Study On Elimination Effect Of Seven Chinese Medicines On Drug Resistance Of Staphylococcus Aureus

Staphylococcus aureus is the major infectious pathogenic bacteria of cow mastitis,which leads to low cure rate,high recurrence rate of this disease,often to decline of milk production and quality,and to larger amount of deserted milk and dealth of cows.It actually causes great loss in economy.Many studies have shown the increasing resistance of S.aureus,and there are many researches on resistant plasmid and genes and the related mechanism.However,the traditional Chinese medicine lacks details of the research on its resistance elimination.To find a way appropriate to solve the severe resistance of S.aureus,this paper focuses on the effects of seven kinds of heat-clearing and detoxifying Chinese medicine which mainly includes: Radix isatidis phellodendri,Herba Andrographitis,Herba Houttuyniae,Rhubarb,Radix Bupleuri,Coptidis rhizoma,to eliminate the resistance of S.aureus.This study separates 19 strains of S.aureus of milk samples in the large-scale cow farms.Through disk diffusion for drug susceptibility,the study covers the disk of antibiotic susceptibility on the blood petri dish.Next select four bacterial stains with strong and multi-drug resistance,and use PCR to detect the presence of resistance genes such as tetracycline(Tet A),aminoglycoside-related(aac(6’)/aph(2’’)),quinolone-related(Nuc),and Florfenicol A(fex A).Then through microdilution broth method,we can measure the minimal inhibitory concentration(MIC)of seven traditional Chinese medicine to S.aureus,and its Sub-MIC elimination effect of No.14 S.aureus R-plasmid.Then adopt division method of each one,set up three groups: experimental group,SDS(Sodium dodecyl sulfate)group,and blank group,record the resistance elimination rate of each group at two timings:24h and 48 h respectively.Then repeat experiments for three times at each timing.From the study,the results are as follow,(1)in this experiment,we collect a total of 87 samples from many places in Hunan province,and 19 strains of S.aureus,with a detection rate of 24.35%.The resistance of the 19 strains to antibiotics is different.All of these are multi-resistant,with the lowest resistant to 2 kinds,the highest resistant to 8 kinds,and 3strains are resistant to 8 kinds of antibiotics.Among them,the resistance rate to β-lactam antibiotic penicillin is 89.3%,to erythrocin and gentamicin is more than 50%,and to vancomycin is generally sensitive.(2)Four resistant genes are generally found in S.aureus.(3)The elimination rate of seven traditional Chinese medicine from 1.2% to 25.2% at24h-28 h.Different medicines have different elimination effects of resistance to S.aureus at24 h and 28 h.(4)The elimination effect of Coptis chinensis,rhubarb,Bupleurum etc.is better,followed by Houttuynia cordata and Phellodendri,and the elimination effect of Radix isatidis is the worst.(5)The effect of Coptis chinensis on the elimination of Staphylococcus aureus aac(6 ’)/ aph(2’ ’)and Nuc resistance genes is obvious...