Effects Of Flos Lonicerae And Forsythia On Drug Resistance And Virulence Genes Of Streptococcus Equis Isolates In Northern Xinjiang

132 horse nose swabs were collected from Changji and Yili horse farms for isolation,culture and identification of streptococci in order to understand the species,drug resistance and virulence gene carrying of streptococci infected by horses in northern Xinjiang.The drug sensitivity of the isolated strains was tested by standard K-B disk diffusion method,and 13 pairs of primers were designed to detect 6 drug resistance genes and 7 virulence genes.As a result,24 strains of Streptococcus were isolated,including 2strains of Streptococcus pneumoniae,9 strains of Streptococcus equi,and the others were common streptococci.The drug sensitivity test showed that the resistance rate of the isolated strains to penicillin was72.41%,to ceftazidime,tetracycline and doxycycline was more than 50%.The positive rates of drug resistance genes bla _TEMand qnr A were 66.7%and 12.5%,respectively.The positive rates of virulence genes fne B,lyt A and ply were 37.5%,33.3%and 12.5%,respectively.Among the isolated strains,one strain of Streptococcus equi(HW5-1-2)and one strain of Streptococcus equi(Y1)carried both drug resistance genes qnr A and bla _TEM.Strain Y1 also carried virulence genes D1,D2 and D3 of Streptococcus equi subspecies fne B;3 and carried virulence genes ply,lyt A and fne B;However,strain Z72-2 did not carry drug resistance genes and virulence genes within the study range.As a result,the drug resistance of Streptococcus equi isolates in northern Xinjiang was serious.Drug resistance genes and virulence genes were widely distributed.This study intends to evaluate the bacteriostatic effect of Flos Lonicerae and Forsythia suspensa,analyze the effects on drug resistance and virulence genes of the above streptococcal isolates,and explore the mechanism of the effect of traditional Chinese medicine on drug resistance and virulence genes of bacteria.This experiment is divided into two parts:in vitro and in vivo bacteriostatic experiments.Flos Lonicerae and Forsythia suspensa were treated with conventional traditional Chinese medicine respectively,and the water extract with the concentration of 1 g/m L was obtained in the in vitro experiment.Through the pre-experiment of the concentration gradient of traditional Chinese medicine,it was determined that the optimum concentration of traditional Chinese medicine was water extract of traditional Chinese medicine?THB medium?bacterial solution to be tested(OD=0.6)was 1000/500/20(unit:?L).The traditional Chinese medicine was divided into three groups:Flos Lonicerae,Forsythia suspensa and Fructus Forsythiae at 1?1.According to the above ratio,they were co-cultured with 23 strains(except strain Z72-2),and the drug resistance genes and virulence genes of the strains were detected.As a result,the drug resistance and virulence genes of the isolates co-cultured with traditional Chinese medicine water extract were not detected.It indicated that Flos Lonicerae and Forsythia suspensa may have a certain effect on eliminating drug resistance and virulence genes in vitro.The bacteriostatic experiments in mice were carried out on 9 strains of Streptococcus equi isolated from equine subspecies.63 mice were divided into three groups:Streptococcus equi original bacteria solution(positive control group),equine Streptococcus equine subspecies bacteria solution co-cultured with traditional Chinese medicine extract of the same volume(experimental group),and corresponding traditional Chinese medicine group(traditional Chinese medicine control group).The experimental group was divided into three groups:honeysuckle group,forsythia group and 1?1 compatibility group of Flos Lonicerae,respectively,which were injected intraperitoneally.The drug resistance and virulence genes of Streptococcus equi isolated from mice were detected.The results showed that there were 27 mice in the positive control group,of which 24 died and 3 survived.The results showed that the virulence resistance gene of the strain isolated from mouse liver was the same as that of the original strain.There were 27 mice in the experimental group,of which 16 died and 11 survived.In the forsythia experimental group,L3(the survival rate of mice was 0%)and L32(the survival rate of mice was 100%)were the most different and the effect was the most obvious.Y2 and Y21 in the Flos Lonicerae experimental group and D2 and D23 in the 1:1 compatibility experimental group of Flos Lonicerae had the worst effect,and the survival rate of mice was 0%.Among the strains isolated from mice in this group,the fne B genes of all strains except one male strain(D33)could be detected,and all the other drug resistance and virulence genes were still not detected.The results indicated that the control effect of forsythia on 9 strains of horse streptococcal disease was more obvious than that of honeysuckle and forsythia.Besides,the reappearance of fne B gene in vivo indicates that the mechanism remains to be studied.