Antimicrobial resistance in Helicobacter pylori isolates from children

Helicobacter pylori antimicrobial resistance in Melbourne, Australia. Time to review therapeutic guidelines?

BACKGROUND

Antimicrobial resistance (AMR) in Helicobacter pylori is a global concern. The AMR data to inform the Australian Therapeutic Guidelines is based upon data over 20 years old.

AIMS

To evaluate the frequency of antimicrobial resistance in H. pylori isolates from gastric biopsy specimens received in our laboratory in Melbourne, Australia To review the literature on resistance rates in Australia and compare historic data.

METHODS

A retrospective, observational study summarising AMR rates in all H. pylori isolates from our laboratory from 2015 to June 2020.

SETTING

Microbiology laboratory in metropolitan Melbourne, Australia, receiving referrals from private hospitals, gastroenterology clinics, and endoscopy suites.

OUTCOME MEASURES

Population minimum inhibitory concentration distributions and frequency of resistance to clarithromycin, amoxicillin, metronidazole, and tetracycline in H. pylori isolates.

RESULTS

386 H. pylori isolates with susceptibility testing data were identified. The frequency of resistance in this cohort was: clarithromycin 89.9%, amoxicillin 23.5%, metronidazole 66.1%, and tetracycline 4.4%. Comparison with historical data may suggest increasing AMR rates in Australia. Main limitation is lack of treatment history to correlate AMR results.

CONCLUSIONS

Definitive conclusions from this cohort cannot be made, but trends suggest rising levels of primary H. pylori AMR rates in Australia. This has important implications for empirical treatment decision making and treatment outcomes. Primary H. pylori AMR requires dedicated studies and current Australian therapeutic guideline recommendations may require re-evaluation. We propose considerations for improving the management of H. pylori in Australia. A centralised public health approach to H. pylori AMR surveillance should be established. This article is protected by copyright. All rights reserved.

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.

High Helicobacter pylori resistance to metronidazole and clarithromycin in Brazilian children and adolescents

OBJECTIVE

The aim of the present study was to assess the primary and secondary resistance of Helicobacter pylori strains to clarithromycin, amoxicillin, furazolidone, tetracycline, and metronidazole, the conventional antibiotics presently used in Brazilian children and adolescents.

METHODS

Seventy-seven consecutive H pylori strains, 71 of 77 strains obtained from patients without previous eradication treatment for H pylori infection, and 6 strains from patients in whom previous eradication treatment had failed.

RESULTS

Global rate of resistance was 49.3% (38/77): 40% of strains were resistant to metronidazole, 19.5% to clarithromycin, and 10.4% to amoxicillin. All of the tested H pylori strains were susceptible to furazolidone and tetracycline. Multiple resistance were detected in 18.2% (14/77 patients) of the strains: 6 of 14 (43%) simultaneously resistant to clarithromycin and metronidazole; 5 of 14 (36%) to amoxicillin and metronidazole; 2 of 14 (14%) to amoxicillin, clarithromycin, and metronidazole; and 1 of 14 (7%) to clarithromycin and amoxicillin.

CONCLUSIONS

The high resistance rate to metronidazole and clarithromycin observed in clinical H pylori isolates can exclude these antimicrobials in empirical eradication treatment in Brazil. Otherwise, furazolidone and tetracycline presented no resistance. Properly assessing the risks and benefits, these 2 antimicrobials and their derivatives could be used in empirical eradication schedules, both associated with amoxicillin, which showed a low resistance rate despite its wide use in pediatric patients.

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.

Efficacy of two triple eradication regimens in children with Helicobacter pylori infection

Triple therapy with bismuth subsalicylate, amoxicillin, metronidazole (BAM) or with omeprazole, amoxicillin, clarithromycin (OAC) has been commonly used for the eradication of Helicobacter pylori infection. We compared the efficacy of these triple therapies in children with H. pylori infection. We retrospectively analyzed results in 233 children with H. pylori infection and treated with OAC (n=141) or BAM (n=92). Overall eradication rates of triple therapy with OAC and BAM were 74% and 85%, respectively, which showed no statistical difference. Our study showed that the triple therapy with BAM was more effective for the first-line eradication of H. pylori infection in Korean children, but has no statistical difference with OAC regimen.

Gastroduodenal diseases of childhood

PURPOSE OF REVIEW

This paper will review new developments in the etiology and management of gastric and duodenal diseases affecting children.

RECENT FINDINGS

Despite dropping prevalence rates in developed nations, most new Helicobacter pylori infections are primarily acquired during childhood. Resistance to standard triple therapy and falling eradication rates are increasing problems for clinicians, necessitating the study of alternative treatment strategies. Eosinophilic diseases of the gastrointestinal tract are being increasingly recognized. Although population-based epidemiology and the natural history of eosinophilic diseases are not yet fully characterized, biologic therapies are in development for the treatment of these chronic, often refractory, conditions. A recent US National Institutes of Health celiac disease consensus conference suggested that infants' diet constituents and timing of solid food introduction are potential environmental influences in the development of celiac disease.

SUMMARY

New methods of diagnosis and treatment are greatly impacting care of pediatric patients with gastric and duodenal diseases. Less invasive but highly accurate tools for diagnosis are becoming better validated. Early diagnosis and effective intervention in most gastroduodenal disorders of childhood can alter natural history and improve overall quality of life.

