RESUMEN
In this study we assessed the genomic stability of Mycobacterium bovis BCG Moreau seed lots used in Poland for BCG vaccine production since 1955 by pulsed field gel electrophoresis (PFGE), amplified fragment length polymorphism (AFLP) and random amplification of polymorphic DNA (RAPD). BCG vaccine lots were more closely related the original lot -M. bovis BCG Rio de Janeiro Moreau compared with seeds used before 1980, which is consistent with seed lot distribution recorded in the archives. We confirmed the presence of RD8, RD2, senX3-regX3, RD14, DU2-I, whiB3, trcR, the second copy of IS6110 inserted in the promoter region of phoP, mutation D322G in phoR, ΔRD1, and ΔfadD26-ppsA in M. bovis BCG Moreau used for BCG production in Poland. However, unlike the Rio de Janeiro parent BCG, the BCG Moreau substrain used in Poland does not harbour a deletion in Rv3887c, a region that is involved in the membrane transport protein that is part of the ESX-2 type VII secretion system. Differences in the distribution of BCG Moreau for its subsequent use for manufacturing influenced the microevolution of BCG Moreau used in Brazil and Poland.