| Pathogenic Escherichia coli(E.coli)is one of the most common pathogenic bacteria in veterinary clinic,which can bring serious detriment for the development of animal husbandry.As the serotype is complicated,ideal broad-spectrum vaccine for the diseases occuring in different regions or periods can't be found.Meanwhile,the problem of bacteria drug resistance caused by the long-term,considerable,unreasonable abuse of antibiotic is more and more serious,the muitidrug resistent strains are aslo brought.In this study,the drug resistance phenotype of the enteropathogenic E.coli in four large pig fields of Chongqing,the traditional Chinese medicine for eliminating antibiotic resistance effectively and the mechanism of the elimination were made.The work can be five-fold:1 Collecting,separating,identifying the clinic patho-materialsThe pathogenic bacteria separated from the clinic patho-materials collected by ster-rectum swab in four pig farms such as Bishan and Hechuan were cultured.131 strains enteropathogenic E.coli of swine wre identified based on cultural,morphological,colored characteristics and biochemistry, mouse pathogenicity test.2 Pathogenic bacteria's pharmacal sensitive test and drug-resistances spectrum test 131 elected pathogenic bacteria's drug resistance for 18 common antibacterials were tested,the mult-persisted stock were analyzed and the different antibacterials' drug fast ratio were compared according to WTO recommended slip-diffusion method and the NCCLS(2007)standard.Test results indicated:different degree drug resistance appeared in all the tested stocks including 7 strains of 16-resistance(5.3%),4 strains of 6- resistance(3.1%),and 120 strains resistant more than 8 kinds of medicine(91.6%).Their drug fast ratio for Benzylpenicillin G was 100%,for Streptomycin was 96.2%.The most sensitive drug were Ceftriaxone Sodium(81.7%)and Cefoperazone(71.8%).The aminoglycosides' drug fast ratio was Streptomycin(96.2%),Kanamycin(81.7%), Gentamicin(71.8%),Tobramycin(59.:5%),Spectinomycin(47.3%),Amikacin(32.8%),Neomycin (27.5%).3 Studying the influence of the traditional Chinese Sanhuang complex prescription and Puhuang broth for the artificial constructed drug resistant strainsThe drug resistant strains were constructed:KA,KD whose drug resistant plasmid and characteristics wre identified by means of Calcium-chloride.The MIC of the KA,KD were tested by the method of the plate dilution and glucose phenol-red broth dilution of the traditional Chinese Sanhuang complex prescription and Puhuang broth choiced.Integrative compare of two mathods the results of MIC was as follows:the Puhuang broth's KA was 100mg/ml and KD was 50mg/ml,the traditional Chinese Sanhuang complex prescription's KA was 100mg/ml and KD was 50mg/ml.4 Bolting the optimizated Eliminated concentration of the traditional Chinese medicine,and verificating the genetic stabilityThrough comparing the influence of the different concentration for the bacteria's growth,we can get that elimination ratio of the traditional Chinese medicine was directly correlated to the traditional Chinese medicine's concentration,and the 1/2 MIC is the optimum concentration. Comparing the eliminated ratio of the plasmid of the drug resistant strains which were cultured in the 1/2 traditional Chinese medicine's MIC and the common broth,the traditional Chinese drug had obvious eliminated function for the drug resistance.Five days later,the drug resistant strains' MIC decreased to 1/8.Through t test,prominent difference(p＜0.05)from the drug resistant Elimination contrasting to blank appeared.Testing the genetic stability of the drug fast phenotype after removing the traditional Chinese drug,the drug resistant strains' MIC had recovered to some extent,but the whole level still decreased.5 Elimination of the traditional Chinese medicine for drug resistance plasmidThe plasmids whose phenotypic changed or not changed from the drug resistant strains were extracted by means of the alkaline lysis,The result indicated:the straps of the former's drug resistant plasmid were lost,but the latter had nothing changed.It confirmed that the traditional Chinese drug had the effect on eliminating the plasmid resistant the pet28a.
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