONS

The prevalence of H. pylori resistance to clarithromycin and metronidazole is rather high in Chinese children and has been increasing over time. A relatively high resistance rate to levofloxacin was also noticed in children, while almost all strains were susceptible to amoxicillin, furazolidone, and tetracycline. It will be of great clinical significance to continuously monitor the antibiotic-resistance patterns of H. pylori in the pediatric population.

Efficacy of Phenotype-vs. Genotype-Guided Therapy Based on Clarithromycin Resistance for Helicobacter pylori Infection in Children

BACKGROUND

Clarithromycin resistance reduces the eradication rate of Helicobacter pylori (H. pylori). Cultures with susceptibility testing and molecular determination of genotypes are recommended to guide-tailored therapy.

METHODS

We retrospectively enrolled patients aged 6 and 18 years with H. pylori infection, who underwent an endoscopy and agreed to undergo both culture and genetic testing for clarithromycin resistance. Patients receiving tailored therapy based on traditional culture results (phenotype-guided therapy) or genetic testing results (genotype-guided therapy) were included in the study. ¹³C-urea breath test was used to evaluate the success of eradication at least 4 weeks after the completion of treatment. We aimed to determine whether the eradication rate of phenotype- or genotype-guided therapy based on clarithromycin resistance is greater than 90% in children.

RESULTS

Between September 2017 and October 2020, 226 eligible patients were enrolled. There were 71 with clarithromycin-sensitive strains in the phenotype-guided therapy group and 87 without 23S rRNA point mutations (A2142G, A2142C, and A2143G) in the genotype-guided therapy group. Eradication rates were 70.4% (50/71, [95% CI: 58.4-80.7%] for phenotype-guided therapy and 92.0% (80/87, [95% CI: 84.1-96.7%]) for genotype-guided therapy (P < 0.01). The incidence of side effects was 4.2% (3/71) and 10.3% (9/87), with no major differences between these two groups (P = 0.15), respectively. The compliance rate was also similar (97.2 vs. 95.4%, P = 0.87).

CONCLUSION

Tailored therapy according to genetic testing results achieved eradication rates of 92% and was superior to tailored therapy guided by traditional culture results.

Pediatric Endoscopy, Update 2020

Optimal management of pediatric endoscopy requires a multidisciplinary approach. In most hospitals, endoscopy in pediatric patients is performed by conventional gastroenterologists and only a few centers have specialized pediatric gastroenterologists. This is due to the fact that the number of pediatric gastroenterologists is limited and not all of them are experienced in endoscopic techniques. However, there are also some pediatric centers offering a high-quality and high-volume endoscopy service provided by very experienced pediatric gastroenterologists. Up to now, the literature on pediatric endoscopy is rather sparse. In this article, we describe current knowledge and practice of endoscopic procedures in pediatric patients, which should be relevant for both the adult and pediatric gastroenterologists.

Helicobacter pylori resistance to clarithromycin and fluoroquinolones in a pediatric population in Turkey: A cross-sectional study

BACKGROUND

Helicobacter pylori antimicrobial resistance is gradually increasing around the world. However, there are a limited number of studies reporting on this issue in the pediatric population. In this study, we aimed to determine H pylori resistance to clarithromycin and fluoroquinolones in the pediatric patients living in Kırıkkale province that were detected with H pylori in gastric biopsies. Moreover, we also aimed to investigate the concordance between the histopathologic and molecular methods used in the diagnosis of H pylori infection.

MATERIALS AND METHODS

Patients aged 2-18 years who had a history of epigastric pain and/or nausea persisting for longer than 1 month underwent upper gastrointestinal endoscopy. Biopsies were taken from the gastric antral mucosa. In the samples detected with H pylori in the histopathologic examination, the presence of H pylori and H pylori resistance to clarithromycin and fluoroquinolones was investigated using the GenoType HelicoDR test which allows the detection of wild-type and mutant genes. The strains detected with more than one mutant gene are defined as hetero-resistant strains.

RESULTS

The 93 patients that underwent DNA extraction and amplification included 68 (73.1%) girls and 25 (26.9%) boys with a median age of 15 ± 2.62 (range 6-17) years. The overall concordance for the diagnosis of H pylori infection between histopathology and PCR was 94%, and H pylori resistance to clarithromycin and fluoroquinolones was 27% and 15%, respectively.

CONCLUSIONS

The high H pylori resistance to clarithromycin and fluoroquinolones among the pediatric patients in our region implicates that the antibiotic sensitivity of strains should be studied prior to administration in accordance with the recommendations provided in the guidelines. Moreover, the presence of hetero-resistant strains in our patients may be a reason for treatment failure.

