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

Optical density of <i>S. aureus</i> samples incubated with the supernatant from <i>P. acnes </i>cultures. <i>P. acnes</i> 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 <i>S. aureus</i> in various concentrations. Here either with 6.25 % supernatant or 100% supernatant.