Table 2.

Characteristics of acquired vancomycin resistance systems.

System	Resistance level	MIC [µg/ml]		Conjugation	Mobility	Expression	Location	Modification	Organisms†
		Vancomycin	Teicoplanin
		VanA	High							64–1000	16–512	Positive	Tn1546	Inducible	Plasmid or chromosome	d-Ala-, d-Lac	Enterococcus faecium, E. faecalis, E. durans, E. gallinarum, E. hirae, E. casseliflavus, E. raffinosus, E. avium, E. mundtii, Streptococcus bovis, S. gallolyticus, Staphylococcus aureus (MRSA), Bacillus circulans et al.
VanB	Variable	4–1000	0.5–1	Positive	Tn1547/ Tn1549 Tn5382	Inducible	Plasmid or chromosome	d-Ala-, d-Lac	E. faecium, E. faecalis, E. durans, E. gallinarium, S. bovis, S. gallolyticus, Clostridium bolteae
VanM	High	>256	>96	Positive	Unknown	Inducible	Plasmid	d-Ala-, d-Lac	E. faecium
VanD	Moderate	64–128	4–64	Negative	Unknown	Constitutive	Chromosome	d-Ala-, d-Lac	E. faecium, E. faecalis, E. raffinosus
VanE	Low	8–32	0.5	Negative	Unknown	Variable	Chromosome	d-Ala-, d-Ser	E. faecalis
VanG	Low	16	0.5	Positive	Unknown	Inducible	Chromosome	d-Ala-, d-Ser	E. faecalis
VanL	Low	8	n.d.	Negative	Unknown	Variable	Chromosome	d-Ala-, d-Ser	E. faecalis
VanN	Low	16	0.5	Positive	Unknown	Constitutive	Chromosome	d-Ala-, d-Ser	E. faecium
VanC (intrinsic)	Low	2–32	0.5–1	Negative	–	Constitutive	Chromosome	d-Ala-, d-Ser	E. gallinarum, E. casseliflavus

^†Limited to clinically relevant species.

d-Ala: d-alanine; d-Lac: d-lactate; d-Ser: d-serine; MRSA: Methicillin-resistant Staphylococcus aureus; n.d: Not determined.

Adapted from [50].