Table II.

The isolates examined and their resistance profiles, with the number of strains inhibited at various minimum inhibitory concentrations (MICs)

Antibiotics	MIC of selected antibiotics for 36 isolates of C. acnes
	Number of isolates inhibited at various MIC (μg/ml)																								Resistance breakpoint (μg/ml)	Resistant strains n (%)
	≤ 0.016	0.023	0.032	0.047	0.064	0.094	0.125	0.19	0.25	0.38	0.5	0.75	1	1.5	2	3	4	8	32	48	64	≥ 256	MIC50	MIC90
Erythromycin	18	6	2	1																		9	≤ 0.016	≥ 256	≥ 0.5	9 (25)
Clindamycin	2	5	7	3	4	2	1	1	1	1	0			1	2	2	1					3	0.064	4	>2	6 (16.7)
Tetracycline				2	4	1	7	10	3		1		4				1	2				1	0.19	4	>4	3 (8.3)
Doxycycline				1	2	2	12	2	7	1	1	1	2			1	1	1	1		1		0.19	4	≥ 1	7 (19.4)
Minocycline		1	7	12	5	2	1	1			2	1	2	1					1				0.047	1	≥ 1	4 (11.1)