Appendix Figure. A) Identification of isolates of the Mycobacterium tuberculosis Beijing clade (6) by using spoligotyping. The spoligotype pattern of the M. tuberculosis Beijing clade is characterized by the absence of hybridization of spacers 1–34 as shown, in combination with hybridization of spacers 35–43. Negative control (Neg.) shows absence of all spacers. For comparison, H37Rv (a laboratory strain) and M. bovis BCG show different patterns of spacers. Also shown are other clades not identified. B) Restriction fragment length polymorphism (7) patterns of strains from the 2 patients. Patterns confirm that both strains belong to the Beijing clade. However, patterns indicate different strains and confirm lack of direct transmission between the patients. The 2 additional clades shown (not from these patients) illustrate differences between the Beijing and other clades.