Effects Of 34 Traditional Chinese Medicines On Drug Resistance And Biofilm Of Staphylococcus Aureus Of Bovine Origin

Staphylococcus aureus(S.aureus)is one of the main pathogens causing mastitis in dairy cows.Milk quality,yield and nutrient content will all decrease after cows are infected with mastitis.The long-term and large-scale use of antibacterial drugs has led to increasingly serious drug resistance of Staphylococcus aureus,increasing the difficulty and cost of treatment of the disease,and causing major economic losses to the dairy industry.This experiment studied the susceptibility of bovine Staphylococcus aureus to commonly used antibacterial drugs,the drug resistance genes carried by it and the influence of traditional Chinese medicine on drug resistance genes and biofilm formation related genes,in order to provide a basis for clinical treatment.The main research contents are as follows:1.The inhibitory effect of 34 traditional Chinese medicine decoctions on Staphylococcus aureus was detected by the plate punching method,MIC and MBC.The results showed that 13 of the 34 traditional Chinese medicines had different degrees of inhibitory effects on Staphylococcus aureus,among which Phellodendron Phellodendron,Burnet,Coptidis Rhizoma and Gallnut had the best antibacterial effects.2.The sensitivity of Staphylococcus aureus to commonly used antibacterial drugs was detected by the K-B disc diffusion method,and the drug resistance genes carried by PCR method were detected.Influence.The results showed that SA1 carried drug-resistant genes mec A and mec B;SA2 carried drug-resistant genes mec A and mef A;SA1 was moderately sensitive to ceftazidime,and to 15 drugs including gentamicin,clindamycin,erythromycin and oxacillin Highly sensitive;SA2 is highly sensitive to 11 kinds of drugs such as gentamicin,kanamycin,ciprofloxacin and tetracycline.Gallnut,Coptis chinensis and Burnet had very significant inhibitory effects on the expression of mec A gene,gallnut,Coptis chinensis and Cortex Phellodendri had extremely significant inhibitory effects on the expression of mec B gene,and Burnet had a significant inhibitory effect on the expression of mef A gene.3.Detect biofilm formation-related genes by PCR method,and study the inhibitory effect of Galla gall,Coptis chinensis,Burnet and Cortex Phellodendri on biofilm formation-related genes.The results showed that 8 biofilm formation related genes including agr A,Sar A,ica A,ica B,clf B,Fnb B,atl E and fib A were detected in both strains;All the genes have different degrees of inhibitory effects,Coptis chinensis is the best,and has significant or very significant inhibitory effects on the 8BF genes of the two strains;Cortex Phellodendron and gallnut are the next,except for no obvious inhibitory effect on the expression of atl E gene of SA2,It has significant or very significant inhibitory effect on other genes;Burnet is the worst,it can inhibit the expression of 8 BF genes of SA2,and only inhibit the expression of ica A,fib A and Fnb B genes of SA1.Summary: Both strains of Staphylococcus aureus are resistant to ciprofloxacin,tetracycline,gentamicin,kanamycin,norfloxacin,ofloxacin,cephradine,cephalexin,ceftriaxone,cefoperazone,Ceftazidime is sensitive,and the strain carries mec A,mec B and mef A resistance genes.Coptis chinensis,Cortex Phellodendron,Galla galla and Burnet have different degrees of inhibitory effects on the expression of drug resistance genes;agr A,Sar A,ica A,ica B,clf B,Fnb B,atl E were detected 8 kinds of genes related to biofilm formation including fib A,and 4 traditional Chinese medicines had different degrees of inhibitory effects on genes related to S.aureus biofilm formation.