Twelve year observation of primary and secondary antibiotic-resistant Helicobacter pylori strains in children

Antibiotic resistance, heteroresistance, and eradication success of Helicobacter pylori infection in children

BACKGROUND

Antibiotic resistance is a well-known factor of Helicobacter pylori eradication failure. Heteroresistance indicates the coexistence of resistant and susceptible strains and might lead to underestimating antimicrobial resistance. This study aims to evaluate the susceptibility profile, the frequency of heteroresistance of H. pylori strains, and their effect on eradication success in a pediatric population.

MATERIALS AND METHODS

Children aged 2-17 years who underwent an upper gastrointestinal endoscopy from 2011 to 2019 with positive H. pylori status were included. Susceptibility was measured by disk diffusion and E-test. The difference in susceptibility profiles between isolates from the antrum and the corpus was used to detect heteroresistance. For those who received eradication treatment, we evaluated eradication rate and factors affecting treatment success.

RESULTS

Inclusion criteria were met by 565 children. Strains susceptible to all antibiotics were detected in 64.2%. Primary resistance rates for clarithromycin (CLA), metronidazole (MET), levofloxacin (LEV), tetracyclin (TET), and amoxicillin (AMO) were 11%, 22.9%, 6.9%, 0.4%, and 0% and secondary resistance rates were 20.4%, 29.4%, 9.3%, 0%, and 0%. Heteroresistance was present in untreated children in 2%, 7.1%, 0.7%, 0.7%, and 0% for CLA, MET, LEV, TET, and AMO. First-line eradication rates were 78.5% in intention-to-treat (ITT), 88.3% in full-analysis-set (FAS), and 94.1% in per-protocol (PP). Factors affecting eradication success were the duration of treatment when the triple-tailored treatment was used, the number of daily doses of amoxicillin administered, and the patient's adherence to treatment.

CONCLUSIONS

This study shows the presence of relatively low primary resistance rates for H. pylori isolates but demonstrates the presence of heteroresistance in our population. Routine biopsies from the antrum and corpus must be considered for susceptibility testing to allow tailored treatments and increase eradication rates. Treatment success is affected by treatment choice, correct dosing of medications, and adherence. All these factors should be considered when evaluating the efficacy of an eradication regimen.

Plant-mediated synthesis of silver-doped zinc oxide nanoparticles and evaluation of their antimicrobial activity against bacteria cause tooth decay

In this research, silver-doped zinc oxide (SdZnO) nanoparticles (NPs) were synthesized in an environmental-friendly manner. The synthesized NPs were identified by UV-vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Finally, the antimicrobial activity of synthesized ZnO and SdZnO NPs was performed. It was observed that by doping silver, the size of ZnO NPs was changed. By adding silver to ZnO NPs, the antimicrobial effect of ZnO NPs was improved. Antibacterial test against gram-positive bacterium Streptococcus mutants showed that SdZnO NPs with a low density of silver had higher antibacterial activity than ZnO NPs; Therefore, SdZnO NPs can be used as a new antibacterial agent in medical applications.

Epidemiology, Diagnosis and Risk Factors of Helicobacter pylori Infection

Helicobacter pylori is a human-specific pathogen, which leads to gastric pathologies including gastric cancer. It is a highly unique bacterium considered as a carcinogenic agent. H. pylori remains a major human health problem, responsible for ~90% of the gastric cancer cases. Approximately four billion individuals have been detected for H. pylori infection worldwide in 2015. At the turn of the twenty-first century, the prevalence of H. pylori has been declining in highly industrialized countries of the Western world, whereas prevalence has plateaued at a high level in developing and newly industrialized countries. However, the infection status remains high in immigrants coming from countries with high prevalence of H. pylori infection. H. pylori can be diagnosed both by invasive and non-invasive methods. Urea breath test and stool antigens detection are among the most commonly used non-invasive ones. Although the way H. pylori is transmitted remains still not fully clear, the level of contamination is strongly dependent on the familial and environmental context, with a drastic impact of living conditions with poor hygiene and sanitation. However, familial socioeconomic status is the main risk factor for H. pylori infection among children. In addition, food and water source have a high impact on the prevalence of H. pylori infection worldwide. This chapter highlights the latest knowledge in the epidemiology of H. pylori infection, its diagnosis and critical risk factors responsible for its high prevalence in some populations and geographic areas.

