Representative AP-PCR patterns exhibited by selected strains. The results obtained with primer 2 and primer 4 are shown as indicated. Lanes: 1, VP1281; 2, VP1282; 3, VPFO1-5; 4, APCCVP9810; 5, 1001A46; 6, VPFOO-10; 7, VP-81; M1, φX174 DNA digested with HaeIII; M2, 1-kb DNA ladder. Arbitrarily designated AP-PCR patterns are indicated at the bottom. The test strains and their AP-PCR patterns are listed in Table 3.