[Preliminary study of effects of andrographolide on Staphylococcus epidermidis biofilms]

To provide a new therapeutic approach for Staphylococcus epidermidis biofilm-associated infections by the study of inhibitory effect of andrographolide (AG) on S. epidermidis biofilm.

S. epidermidis biofilms were set up in vitro, erythromycin was acted as the positive control agent, XTT reduction assay was used to evaluate AG on the initial adhesion of S. epidermidis and bacterial metabolism within biofilm, microscope was applied to observe biofilm morphology, and Congo red assay was used to detect polysacchatide interc-ellular adhesion (PIA)formation when exposed to AG.

AG showed inhibitory effects against the initial adhesion of S. epidermidis at concentrations of 1 000,100, 10 mg x L(-1), respectively,and inhibited metabolism of biofilm bacteria at the concentration of 31.25 mg x L(-1), and exhibited significantly inhibition against the biofilm morphology at the concentration of 250 mg x L(-1), while did not display inhibition against PIA formation at the concentration of 10 mg x L(-1).

AG could remarkably inhibit biofilm formation of S. epidermidis, although it was less potent than erythromycin.