OBJECTIVETo investigate the effect of houttuyfonate sodium (HS) on eliminating adhesion of Psedomonas aeruginosa (Pa) and forming biofilms.

METHODPa biofilms were established in 96-hold plates. MTT assay was used to evaluate the changes in metabolism of biofilms and assess the minimum eliminating concentration and minimum biofilm inhibitory concentration for adherent Pa. The colony counting method was used to observe the effect of HS on Pa adhesion and biomass in biofilms. SEM was employed to examine the effect of HS on adhesion of tested Pa and morphology of biofilms.

RESULTMEC80 and MEC50 of HS for adherent Pa was 500 mg x L(-1) and 125 mg x L(-1), respectively. Meanwhile, its SMIC80 for either early or mature biofilms of Pa was 500 mg x L(-1), and SMIC50 for early and mature biofilms of Pa were 31.25, 1.95 mg x L(-1), respectively. At the concentration of 250 mg x L(-1), the number of viable bacteria in the state of adhesion and in initial and mature biofilms decreased significantly, compared with the control group (P < 0.05). The number of bacteria on adherent carriers notably reduced under SEM. Following the continuous administration, there were no visible biofilms on carriers in the mature biofilm phase, with the biomass remarkably shrinking and the bacterial morphology changing from bacillus into coccobacillus.

CONCLUSIONHS displayed powerful effect on eliminating adherent Pa, and can inhibit Pa biofilm from being formed through continuous administration.