Helicobacter pylori Infection in Pediatric Patients: Update on Diagnosis and Eradication Strategies

Helicobacter pylori infection is acquired mainly in childhood and remains an essential cause of peptic ulcer disease and gastric cancer. This article provides commentary on the last ESPGHAN/NASPGHAN guidelines and on publications made after the consensus conference of 2015. The majority of infected children are asymptomatic and pediatric studies do not support a role for H. pylori in functional disorders such as recurrent abdominal pain. The role of H. pylori infection in failure to thrive, children's growth, type I diabetes mellitus (T1DM), and celiac disease remains controversial. The diagnosis of infection should be based on upper-digestive endoscopy with biopsy-based methods. Eradication control after treatment should be based on validated non-invasive tests. Nodular gastritis is the main endoscopic finding of childhood H. pylori infection, but gastroduodenal erosions/ulcers are seen in some children, especially after 10 years of age. When indicated, eradication treatment should be given when good compliance is expected and based on the antimicrobial susceptibility profile.

Increasing metronidazole and rifampicin resistance of Helicobacter pylori isolates obtained from children and adolescents between 2002 and 2015 in southwest Germany

BACKGROUND

Increasing antibiotic resistance has been reported for Helicobacter pylori, but data on the prevalence of antibiotic resistance of H. pylori in pediatric patients and the development of resistance over time are sparse.

METHODS

Data for 610 H. pylori isolates obtained between 2002 and 2015 from gastric biopsies of 582 (mainly treatment-naïve) pediatric patients from southwest Germany were analyzed retrospectively regarding the antibiotic susceptibility determined by Etest and patients' characteristics.

RESULTS

Overall resistance to metronidazole, clarithromycin, and rifampicin was 28.7%, 23.2%, and 13.3%, respectively, while resistance to amoxicillin was rare (0.8%). Simultaneous resistance to metronidazole and clarithromycin was observed for 7.7% of the isolates, and 2.3% were resistant to metronidazole, clarithromycin, and rifampicin. Differences between primary vs secondary resistance existed for metronidazole (24.7% vs 38.8%, P=.01) and clarithromycin (17.2% vs 54.1%, P=.0001). From 2002-2008 to 2009-2015, resistance to metronidazole increased from 20.8% to 34.4% (P=.003) and to rifampicin from 3.9% to 18.8% (P=.0001); this was not associated with increased numbers of patients previously treated for H. pylori infection in the second study period. In contrast, resistance to clarithromycin did not change significantly over time. Resistance was not associated with age, sex, or family origin in Europe.

CONCLUSIONS

The considerable antibiotic resistance of H. pylori isolates argues for standard antibiotic susceptibility testing of H. pylori in pediatric patients prior to the initiation of antibiotic therapy.

Sequential Therapy for Helicobacter pylori Infection in Treatment-naïve Children

The goal of first-line Helicobacter pylori therapy is to reach an eradication rate of 90% to avoid further investigations, antibiotic use, and spreading of resistant strains.

AIM

To evaluate the eradication rate of high-dose sequential therapy in treatment-naïve children and to assess factors associated with failure.

METHODS

Prospective data assessed in a registry from nine European centers between October 2009 and December 2011. Children with biopsy-proven Helicobacter pylori infection were prescribed 5 days of esomeprazole and amoxicillin, followed by 5 days of esomeprazole, clarithromycin, and metronidazole according to bodyweight. Eradication was assessed after 8-12 weeks. Primary endpoint was the eradication rate in children who received at least one dose and had follow-up data. Multivariate analysis evaluated potential factors for treatment success including sex, age, center, migrant status, antibiotic resistance, and adherence to therapy.

RESULTS

Follow-up was available in 209 of 232 patients (age range 3.1-17.9 years, 118 females). Primary resistance occurred for clarithromycin in 30 of 209 (14.4%), for metronidazole in 32 (15.3%), for both antibiotics in 7 (3.3%), and culture failed in 6 (2.9%). Eradication was achieved in 168 of 209 children (80.4%, 95% CI 75.02-85.78), in 85.8% with no resistance, 72.6% with single resistance, and 28.6% with double resistance. Independent factors affecting eradication rate included resistance to clarithromycin (adjusted ORs 0.27 (0.09-0.84), p = .024), to metronidazole (0.25 (0.009-0.72), p = .010) or to both (0.04 (0.01-0.35), p = .004), and intake of ≤ 90% of prescribed drugs (0.03 (0.01-0.18), p < .001).

CONCLUSION

A high-dose 10-day sequential therapy cannot be recommended in treatment-naïve children.

Clinical practice: Helicobacter pylori infection in childhood

Helicobacter pylori infection is recognised as a cause of gastritis and peptic ulcer disease (PUD) and usually acquired during the first years of life. While there is a decline in the prevalence of H. pylori infection in northern and western European countries, the infection is still common in southern and eastern parts of Europe and Asia. Symptoms of H. pylori-related PUD are nonspecific in children and may include epigastric pain, nausea and/or vomiting, anorexia, iron deficiency anaemia and hematemesis. Besides, only a small proportion of children develop symptoms and clinically relevant gastrointestinal disease. H. pylori infection can be diagnosed either by invasive tests requiring endoscopy and biopsy or non-invasive tests including the (13)C-urea breath test, detection of H. pylori antigen in stool and detection of antibodies in serum, urine and saliva. The aim of treatment is at least 90 % eradication rate of the bacteria, and a combination of two antibiotics plus a proton pump inhibitor has been recommended as first-line treatment. However, frequent use of antibiotics during childhood is associated with a decline in eradication rates and the search for new treatment strategies as well. This is an overview of the latest knowledge and evidence-based guidelines regarding clinical presentation, diagnosis and treatment of H. pylori infection in childhood.

