Table 1.

MICs of 106 P. acnes strains to five antibiotics.

ANTIBIOTIC	MIC VALUES, µg/mL		CLSIa RESISTANCE BREAKPOINT	EUCASTb RESISTANCE BREAKPOINT	% OF STRAINS RESISTANT
	MIC50	MIC90
Penicillin G	0.016	0.032	≥2	≥0.5	0
Cephalothin	0.094	0.094	–c	–c	–
Vancomycin	0.38	0.5	–c	≥2	0
Ciprofloxacin	0.25	0.5	–c	≥1	2.8
Clindamycin	0.047	1.5	≥8	≥4	8.5*

Notes:

^aClinical Laboratory Standards Institute.

^bEuropean Committee on Antimicrobial Susceptibility Testing.

^cNo interpretive standards yet established.

^*Based on the CLSI breakpoints.