TABLE 1.

23S and L4 mutations and characterization of mutated isolates^e

Strain no.	Mutation in 23S rRNA gene at:		No. of mutated genesf	Mutation in protein L4 (position 69GTG71b)	Acquired macrolide resistance gene	PFGE subtypec	Sero- type	Specimen type	MIC (μg/ml) of:
	A2059a	C2611a							Azithromycin	Erythromycin	Clarithromycin	Clindamycin	Lincomycin	Spiramycin	Telithromycin (HMR 3647)	HMR3004	Dalfopristin (streptogramin A)	Quinupristin (streptogramin B)	Quinupristindalfopristin (RP59500)	Chloramphenicol
r330d	wt	wt	0	wt	S	ND	ND	Ear	0.5	0.063	1	0.125	2	0.5	0.031	0.063	>64	8	1	4
r744d	wt	wt	0	wt	erm(B)	ND	23F	Ear	>512	>512	>512	>64	>128	>512	0.063	0.125	>64	32	2	16
r490	C	wt	4	wt	None	A	14	Sinus	128	256	512	0.5	16	512	0.063	0.25	32	16	1	2
r678	C	wt	4	wt	None	A	14	Ear	512	>512	>512	1	16	>512	0.063	0.5	64	32	2	2
r684	C	wt	4	wt	None	L	14	Ear	512	>512	>512	1	16	>512	0.125	0.5	64	32	1	2
r733	C	wt	4	wt	None	A	14	Not known	512	>512	>512	1	16	>512	0.125	0.5	64	32	2	2
r1152	C	wt	4	wt	None	A	14	Nose	512	512	>512	1	16	512	0.125	0.5	64	32	2	2
r1317	C	wt	3	wt	None	F	23	Sinus	512	>512	>512	2	32	>512	0.125	0.5	>64	32	2	2
r506	C	wt	2	wt	None	A	14	Ear	128	256	512	1	8	512	0.063	0.25	64	32	2	2
r771	G	wt	2	wt	None	I	15	Sputum	>512	256	>512	2	32	>512	0.25	0.5	64	32	4	4
r1341	G	wt	2	wt	None	H	14	Blood	>512	64	256	1	16	512	0.063	0.125	64	16	2	2
r1045	wt	G	4	wt	None	N	6B	Ear	128	>512	>512	1	8	16	0.5	2	8	>64	2	4
r791	wt	wt	0	TPS	None	J	19A	Throat	>512	>512	>512	0.25	2	64	0.25	0.5	>64	16	2	4
ATCC 49619d	wt	wt	0	ND	None				0.5	0.125	0.5	0.125	1	0.5	0.016	0.125	64	4	1	2

^aNucleotides in the wild-type 23S rRNA gene.

^bAmino acids in the wild-type L4 protein.

^cDifferent PFGE subtypes are listed in alphabetical order.

^dControl strain.

^eAbbreviations: S, erythromycin-susceptible strain; wt, wild type; ND, not done.

^fOut of four examined.