Follow-up of Helicobacter pylori infection in children over two decades (1988-2007): persistence, relapse and acquisition rates

Helicobacter pylori culture on gastric biopsy was performed on 4964 subjects aged <18 years from 1988 to 2007 at a central laboratory in Brussels. The total number of biopsies increased markedly from 941 in 1988-1993 to 1608 in 2004-2007. Biopsies were repeated at least once for 922 subjects (603 initially negative and 319 initially positive for H. pylori). Persistence rate of H. pylori at 1 year after initial positive biopsy was greater in the 1998-2007 cohort than in the 1988-1997 cohort (72.7% vs. 45.8%, P = 0.002), suggesting a tailored selection of candidates for biopsy with non-invasive tests (13C urea breath test). Of 68 subjects initially positive and re-examined subsequently after a documented cure, re-infection/relapse rate was 48.6% within 5 years post-elimination of H. pylori. Acquisition rate over 10 years follow-up in the initially negative cohort (603 patients) was 38.7% (re-infection/relapse vs. acquisition: P < 0.001). Multivariate analysis showed a fourfold greater risk of H. pylori acquisition in children of non-European origin vs. European origin (P < 0.001). Clarithromycin and metronidazole susceptibility were determined in 226 and 223 paired positive cultures in cases of re-infection/relapse or persistence. An initial non-susceptibility profile was highly predictive of a subsequent non-susceptibility profile, and the non-susceptible proportion increased markedly from 13.3% to 21.2% for clarithromycin (P < 0.001) and from 27.3% to 35.0% for metronidazole (P = 0.014), with no difference regarding European or non-European origin.

Sequential therapy versus tailored triple therapies for Helicobacter pylori infection in children

AIMS

The aim of the study was to compare sequential versus tailored triple therapy regimens on Helicobacter pylori (H pylori) eradication rates in children and to assess the effect of antimicrobial susceptibility.

PATIENTS AND METHODS

Prospective, open-label, multicenter study. Children received randomly either a 10-day sequential treatment comprising omeprazole (OME) with amoxicillin for 5 days and OME, clarithromycin (CLA), and metronidazole (MET) for the remaining 5 days, or a 7-day triple therapy comprising OME with amoxicillin and CLA in cases of a CLA-susceptible strain or MET in cases of CLA-resistant strain. H pylori eradication was assessed by C-urea breath test.

RESULTS

One hundred sixty-five children, 95 girls and 70 boys, of median age 10.4 years, were included. The intention-to-treat (ITT) eradication rate was 76.9% (sequential 68/83 = 81.9%, triple therapy 59/82 = 71.9%, ns), and the per-protocol (PP) eradication rate was 84.6% (sequential 68/77 = 88.3%, triple therapy 59/73 = 81.8%, ns). Eradication rates tended to be higher using the sequential treatment, but the difference was only statistically significant for ITT analysis in children harboring both CLA- and MET-susceptible strains (87.8% vs 68.5%, odds ratio [OR] 3.3, P = 0.03). Both ITT and PP eradication rates were significantly lower with sequential treatment in CLA-resistant compared with CLA-susceptible strains (ITT: 56.2% vs 72.7%, OR 5.5, P = 0.008; PP 64.3% vs 80.0%, OR 7.9, P = 0.009). Both treatments were well tolerated.

CONCLUSIONS

Sequential treatment is greatly effective for eradicating H pylori in children except in CLA-resistant strains. Sequential treatment can be used as a first-line therapy, but only in areas with a low CLA resistance rate.

Evidence-based guidelines from ESPGHAN and NASPGHAN for Helicobacter pylori infection in children

OBJECTIVE

As the clinical implications of Helicobacter pylori infection in children and adolescents continue to evolve, ESPGHAN and NASPGHAN jointly renewed clinical guidelines using a standardized evidence-based approach to develop updated recommendations for children and adolescents in North America and Europe.

METHODS

An international panel of 11 pediatric gastroenterologists, 2 epidemiologists, 1 microbiologist, and 1 pathologist was selected by societies that developed evidence-based guidelines based on the Delphi process with anonymous voting in a final face-to-face meeting. A systematic literature search was performed on 8 databases of relevance including publications from January 2000 to December 2009. After excluding nonrelevant publications, tables of evidence were constructed for different focus areas according to the Oxford classification. Statements and recommendations were formulated in the following areas: whom to test, how to test, whom to treat, and how to treat. Grades of evidence were assigned to each recommendation based on the GRADE system.