Neutralizing antibodies for Helicobacter pylori urease inhibit bacterial colonization in the murine stomach in vivo

Helicobacter pylori (H. pylori) urease is a key protein for persistent infection of the bacteria in the stomach. Although H. pylori generally induce anti-H. pylori-specific antibodies (Abs), these Abs do not usually work for eradication or prevention of the H. pylori infection. In our previous study, we identified a linear epitope composed of 19-mer peptides termed UB-33, CHHLDKSIKEDVQFADSRI, within the large subunit of H. pylori urease. Anti-UB-33-specific Abs neutralized the enzymatic activity of H. pylori urease in vitro. In the present study, we evaluated the effect of immunization of BALB/c mice with H. pylori UB-33 peptide. After confirming the production of anti-UB-33-specific Abs, mice were challenged orally with H. pylori Sydney Strain-1 (SS-1). Mice producing anti-UB-33-specific Abs were not infected with SS-1, and the amount of SS-1 isolate in their stomach was significantly reduced. Also, the urease-negative mutant of H. pylori, HPP1801, did not colonize in the stomach, indicating that H. pylori urease was a critical element for infection of H. pylori in the gastric mucosa. Moreover, mice producing UB-33-specific Abs apparently suppressed H. pylori infection in the stomach where anti-UB-33 Abs were secreted in the gastric juice, indicating that H. pylori colonization was inhibited in the presence of anti-UB-33 Abs. In addition, the neutralization activity of sera from mice immunized with purified urease was less potent than that in the sera from mice immunized with UB-33. Furthermore, the recognition of epitope UB-33 was mediated through Toll-like receptor 2 (TLR2) on the B-1 cells using TLR2-knockout BALB/c mice in vivo. These results indicate that liner peptide UB-33 should be used for immunization to induce neutralizing Abs instead of purified H. pylori urease to prevent H. pylori infection and their colonization in the stomach.

Prevalence of Antibiotic Resistance in Helicobacter pylori: A Systematic Review and Meta-analysis in World Health Organization Regions

BACKGROUND & AIMS

In 2017, the World Health Organization (WHO) designated clarithromycin-resistant Helicobacter pylori a high priority for antibiotic research and development. However, there are no clear data on the global distribution of resistance or its clinical effects. We performed a systematic review and meta-analysis to assess the distribution of H pylori resistance to commonly used antibiotics and to measure the association between antibiotic resistance and treatment failure.

METHODS

We searched publication databases for studies that assessed rates of H pylori resistance to clarithromycin, metronidazole, levofloxacin, amoxicillin, or tetracycline. Pooled estimates of primary and secondary resistance and 95% confidence intervals (CIs) were grouped by WHO region. The association between antibiotic resistance and treatment failure was measured by extracting data on treatment efficacy in patients with resistant and susceptible isolates and pooling odds ratios with 95% CIs.

RESULTS

We identified 178 studies, comprising 66,142 isolates from 65 countries. Primary and secondary resistance rates to clarithromycin, metronidazole, and levofloxacin were ≥15% in all WHO regions, except primary clarithromycin resistance in the Americas (10%; 95% CI, 4%-16%) and South-East Asia region (10%; 95% CI, 5%-16%) and primary levofloxacin resistance in the European region (11%; 95% CI, 9%-13%). There was considerable heterogeneity (I2 > 75%) among all analyses-this might have resulted from the grouping of resistance rates by country. Increasing antibiotic resistance was observed in most WHO regions. Resistance to clarithromycin was significantly associated with failure of clarithromycin-containing regimens (odds ratio, 6.97; 95% CI, 5.23-9.28; P < .001).

CONCLUSIONS

Resistance of H pylori to antibiotics has reached alarming levels worldwide, which has a great effect on efficacy of treatment. Local surveillance networks are required to select appropriate eradication regimens for each region.

Antibiotic Resistance of Helicobacter pylori in Iranian Children: A Systematic Review and Meta-Analysis

Antibiotic therapy for children infected with Helicobacter pylori is important. However, resistance to antibiotics is one of the main causes of treatment failure. This study was designed to evaluate the prevalence pattern of antibiotic resistance of H. pylori in Iranian children using a systematic review and meta-analysis of literature. A computerized search (until June 10, 2017) using related keywords in the national and international databases was performed. A total of 261 original articles on antibiotic resistance of H. pylori in Iranian children were collected. After screening for inclusion and exclusion criteria, six eligible articles were included in the meta-analysis. Resistance rates of H. pylori to different antibiotics were as follows: metronidazole: 71%, clarithromycin: 12.2%, amoxicillin: 20.4%, tetracycline: 8.4%, ampicillin: 21.4%, rifampin: 28.6%, furazolidone: 8.4%, ciprofloxacin: 16.2%, azithromycin: 19%, erythromycin: 15.3%, and nitrofurantoin: 0%. The prevalence of H. pylori resistance to metronidazole, amoxicillin, ampicillin, and rifampin among Iranian children was high. Therefore, a careful monitoring of antibiotic resistance to select the best treatment options and prevent treatment failure is required. Although resistance to some antibiotics such as clarithromycin, tetracycline, furazolidone, and ciprofloxacin was less prevalent, frequent consumption of these drugs in children should be controlled owing to their known adverse events.

