High Levels of Resistance to Metronidazole and Clarithromycin in
            <i>Helicobacter pylori</i>
            Strains in Children

Kalach, Nicolas; Bergeret, M.; Benhamou, Pierre-Henri; Dupont, Christophe; Raymond, Josette

doi:10.1128/jcm.39.1.394-397.2001

Cited by 66 publications

(55 citation statements)

References 21 publications

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“…Table 1 shows the MIC 50 s (MICs at which 50% of the isolates tested are inhibited), MIC 90 s, and MIC ranges of, and percentages of resistance to, the three antimicrobial agents tested against the total number of strains. A high percentage of clarithromycin-resistant strains was detected among our pediatric strains, similar to other studies (12,25). In some countries resistance is higher in children than in adults (9), although not in others (21).…”

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confidence: 76%

Clarithromycin Resistance among Helicobacter pylori Strains Isolated from Children: Prevalence and Study of Mechanism of Resistance by PCR-Restriction Fragment Length Polymorphism Analysis

et al. 2003

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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.Helicobacter pylori is a gram-negative microaerophilic rod found in the human gastric mucosa associated with different digestive diseases, such as peptic ulcer, gastritis, and mucosaassociated lymphoid tissue lymphoma (7), and it is considered a risk factor in the development of gastric cancer (24). H. pylori infection is frequently acquired during childhood, and symptoms such as vomiting and epigastric or recurrent abdominal pain are associated with H. pylori infection (6).Amoxicillin, tetracycline, metronidazole, and clarithromycin are frequently used, combined with proton pump inhibitors or bismuth salts, for the treatment of H. pylori infections (22). However, side effects, poor compliance, and resistance to antibiotics are causes of treatment failure (4, 16). Resistance to metronidazole and clarithromycin is population dependent, and several studies suggest that clarithromycin resistance is higher in strains obtained from children than in those from adults (9).The aim of this study was to determine the rate of resistance to clarithromycin in H. pylori strains obtained from pediatric patients according to the age of the patients. Metronidazole and amoxicillin resistance was also studied. The mutation involved in clarithromycin resistance was detected by PCR-restriction fragment length polymorphism analysis.Ninety-six pediatric patients, aged from 4 to 18 years (mean age Ϯ standard deviation, 10.86 Ϯ 3.3 years), attending the Gastroenterology Unit at the Hospital del Niño Jesus during 1999 and 2000, were included in this study. Patients were referred for endoscopy due to different symptoms, with epigastric pain (74.2%), vomiting (33.3%), and recurrent abdominal pain (25.8%) being the most prevalent. Parents signed an informed consent form for the endoscopy, and the Ethical Committee supervised the study. Patients previously treated for H. pylori infections were not included. Strains were grouped according to the age of the patient at the time of endoscopy.Only culture-positive patients were included. H. pylori clinical isolates were obtained from gastric biopsy specimens according to standard procedures.Clarithromycin was obtained from Abbott Laboratories SA, Madrid, Spain, and metronidazole and amoxicillin were obtained from Sigma-Aldrich, Madrid, Spain. MICs were determined by an agar dilution technique with Mueller-Hinton agar plus 7% horse blood according to NCCLS recommendations (17). Plates with twofold dilutions of each antibiotic were inoculated with 1 to 2 l of 10 9 CFU/ml ...

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confidence: 76%

Clarithromycin Resistance among Helicobacter pylori Strains Isolated from Children: Prevalence and Study of Mechanism of Resistance by PCR-Restriction Fragment Length Polymorphism Analysis

et al. 2003

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“…The prevalence of metronidazole-resistant strains in children has been reported to be 19% in Portugal (2), 23% in Spain [Lopez-Brea et al, Gut 47(Suppl. 1):A95, 2000], and 43% in France (17). In contrast, a Canadian study has reported that all strains of H. pylori were susceptible to metronidazole (23).…”

Section: Vol 40 2002mentioning

confidence: 84%

“…In Brazil, resistance to amoxicillin has been detected in 29% of strains recovered posttreatment (27). However, many studies have shown that all strains examined are susceptible to amoxicillin (1,17). The clinical significance of amoxicillin susceptibility testing has not been documented (26).…”

