Table 2.

Minimum inhibitory concentrations of various antimicrobial agents against groups of Gram-positive bacteria including isolates with defined resistance mechanisms.

Organism (No. Tested) and Antimicrobial Agent	Concentration (mg/L)
	Mode	MIC50	MIC90	Range
All S. aureus (n = 50)
Alafosfalin	4	4	8	0.125–16
Di-alanyl fosfalin	4	8	16	0.5–32
β-Cl-Ala-β-Cl-Ala	2	2	4	0.125–16
Fosfomycin	8	4	16	0.5–> 32
MRSA (n = 37)
Alafosfalin	4	4	8	0.125–16
Di-alanyl fosfalin	4	8	16	0.5–32
β-Cl-Ala-β-Cl-Ala	2	2	4	0.125–16
Fosfomycin	8	4	16	0.5–> 32
MSSA (n = 13)
Alafosfalin	4	4	8	0.25–16
Di-alanyl fosfalin	16	8	16	0.5–32
β-Cl-Ala-β-Cl-Ala	1	1	2	0.5–2
Fosfomycin	4	4	16	2–16
All Enterococci (n = 50)
Alafosfalin	8	16	> 32	4–> 32
Di-alanyl fosfalin	0.5	0.5	2	≤ 0.016–> 32
β-Cl-Ala-β-Cl-Ala	16	16	32	2–16
Fosfomycin	> 32	> 32	> 32	16–> 32
E. faecalis (n = 11)
Alafosfalin	8	8	32	4–> 32
Di-alanyl fosfalin	0.031	0.063	0.5	≤ 0.016–> 32
β-Cl-Ala-β-Cl-Ala	8	8	16	4–16
Fosfomycin	32	32	> 32	32–> 32
E. faecium (n = 34)
Alafosfalin	16	16	16	4–32
Di-alanyl fosfalin	0.5	0.5	2	≤ 0.016–4
β-Cl-Ala-β-Cl-Ala	16	16	32	2–> 32
Fosfomycin	> 32	> 32	> 32	16–> 32
GRE (n = 43)
Alafosfalin	16	16	> 32	4–> 32
Di-alanyl fosfalin	0.5	0.5	> 32	≤ 0.016–> 32
β-Cl-Ala-β-Cl-Ala	16	16	> 32	4–> 32
Fosfomycin	> 32	> 32	> 32	32–> 32

Abbreviations: MIC₅₀: concentration of antimicrobial required to inhibit 50% of isolates. MIC₉₀: concentration of antimicrobial required to inhibit 90% of isolates. MRSA: methicillin-resistant S. aureus; MSSA: methicillin-susceptible S. aureus; GRE: glycopeptide-resistant enterococci.