Helicobacter pylori antibiotic resistance in Portugal: Systematic review and meta-analysis

BACKGROUND

Portugal presents both a high prevalence of Helicobacter pylori (Hp) infection and a high prevalence of antibiotic resistance. However, conclusive data on its magnitude are lacking. We aimed at summarizing the existing data.

MATERIALS AND METHODS

A systematic review was conducted after searching in two databases (PubMed and SciELO). Meta-analysis was performed, and comparison of resistance rates between children and adults and by type of resistance (primary and secondary) was made.

RESULTS

Eight cross-sectional studies assessing Hp resistance to antibiotics were included. Overall resistance rates were as follows: clarithromycin (CLA) 42% (95% CI: 30-54), metronidazole (MTZ) 25% (95% CI: 15-38), ciprofloxacin (CIP) 9% (95% CI: 3-18), levofloxacin (LVX) 18% (95% CI: 2-42), tetracycline (TTC) 0.2% (95% CI: 0-1), and amoxicillin (AMX) 0.1% (95% CI: 0-0.2). Multidrug resistance was also an important problem, with the following global resistance rates: CLA plus MTZ of 10% (adults 20% (95% CI: 15-26) vs children 6% (95% CI: 4-9)) and CLA plus CIP of 2% (primary resistance in children's group). High secondary resistance rates were found for all antibiotics. Resistance was higher among adults for all antibiotics, except CLA that had high resistance levels both among adults and children (42% 95% CI: 14-71 and 40% 95% CI: 33-47).

CONCLUSIONS

Hp resistance to the most widely used antibiotics is high in Portugal. Accordingly, our results suggest that the best therapeutic strategy for Hp in Portugal may be quadruple therapy with bismuth for adults and triple therapy including AMX plus MTZ or bismuth-based therapy for children.

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.

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.

Helicobacter pylori antimicrobial resistance rates in the central region of Portugal

Helicobacter pylori resistance to antimicrobial agents is steadily increasing. It is extremely important to be aware of the local prevalence of antibiotic resistance so as to adjust treatment strategies. During this single-centre, prospective study, we aimed to determine primary and secondary resistance rates of H. pylori to antibiotics as well as host and bacterial factors associated with this problem. Overall, 180 patients (131 female; mean age 43.4±13.5 years; primary resistance 103; secondary resistance 77) with positive (13) C-urea breath test were submitted to upper endoscopy with gastric biopsies. Helicobacter pylori was cultured and antimicrobial susceptibility was determined by Etest and molecular methods. Clinical and microbiological characteristics associated with resistance were evaluated by logistic regression analysis. Among the 180 isolates 50% were resistant to clarithromycin (primary 21.4%; secondary 88.3%), 34.4% to metronidazole (primary 29.1%; secondary 41.6%), 33.9% to levofloxacin (primary 26.2%; secondary 44.2%), 0.6% to tetracycline and 0.6% to amoxicillin. Being female was an independent predictor of resistance to clarithromycin and metronidazole. Previous, failed, eradication treatments were also associated with a decrease in susceptibility to clarithromycin. History of frequent infections, first-degree relatives with gastric carcinoma and low education levels determined increased resistance to levofloxacin. Mutations in the 23S rRNA and gyrA genes were frequently found in isolates with resistance to clarithromycin and levofloxacin, respectively. This study revealed that resistance rates to clarithromycin, metronidazole and levofloxacin are very high and may compromise H. pylori eradication with first-line and second-line empiric triple treatments in Portugal.

Antimicrobial resistance and characteristics of eradication therapy of Helicobacter pylori in Japan: a multi-generational comparison

BACKGROUND

Eradication of Helicobacter pylori (H. pylori) at a younger age is considered to be effective in preventing gastric cancer. This study assessed the characteristics of eradication therapy in young patients.

MATERIALS AND METHODS

We enrolled 1073 patients with H. pylori infection between 2000 and 2013. The subjects were divided into three groups according to age into the young (≤30 years), middle-aged (31-50 years), and elder (≥51 years) groups. We also examined 472 cases to investigate clinical eradication characteristics.

