TABLE 3.

Antibiogram and doubling time of Mu3-derived and N315ΔIP-derived rpoB mutant strains

Straina	RpoB amino acid substitution	Phenotype of vancomycin resistanceb	DT (min)c	Etest MIC (mg/liter) with MH or BHI agar mediumd
				Vancomycin		Teicoplanin		Rifampin BHI	Daptomycin BHI	Linezolid BHI	Oxacillin BHI	Imipenem BHI	Bacitracin MH	Gentamicin MH
				MH	BHI	MH	BHI
Clinical
Mu50	H481Y	VISA	37.1	8	12	12	24	>32	4	0.38	>256	>32	>256	>256
Mu3	WTe	hVISA	36.9	2	3	12	24	0.008	1.5	0.75	>256	>32	256	256
Mu3-derived
6R-P	R512P	sVISA	62.2	4	12	16	32	0.006	3	0.5	>256	>32	>256	>256
L1	P512L	hVISA	38.2	2	3	12	32	0.012	2	0.75	>256	>32	256	256
L2	P512S	hVISA	39.7	2	3	12	32	0.008	2	0.75	>256	>32	>256	256
L3	P512H	hVISA	36.9	2	4	12	32	0.012	2	0.75	>256	>32	>256	>256
N315ΔIP-derived
ΔIP	WT	VSSA	26.7	0.5	1	1	1.5	0.008	0.5	1	8	32	24	1
ΔIPrpoB(R512P)	R512P	hVISA	41.2	1.5	4	2	4	0.016	3	0.75	>256	>32	256	0.25
H14	WT	hVISA	28.3	1.5	3	4	16	0.008	2	0.75	>256	>32	64	0.75
H14rpoB(R512P)	R512P	sVISA	45.2	4	8	12	24	0.012	3	0.5	>256	>32	>256	0.25

^aThe 6R-P culture did not include LC or SC at a frequency of >1 × 10⁻⁷. H14 is equal to ΔIPvraS(S329L).

^bsVISA, slow VISA; hVISA, heterogeneous VISA.

^cDT, doubling time.

^dMH, Mueller-Hinton broth; BHI, brain heart infusion broth or agar.

^eWT, wild type.