The Research Of Relationship Between Biofilms And Different Clinical M Serotypes Of Streptococcus Pyogenes

Background:Background Group A streptococcus pyogens(GAS)is a kind of bacteria with strong pathogenicity among streptococcus and is the main pathogen of acute respiratory tract infections especially upper respiratory infection.It call causes acute tonsillitis,scarlet fever and impetigo , and Can also arouse severe invasive infection such as septicemia , necrotizing fasciitis and streptococcus poisoning shock syndrome.M protein is the main pathogenic factor of GAS and is emiTl gene coded.The variation of M protein antigen is the basis of M—type.So far,GAS Can be classified into more than 1 00 types by the specificity of M protein antigen and different types have different pathogenicities.Some strain infections can cause serious complications such as rheumatic fever,rheumatic valvular heart disease and acute glomerulonephritis etc.Biofilm formation is a kind of microbial cell colonies Lands on abiotic or biological surface irreversibly, Packaging in extracellular matrix norbornene-type homopolymers . It is a survival way that formed by bacteria and fungus in order to adapt to the living environment in the growth process , Corresponding Planktonic cells.BF is recognized as an important virulence factor for both opportunistic pathogens and true pathogens,Can help bacteria escape from antibiotics or the immune system. It has become increasingly recognized that biofilm formation makes an important contribution to many bacterial diseases such as endocarditis, osteomyelitis, dental caries, middle ear infections, medical device-related infections, ocular implant infections, and chronic lung infections in cystic fibrosis patients , Causing persistent infection or immune diseasesSo far the most research on BF is Staphylococcus epidermidis,staphylococcus aureus,pseudomonas aeruginosa,streptococcus Streptococcus Mutans and treptococcus gordonii.A lot of foreign tials confirm that GAS can form biofilm and different emm genotypes of biofilm formed by existing difference. But there is no related reports in the literature in China.Objectives:To understand the condition of Biofilm formation of group A streptococcus pyogens in Chongqing; To understand the relationship of emm genes of infectious GAS strains and Biofilm formation.Methods: Cultivate the 20 GAS from our hospital collected from 2000～2009,Polymerase chain reaction(PCR)is amplified and sequenced to determine the type of emm genes。Culture the Biofilm of all stains and ,meature the absorbance of the Biofilm. Results:(一)the emm type of group A streptococcus pyogensThe emm type fo 20 stains of group A streptococcus pyogens is emm12.0,emm1.0,emm22.0,emm6.5和emm12.43,emm63.0,emm3.1,emm80.0,emm12.4,emm75.0,emml2.21,emm3.1,emml02.2,emmST181 .5,emm st38.(二)the condition of Biofilm formationAll fifteen emm types can produce substantial biofilms which was comparable to the positive contro(lStreptococcus mutans UA159).But biofilms between different types exist differences.The ability of emmst38 and emm12.43 to produce biofilms is better than the positive control Emm12.0 and emm75.0 are the worst。Conclusions(1) All of the genetic type can form biofilm;(2) there are differences between different emm genotype biofilm in different time periods.(3) And the growth situation of the same genotype biofilm in different time periods of is different.