Fig. 1.

Oligonucleotides specificity used in the PCR for 16S rRNA gene and vacA s2, m2 alleles of H. pylori. a Amplification of 522 bp fragment of the 16S rRNA gene of H. pylori. Lane 1 1 kb plus molecular weight marker; lane 2 negative control; lane 3 H. pylori strain ATCC43504; lane 4 Staphylococcus aureus strain; lane 5 Escherichia coli strain; lane 6 Campylobacter sp strain; lanes 7 and 8 unidentified bacteria strains isolated from gastric biopsies. b, c PCR amplification products of vacA alleles, s2 (b) and m2 (c). Lanes 3 H. pylori strain 26695 (vacA s1m1); lanes 4 H. pylori strain 8822 (vacA s2m2); lanes 5 H. pylori strain Tx30 (vacA s2m2); lanes 6 DNA of clinical strain HG-182 with vacA s2m2 genotype isolated from a patient with antral chronic gastritis on March 10th, 2014 and lanes 7 H. pylori vacA s2m2 in DNA from gastric biopsy UEGE-111 obtained from a patient with chronic gastritis on November 10th, 2007 (In this patient, the same genotype was detected in another biopsy taken on April 24th, 2007); lbanes 8 b and c, empty