Cellular mucosal defense during Helicobacter pylori infection: a review of the role of glutathione and the oxidative pentose pathway

Helicobacter pylori is the primary cause of gastritis and peptic ulcer disease and is known to infect greater than 50% of the world's population. It is also known to lead to the onset of gastric cancer and unless treated, lasts throughout life in most individuals. Mouse models of H. pylori infection have improved our ability to study this organism and can be used to investigate the host mucosal response to the infection, particularly the early events postinoculation. Previous studies have shown that H. pylori infection leads to an increased production of reactive oxygen species within the gastric mucosa which are thought to play a major role in the mediation of associated disease. Recent studies have shown differences in the availability of an important antioxidant, glutathione, during chronic H. pylori infection. The availability of glutathione is primarily controlled by the activity of the oxidative pentose pathway. This review proposes that the severity of inflammation and damage associated with H. pylori infection is dependent on the ability of mucosal cells to counteract the increased load of reactive oxygen species. It is hypothesized that the oxidative pentose pathway and glutathione availability are important factors modulating this response. It is suggested that the therapeutic regulation of glutathione availability could provide a novel method for preventing or reducing the damage caused during H. pylori infection.

Molecular biology methods for the characterization of Helicobacter pylori infections and their diagnosis

Helicobacter pylori infects approximately half of the human population; however, the outcome of infection is affected by many factors, including strain and host genotype characteristics and bacterial density within the stomach. Many molecular methods have been developed to provide information with respect to these characteristics. Methods that provide results within 24 h of endoscopy may be used to develop individualized treatment that is more effective, results in fewer side effects, cuts costs,decreases the number of treatment failures and results in the development of fewer antibiotic-resistant H. pylori strains.

Acidified litter benefits the intestinal flora balance of broiler chickens

The alterations in the balance of the normal intestinal bacterial flora of chickens exposed to acidified wood-derived litter were analyzed and compared to those of a control group exposed to nonacidified litter. A total of 1,728 broilers were divided into two groups, with six replicates in each. One group was exposed to dry wood-derived litter, and the other was exposed to dry wood-derived litter sprayed with a mixture of sodium lignosulfonate, formic acid, and propionic acid. At five different times, five chickens from each pen were killed and the intestinal contents from ileum and caeca were collected. The samples were diluted and plated onto selective media to identify coliforms, Lactobacillus spp., Clostridium perfringens, and Enterococcus spp. Covariance analysis of bacterial counts showed significantly lower counts for C. perfringens in the caeca and the ileum and for Enterococcus spp. and Lactobacillus spp. in the ileum in chickens exposed to the acidified litter. Lactobacillus spp. showed significantly higher counts in the caeca in chickens exposed to acidified litter. There was no difference between the two litters with regard to coliforms in the ileum and the caeca or to Enterococcus spp. in the caeca. The study shows that exposing the chickens to acidified litter lowers the intestinal bacterial number, especially in the ileum, without negative consequences for the chicken's health or performance. Of special interest are the lower counts of C. perfringens and Enterococcus spp. that might reduce the risk of developing clinical or subclinical necrotic enteritis and growth depression.

Risk factors for primary Helicobacter pylori resistance in Bulgarian children

Risk factors for primary Helicobacter pylori resistance in 186 children with gastroduodenal diseases (44 from villages/small towns and 130 from large towns/cities) in 2000-2003 were tested. Susceptibility was tested by a limited agar dilution method. Overall resistance rates to metronidazole, clarithromycin, tetracycline and both metronidazole and clarithromycin were 14.5, 11.9, 3.3 and 4.3 %, respectively. No amoxycillin resistance was observed. Tetracycline resistance was found in six children aged 7-18 years. Clarithromycin resistance was more common in children from small towns/villages (22.7 %) than in those from large towns/cities (8.5 %, P < 0.05). There were no significant differences (P > 0.05) in resistance rates between children from northern Bulgaria and those from southern regions. Resistance rates in duodenal ulcer patients and other children were, respectively, 10.5 and 15 % (P > 0.20) for metronidazole and 10.5 and 12 % (P > 0.20) for clarithromycin. No combined resistance to metronidazole and clarithromycin was found in 22 children aged 1-7 years and in 34 children living in northern Bulgaria. There were no significant associations of resistance with sex and age group (1-7- versus 8-18-year-old children) for all antibacterial agents tested. In conclusion, primary H. pylori resistance was absent (for metronidazole + clarithromycin) or low (4.5 % for clarithromycin) in children aged 1-7 years. Place of residence was associated with clarithromycin resistance rates.

Helicobacter pylori infection in pediatrics

The proposed route of Helicobacter pylori transmission appears to be fecal-oral, oral-oral and gastro-oral, yet, a number of studies challenged these hypotheses in 2003. The use of the stool antigen test and[13]-C urea breath testing were the tests of choice for diagnosis and 'test for cure' of H. pylori in Europe in 2003 but have not yet become accepted standard of care in North America. Pediatric H. pylori consensus guidelines are not yet revised; upper endoscopy and biopsy remain the gold standard for diagnosis of pediatric H. pylori infection. In addition to stronger evidence supporting the role of host influences of H. pylori-associated gastric cancer risk, compelling evidence was provided for the role of H. pylori in iron deficiency anemia of childhood. Antibiotic resistance remains a problem in conferring treatment failure and 2003 studies indicate that macrolide resistance is higher in children than in adults. Treatment with proton pump inhibitor-based triple therapy for 10-14 days remains the mainstay for eradication of H. pylori in childhood. Finally, multinational studies are needed to develop screening guidelines for childhood infection to avoid long-term severe gastroduodenal disease sequelae.