Susceptibility of Staphylococcus aureus and group A, B, C, and G streptococci to free fatty acids

Abstract

The susceptibility of 242 strains of S. aureus and 117 strains of streptococci of groups A, B, C and G to decanoic, dodecanoic, octadeca-9,12-dienoic and octadeca-9,12,15-trienoic acids was estimated by determination of minimal inhibitory concentrations. S. aureus strains appeared generally less susceptible to all 4 fatty acids than streptococcal strains of all groups. Dodecanoic acid was the most inhibitory fatty acid against staphylococci and streptococci. Both saturated fatty acids used were more active than the unsaturated acids. Among the unsaturated acids, octadeca-9,12,15-trienoic acid appeared more inhibitory for Staphylococcus and Streptococcus strains than octadeca-9,12-dienoic acid. No differences in susceptibility to fatty acids among staphylococcal and streptococcal strains isolated from [human] skin, throat or other sites were found.