TABLE 2.

Sequences of mutant marR genes in six clinical Mar mutants with different ofloxacin susceptibilities

Straina	Ofloxacin MIC (μg/ml)	Cyclo- hexane toleranceb	Mutation in marR (nucleotide changed) at amino acidc:
			Glu31	Ile49	Leu78	Arg94	Gly103	Tyr137
S20	0.25	+				Ser (1724C→A)	Ser (1751G→A)	His (1853T→C)
M19	2	+	Stop codon inserted (1535G→T)				Ser (1751G→A)	His (1853T→C)
NH52	8	−					Frameshift (Δ1751d)
HO17	32	+				His (1725G→A)	Ser (1751G→A)	His (1853T→C)
HO99	32	+			Met (1676C→A)
E22	64	+		Ser (1590T→G)

^aSee Materials and Methods for strain designations. 

^bCyclohexane tolerance of strains was tested on LB agar overlaid by the organic solvent and grown for 24 h at 30°C (33). 

^cSee reference 10. 

^dΔ1751, nucleotide 1751 deleted.