Universal high-level primary metronidazole resistance in Helicobacter pylori isolated from children in Egypt

Alaska sentinel surveillance for antimicrobial resistance in Helicobacter pylori isolates from Alaska native persons, 1999-2003

BACKGROUND

Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among Helicobacter pylori isolates.

MATERIALS AND METHODS

We analyzed H. pylori data from the Centers for Disease Control and Prevention (CDC)'s sentinel surveillance in Alaska from July 1999 to June 2003 to determine the proportion of culture-positive biopsies from Alaska Native persons undergoing routine upper-endoscopy, and the susceptibility of H. pylori isolates to metronidazole [minimum inhibitory concentration (MIC) of > 8 g metronidazole/mL), clarithromycin (MIC > or = 1), tetracycline (MIC > or = 2) and amoxicillin (MIC > or = 1)] using agar dilution.

RESULTS

Nine-hundred sixty-four biopsy specimens were obtained from 687 participants; 352 (51%) patients tested culture positive. Mean age of both culture-positive and culture-negative patients was 51 years. Metronidazole resistance was demonstrated in isolates from 155 (44%) persons, clarithromycin resistance from 108 (31%) persons, amoxicillin resistance from 8 (2%) persons, and 0 for tetracycline resistance. Metronidazole and clarithromycin resistance varied by geographic region. Female patients were more likely than male subjects to show metronidazole resistance (p < .01) and clarithromycin resistance (p = .05).

CONCLUSIONS

Resistance to metronidazole and clarithromycin is more common among H. pylori isolates from Alaska Native persons when compared with those from elsewhere in the USA.

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.

Combinations containing amoxicillin-clavulanate and tetracycline are inappropriate for Helicobacter pylori eradication despite high in vitro susceptibility

BACKGROUND

The purpose of the present paper was to evaluate the efficacy and tolerability of amoxicillin-clavulanate and tetracycline-based quadruple therapy as an alternative second-line treatment for H. pylori infection.

METHODS

The study subjects consisted of 54 patients infected with H. pylori, in whom initial triple therapy had failed. Subjects were randomized to receive the following 7-day therapies: (i) pantoprazole 40 mg b.i.d., tripotassium dicitrate bismuthate 300 mg q.i.d., amoxicillin-clavulanate 1000 mg b.i.d., and tetracycline 500 mg q.i.d. (PBAT); or (ii) pantoprazole 40 mg b.i.d., tripotassium dicitrate bismuthate 300 mg q.i.d., metronidazole 500 mg t.i.d., and tetracycline 500 mg q.i.d. (PBMT). Eradication rates based on antibiotic susceptibility, drug compliance and side-effect rates were evaluated and compared.

RESULTS

The H. pylori eradication rates were 16.0%/17.4% with PBAT and 65.5%/70.4% with PBMT by intention-to-treat (P<0.001) and per-protocol analyses (P<0.001), respectively. In patients who received PBAT, the eradication rates were only 16.7% (2/12) for both amoxicillin and tetracycline-susceptible H. pylori strains. Drug compliance and side-effect rates were similar in the two groups.

CONCLUSIONS

Despite high individual in vitro antimicrobial activity, amoxicillin-clavulanate and tetracycline-based quadruple therapy showed low eradication rates, which strongly suggests that it should not be considered as a therapeutic option for H. pylori eradication.

Institutional difference of antibiotic resistance of Helicobacter pylori strains in Korea

GOALS

This study was performed to evaluate whether the prevalence rates of primary antibiotic resistance in Helicobacter pylori isolates could be different between 2 institutions, which are located in the different areas in Korea, and to evaluate the effect of antibiotic resistance on the eradication rate of H. pylori.

STUDY

H. pylori were isolated from gastric mucosal biopsy specimens obtained from 113 Koreans, who did not have any eradication history. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin, and moxifloxacin were examined according to the agar dilution method by 1 technician.

