Representative 2D-PAGE image for BCG Mexico and comparison with the proteomes of BCG Danish, Phipps and Tokyo. One hundred micrograms of cellular protein were loaded onto IPG strips (pH 4-7) for isoelectrofocusing at 52,000 VH and run on sodium dodecyl sulphate (SDS) 12.5% polyacrylamide gels. The gels were silver-stained and analysed using PDQuest 2D Analysis V8.0 (Bio-Rad). Green triangles indicate spots common to all strains; red squares mark spots unique to BCG Mexico. *Percentage calculated based on the number of spots in the BCG Mexico proteome.