Restriction enzyme digestion pattern of the second-step PCR products. Five microliters of the second-step products was digested with 1 U of HindIII or VspI, electrophoresed in a 2% agarose gel, and stained with ethidium bromide. Lanes 1 and 8, 2,000- to 50-bp DNA marker; lanes 2, M. penetrans; lanes 3, M. fermentans; lanes 4, M. genitalium; lanes 5, M. pirum; lanes 6, M. hominis; lanes 7, M. salivarium ATCC 23064, used as a positive control. (A) HindIII-cleaved PCR products; (B) VspI-cleaved PCR products.