Identification and partial characterisation of an extracellular activator of fatty acid modifying enzyme (FAME) expression in Staphylococcus epidermidis

Fatty acid modifying enzyme (FAME) is an extracellular enzyme that inactiva tes bactericidal fatty acids by esterifying them to cholesterol, Inactivati on of these fatty acids may allow Staphylococcus epidermidis to live for lo ng periods of time on the skin. This study describes the identification and partial characterisation of an extracellular activator of FAME production, Addition of FAME-free concentrated culture filtrate (activator) to S, epid ermidis cultures (OD600 = 0.05) caused a 3-5-fold increase in FAME activity . Addition of the activator did not increase the amount of exopolysaccharid e produced by S, epidermidis. The mol,wt of this activator was <3000 kDa an d it was quite resistant to boiling. Treatment of the activator with protei nase K did not destroy its ability to induce FAME expression. Addition of S , aureus activator to S, epidermidis cultures also increased FAME expressio n. However, when S, epidermidis activator was added to S, aureus cultures n o increase or inhibition in FAME production was observed.