Lack of correlation between vacuolating cytotoxin activity,cagA gene inHelicobacter pylori, and peptic ulcer disease in children

To determine the prevalence of thecagA gene and vacuolating cytotoxin inHelicobacter pylori isolates obtained from children and to characterize the relationship betweencagA, cytotoxin production, and ulcerogenesis, pediatricHelicobacter pylori isolates were tested forcagA by the polymerase chain reaction and for vacuolating cytotoxin by a cell culture assay.Helicobacter pylori isolates were obtained from 33 children referred for upper gastrointestinal endoscopy. Twenty-six of these isolates were tested forcagA by the polymerase chain reaction; all 26 (100%) were positive. Of the 26 children from whom these isolates were obtained, 26 (100%) had chronic gastritis and 12 (46%) had duodenal ulcers. Nine (30%) of 30 isolates tested showed expression of vacuolating cytotoxin, only three of which came from patients with duodenal ulceration (odds ratio 0.81, 95% confidence interval 0.1–5.3). Of the 23cagA-positive isolates tested for cytotoxin, only nine (39%) were positive. There was no association between vacuolating cytotoxin and clinical symptoms, nor was cytotoxicity associated with ulcerogenesis. In summary, the findings suggest thatcagA is not a marker of duodenal ulceration or of vacuolating cytotoxin production in children referred for endoscopy.