RESULTS

A total of 2290 publications were identified, from which 738 were finally reviewed. A total of 21 recommendations were generated, and an algorithm was proposed by the joint committee providing evidence-based guidelines on the diagnostic workup and treatment of children with H pylori infection.

CONCLUSIONS

These clinical practice guidelines represent updated, best-available evidence and are meant for children and adolescents living in Europe and North America, but they may not apply to those living on other continents, particularly in developing countries with a high H pylori infection rate and limited health care resources.

New effective treatment regimen for children infected with a double-resistant Helicobacter pylori strain

BACKGROUND

The increasing number of pediatric patients infected with multiresistant Helicobacter pylori strains calls for evaluation of treatment regimens. Second-line antibiotics such as tetracycline or quinolones are not licensed for children. Because in vivo resistance to metronidazole may be overcome in vivo by a high dose and prolonged intake, we evaluated the eradication rate and side effects of a high-dose triple therapy in pediatric patients with culture-proven double resistance.

PATIENTS AND METHODS

In this open multicentre trial, 62 children (<18 years, body weight >15 kg) infected with an H pylori strain resistant to metronidazole and clarithromycin were treated according to body weight classes with amoxicillin (∼ 75 mg/kg/day), metronidazole (∼ 25 mg/kg/day) and esomeprazole (∼ 1.5 mg/kg/day) for 2 weeks. Adherence and adverse events were assessed by a 2-week diary and telephone interviews at days 7 and 14 of treatment. Primary outcome was a negative C-urea breath test after 6 weeks.

RESULTS

Of 62 patients, 5 were lost to follow-up, 12 were nonadherent, and 45 treated per protocol. Eradication rates were 66% (41/62) [confidence interval 54-78] (intention to treat) and 73% (33/45) [confidence interval 60-86] (per protocol). Success of treatment was not related to dose per kilogram body weight. Mild to moderate adverse events were reported by 21 patients, including nausea (10.8%), diarrhoea (8.9%), vomiting (7.1%), abdominal pain (5.4%), and headache (3.6%), and led to discontinuation in 1 child.

CONCLUSION

High-dose amoxicillin, metronidazole, and esomeprazole for 2 weeks is a good treatment option in children infected with a double resistant H pylori strain.

Multicenter survey of routine determinations of resistance of Helicobacter pylori to antimicrobials over the last 20 years (1990 to 2009) in Belgium

We analyzed the rates of antimicrobial resistance of Helicobacter pylori strains isolated from patients from 1990 to 2009 and identified risk factors associated with resistance. Gastric biopsy specimens were collected from several digestive disease centers in Brussels, Belgium. We routinely performed antimicrobial susceptibility testing for clarithromycin (CLR), metronidazole, amoxicillin, tetracycline, and ciprofloxacin. Evaluable susceptibility testing was obtained for 9,430 strains isolated from patients who were not previously treated for Helicobacter pylori infection (1,527 isolates from children and 7,903 from adults) and 1,371 strains from patients who were previously treated (162 isolates from children and 1,209 from adults). No resistance to amoxicillin was observed, and tetracycline resistance was very rare (<0.01%). Primary metronidazole resistance remained stable over the years, with significantly lower rates for isolates from children (23.4%) than for isolates from adults (30.6%). Ciprofloxacin resistance remained rare in children, while it increased significantly over the last years in adults. Primary clarithromycin resistance increased significantly, reaching peaks in 2000 for children (16.9%) and in 2003 for adults (23.7%). A subsequent decrease of resistance rates down to 10% in both groups corresponded to a parallel decrease in macrolide consumption during the same period. Multivariate logistic regression revealed that female gender, age of the patient of 40 to 64 years, ethnic background, the number of previously unsuccessful eradication attempts, and the different time periods studied were independent risk factors of resistance to clarithromycin, metronidazole, and ciprofloxacin. Our study highlights the need to update local epidemiological data. Thus, the empirical CLR-based triple therapy proposed by the Maastricht III consensus report remains currently applicable to our population.

