Table 4.

MIC₅₀ values for penicillin G garvicin KS and micrococcin P1 determined in biofilms for the indicated strains.

Antimicrobial (mg/ml)	Strain
	ATCC 10832	Newman	USA 300	ATCC 29213	ATCC 33591	S.a. 3255
Individual components
Penicillin G	10	10	>10	10	>10	10
Combination
Garvicin KS	3.1 × 10−1	6.3 × 10−1	>5	1.25	>5	3.1 × 10−1
Penicillin G	6.3 × 10−1	1.3	>10	2.5	>10	6.3 × 10−1
FICa	0.12	0.63	NDc	1.25	NDc	0.31
Combination
Garvicin KS	1.6 × 10−1	1.25	5	3.1 × 10−1	5	3.1 × 10−1
Micrococcin P1	3.1 × 10−3	2.5 × 10−2	1 × 10−1	6.3 × 10−3	1 × 10−1	6.3 × 10−3
Penicillin G	3.1 × 10−1	2.5	10	6.3 × 10−1	10	6.3 × 10−1
FICb	0.12	1.5	NDc	0.41	NDc	0.41

^aSynergy with fractional inhibition concentration (FIC) ≤ 0.5, for two components.

^bSynergy with fractional inhibition concentration (FIC) ≤ 0.75, for three components.

^cNot determined. The MIC values exceeded the maximum concentration tested: penicillin G, 10 mg/ml; micrococcin P1 1.0 × 10⁻¹ mg/ml; garvicin KS 5 mg/ml.