Analysis of biofilm formation related genes and its influence factors for Staphylococcus aures food isolates

The present study investigated 14 biofilm formation related genes involved in Staphylococcus aureus food isolates and further evaluated the effect of tea polyphenols and Nisin on the growth and biofilm formation of these strains.All the 16 S.aureus strains were collected from food source. 14 adhesin genes were detected by polymerase chain reaction ( PCR) using specific primer.The antibacterial activity and minimal inhibitory concentration ( MIC) of tea polyphenols and Nisin were tested using the microtiter-plate method.The effects of tea polyphenols and Nisin on the biofilm formation were also executed using microtiterplate method.The results showed that 10/14 adhesin genes were detected.The detection rates of cna, ebp S, fib and ica AD genes were 100%, followed by sas C ( 87.5%) , fnb A ( 68.75%) , sas G ( 68.75%) , clf B ( 68.75%) , eno ( 62.5%) and ica BC ( 56.25%) , respectively.However, the bbp, bap, clf A and fnb B genes were not present in any strains detected. All the tested strains were found to have the ability to form and accumulate biofilm. F23、F44、F58、F64、F71、F86、F107 and F109 were strong biofilm producers, and F7、F19、F40、F46、F60、F99、F101、F106 were weak biofilm producers. The MIC values of tea polyphenols and Nisin to 16 strains ranged from 0.1 to 0.2 g/L and 0.125 to 1 g/L, respectively.1/2 MIC and 1/4MIC of tea polyphenols and Nisin had very significant inhibitory effect on the biofilm formation to the tested strains ( p < 0.05) , and tea polyphenols had better antibacterial activity to S.aureus strains than Nisin.The results of this study would play a valued role to the S.aureus food isolates biofilm formation and control strategy.