. 2007 Oct 15;52(1):77–84. doi: 10.1128/AAC.01229-07

TABLE 5.

S. pneumoniae multistep resistance selection results

Strain	Agent	Initial MIC (μg/ml)	Resistance selection		Retest MIC (μg/ml) after 10 drug-free subcultures^a							Mutation(s) in:
Strain	Agent	Initial MIC (μg/ml)	MIC (μg/ml)	No. of days	DC-159a	LEVO	MOXI	GATI	GEMI	Azithro	Amox/ Clav	GyrA	GyrB	ParC	ParE
HMC 5055	DC-159a	0.125	0.125	50
	Levofloxacin	1	2	50
	Moxifloxacin	0.125	0.125	50
	Gatifloxacin	0.25	0.5	50
	Gemifloxacin	0.03	0.06	50
	Azithromycin	8	8	50
	Amox/Clav	0.03	0.03	50
HMC 63	DC-159a	0.125	0.125	50
	Levofloxacin	1	1	50
	Moxifloxacin	0.25	0.25	50
	Gatifloxacin	0.5	1	50
	Gemifloxacin	0.03	0.5	34	1	16	4	8	0.5	0.03	0.03	S81F		D83Y	I460V^b
	Azithromycin	0.03	0.06	50
	Amox/Clav	0.016	0.03	50
HMC 5048	DC-159a	0.06	0.125	50
	Levofloxacin	0.5	0.5	50
	Moxifloxacin	0.06	0.125	50
	Gatifloxacin	0.125	0.5	50
	Gemifloxacin	0.03	0.125	50
	Azithromycin	4	8	50
	Amox/Clav	0.5	1	50
HMC 99	DC-159a	0.125	0.125	50
	Levofloxacin	0.5	2	50
	Moxifloxacin	0.125	4	41	1	32	4	16	1	0.016	0.25	S81Y		S79Y
	Gatifloxacin	0.25	0.5	50
	Gemifloxacin	0.03	0.125	50
	Azithromycin	0.03	0.06	50
	Amox/Clav	0.25	0.5	50
HMC 100	DC-159a	0.125	0.5	50
	Levofloxacin	1	32	42	1	32	4	8	0.5	0.03	0.25	S81Y		S79Y
	Moxifloxacin	0.25	2	22	0.5	8	1	4	0.25	0.03	0.25	S81Y
	Gatifloxacin	0.5	0.5	50
	Gemifloxacin	0.06	1	34	0.5	16	2	4	1	0.06	0.25			S79Y
	Azithromycin	0.03	0.03	50
	Amox/Clav	0.125	0.25	50
HMC 3041	DC-159a	0.06	0.125	50
	Levofloxacin	0.5	1	50
	Moxifloxacin	0.06	0.25	50
	Gatifloxacin	0.5	0.5	50
	Gemifloxacin	0.03	0.03	50
	Azithromycin	>64	NT^c	NT
	Amox/Clav	0.25	0.25	50
HMC 228	DC-159a	0.125	1	28	1	16	2	4	1	>64	2	S81F		D83N	I460V^b
	Levofloxacin	1	2	50
	Moxifloxacin	0.125	2	36	1	32	2	16	2	>64	2	S81F		S79Y	I460V^b
	Gatifloxacin	0.5	4	38	1	16	4	4	1	>64	2	S81F		D83N	I460V^b
	Gemifloxacin	0.06	0.25	50
	Azithromycin	>64	NT	NT
	Amox/Clav	2	2	50
HMC 3583	DC-159a	0.125	1	49	1	8	2	4	0.25	2	2	S81F		D83N	I460V^b
	Levofloxacin	1	8	44	1	8	2	4	0.25	2	2	S81F		D83N	I460V^b
	Moxifloxacin	0.125	0.5	50
	Gatifloxacin	0.5	4	46	1	16	4	8	0.25	1	2	S81F			I460V,^b D435N
	Gemifloxacin	0.03	0.25	41	1	4	0.5	2	0.25	1	2				I460V^b
	Azithromycin	2	4	50
	Amox/Clav	1	2	50
HMC 1072	DC-159a	1	1	50
	Levofloxacin	16	32	50
	Moxifloxacin	4	4	50
	Gatifloxacin	8	8	50
	Gemifloxacin	0.5	1	50
	Azithromycin	>64	NT	NT
	Amox/Clav	0.016	0.016	50
HMC 1074	DC-159a	1	1	50
	Levofloxacin	16	16	50
	Moxifloxacin	4	8	50
	Gatifloxacin	4	8	50
	Gemifloxacin	0.5	4	27	4	64	16	16	2	0.016	0.03	S81F,^b E85K		S79F^b	I460V^b
	Azithromycin	0.03	0.03	50
	Amox/Clav	0.03	0.03	50

Cross-reacting strains are designated in boldface (increase in the MIC of eight times or greater). LEVO, levofloxacin; MOXI, moxifloxacin; GATI, gatifloxacin; GEMI, gemifloxacin; Azithro, azithromycin; Amox/Clav, amoxicillin-clavulanic acid.

This mutation was present in the parent strain prior to resistance selection.

NT, not tested.