Table 2.

Minimal inhibitory concentration (MIC) range, MIC₅₀, MIC₉₀ of antimicrobial agents against C. acnes; breakpoint resistance, percentage and no. of resistant strains

Antimicrobial agent	Test	MIC range (min to max) [µg/mL]	MIC₅₀ [µg/mL]	MIC₉₀ [µg/mL]	Breakpoint resistance [µg/mL]	% resistance (no. of strains)
Nadifloxacin	Agar dilution	0.097 to 0.390	0.195	0.195	≥4^†	0.00 (0)
Clindamycin	E‐Test	0.023 to >256	0.047	0.750	≥8^†, ^‡, ^§, ^¶	4.11 (3)
Erythromycin	Agar dilution	<0.024 to >200	0.024	200	≥2^‡ ≥8^†	For both breakpoints: 15.07 (11)
Tetracycline	Agar dilution	0.390 to 3.125	0.390	0.780	≥16^‡, ^§	0.00 (0)

^†

Alba et al. ¹ .

^‡

Sardana et al. ⁸ .

^§

Clinical and Laboratory Standards Institute (CLSI) Performance Standards for Antimicrobial Susceptibility Testing, 29th Edition, CLSI Supplement M100, Wayne PA: Pennsylvania; 2019.

^¶

The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters. Version 9.0, 2019. http://www.eucast.org.