Primary resistance in Helicobacter pylori isolated in children from Iran

Helicobacter pylori-associated infection is extremely common in Iran, as in other developing countries, but few data exist on the susceptibility of H. pylori to antimicrobials commonly used in the eradication schedules in this country. This study was performed to determine the resistance rate to six antimicrobial agents used in the treatment of H. pylori infection in dyspeptic Iranian children and to recommend an updated anti-H. pylori treatment regimen to use in children. All H. pylori isolated from children who were undergoing gastroscopy were prospectively collected and subcultured to yield their susceptibility to six antimicrobial agents, by E test and disk diffusion methods. Demographic data and presenting symptoms were also collected. A prospective study was carried out from January 2003 to January 2005 with 100 strains of H. pylori isolated from children (40 girls and 60 boys; age range, 1.5 to 16 years [mean, 9.22 +/- 3.25 years]); the strains had been successfully subcultured to yield antimicrobial sensitivity. Overall the H. pylori resistance rate was 95% to metronidazole, 59% to amoxicillin, 16% to clarithromycin, 9% to furazolidone, 7% to ciprofloxacin, and 5% to tetracycline. The most common presenting symptom was abdominal pain. There were no statistically significant differences in antimicrobial resistance rates related to age, sex, or clinical presentation. In the Iranian children, the prevalence of H. pylori resistance was very high to metronidazole and amoxicillin, moderate to clarithromycin, and low to ciprofloxacin and tetracycline.

Rapid detection of clarithromycin-resistant Helicobacter pylori in patients with dyspepsia by fluorescent in situ hybridization (FISH) compared with the E-test

BACKGROUND

Clarithromycin is the antibiotic of choice for treatment of H.pylori-related dyspepsia, but unfortunately, resistance to clarithromycin is not rare. Detection of resistant strains takes 2 to 4 days by conventional methods. In this report, we applied the FISH technique for rapid detection of H.pylori in biopsies of dyspeptic patients.

METHODS

Gastric biopsies from 50 patients suffering from dyspepsia were tested in this study. Part of each biopsy specimen was cultured and the remainder was fixed in liquid nitrogen. After mounting of frozen sections on microscopic slides, they were hybridized with oligonucleotide probes for detection of clarithromycin-resistant H.pylori. The slides were visualized under a fluorescent microscope. Susceptibility of cultured strains of H. pylori to clarithromycin was also determined by the E-test and the results were compared.

RESULTS

Twenty-five of 50 biopsy specimens examined by FISH were positive for H.pylori. FISH showed that 17 strains (68%) were susceptible to clarithromycin and 6 strains (24%) were resistant. Bacteria isolated following culture of 2 biopsy specimens had a mixture of both clarithromycin-susceptible and resistant strains (8%). There was no discrepancy between the E-test and FISH technique for detection of resistant strains of H.pylori.

CONCLUSION

FISH is a rapid technique for detection of H.pylori in clinical samples. Moreover, strains susceptible to clarithromycin can be detected quickly. Therefore, this method is suitable for determination of susceptibility of H.pylori to clarithromycin, especially when a quick decision is necessary for treating dyspeptic patients.

Improvement of the eradication rate of Helicobacter pylori gastritis in children is by adjunction of omeprazole to a dual antibiotherapy

AIM

The possible improvement of efficacy and tolerability of a 7-day dual antibiotherapy amoxicillin-clarithromycin (AC) on the eradication of Helicobacter pylori (H. pylori) gastritis in children by the adjunction of omeprazole (OAC) was studied.

METHODS

Forty-six children presenting with H. pylori gastritis, assessed at inclusion by endoscopy, H. pylori urease test, histology and/or culture were randomised to a twice-daily regimen of AC or OAC. A (13)C-urease breath test was performed 4-6 weeks after the end of the treatment period to evaluate H. pylori eradication.

RESULTS

A larger proportion of patients was H. pylori negative (69%) in the OAC regimen treatment 4-6 weeks after eradication treatment compared with those who received dual AC therapy (15%). A total of seven patients (three in the OAC and four in the AC group) reported adverse events (AEs). Only vomiting was reported in more than one patient (one in each treatment regimen) and only one AE was severe (urticaria: in the OAC group, but considered not related to treatment).

CONCLUSION

A larger eradication rate of H. pylori was obtained in the triple OAC group than in the dual AC group. Both therapy regimens can be safely administered to children for 7 days.

Esomeprazole-based 1-week triple therapy directed by susceptibility testing for eradication of Helicobacter pylori infection in children

BACKGROUND

Poor compliance to therapy and antibiotic resistance are the main causes for failure of anti-Helicobacter pylori therapy.

OBJECTIVE

To evaluate the effectiveness of esomeprazole-based triple therapy directed by susceptibility testing.

METHODS

Symptomatic children with H. pylori infection, who underwent successful susceptibility testing and were colonized by no double-resistant strain, received 1-week triple therapy with esomeprazole, amoxicillin and either clarithromycin or metronidazole. Success of eradication was investigated by C-urea breath test.