RESULTS

All of these patients were treated with the same regimen, proton pump inhibitor-amoxicillin-clarithromycin triple therapy. There was a statistical difference in resistance to metronidazole, levofloxacin, and moxifloxacin among 6 antibiotics between 2 institutions located in Seoul and Gyeonggi province. The rates of eradication were 94.2% for the clarithromycin and amoxicillin-susceptible strains, and 42.8% for the amoxicillin-susceptible and clarithromycin-resistant strains. In contrast, eradication rate was 100% for the amoxicillin-resistant strains.

CONCLUSIONS

These results show that there is institutional difference of antibiotic resistance of H. pylori, explaining the institutional difference of eradication rate of H. pylori. The resistance to clarithromycin seems to be an important determinant for the eradication by proton pump inhibitor triple therapy but resistance to amoxicillin does not have any effect.

Efficacy of moxifloxacin-based triple therapy as second-line treatment for Helicobacter pylori infection

BACKGROUND AND AIM

Metronidazole and tetracycline-based second-line quadruple therapy, widely used for Helicobacter pylori infection, often ends up in failure due to antibiotic resistance and poor compliance in Korea. Our aim is to evaluate the efficacy and tolerability of moxifloxacin-based triple therapy as an alternative second-line treatment for H. pylori infection.

METHODS

The subjects consisted of 85 patients infected with H. pylori, in whom initial proton pump inhibitor triple therapy had failed. They were randomized to receive the following 7-day therapy: 1, moxifloxacin 400 mg q.d., esomeprazole 20 mg b.i.d., and amoxicillin 1 g b.i.d.; and 2, esomeprazole 40 mg b.i.d., tripotassium dicitrate bismuthate 300 mg q.i.d., metronidazole 500 mg t.i.d., and tetracycline 500 mg q.i.d. Eradication rates, drug compliance, and side-effect rates of each group were evaluated.

RESULTS

The eradication rates were 75.6 and 83.8% with moxifloxacin triple therapy, and 54.5 and 72.7% with quadruple therapy by intention-to-treat (p = .042) and per-protocol analyses (p = .260), respectively. Moxifloxacin triple therapy was significantly superior to quadruple therapy in terms of side-effect rates (p = .039). Compliance for therapy, i.e., the percentage of tablets taken (> 85%), was 90.2 and 75.0%, numerically higher in moxifloxacin triple therapy group than in quadruple therapy group, but without statistical difference (p = .065).

CONCLUSIONS

Moxifloxacin-based triple therapy showed high eradication rates with few side effects and good drug compliance, suggesting this regimen could be a safe and effective option as second-line therapy for H. pylori infection in Korea.

Treatment of Helicobacter pylori

The efficacy of established Helicobacter pylori regimes needs to be reviewed. In view of drug resistance, side effects, and compliance and expense of therapy, treatment failure is increasing and second-line treatment strategies need to be developed. A simulation model suggested by the Cochrane review group showed that H. pylori eradication is cost-effective for duodenal and gastric ulcer long-term. The duration of eradication therapy continues to be controversial. In Europe and other parts of the world, 7-day triple regimes are used, whereas guidelines from the United States recommend 10-14 days of therapy. Antibiotic resistance is a major factor affecting the outcome of eradication therapy. New modified eradication regimes involve substitution of antibiotics used in conjunction with other drugs. The newer generation fluoroquinolones have shown some promise as part of an eradication regimen. Quadruple therapy (bismuth, proton pump inhibitor [PPI] and two antibiotics and sequential treatment [PPI with three antibiotics]) are promising first-line treatments. Novel agents have been tried, but with disappointing results. New drugs and administration forms have been reported but their efficacy needs confirmation.

Helicobacter pylori infection in pediatrics

The diagnosis of Helicobacter pylori infection continues to challenge practicing physicians around the world. In the last year, several reports from Africa tried to examine the epidemiology of H. pylori infection in nursing babies, while others investigated the association between recurrent abdominal pain symptoms and H. pylori. In the diagnostic arena, attempts were made to improve diagnostic accuracy, mainly by using a new monoclonal version of the stool antigen test, and by applying the urea breath test in smaller children. In the current report, the most important studies on H. pylori infection in children published in the last year are also reviewed.