FIG. 4.

HinfI RFLP. Genomic DNA was digested with HinfI and probed on Southern blots with a digoxigenin-labelled 347-bp fragment of the gyrA gene. Quinolone-sensitive strains produced a 277-bp HinfI fragment, whereas nalidixic acid-resistant strains yielded a 376-bp fragment, indicating the loss of the HinfI site at position 244. Lanes: 2, SB96-65; 3, SA96-9; 4, SB96-52; 5, SH96-14; 6, LT2; 7, SB95-25; 8, SA95-10; 9, SB95-6; 10, SB96-11; 11, SB96-21; 12, SP95-111; 1 and 13, Marker VI (Boehringer) molecular size markers (in base pairs) labelled with digoxigenin. Lanes 5, 7, 8, 9, and 12 contain nalidixic acid-resistant strains.