The Journal of Medical Microbiology, Vol 13, Issue 3 469-475, Copyright © 1980 by Society for General Microbiology
Qualitative and quantitative methods of studying the effect of lipids on bacteria grown on the surface of solid culture media
C. Davidson, C. Rogers, A. E. Taylor, D. F. Brown and G. R. Naylor
New qualitative and quantitative methods are described for the
investigation of the antibacterial activity of lipids on solid media by the
application of lipid-impregnated filter paper over a lawn of the organisms.
The methods have been used to investigate the antibacterial activity of
unsaturated fatty acids that are important in skin defence. Oleic and
linoleic acids inhibited Streptococcus pyogenes markedly, Staphylococcus
aureus and Staph epidermidis to a lesser extent and had no effect on
Escherichia coli and Pseudomonas aeruginosa. The inhibition of growth of a
strain of Str. pyogenes from a sore throat was greater than that of a
strain from an outbreak of impetigo. Linoleic acid was a more potent
inhibitor of bacterial growth than oleic acid, and with both acids
inhibition was more pronounced under aerobic than under anaerobic
conditions of incubation. The methods described could be applied in other
fields such as pharmacology, horticulture and industry.
