TABLE 5.

Resistance mechanisms of selected clones obtained during serial passage; five mutants with elevated MICs towards moxifloxacin

Parental strain	Antibiotic	Initial MIC (μg/ml)	Increased MIC	No. of passages	Mutation in topoisomerases II and IV
					GyrA	GyrB	ParC	ParE
1076	MXFa	2	32	50	E85K	G406V	—	K458N
3406	MXF	0.5	4	50	S81F	—	D83N	—
3413	MXF	0.125	1	50	E85Q	—	—	P454S
3656	MXF	0.125	1	50	—b	—	S79Y	—
6733	MXF	0.125	1	50	S81Y	—	—	—

^aMXF, moxifloxacin.

^b—, no mutation.