RESULTS

Fifty-eight children (median age, 11.4 years; range, 2.2-17.7 years; 81% immigrants) were included. Helicobacter pylori was resistant to clarithromycin in 5 (9%) and to metronidazole in 9 children (16%). Eradication was successful in 49 (92%) of 53 children receiving esomeprazole, amoxicillin and clarithromycin and in all 5 children treated with metronidazole instead of clarithromycin, resulting in an eradication rate of 93% (95% confidence interval, 83%-98%, intention-to-treat analysis). All 4 treatment failures occurred in immigrants with language problems; 2 of them were obviously noncompliant.

CONCLUSION

Esomeprazole-based 1-week triple therapy directed by susceptibility testing is highly effective for eradication of H. pylori infection in children.

Antibacterial resistance in Helicobacter pylori strains isolated from Bulgarian children and adult patients over 9 years

The aim of this study was to evaluate the primary, combined and post-treatment antibacterial resistance rates in 1205 Helicobacter pylori strains from non-treated (786 adults, 282 children) and treated (109 adults, 28 children) patients in Bulgaria. Susceptibility was tested by the limited agar dilution method. Overall primary resistance rates to metronidazole, clarithromycin, amoxicillin, tetracycline and both metronidazole and clarithromycin were respectively 15·0, 12·5, 1·5, 3·4 and 4·7 % in children and 25·6, 12·6, 0·8, 5·2 and 4·9 % in adults. Primary metronidazole resistance in adults was more common than in children, but the differences for other agents tested were not significant. Primary resistance rates were in the range of those reported worldwide. There was no significant increase in primary resistance rates from 1996/1999 to 2003/2004; however, clarithromycin resistance rates exhibited a slight tendency to increase. Post-treatment resistance to amoxicillin was detected in 1·6 % of 63 strains. Post-treatment resistance to metronidazole was common (81·6 %) and that to clarithromycin was considerable (36 %). Alarming emergence of strains with triple resistance to amoxicillin, metronidazole and clarithromycin was found in two non-treated and three treated patients. The results motivate a larger and continuing surveillance of H. pylori resistance in Bulgaria and worldwide.

Helicobacter pylori and recurrent pain abdomen

OBJECTIVE

Pain abdomen is a common problem in childhood. Many factors i.e., organic changes in the gut, psychological and environment contribute to recurrent pain abdomen (RAP) in children. Helicobacter pylori infects children very early in childhood and stays indefinitely in the gut without its eradication. It may be responsible for pain abdomen and peptic ulcers in children. This study was done to assess the HP status in children with RAP diagnosed and evaluate the effects of eradication of HP infection in them.

METHODS

76 children were included in the study.

RESULT

Out of 76 children studied 14.8% had evidence of a secondary cause for pain abdomen and responded to appropriate therapy. 65.45% of children who had undergone UGIE, had evidence of HP infection in the upper gastrointestinal tract. Most of these children responded to HP eradication therapy by becoming free of abdominal pain after the eradication therapy with OCA or OMA regimen. We could not do repeated endoscopies in all of them to prove the eradication due to parents' refusal and this is the main drawback of this study.

CONCLUSION

However, in view of clinical response to HP eradication therapy in almost all the cases, we strongly advocate this therapy for those children with RAP, in whom HP infection of the upper gastrointestinal tract can be established beyond doubt.

Antibiotic-resistant Helicobacter pylori strains in Portuguese children

BACKGROUND

Data concerning the effectiveness of Helicobacter pylori eradication regimens based in antibiotic susceptibility testing are scanty in children.

AIMS

To identify the prevalence of antibiotic resistance in H. pylori strains isolated from Portuguese children in 1999-2003; to evaluate eradication rate after antibiotic susceptibility testing-based treatment; and to identify factors associated with resistance and eradication outcome.

METHODS

Included were 109 children with a gastric biopsy culture positive for H. pylori. First treatment (amoxicillin, omeprazole and clarithromycin or metronidazole) was guided by susceptibility testing (E test), and eradication was assessed by [C]urea breath test.

RESULTS

Strains were susceptible to amoxicillin and tetracycline; 39.4% were resistant to clarithromycin, 16.5% to metronidazole and 4.5% to ciprofloxacin. No significant association was found between resistance and sex, age, clinical status, gastritis scores, H. pylori density scores and genotype. Clarithromycin resistance was significantly associated with European origin [odds ratio (OR), 3.9], previous H. pylori empiric therapy (OR 2.8) and amoxicillin minimal inhibitory concentration, > or =0.016 (OR 6.0). Eradication rate after susceptibility-based treatment was 74.7% (59 of 79; 95% confidence interval, 65.9-82.9), and a significant association was found between eradication failure and presence of resistance to 1 or more antibiotics (P < 0.05).

CONCLUSIONS

The prevalence of H. pylori antibiotic resistance was high in the studied population. The modest therapeutic success of clarithromycin and metronidazole susceptibility-based regimens suggests that in addition to resistance, other factors may be involved. The need of susceptibility-based treatment studies in children and of antimicrobial resistance surveillance in high prevalence areas for H. pylori are emphasized.

