Combined treatment of Pseudomonas aeruginosa PA01 biofilm formation with the water-soluble extract of Ligustrum sinense and gentamicin sulphate.

Ligustrum sinense are commonly used for their anti-inflammatory, anti-rheumatic, diuretic, and hypotensive activities in traditional Chinese medicine. To observe the effects of the combined treatment of a water-soluble extract of Ligustrum sinense (WEL) and gentamicin sulphate (GS) on Pseudomonas aeruginosa PA01, the micro-dilution method was used to determine the minimal inhibitory concentration (MIC) of GS. Formation of a PA01 biofilm was observed under an optical microscope after treatment with different dosages of WEL and combined treatment with GS. The MIC of WEL was 8g l(-1), and permanent activity was also observed. The effect of WEL with GS was synergistic. The motility, biomass of biofilms, and production of pyocyanin of P. aeruginosa were strongly suppressed in the presence of WEL. The conclusion can be drawn that combined antibiotics can be used to treat the contamination due to the biofilm formation caused by P. aeruginosa.