RESULTS

The rate of clarithromycin (CAM) resistance was 57.9%, 34.5%, and 35.2% in the young, middle-aged, and elder group, respectively, in 2012-2013 and was significantly higher in the young group than in the elder group (p = .01). Metronidazole (MNZ) resistance was similar among the three groups at each time point. While CAM resistance rose over the study period, MNZ resistance was noted to have decreased of late. The overall initial eradication success rate was 91.9% (95% CI, 89.1-94.1) in our cohort. Eradication efficiency was comparable in the young, middle-aged, and elder group at 94.3% (95% CI, 87.4-97.5), 90.2% (95% CI, 82.9-94.6), and 91.8% (95% CI, 88.1-94.5) respectively. Side effects such as skin rash were observed in 14.8%, 3.9%, and 3.5% of the respective groups. There were significant differences in the incidence of side effects between the young group and other groups (p < .05, respectively).

CONCLUSION

Since CAM resistance and the incidence of side effects are higher in young individuals, it is especially important to select eradication regimens based on testing for antimicrobial susceptibility.

Virulence factors and antibiotic resistance in children with Helicobacter pylori gastritis

OBJECTIVES

There are limited data regarding the pattern of Helicobacter pylori (Hp) antibiotic resistance and virulence factors in children. Evaluation of prevalence of drug resistance and virulence-factor genotype in children with Hp gastritis and to investigate whether there is any relation between drug resistance and genotype were our aims in this study.

METHODS

Ninety-eight children with polymerase chain reaction-positive Hp gastritis were included. Antimicrobial susceptibility was tested by disc diffusion method and polymerase chain reaction assays were used for the determination of virulence factors.

RESULTS

The resistance rates to clarithromycin, metronidazole, and amoxicillin were 23.5%, 11.7%, and 3.9%, respectively. All strains carried vacA genotype, and 51%, 70.4%, 49%, 34.7%, and 25.5% were cagA-, cagE-, babA2-, iceA1-, and iceA2-positive, respectively. Of those 98 specimens, 81.6%, 19.4%, 38.8%, and 63.3% carried vacAs1, vacAs2, vacAm1, and vacAm2, respectively. Dominant vacA type was s1am2 (32.7%), followed by s1am1 (14.3%) and s2m2 (12.2%). Significant rates of clarithromycin resistance were observed in cagE-, iceA1-, babA2-, and vacAs1c-positive groups. In those with metronidazole resistance, vacAs1 and vacAs1c were more common (P < 0.05).

CONCLUSIONS

The cagE-positive and vacA s1a/m2 genotypes, which are correlated with increased antibiotic resistance, were predominant in our population. In countries where Hp infection is prevalent, studies focusing on virulence factors and antibiotic susceptibility may provide anticipation of the prognosis and may be helpful to reduce morbidity and mortality.

Changing pattern of antibiotic resistance of Helicobacter pylori in children during 20 years in Jinju, South Korea

BACKGROUND

The antimicrobial resistance capability of Helicobacter pylori is one of the critical factors in the failure to treat this pathogen. The purpose of this study was to investigate the changing pattern of primary antibiotic resistance rates in children in the southern central part of South Korea from 1990 to 2009.

METHODS

H. pylori strains were isolated from children who had undergone upper endoscopy at Gyeongsang National University Hospital, including 58 children from 1990-1994 and 33 children from 2005-2009. The susceptibility of H. pylori strains to erythromycin, clarithromycin, azithromycin, amoxicillin, tetracycline, metronidazole, furazolidone, levofloxacin, ciprofloxacin, moxifloxacin, and rifabutin was tested using the serial twofold agar dilution method.

RESULTS

The resistance rate to erythromycin increased significantly from 13.8% in 1990-1994 to 33.3% in 2005-2009 (P = 0.032). Clarithromycin resistance increased from 6.9% to 18.2%. Metronidazole resistance decreased from 32.8% to 27.3%. The minimum inhibitory concentration of azithromycin and erythromycin showed definite shifts to higher concentrations in 2005-2009 compared with the strains sampled in 1990-1994 (P = 0.021 and P = 0.025, respectively). The frequency of both macrolide- and metronidazole-resistant strains was 13.8% in 1990-1994 and 15.2% in 2005-2009. No associations were detected between multidrug-resistant strains and the two study periods.

CONCLUSIONS

The antibiotic resistance rates of H. pylori in Jinju had a different pattern to other regions. The antibiotic resistance rates of H. pylori showed geographic variation, and local data should be provided as a guideline for treating H. pylori infection.

Detection of clarithromycin-resistant Helicobacter pylori by stool PCR in children: a comprehensive review of literature

BACKGROUND

Helicobacter pylori infection is acquired mainly during childhood. To eradicate H. pylori, clarithromycin-based triple therapy has been recommended in children and adults by the latest Maastricht Consensus. However, the prevalence of clarithromycin-resistant H. pylori was higher in children than that in adults. Therefore, rapid, reliable and noninvasive methods for detecting clarithromycin-resistant H. pylori strains should be developed for children.

