TABLE 2.

Fluoroquinolone susceptibilities of S. oralis and S. mitis and their respective amino acid substitutions at the QRDRs of the gyrase and topoisomerase genes^a

Isolate no.	MIC (μg/ml) for:		Result for efflux phenotype detection	Amino acid substitution at indicated QRDRb
	CIP	LEV		gyrA			gyrB			parC							parE
				Ser 81	Ser 114	Leu 155	Ile 385	Met 483	Ser 494	Ser 52	Ser 79	Asp 83	Asn 91	Glu 135	Pro 140	Ala 142	Arg 447
S. pneumoniae R6	0.5	0.5	-
S. oralis																	-
ATCC 10557	2	1	N		Gly				-				Asp				-
HK575	1	1	-		Gly	Val			-	Gly			Asp		Ser		-
HK323	2	1	P		Gly				-	Gly			Asp				-
HK417	2	1	P		Gly				-	Gly			Asp				-
HK496	2	1	P		Gly				-	Gly			Asp				-
HK553	2	1	P		Gly				-	Gly			Asp				-
HK62	4	1	P		Gly				-	Gly			Asp				-
HK122	4	1	P		Gly				-	Gly			Asp				-
HK123	4	1	P		Gly				-	Gly			Asp				-
HK271	4	1	P		Gly				-	Gly			Asp				-
HK300	4	1	P		Gly				-	Gly			Asp				-
HK312	4	1	P		Gly				-	Gly			Asp				-
HK51	4	2	P		Gly				-	Gly			Asp				-
HK299	4	2	P		Gly				-	Gly			Asp				-
HK579	4	2	P		Gly				-	Gly			Asp				-
HK587	4	2	P		Gly				-	Gly			Asp				-
HK386	4	2	P		Gly				-	Gly			Asp				-
HK619	4	2	P		Gly				-	Gly			Asp				-
HK574	8	2	P		Gly		Val	Thr	Thr	Gly			Asp
HK816	32	32	N	Leu	Gly				-	Gly	Tyr		Asp
HK754	128	≥32	N	Leu	Gly				Thr	Gly		Tyr	Asp				Ser
S. mitis
ATCC 49456	1	1	-		Gly					Gly			Asp	Asp		Ser
HK260	<0.5	<0.25	-		Gly				-	Gly			Asp				-
HK141	1	0.5	-		Gly				-	Gly			Asp				-
HK188	1	0.5	-		Gly				-	Gly			Asp	Asp			-
HK651	1	0.5	-		Gly				-	Gly			Asp				-
HK137453	2	1	P		Gly				-	Gly			Asp				-
HK680	2	1	P		Gly				-	Gly			Asp
HK125807	2	1	P		Gly				-	Gly			Asp				-
HK467	2	1	N		Gly	Val			-	Gly			Asp				-
HK666	2	2	P		Gly				-	Gly			Asp	Asp			-
HK135786	4	1	P		Gly				-	Gly			Asp				-
HK29	4	2	P		Gly				-	Gly			Asp				-
HK677	128	≥32	N	Leu	Gly				Thr	Gly	Tyr		Asp				-

^aP, positive; N, negative; -, not done.

^bPosition of amino acid substitution compared to the corresponding amino acid position of S. pneumoniae R6.