TABLE 2.

Quinolone susceptibility and mutations in the gyrA and parC genes of 36 E. coli isolates from two hospitals in Taiwan

Isolate no.a	Disk zone diam (mm)b			MIC (μg/ml)		Amino acid change
	CIP	OFX	NAL	CIP	OFX	gyrA		parC
						83	87	80	81	84
K-12						Ser	Asp	Ser	Ala	Glu
1	6	6	6	>32	>32	Leu	Asn	Ile	—c	Gly
2	6	6	6	>32	>32	Leu	Asn	—	—	Lys
3	6	6	6	>32	>32	Leu	Asn	Ile	—	—
4	6	6	6	>32	>32	Leu	Asn	Ile	—	—
5	6	6	6	>32	>32	Leu	Asn	Ile	—	—
6	6	6	6	>32	>32	Leu	Asn	Ile	—	—
7	6	6	6	>32	>32	Leu	Asn	Ile	—	—
8	6	6	6	>32	>32	Leu	Asn	Ile	—	—
9	12	6	6	>32	>32	Leu	Asn	Ile	—	—
10	18	17	6	0.75	2	Leu	—	—	Pro	—
11	22	21	6	0.38	1	Leu	—	Ile	—	—
12	23	21	6	0.5	1	Leu	—	Arg	—	—
13	24	21	6	0.25	0.75	Leu	—	—	—	—
14	24	22	6	0.25	1	Leu	—	—	—	—
15	24	20	6	0.19	0.75	Leu	—	—	—	—
16	25	21	6	0.38	1	Leu	—	—	—	—
17	26	22	6	0.23	1	Leu	—	—	—	—
18	26	22	6	0.19	0.75	Leu	—	—	—	—
19	26	24	6	0.19	0.5	Leu	—	—	—	—
20	26	23	6	0.19	0.5	Leu	—	—	—	—
21	26	23	6	0.19	0.5	Leu	—	—	—	—
22	26	22	6	0.125	0.75	Leu	—	—	—	—
23	27	23	6	0.125	0.5	Leu	—	—	—	—
24	28	25	6	0.19	0.38	—	Tyr	—	—	—
25	28	26	6	0.094	0.38	—	Asn	—	—	—
26	29	25	6	0.19	0.38	Leu	—	—	—	—
27	29	27	6	0.094	0.38	—	Gly	—	—	—
28	30	26	6	0.125	0.38	—	Tyr	—	—	—
29	31	27	22	0.047	0.125	—	—	—	—	—
30	32	29	23	0.016	0.094	—	—	—	—	—
31	34	30	29	0.016	0.094	—	—	—	—	—
32	34	30	27	0.012	0.064	—	—	—	—	—
33	35	29	24	0.032	0.125	—	—	—	—	—
34	35	33	27	0.016	0.064	—	—	—	—	—
35	37	32	28	0.023	0.064	—	—	—	—	—
36	38	34	26	0.016	0.064	—	—	—	—	—

^aIsolates 1 to 9 are fully resistant, isolates 10 to 28 have reduced susceptibility, and isolates 29 to 36 are fully susceptible, as described in Materials and Methods. Isolate K-12 is a wild-type E. coli strain. 

^bCIP, ciprofloxacin; OFX, ofloxacin; NAL, nalidixic acid. 

^c—, no change.