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.

In vitro exposure to macrolide antibiotics in Helicobacter pylori strains isolated from children

Clarithromycin resistance of Helicobacter pylori is a serious problem in eradication therapy. We investigated whether the use of maclorides (clarithromycin, erythromycin, and azithromycin) induces clarithromycin resistance in the organism. Twenty H. pylori strains were isolated from pediatric patients with gastrointestinal symptoms. The minimum inhibitory concentrations (MICs) of each macrolide antibiotic were determined by the Etest. Among these, 17 strains susceptible to macrolide antibiotics were used for the in vitro induction of drug resistance. In each of these 17 strains of H. pylori, 30-day exposure to clarithromycin in experiments for in vitro induction did not change the MIC of any antibiotic, nor did it induce either the A2143G or the A2144G mutation in the 23S rRNA gene. These results suggest that the use of macrolide antibiotics does not induce clarithromycin resistance in H. pylori by 23S rRNA gene mutation.

Helicobacter pylori infection in Turkish children: comparison of diagnostic tests, evaluation of eradication rate, and changes in symptoms after eradication

BACKGROUND

Helicobacter pylori infection is most frequently acquired in childhood. After this organism is eradicated, the rate of reinfection is low. Thus, it is very important to diagnose and treat the disease appropriately in childhood, and to be able to assess eradication with certainty. Eradication of H. pylori infection is reported to reduce or eliminate abdominal pain and dyspeptic symptoms in children.

PATIENTS AND METHODS

The study involved 102 children who had already been diagnosed with symptomatic H. pylori infection based on gastric histopathological examination, urea breath test, rapid urease test, serology and culture. Each patient's symptoms and family history of gastrointestinal problems were recorded. Using histology as the gold standard for identifying H. pylori infection, we determined the diagnostic sensitivity of each of the other methods. Omeprazole or lansoprazole, amoxicillin and clarithromycin were administered as eradication treatment, and each patient was re-evaluated by urea breath test 8 weeks later. Each child was re-interviewed about symptoms after treatment. These answers and the results of drug sensitivity testing were recorded. Cases of failed eradication were re-treated with a quadruple-drug regimen of tetracycline, metronidazole, bismuth subsalicylate and omeprazole.

RESULTS

The most frequent symptom was abdominal pain (89.2%). Fifty-four per cent of the subjects had a family history of dyspeptic symptoms. Sixty-six patients (64.7%) exhibited nodularity in the antral mucosa. The sensitivities of the diagnostic tests in histologically proven cases were as follows: urea breath test 100%, rapid urease test 89.2%, serology 71.9%, and culture 54.9%. Metronidazole had the highest frequency of resistance (36.4%) and the rate of clarithromycin resistance was 18.2%. The eradication rate after first-line therapy was 75.5%, and abdominal pain and dyspeptic symptoms were reduced or completely resolved in 75.7% of the successful-eradication cases. The proportion of failed-eradication cases that responded well to quadruple-drug therapy was 93.8%.

CONCLUSION

Symptomatic H. pylori infection in a child should always be treated. The urea breath test is an accurate and reliable way to identify H. pylori-positive patients and to determine the response to treatment. Triple-agent therapy is effective for eradicating H. pylori infection in children and usually helps reduce or eliminate dyspeptic symptoms. The level of H. pylori resistance to metronidazole is high in our region. The significant rate of resistance to clarithromycin (18.1%) may explain the treatment failure observed in this study.

Susceptibilities to different antibiotics of Helicobacter pylori strains isolated from patients at the pediatric medical center of Tehran, Iran

Antibiotic susceptibility testing of 70 pediatric Helicobacter pylori isolates was performed by using screening agar and disk diffusion methods. Resistance to metronidazole and tinidazole was 72 to 79% and 71 to 81% by modified disk diffusion and 77% and 78% by screening agar, respectively. Susceptibilities to amoxicillin, ampicillin, clarithromycin, tetracycline, erythromycin, and ciprofloxacin were 58, 69, 75, 68, 68, and 65%, respectively.

Infection à Helicobacter pylori et résistance aux antibiotiques

PURPOSE

Seven days triple therapies combining a proton pump inhibitor (PPI) and 2 antimicrobial agents (clarithromycin [C], amoxicillin [A], metronidazole [M]), are recommended for the treatment of Helicobacter pylori infection. The eradication failures have increased these last years, particularly in France (about 30%). They are essentially related to the development of antimicrobial agents resistance, mainly concerning macrolides and nitro-imidazoles.