MATERIALS AND METHODS

Studies on evaluating stool PCR in detecting clarithromycin-resistant H. pylori and epidemiological surveys of the prevalence of clarithromycin-resistant H. pylori in children were searched in PubMed (from 1966 to December, 2011) for reviewing.

RESULTS

The average rates of primary clarithromycin-resistant H. pylori ranged from less than 10% to more than 40% in different regions. The rates of secondary resistance to clarithromycin were higher than primary resistance in the same population. In H. pylori isolated from children, the frequent point mutations that are responsible for the clarithromycin resistance included A2143G, A2142G, A2142C and A2144G, and they varied geographically. Comparing with culture-based susceptibility tests, stool PCR performed excellently for their rapidity, independence of bacterial growth, reproducibility and easy standardization. However, stool PCR showed lower sensitivity but perfect specificity in detection of clarithromycin-resistant H. pylori in children. Methodology and mixed infections of resistant H. pylori strains might contribute to the considerable discrepancies of stool PCR results.

CONCLUSION

Detection of clarithromycin-resistant H. pylori by stool PCR for children are reliable, rapid, noninvasive methods that are worthy of further clinical promotion. However, more evaluations of stool PCR in detection of clarithromycin-resistant H. pylori in children need to be conducted.

Antibiotic resistance of Helicobacter pylori in pediatric patients -- 10 years' experience

The aim of this study was to assess the pattern of evolution of resistance to antibiotics in Helicobacter pylori isolated from children who underwent upper endoscopy with antral biopsy during a 10-year period (2001-2010). We retrospectively analyzed data of all children (n = 3,008) who underwent upper endoscopy during the observed period at the Children's Hospital Zagreb, a university tertiary medical center. We calculated the rate, antibiotic susceptibility and risk factors for the H. pylori infection in our cohort. Antral biopsy was performed in 2,313 (76.89%) patients. Altogether, 382 (16.51%) children had positive biopsy for H. pylori (histology and/or culture). There was no significant difference in the incidence of H. pylori during 10 years of observation (p = 0.21). Infected children compared to non-infected group were older (p = 0.005), and had more often antral nodularity (p < 0.0001), and duodenal ulcer (p = 0.002). Altogether, 22.4% of treatment-naïve patients had strains resistant to tested antibiotics: majority to azithromycin (17.9%), followed by clarithromycin (11.9%), metronidazole (10.1%) and amoxicillin (0.6%). In the eradication failure group, 9/11 of children had strains resistant to tested antibiotics, mostly to metronidazole (7/11), followed by azithromycin (3/11) and clarithromycin (1/11). No correlation was found between age or gender and antibiotic resistance (p = 0.32, for both). In conclusion, our data strongly support current guidelines which recommend antibiotic susceptibility testing prior to eradication therapy. Based on our results we recommend the use of amoxicillin-metronidazole-based regimen as the first-line therapy in our study population.

Eradication of Helicobacter pylori in children in Vietnam in relation to antibiotic resistance

BACKGROUND

Low Helicobacter pylori eradication rates are common in pediatric trials especially in developing countries. The aim of the study was to investigate the role of antibiotic resistance, drug dosage, and administration frequency on treatment outcome for children in Vietnam.

MATERIALS AND METHODS

 Antibiotics resistance of H. pylori was analyzed by the Etest in 222 pretreatment isolates from children 3-15 years of age who were originally recruited in a randomized trial with two treatment regiments: lansoprazole with amoxicillin and either clarithromycin (LAC) or metronidazole (LAM) in two weight groups with once- or twice-daily administration. The study design was an observational study embedded in a randomized trial.

RESULTS

 The overall resistance to clarithromycin, metronidazole, and amoxicillin was 50.9%, 65.3%, and 0.5%, respectively. In LAC, eradication was linked to the strains being susceptible to clarithromycin (78.2% vs 29.3%, p = .0001). Twice-daily dosage of proton-pump inhibitor (PPI) and clarithromycin was more effective for eradication than once-daily dosage for resistant strains (50.0% vs 14.7%, p = .004) and tended to be so also for sensitive strains (87.5% vs 65.2%, p = .051). Exact antibiotic dose per body weight resulted in more eradication for resistant strains (45.3% vs 8.0%, p = .006). These differences were less pronounced for the LAM regimen, with twice-daily PPI versus once daily for resistant strains resulting in 69.2% and 50.0% eradication (p = .096), respectively.

