Optical density measurements of the influence of P. acnes fermentation products on the growth of S. aureus.

Optical density of S. aureus samples incubated with the supernatant from P. acnes cultures. P. acnes was cultured in Luria broth medium in the absence ( n = 5) or in the presence ( n = 5) of glycerol for five days.
Subsequently, the cultures were centrifuged at 5000 rpm for 30 minutes and the supernatant was
used as the medium to culture S. aureus in various concentrations. Here either with 6.25 % supernatant or 100% supernatant.