Effect Of Rutin On Content And Structure Of Capsular Polysaccharide In Streptococcus Suis Biofilm Formation

Streptococcus suis(S.suis)2 is an important zoonotic pathogen 。 The bacteria resistance is extremely strong after biofilm formation(BF),and the site of infection is difficult to completely remove and delayed healing.Therefore,how to inhibit biofilm formation and reduce biofilm infection is a difficult problem to be solved in veterinary clinic that has become the focus of domestic and foreign scholars.S.suis 2 biofilm formation is a complex process,which undergoes the process of adhesion,aggregation,maturation and dispersion of recycling process.After 24 h of culture,the adhesion process was completed and maturation stage from 60 to 72 h.Adhesion is the first step of biofilm formation,which is also the key to the biofilm formation and the reduction of biofilm infection.Capsular polysaccharide(CPS)is a virulence factor of S.suis 2,which not only has the function of anti phagocytosis,adhesion and colonization,but also mediates S.suis biofilm formation.When the content of CPS decreased,the biofilm formation was promoted,but the effect of the structural changes on biofilm was not clear.Rutin was a kind of flavonoid which is widely found in nature with a wide range of biological activities,cheap and easy to get.In our laboratory we found that Syringa oblata Lindl aqueous extract has an good effect on S.suis biofilms.The rutin active was discovered via analyzing the relationship between the grey correlation and spectrum,and it was the main components of clove leaf,which is not clear whether it is influence on the content and structure of capsular polysaccharides.In this paper,we studied the relationship between the changes of the content and structure of CPS and effect the S.suis biofilm formation in adhesion stage.The effect of rutin on the S.suis biofilm formation during adhesion stage,and the extraction of crude CPS by centrifugation and enzymolysis methods.The crude CPS were further purified by Sepharcryl S-300 gel permeation chromatography column.The content of polysaccharide in control group and rutin group was 50.54 ± 2.69% and 60.46 ± 4.91%,respectively,and the content of CPS was significantly increased after rutin effect the S.suis biofilm formation(P<0.05).After the analysis of thin layer chromatography(TLC)and high performance liquid chromatography(HPLC),the control group and rutin group contained galactose(Gal),glucose(Glc),N-acetyl glucosamine(Glc N),rhamnose(Rha)and sialic acid(Neu5Ac).The molar ratio of the control group is Rha: Gal: Glc: GlcN=1: 2.12: 1.09: 0.71,the molar ratio of the rutin group was composed of Rha: Gal: Glc: GlcN =1: 2.26: 0.95: 0.73.There was no significant difference in the molar ratio of monosaccharide of CPS after rutin effect the S.suis biofilm formation(P>0.05).The study of the control group and rutin group CPS and its corresponding product afterremoval of sialic acid were analysis by NMR.The results showed that 1H-NMR spectrum of the control group and rutin group CPS is consistent,and 1H-NMR spectrum of its corresponding product after removal of sialic acid is consistent,too.CPS structure unchanged after the effects of rutin on the biofilm of S.suis.In conclusion,after the effect of rutin on the S.suis biofilm during adhesion stage,the content of CPS was increased and the biofilm formation was reduced.Therefore,it is the adhesion inhibitor of S.suis biofilm formation.