CURRENT KNOWLEDGE AND KEY POINTS

Primary resistance to clarithromycin is variable, but reaching now about 10% throughout the world and about 20% in France. It reduces the eradication success rate at 25%. The secondary resistance is very high, contra-indicating the use of clarithromycin in second line regimens. Primary resistance to amoxicillin has recently appeared, but remains very low until now, less than 2%, as the tetracyclin (T) resistance. Primary resistance to metronidazole is 3 times higher than macrolides resistance, but its determination is less accurate. Metronidazole resistance reduces eradication rate of about 25%, leading to the use of metronidazole in second line therapy, in increasing the triple therapy duration at 14 days (PPI-A-M), or in combination with quadruple therapy (Bismuth-PPI-T-M). Other rescue-treatments are efficacious, based on ranitidine bismuth citrate combined regimens or on rifabutine (R) based regimens (PPI-A-R).

FUTURE PROSPECTS AND PROJECTS

The recent knowledge of the mutations mainly responsible for H. pylori resistance to antimicrobial agents now allows the development of detection methods based on the study of bacterial DNA. These methods have been validated for clarithromycin and should favour in the near future the determination of resistance by the use of biopsy culture or directly on the gastric biopsy.

[Is upper gastro-intestinal endoscopy required for diagnosis and treatment of Helicobacter pylori infection in childhood? Pro and cons]

Non invasive tests are available and accurate for the diagnosis of H. pylori infection in children. They are safer and cheaper than endoscopy. Peptic ulcer and severe gastro-intestinal lesions associated with H. pylori infection are rare in childhood. However since the resistance to antibiotics is steadily increasing, biopsies are still required to assess sensitivity of germs to antibiotics. Search of H. pylori infection should be limited to the children presenting digestive symptoms severe enough to justify endoscopy and treatment.

Detection of Helicobacter pylori in paraffin-embedded and in shock-frozen gastric biopsy samples by fluorescent in situ hybridization

We report on the successful application of fluorescent in situ hybridization for detection of Helicobacter pylori and determination of its clarithromycin susceptibility in formalin-fixed and paraffin-embedded gastric biopsy specimens that had been prepared for pathological examination. This method is useful when results from conventional culturing with antibiotic susceptibility testing are not available.

Clarithromycin resistance among Helicobacter pylori strains isolated from children: prevalence and study of mechanism of resistance by PCR-restriction fragment length polymorphism analysis

Clarithromycin and metronidazole resistance was 29.1 and 23.9%, respectively, in 96 Helicobacter pylori strains obtained from pediatric patients. No resistance to amoxicillin was observed. Resistance according to patients' ages to clarithromycin and metronidazole was 45.4 and 18.2% in 22 patients from 4 to 8 years old, 30.2 and 20.7% in 53 patients from 9 to 13 years old, and 9.5 and 38.1% in 21 patients from 14 to 18 years old, respectively. The A2143G mutation was the most prevalent (82.1%) among clarithromycin-resistant strains.

Fluorescence in situ hybridization vs. epsilometer test for detection of clarithromycin-susceptible and clarithromycin-resistant Helicobacter pylori strains in gastric biopsies from children

AIM

To compare the results of culture and epsilometer test with fluorescence in situ hybridization for the detection of Helicobacter pylori and the presence of clarithromycin-susceptible and clarithromycin-resistant strains in antral biopsies from children.

METHODS

Antral biopsies from 149 unselected children were investigated prospectively; 15 had previously received anti-H. pylori therapy. H. pylori status was defined by histology, rapid urease test and 13C-urea breath test. Fluorescence in situ hybridization was applied on fresh tissue with probes specific for the clarithromycin-susceptible wild type and three clarithromycin-resistant mutants. Susceptibility to clarithromycin was tested by epsilometer test in two laboratories.

RESULTS

Culture and fluorescence in situ hybridization gave negative results in all 66 H. pylori-negative children (specificity, 100%). Of 83 infected children, cultures were successful in 75 (90%), epsilometer test in 71 (86%) and fluorescence in situ hybridization in 77 (93%). Eleven children (13%) showed discrepant results between the applied methods, indicating mixed infection. Clarithromycin-resistant isolates were identified in 16 of 73 previously untreated children.

CONCLUSIONS

Primary resistance to clarithromycin is common (22%) in H. pylori isolates from children living in Germany. Fluorescence in situ hybridization is an excellent, fast method for the detection of H. pylori and clarithromycin-resistant mutants in gastric biopsies. Multiple biopsies identify mixed infections, indicating that clarithromycin-resistant and clarithromycin- susceptible strains are not evenly distributed within the stomach.

Helicobacter pylori infection in pediatrics

In the past year the main interest was focused on the role of family for transmission of Helicobacter pylori to children; the evaluation of noninvasive diagnostic tests, especially in young children; extra-intestinal clinical manifestations; the lack of consensus on treatment; and the problem of high resistance of the microorganism to antibiotics.