Genotyping of main virulence factor genes in Cuban H pylori isolates. The images shown are from a representative gel electrophoresis of two independent PCR amplification products of vacA (s1, s2, m1, m2), cagA and babA2 genes from Cuban isolates and J99 control strain. A: Lanes 1 and 7, reference strain J99 (vacAs1 and m1 alleles, respectively); Lanes 2 and 6, vacAs1 strains; Lanes 3-5, vacAs2 strains; Lanes 8 and 10 vacAm2 strains; Lane 9, vacAm1 strain. B: Lanes 1 and 4, J99 strain (cagA and babA2 gene, respectively); Lanes 2 and 3, cagA-positive strains; Lanes 5 and 6 babA2-positive strains. MW: 100 bp DNA Ladder (Promega, USA).