TABLE 1.

Effect of ciprofloxacin on spontaneous MRs, MICs before and after 10 passages in ciprofloxacin-containing medium, and accumulation of mutations in the gyrA and grlA genes after 10 passages

Strain	Inoculum (CFU/ml)	Spontaneous MR	MIC of the parent strain (μg/ml)	MIC after 10 passages (μg/ml)	Mutation(s) in gene after 10 passages
					gyrA	grlA
MSSA1	2.0 × 1010	5.1 × 10−5	0.25	64	Ser-84→Leu	Ser-80→Phe
MSSA2	1.2 × 109	4.9 × 10−6	0.25	128	Glu-88→Lys	Ser-80→Tyr
MSSA3	5.3 × 109	1.6 × 10−7	0.12	128	Ser-84→Leu	Ser-80→Phe
MSSA4	7.0 × 109	1.9 × 10−5	0.12	256	Glu-88→Lys	Ser-80→Phe, Glu-84→Val
MSSA5	4.6 × 109	3.4 × 10−7	0.25	1,024	Ser-84→Lys	Ser-80→Tyr, Glu-84→Val
MSSA6	1.2 × 1010	4.5 × 10−6	0.25	128	Ser-84→Leu	Glu-84→Val
MSSA7	2.2 × 1010	1.3 × 10−5	0.06	64	Glu-88→Val	Glu-84→Val
MSSA8	7.3 × 109	5.4 × 10−6	0.12	>1,024	Ser-84→Leu	Ser-80→Tyr, Glu-84→Val
MSSA9	6.5 × 109	9.0 × 10−7	0.25	128	Ser-84→Lys	Ser-80→Phe
MSSA10	8.5 × 109	4.7 × 10−5	0.25	512	Glu-88→Lys	Ser-80→Phe, Glu-84→Val
MRSA1	2.9 × 1010	7.2 × 10−6	0.12	64	Ser-84→Leu	Glu-84→Val
MRSA2	9.2 × 109	8.5 × 10−6	0.25	1,024	Ser-84→Lys	Ser-80→Phe, Glu-84→Val
MRSA3	7.3 × 109	3.6 × 10−7	0.12	256	Glu-88→Lys	Ser-80→Phe, Glu-84→Val
MRSA4	6.5 × 109	4.6 × 10−5	0.25	512	Ser-84→Leu	Ser-80→Tyr, Glu-84→Val
MRSA5	5.2 × 109	6.3 × 10−6	0.12	256	Ser-84→Lys	Ser-80→Phe, Glu-84→Val
MRSA6	1.1 × 1010	7.8 × 10−7	0.06	128	Glu-88→Val	Ser-80→Tyr
MRSA7	6.9 × 109	5.9 × 10−6	0.06	64	Glu-88→Lys	Glu-84→Val
MRSA8	8.2 × 109	6.8 × 10−7	0.12	1,024	Ser-84→Lys	Ser-80→Phe, Glu-84→Val
MRSA9	5.1 × 109	1.4 × 10−5	0.06	128	Ser-84→Leu	Glu-84→Val
MRSA10	4.9 × 109	7.9 × 10−6	0.12	>1,024	Glu-88→Val	Ser-80→Phe, Glu-84→Val
BB255	4.8 × 109	3.8 × 10−6	0.25	256	Ser-84→Lys	Ser-80→Phe, Glu-84→Val
BB270	5.7 × 109	4.1 × 10−6	0.25	512	Ser-84→Leu	Ser-80→Tyr, Glu-84→Val