Although infection with a cagA-positive Helicobacter pylori strain is considered a risk factor for the development of duodenal peptic ulcer in adults, this association has not been demonstrated in children. The presence of cagA was investigated by polymerase chain reaction in H. pylori strains isolated from 27 children with duodenal ulcer and 53 without duodenal ulcer. All patients (100%) with duodenal ulcer and 33 (62.3%) without ulcer were colonized by a cagA-positive strain (P=.00007). A cagA-positive status was also associated with a more marked macroscopic gastritis, with a greater inflammatory infiltrate of both mononuclear and polymorphonuclear cells in the antral and oxyntic gastric mucosae and degenerative and regenerative changes of the gastric mucosa. Increased cagA positivity was also associated with increased age, but no association between cagA-positive status and sex was observed.

The [13 C]urea breath test ( 13 C-UBT) and Helicobacter pylori stool antigen test (HpSA) for the diagnosis of H. pylori infection in children were validated. The sensitivity, specificity, and positive and negative predictive values were 93.8, 99.1, 97.8, and 98.0%, respectively, for the 13 C-UBT and 96.9, 100, 100, and 98.0%, respectively, for HpSA. Both tests are appropriate for diagnosing H. pylori infection in children. The [13 C]urea breath test ( 13 C-UBT) and a new developed immunoassay for the detection of Helicobacter pylori antigens in stool, the H. pylori stool antigen test (HpSA) (3), are noninvasive tests for H. pylori diagnosis.Although the 13 C-UBT has a good sensitivity for the diagnosis of the infection in all ages, low specificity for very young children has been found (6). With respect to the stool test, low sensitivity for this age group has been also reported (2, 10). Thus, we aimed to validate the 13 C-UBT and HpSA for the diagnosis of H. pylori infection in children.We studied prospectively 210 consecutive children aged 1 to 18 years who underwent esophagogastroduodenoscopy for investigation of gastric complaints. This project was approved by the Ethics Committee of our institution.At endoscopy, biopsy specimens were obtained from the antral and oxyntic gastric mucosa for culture, urease test, and histology. Children were considered to be H. pylori positive if at least two of the three tests were positive or if the culture alone was positive. They were considered negative if all tests were negative.The 13 C-UBT was performed on fasting children within 1 week after endoscopy. The children received 200 ml of orange juice containing 75 mg of [ 13 C]urea (or 100 ml containing 50 mg for those Ͻ30 kg). Breath samples at baseline and after 30 min were analyzed with a nondispersive infrared spectrometer (NDIRIS; Wagner Analysen Technik, Bremen, Germany). The results were considered positive when delta over baseline (DOB) was Ͼ4.0‰.Stool samples, collected on the occasion of the endoscopy, were maintained at Ϫ20°C for up 1 year before testing. HpSA (Premier Platinum HpSA; Meridian Diagnostic, Cincinnati, Ohio) was performed according to the manufacturer's recommendation, slightly modified: instead of a stick, a 10-l disposable loop was used to dilute stool samples, as proposed by Oderda et al. (9), and the plates were washed exhaustively to remove unbound material.Among the 210 children enrolled, 167 underwent the 13 C-UBT but 6 children were excluded (4 had only one positive test and 2 had equivocal results in the 13 C-UBT). The remaining 161 children (76 boys; mean age, 8.6 Ϯ 3.8 years; range, 1 to 18 years) were included in the final analysis (48 were H. pylori positive and 15 had peptic ulcer). The 13 C-UBT was positive for 45 of 48 infected children and for one of the 113 noninfected ones (Table 1). The three children with false-negative 13 C-UBT results were a 5-year-old boy (DOB ϭ 0.3), a 9-yearold girl (DOB ϭ 0.5), and a 14-year-old girl (DOB ϭ 0.2). The cultures for all of them were positiv...

Data concerning the geographic distribution of iceA alleles are scarce, and information on the association of the gene with the disease is rare and still controversial. Furthermore, no such study has been developed in Brazil, where duodenal ulcer and gastric adenocarcinoma are very common. We investigated, by PCR, the frequency of iceA alleles and cagA status in Helicobacter pylori strains isolated from 142 patients (62 children and 80 adults; 66 female; mean age, 30.0 years; age range, 3 to 78 years) with gastritis, duodenal ulcer, or gastric adenocarcinoma. iceA was identified in bacterium samples obtained from all patients. Eleven (7.7%) of them were infected with multiple strains. Among the patients with nonmixed infection, iceA2 allele was detected in 118 (90.1%). iceA2 allele was associated with ulcer (P ‫؍‬ 0.02) and with carcinoma (P ‫؍‬ 0.001). iceA2 amplicons of 229, 334, or 549 bp were detected, but none of them was associated with the patient's disorder. iceA2 strains were more frequent in patients older than 7 years (P ‫؍‬ 0.001). The gene was also more frequent in strains obtained from males (P ‫؍‬ 0.02). cagA was more common in strains obtained from carcinoma (P ‫؍‬ 0.0008) and ulcer patients (P < 0.006). cagA-positive strains were more frequent in children older than 7 years (P < 0.003). No association between cagA status and sex was found (P ‫؍‬ 0.28). In conclusion, we think iceA should not be used as a reliable marker for predicting the clinical outcome of H. pylori infection.

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There are differences between children and adults in certain aspects of the Helicobacter pylori (HP) infection, among them the lower titre of IgG antibodies anti-HP in the former group. Thus, we investigated by means of flow cytometry