Section: Vol 40 2002mentioning

confidence: 99%

Antibiotic Resistance of Helicobacter pylori Strains in Japanese Children

et al. 2002

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The resistance of Helicobacter pylori to the recently available antibiotic treatment regimens has been a growing problem. We investigated the prevalence of H. pylori resistance to clarithromycin, metronidazole, and amoxicillin among 51 H. pylori isolates from Japanese children. In addition, the mutations of the corresponding gene were studied by PCR and restriction fragment length polymorphism analysis. Primary resistance to clarithromycin, metronidazole, and amoxicillin was detected in 29, 24, and 0% of strains, respectively. The eradication rates in clarithromycin-susceptible and -resistant strains were 89 and 56%, respectively (P < 0.05). The prevalence of strains with acquired resistance to clarithromycin (78%) was higher than that of strains with primary resistance (P < 0.01). Among the clarithromycin-resistant strains studied, 92% showed cross-resistance to azithromycin. No acquired resistance to amoxicillin was demonstrated. The A2144G mutation in the 23S rRNA gene was detected in 11 of 12 (92%) clarithromycin-resistant strains tested, whereas the mutation was not detected in any of the 15 susceptible strains. The deletion of the rdxA gene was not demonstrated in any of the strains. The results indicate that a high prevalence of clarithromycin-resistant strains is associated with eradication failure. Testing of susceptibility to clarithromycin is recommended.In adults, Helicobacter pylori plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease, and possibly, gastric carcinoma. H. pylori infection is also associated with chronic gastritis and duodenal ulcer in children (5, 13). Eradication of the organism not only accelarates ulcer healing (14) but also prevents long-term ulcer relapse (12). Recently, proton pump inhibitor (PPI)-based eradication regimens containing two antibiotics have been demonstrated to have high eradication rates (greater than 90%) (3, 22). Amoxicillin, clarithromycin, and metronidazole are the most frequently used antibiotics for the treatment of H. pylori infection. However, antibiotic resistance frequently causes failure of eradication of H. pylori (1,16,21). The resistance of H. pylori to the recently available antibiotic treatment regimens has been a growing problem. In developed countries, metronidazole resistance is found in 10 to 50% of adult patients infected with H. pylori (1, 10, 11), whereas virtually all strains are resistant to the agent in developing countries (26). On the other hand, although the rates of clarithromycin resistance are relatively low, ranging from 2 to 15% (1, 2, 10, 11, 27), the rate of clarithromycin resistance has been increasing during recent years.With regard to antibiotic resistance, however, there have been few reports of antibiotic resistance in children 2, 17, 23; M. Lopez-Brea, M. Martinez, D. Domingo, and T. Alarcon, abstract from the XIII International Workshop on Gastroduodenal Pathology and Helicobacter pylori, Gut 47(Suppl. 1): A95, 2000], and its clinical significance remains to be established. The purpose ...

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“…We have already shown that the rates of resistance to metronidazole and clarithromycin among isolates of H. pylori from children are high before treatment (i.e., 43 and 21%, respectively) (5). No data are available concerning the antimicrobial susceptibility patterns of strains obtained from cultures from children who had failed an initial course of therapy.…”

mentioning

confidence: 99%

Helicobacter pylori in Children: Acquisition of Antimicrobial Resistance after an Initial Course of Treatment

Kalach¹,

Benhamou²,

Dupont³

et al. 2001

J Clin Microbiol

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High Levels of Resistance to Metronidazole and Clarithromycin in Helicobacter pylori Strains in Children

Cited by 66 publications

References 21 publications

Clarithromycin Resistance among Helicobacter pylori Strains Isolated from Children: Prevalence and Study of Mechanism of Resistance by PCR-Restriction Fragment Length Polymorphism Analysis

Clarithromycin Resistance among Helicobacter pylori Strains Isolated from Children: Prevalence and Study of Mechanism of Resistance by PCR-Restriction Fragment Length Polymorphism Analysis

Antibiotic Resistance of Helicobacter pylori Strains in Japanese Children

Helicobacter pylori in Children: Acquisition of Antimicrobial Resistance after an Initial Course of Treatment

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