Abstract: In order to initially investigate antimicrobial mechanisms of pyrolin against Staphylococcus S.aureus and Pseudomonas aeruginosa, the growth curves, the membrance patency and the structure under scanning electron microscope were studied. The results showed that pyrolin is able to effectively inhibit the growth of S.aureus and P.aeruginosa. The inhibitory effect against them increased with the concentration of pyrolin. Pyrolin had strong bactericidal action against S.aureus. The membrance patency of the cells affected by pyrolin of S.aureus compared with that of the normal cells dramatically increased. But that of P.aeruginosa did not change. Observation under scanning electron microscope revealed that the structure of the cells of S.aureus were significantly destroyed by pyrolin, and the cells wall were melted. The cells were sticked by the melt, the boundary between cells became obscure. The boundary between cells of P.aeruginosa also got obscure, but the structure of it was not destroyed by pyrolin. In a conclusion, the antimicrobial activity of pyrolin against S.aureus is relevant to the structure destruction of cells membrance and wall. But that of P.aeruginosa is not.

Key words: pyrolin, Pseudomonas aeruginosa, Staphylococcus aureus, antimicrobial mechanism