Drug Resistance Elimination And Antibacterial Mechanism Of Sanguisorba Officinalis L. Against Multidrug-resistant Escherichia Coli

Escherichia coli can cause a variety of diseases in veterinary clinic.In recent years,the increasingly serious drug resistance problem is a great threaten to the animal husbandry and human health.Searching for new antibacterial drugs or drug resistance inhibitors from traditional Chinese medicine has received widespreading attention.Sanguisorba Radix is the dried root of Sanguisorba officinalis L.or S.officinalis L.var.longifolia(Bert.)Yü et Li;It's cold in natrue,bitter and sour in taste,distributing to liver and large intestine meridian.It has the functions on cooling blood and detoxify,hemostasis and converging sores.Modern research has proved that it has antibacterial,anti-inflammatory,anti-tumor,anti-oxidant and other pharmacological effects.This experiment screened the antibacterial active parts of S.officinalis,the antibacterial elimination and the antibacterial mechanism of active parts against multidrug-resistant E.coli.The results below were obtained:(1)Screen antibacterial active parts of S.officinalis : Ethanol reflux extraction method was used to prepare ethanol extract of S.officinalis.Systematic solvent method was used to prepare different extracts.Antibacterial activities of different extracts were tested by agar plate punching and broth micro-dilution method.The results showed that the ethyl acetate,n-butanol and water extracts of S.officinalis had different degrees of antibacterial effects on Salmonella,Escherichia coli,Staphylococcus aureus and Streptococcus.Ethyl acetate extract had the strongest activity against Streptococcus.The extract of n-butanol showed strongest activity against Escherichia coli,Salmonella and Staphylococcus aureus.(2)Study on the resistance elimination of the S.officinalis extract against multidrugresistant Escherichia coli:The combined checkerboard method was used to determine the effect of S.officinalis n-butanol extract combined with antibacterial drugs.The resistance elimination rate of n-butanol extract against multidrug-resistant Escherichia coli was tested.The results showed that n-butanol extract mainly performed synergy effect with tetracyclines,quinolones,chloramphenicol and carbapenem.The elimination rate for multidrug-resistant Escherichia coli was 3.1%.The sensitivity of the drug resistance to ropenem,aztreonam,ciprofloxacin,enrofloxacin,and florfenicol were increased to varying degrees.(3)Antibacterial mechanism of S.officinalis n-butanol extract against multidrugresistant Escherichia coli:Scanning electron microscope,alkaline phosphatase(AKP)assay and SDS-PAGE were carried out to detect the influence of S.officinalis n-butanol extract on the morphology,AKP,DNA leakage and protein synthesis of multidrug-resistant Escherichia coli.The results showed that the antibacterial mechanism of S.officinalis n-butanol extract destroyed the bacterial cell wall,changed the bacterial cell membrane permeability,and interfered the bacterial protein synthesis.