CONCLUSIONS

 Helicobacter pylori clarithromycin resistance was unexpectedly high in young children in Vietnam. Clarithromycin resistance was an important cause for eradication treatment failure. Twice-daily administration and exact antibiotic dosing resulted in more eradicated infections when the strains were antibiotic resistant, which has implications for the study design in pediatric H. pylori eradication trials.

Monitoring of antibiotic resistance rates of Helicobacter pylori in Austrian children, 2002-2009

We retrospectively studied antibiotic resistance rates of H. pylori and their temporal changes in children. Resistance rates were 21.6% for both clarithromycin and metronidazole. There was no overall difference between children with or without migrational background. Resistance rates increased over time, and patients without migrational background showed a significant increase in metronidazole resistance. Our study emphasizes antibiotic resistance monitoring of H. pylori in children.

Geographic map and evolution of primary Helicobacter pylori resistance to antibacterial agents

Antibiotic resistance in Helicobacter pylori is the major cause of eradication failure. Primary H. pylori susceptibility patterns, however, are becoming less predictable. Currently, high (> or =20%) clarithromycin resistance rates have been observed in the USA and in developed countries in Europe and Asia, while the highest (> or =80%) metronidazole-resistance rates have been reported in Africa, Asia and South America. Primary quinolone-resistance rates of 10% or more have already been reported in developed countries in Europe and Asia. Primary amoxicillin resistance has been low (0 to <2%) in Europe but higher (6-59%) in Africa, Asia and South America. Similarly, tetracycline resistance has been absent or low (<5%) in most countries and higher (9-27%) in Asia and South America. The increasing clarithromycin and quinolone resistance, and multidrug resistance detected in 0 to less than 5% in Europe and more often (14.2%) in Brazil are worrying. Growing resistance often parallels national antibiotic consumption and may vary within patient groups according to the geographic region, patient's age and sex, type of disease, birthplace, other infections and other factors. The geographic map and evolution of primary H. pylori resistance are clinically important, should be considered when choosing eradication regimens, and should be monitored constantly at national and global levels in an attempt to reach the recently recommended goal of eradication of more than 95%.

Time trends of Helicobacter pylori resistance to antibiotics in children living in Vienna, Austria

BACKGROUND

Increase of antibiotic resistance is a worldwide problem. Within the 4 years before the turn of the millennium Helicobacter pylori strains isolated in children living in Vienna, Austria, showed a primary clarithromycin and metronidazole resistance of 20% and 16%, respectively. The aim of this retrospective follow-up survey was to assess the further development and current antimicrobial resistance status.

METHODS

Children having undergone upper endoscopy between March 2002 and March 2008 at the same two co-operating pediatric gastroenterology units which had also been collaborating on the prior assessment were included. H. pylori infection was diagnosed by rapid urease test, histology, and culture. If the latter was positive, susceptibility testing to amoxicillin, clarithromycin and metronidazole by E-test followed. From March 2004 onwards, susceptibility to levofloxacin, tetracycline and rifampin was additionally assessed.

RESULTS

Out of 897 children, 153 had a proven infection with H. pylori and no history of prior eradication treatment. Their median age was 11.5 years (range 0.5-20.9 years). Primary resistance to clarithromycin and metronidazole were 34% and 22.9%, respectively; dual resistance was found in 9.8% of the strains; 0.9% was resistant to tetracycline and rifampin, respectively. No case of amoxicillin resistance was detected. The only independent risk factor for clarithromycin resistance turned out to be the origin of a child from Austrian parents.

CONCLUSIONS

In the last decade, the rate of primary resistance of H. pylori to clarithromycin continued to rise. No significant change was found regarding primary resistance to metronidazole or dual resistance to metronidazole and clarithromycin, respectively.

Antibiotic resistance of Helicobacter pylori in Israeli children

OBJECTIVES

To determine the antibiotic susceptibility of Helicobacter pylori isolates from Israeli children; assess the role of previous antibiotic use in the development of antibiotic resistance and examine the possibility of simultaneous colonization of strains with different resistance patterns in the same patients.

MATERIAL AND METHODS

A prospective case-series design was used. The study group included 174 patients aged 1-18 years referred to the Schneider Children's Medical Center of Israel for gastroscopy over a 2.5-year period. Antibiotic susceptibility to amoxicillin, clarithromycin, metronidazole, tetracycline, and levofloxacin was determined by E-test on gastric biopsies (2 per patient). Clinical and demographic data were obtained by questionnaire.

