. 2007 Jun 4;51(8):2690–2700. doi: 10.1128/AAC.00258-07

TABLE 1.

Phenotypic and genotypic characteristics of typical and atypical pneumococci and of viridans streptococci, their MICs to fluoroquinolones, and respective amino acid substitutions at the QRDRs of the gyrase and topoisomerase genes

Group and isolate no.	Characteristics^a				Sero-type	Amino acid substitution for indicated position and gene^b														MIC (μg/ml) for:
	Characteristics^a					gyrA			gyrB	parC									parE	MIC (μg/ml) for:
	Phenotype		PCR			Ser 81	Ser 114	Asp 142	Ser 494	Ser 52	Phe 55	Ser 58	Ser 79	Asp 83	Asn 91	Glu 96	Glu 135	Lys 137	Ile 460	CIP	LEV
	OPT	Bile	lytA	ply		Ser 81	Ser 114	Asp 142	Ser 494	Ser 52	Phe 55	Ser 58	Ser 79	Asp 83	Asn 91	Glu 96	Glu 135	Lys 137	Ile 460	CIP	LEV
Typical S. pneumoniae
L5	S	P	P	P	NT														Val	4	2
L6	S	P	P	P	23F	Phe												Asn	Val	8	16
L12	S	P	P	P	19F	Phe							Phe						Val	64	16
L13	S	P	P	P	19F									Tyr					Val	4	2
L14	S	P	P	P	NT													Asn	Val	4	2
L15	S	P	P	P	23F									Asn				Asn	Val	8	2
L22	S	P	P	P	23F													Asn	Val	4	2
L24	S	P	P	P	23F	Phe			Thr					Asn				Asn	Val	≥16	8
Viridans streptococci
L2	R	N	N	N	Rough		Gly		Thr	Gly					Asp				-	4	2
L7	R	N	N	N	Rough		Gly		Thr	Gly					Asp				-	4	2
L16	R	N	N	N	Rough		Gly		Thr	Gly					Asp				-	4	1
L17	R	N	N	N	Rough		Gly		Thr	Gly					Asp				-	4	1
L18	R	N	N	N	Rough		Gly	Asn	Thr										Val	4	2
L19	R	N	N	N	Rough		Gly		Thr	Gly					Asp				Val	4	2
L20	R	N	N	N	Rough				Thr	Gly					Asp				-	8	2
L21	R	N	N	N	Rough				Thr									Asn	-	16	2
L26	R	N	N	N	Rough	Phe												Asn	-	16	16
Atypical pneumococci
a
L3	R	N	P	P	Rough													Asn	-	4	1
L8	R	N	P	P	Rough					Gly	His	Gly			Asp			Asn		8	2
L9	R	N	P	P	Rough		Gly		Thr									Asn	-	4	2
L10	R	N	P	P	Rough	Phe												Asn	-	4	2
L4	R	P	P	P	Rough														-	4	2
L1	R	I	P	P	Rough	Phe							Phe			Asp		Asn	-	>32	16
b
L25	S	I	N	P	Rough													Asn	-	4	2
L27	S	I	P	P	Rough					Gly					Asp		Asp		-	4	1
L11	S	I	P	P	Rough					Gly					Asp		Asp		-	8	2

Within the atypical pneumococcal group, all isolates possess the lytA and ply genes, but group “a” strains have reduced susceptibilities to optochin, while group “b” strains are optochin susceptible. Isolates may be bile soluble (P), insoluble (N), or incompletely soluble (I). OPT, optochin test; Bile, bile solubility test; lytA, autolysin gene; ply, pneumolysin gene.

Position of amino acid substitution compared to the corresponding amino acid position of S. pneumoniae R6. Bold characters indicate QRDR and amino acid substitutions unique compared to those of R6 and more compatible with those of viridans streptococci. -, not done.