A simplified medium for detecting the effect of lecithin on the growth of Propionibacterium acnes.

Thirty strains of Propionibacterium acnes were assayed to detect the effect of lecithin on their growth and to test the nutritional requirement of this bacterium for this phospholipid. The liquid lecithin medium (LLM) and solid lecithin medium (SLM), containing purified bovine lecithin (PBL) supported the growth of P. acnes strains assayed. Two percent PBL, which was an optimal concentration of lecithin (w/v in LLM and SLM) for the normal growth of P. acnes, was found to be inhibitory for the growth of a strain of Staphylococcus aureus tested. the growth of P. acnes in lecithin media was consistently comparable to the growth patterns of P. acnes in complex media. These results indicated that lecithin in lower concentrations than 2% stimulated the growth of P. acnes. There was an indication that this bacterium may produce enzymes capable of hydrolyzing this phosphoglyceride, incorporated in a defined basal medium, to use it as a source of carbon, energy and fatty acids.