RESULTS

Cultures for H. pylori yielded 55 isolates from 53 children. In treatment-naïve children, the prevalence rate of primary resistance to clarithromycin was 25% and to metronidazole, 19%. Respective rates in children previously treated for H. pylori infection were 42% (p = 0.22) and 52% (p = 0.016). Simultaneous resistance to both drugs was found in 13% of isolates (n = 7), all from children with previous treatment failure. No resistance was found to amoxicillin, tetracycline or levofloxacin. Clarithromycin resistance was associated with macrolide use for any indication during the previous year (p = 0.033). In 2 patients (3.8%), a different H. pylori strain was cultured from each biopsy.

CONCLUSIONS

H. pylori resistance to clarithromycin and metronidazole is high in Israeli children, particularly in those previously treated for H. pylori infection, in whom culture-based treatment should be considered. The simultaneous colonization of multiple strains in a minority of patients needs to be further characterized.

In vitro activity of Impatiens balsamina L. against multiple antibiotic-resistant Helicobacter pylori

Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures, and fingernail inflammation. In this study, anti-H. pylori activity of I. balsamina L. was investigated. The MICs, MBCs, time-kill assay, and effect of environmental pH for the plant extracts were determined. The test H. pylori strains have resistance to clarithromycin (CLR), metronidazole (MTZ), and levofloxacin (LVX). From our results, all part (root/stem/leaf, seed, and pod) extracts of I. balsamina L. exhibited bactericidal H. pylori activity. Specifically, the pod extract had significantly lower MICs and MBCs (1.25-2.5 and 1.25-5.0 microg/ml, respectively). Of the five pod-extraction solvents, both ethyl acetate and acetone were the most efficient for the anti-H. pylori compounds of the pod extraction. The dose-dependency of the pod extract's bactericidal activity was H. pylori strain-dependent. Bactericidal H. pylori activity of the pod extract was not affected by the environmental pH (2-8). In summary, the acetone and ethyl acetate pod extracts of I. balsamina L. exhibited very strong anti-H. pylori activity. This activity exceeded that of MTZ and approximated to that of AMX.

Clarithromycin resistance of Helicobacter pylori strains isolated from children' gastric antrum and fundus as assessed by fluorescent in-situ hybridization and culture on four-sector agar plates

AIM

To assess validity of culture on four-sector agar plates and fluorescent in-situ hybridization (FISH) test, and clarithromycin resistance rate in Helicobacter pylori strains isolated from children in the last 10 years.

METHODS

In the last 5 years, gastric biopsy specimens from antrum and fundus were taken from 89 consecutive children (median age 9 years) with H. pylori gastritis and from 21 controls. Culture was performed on 176 gastric biopsies (89 from antrum, 87 from fundus) on four-sector agar plates, and FISH test with DNA ProbeMix. After its validity was evaluated, FISH test was applied on additional 119 biopsies from 68 children (68 from the antrum, 51 from the fundus) stored in the Pathology archive in the previous 5 years.

RESULTS

Culture was positive in 157 of 176 biopsies (sensitivity: 89.2%, 95% confidence interval (CI) 85-94). In 33 of 89 children (37%) resistant strains were found in one or both gastric sites. FISH test was positive in 148 of 176 biopsies from infected children (sensitivity 84.1%, 95%CI 79-89) and in none of 42 biopsies from controls (specificity 100%). When applied on archive biopsies, FISH test was positive in 96 of 119 (80.7%, 95%CI 74-88). Total children harboring resistant strains in the last 10 years, as assessed by FISH test, were 66 of 157 (42%). Mixed infection with both sensitive and resistant strains were found in 40 children (25%) and in 12 of them resistant strains were in the fundus only.

CONCLUSIONS

Culture on four-sector agar plates and FISH test had a high sensitivity and specificity and showed co-presence of sensitive and resistant strains. In one-third of children with mixed infection, the resistant strains were in the fundus only. Clarithromycin resistance should be assessed in biopsies both from the antrum and the fundus, utilizing antral biopsies only can underestimate its prevalence.

Helicobacter pylori infection in children: management and pharmacotherapy

Helicobacter pylori infection is mainly acquired during childhood: it is recognised as a cause of gastritis and peptic ulcer and it has been classified as a group A carcinogen by the World Health Organisation. The exact mode of transmission is as yet unknown. The aim of this review was to analyse the literature about H. pylori infection in paediatric patients. The large diffusion of H. pylori infection in paediatric patients, the absence of a specific clinical feature, the new non-invasive methods for diagnosis and follow-up, which are still not validated and the different therapeutic schedules have led to the necessity of determining the real clinical outcome in affected children and adolescents. The scope of the review was to identify better eradication therapy and the most important factors in treatment failure. The international literature has shown the importance of culture, antibiograms, the compliance of families and patients and the use of probiotics during triple eradication therapy. The review paid attention to the management, diagnostic techniques and therapy of this infection in paediatric patients.

