Single-step PCR amplification and enzyme restriction analysis of the entire Helicobacter pylori cytotoxin vacA gene for genetic variability studies

To monitor changes along the entire Helicobacler pylori vacA gene we carrie d out full-length single-step PCR amplification in 21 gastritis and gastric cancer isolates. HindIII restriction analysis led us to detect a > 400-bp internal insertion in vacA subsequently shown to be a direct 451-bp gene du plication. We found HindIII profiles for 16 genes that allowed their groupi ng into two restriction patterns that were related to theoretical profiles for previously sequenced Western genes. Comparisons with theoretical HindII I patterns for Japanese isolates appear suggestive of geographical H. pylor i clonality. Full-length single-step PCR amplification seems suitable for q uick restriction pattern assignment and detection of gene size changes. (C) 1999 Published by Elsevier Science B.V. All rights reserved.