Triclosan inhibition of fatty acid synthesis and its effect on growth of Escherichia coli and Pseudomonas aeruginosa.
by
Escalada MG, Harwood JL, Maillard JY, Ochs D.
Welsh School of Pharmacy,
Cardiff University,Cardiff CF10 3XF, UK. J Antimicrob Chemother. 2005Jun;55(6):879-82. Epub 2005 Apr 28.
ABSTRACT
OBJECTIVES: To assess the effect of triclosan on fatty acid synthesis
and to relate the inhibition of enoyl reductase to bacterial viability.
METHODS: The effect of triclosan on fatty acid synthesis in a
triclosan-resistant Escherichia coli and its sensitive counterpart and
in Pseudomonas aeruginosa was investigated by measuring acetate
incorporation into total lipid followed by analysis of fatty acid
methyl esters by gas chromatography. Concurrently, the bactericidal
effect of triclosan against these bacterial strains was assessed.
RESULTS: Triclosan inhibited fatty acid biosynthesis in all the strains
tested. However, for triclosan-resistant E. coli (MIC > 1000 mg/L)
the concentration required to achieve inhibition was higher than that
required for the susceptible counterpart. These concentrations did not
significantly affect cell survival in any of the strains tested.
CONCLUSIONS: This study shows that the inhibition of fatty acid
biosynthesis by the bisphenol might be involved in its
growth-inhibitory action and that other mechanisms are involved in its
lethal effect. In addition, although microorganisms with a high
triclosan MIC were still susceptible to the inhibitory effect of the
bisphenol on fatty acid biosynthesis, a higher concentration of the
compound was required. This suggested that triclosan bioavailability
was different in these strains.