TABLE 1.
Enterococcus faecium strains used in this study
| Strain | Reference | Genotype | MICa |
||||
|---|---|---|---|---|---|---|---|
| CPT (mg/liter) | COL (mg/liter) | PB (mg/liter) | DAP (mg/liter) | LL-37 (μM) | |||
| D344R | 9 | Wild-type E. faecium | 32 | 128 | 128 | 4 | 32 |
| D344S | 10 | Δpbp5 (ΔPBP5) derivative of D344R | 32 | >256 | 192 | 3 | 32 |
| CV536 | 11 | ΔpbpF (ΔPBP3) derivative of D344R | 32 | >256 | 256 | 2 | 32 |
| CV537 | 11 | ΔpbpZ (ΔPBP2) derivative of D344R | 8 | 192 | 192 | 2 | 8 |
| CV551 | 11 | ΔpbpF ΔpbpZ derivative of D344R | 32 | 192 | 128 | 1 | 8 |
| CV558 | 11 | ΔpbpF ΔponA derivative of D344R | 32 | 256 | 192 | 1.5 | 32 |
| CV598 | 11 | ΔpbpF ΔpbpZ ΔponA derivative of D344R | 16 | 48 | 48 | 1 | 16 |
| CV571/pCWR1686 | 11 | ΔponA (ΔPBP1) (cv558 complemented with pbpF plasmid; Kmr) | 16 | 192 | 192 | 2 | 8 |
| 8019 | 6 | Contemporary vancomycin-resistant E. faecium | NP | NP | NP | 0.38 | 2 |
a
CPT, ceftaroline (broth microdilution); COL, colistin (Etest); PB, polymyxin B (Etest); DAP, daptomycin (Etest); LL-37 (broth microdilution). NP, not performed. Kmr, kanamycin resistance. For D344R and all its mutants, the MICs were as follows: vancomycin, 2 mg/liter (Etest); telavancin, <0.5 mg/liter (broth microdilution); linezolid, 0.75 to 1.0 mg/liter (Etest); and minocycline, 16 mg/liter (Etest).