Helicobacter pylori vaccine: from past to future

Helicobacter pylori infection is highly prevalent worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma (MALToma), and gastric adenocarcinoma. Infection is usually acquired during childhood and tends to persist unless treated. Because eradication requires treatment with multidrug regimens, prevention of initial infection by a suitable vaccine is attractive. Although immunization with H pylori protein subunits has been encouraging in animals, similar vaccine trials in humans have shown adjuvant-related adverse effects and only moderate effectiveness. Newer immunization approaches (use of DNA, live vectors, bacterial ghosts, and microspheres) are being developed. Several questions about when and whom to vaccinate will need to be appropriately answered, and a cost-effective vaccine production and delivery strategy will have to be useful for developing countries. For this review, we searched MEDLINE using the Medical Subject Heading (MeSH) terms Helicobacter pylori and vaccines for articles in English from 1990 to 2007.

Prevalence and evolution of Helicobacter pylori resistance to 6 antibacterial agents over 12 years and correlation between susceptibility testing methods

The aim of this study was to evaluate Helicobacter pylori antibacterial resistance in 2005 to 2007, resistance evolution since 1996 to 1999, and performance of breakpoint susceptibility testing (BST) compared with E test for clarithromycin or agar dilution method (ADM) for metronidazole, amoxicillin, tetracycline, and ciprofloxacin. Resistance in 613 untreated adults, 91 treated adults, and 75 untreated children was 25%, 48.4%, and 16% for metronidazole; 17.8%, 45.1%, and 18.7% for clarithromycin; 4.4%, 13.3%, and 2.7% for tetracycline; and 7.7%, 18.2%, and 6.8% for ciprofloxacin, respectively. Resistance to amoxicillin (0.9%) and nitrofurantoin (1.3%) was uncommon. Three strains (0.4%) exhibited triple resistance to amoxicillin, metronidazole, and clarithromycin. Primary resistance rates in adults and children were comparable. Metronidazole resistance was less common in ulcer adults than in the rest. Primary clarithromycin resistance increased significantly from 10% in 1996 to 1999 to 17.9% in 2005 to 2007. Many strains (26.4%) from treated adults showed resistance to metronidazole and clarithromycin. Category agreement between the BST and E test or ADM results was good (93.3-100%). In conclusion, the increasing clarithromycin resistance and presence of multidrug resistance are worrying. Fluoroquinolones should be used with caution for H. pylori eradication in treated patients.

Eradication therapy for Helicobacter pylori

Eradication therapy for Helicobacter pylori is recommended in a number of clinical conditions. In this article, we discuss the epidemiology and cellular mechanisms that result in antimicrobial resistance, the results of current eradication therapies, and new approaches to the management of Helicobacter pylori infection.

Helicobacter pylori primary resistant strains over 11 years in French children

The yearly prevalence between 1994 and 2005 of primary resistance to amoxicillin, metronidazole, and clarithromycin of 377 Helicobacter pylori strains isolated from children was studied. All the H. pylori strains were susceptible to amoxicillin, 138/377 (36.7%) were resistant to metronidazole, 86/377 (22.8%) to clarithromycin, and 30/377 (7.9%) to both metronidazole and clarithromycin. Over the entire period, resistance to clarithromycin did not change, whereas metronidazole resistance decreased significantly from 43.3% (1994-1998) to 32% (1999-2005), P = 0.001.

Clarithromycin resistance in Helicobacter pylori strains isolated from French children: prevalence of the different mutations and coexistence of clones harboring two different mutations in the same biopsy

BACKGROUND

The aim of our study was to assess the different mutations involved in clarithromycin-resistant Helicobacter pylori strains isolated from French children and their temporal trends.

METHODS

The point mutations of H. pylori were detected by PCR followed by RFLP technique in 50 clarithromycin-resistant strains collected between 1993 and 2004 in France.

RESULTS

Clarithromycin resistance was observed in 23% (50/217) of H. pylori isolates. Two mutations A2143G and A2142G in the 23S rRNA genes of H. pylori were detected. The former was found in 45/50 (90%) of isolates. The rate of resistance increased with time from 18.6% in the period 1993-1996 to 41.6% in 2001-2004. No significant difference was observed in the distribution of mutations during the same periods. No correlation was found between any mutation and age, sex, and ethnic origin of children. Furthermore, no significant differences in minimal inhibitory concentrations level were observed according to the different point mutations. In all cases, only one point mutation was present, except in two cases where two different mutations were found in two different clones from the same biopsy.

CONCLUSION

The mutation A2143G is predominant in clarithromycin-resistant H. pylori strains isolated from children in France. We report for the first time the presence of two clarithromycin-resistant clones harboring two different mutations of the 23S rRNA genes present in the same biopsy specimen and genotypically identical as demonstrated by RAPD fingerprinting.