Isolation,Identification Of Escherichia Coli From Mink And Related Research Of Some Biological Characteristics From Shandong Province

Recently,the incidence and prevalence of Escherichia coli diseases bring serious threat to the healthy development of mink farming industry in Shandong province. In order to prevent mink Escherichia coli disease, many antibacterial drugs have been used widely, resulting the resistance of Escherichia coli strains and bringing a lot of difficulties to the prevention and control of these phenomenon. In addition, the resistance genes, carried by resistant bacterias in animal origin, can be transferred to other species of pathogenic bacteria, threating to the human health. For exploring the main resistances serotypes of Escherichia coli from mink in Shandong Province, this paper carries out the following researches: the bacterias have been isolated and purified form the diseased materials(dead mink brains) from 2010 to 2014 in Shandong Province, using biochemical tests with the methods of isolation and identification of strains; the isolated Escherichia coli O antiserum type has been identified; the Escherichia coli resistance genes have been detected in drug susceptibility tests. Furthermore, for understanding of the pathogenicity of Escherichia coli, the regression animal experiment has been used by the isolated Escherichia coli.The results are as follows: the isolated 27 strains of Escherichia coli and pathogenic serovars including O88(7 strains), O114(3 strains), O78(2 strains), O167(2 strains), O18(3 strains), O20(2 strains), O15(4 strains), O10?O35?O91?O92(1 strain each),O88 is mostly prevalent serotype, accounted for 25.9%; Through drug sensitivity test, we found that bacteria be sensitive to cephalosporins, quinolones, even more like colistin multi drug resistance. The isolated bacteria have different degree of carrying resistance genes: 5 strains(18.5%) of TEM,1 strain(3.7%) of CFR, 5 strains(18.5%) of qnr A, 11 strains(40.7%) of oqxA, 12 strains(44.4%) of tet A, 10 strains(37%) of gyr A. Among the 27 strains, 6 strains(22.2%) carrying at least one resistance genes, 4 strains(14.8%) carrying three kinds of drug resistance genes, 4 strains(14.8%) carrying four kinds of drug resistance genes, and 5 strains(18.5%) carrying 5 kinds of drug resistance genes. In mink animal regression test, 27 groups of mink in 3~5d after inoculation, groups have diarrhea and other symptoms. Disease material from mink's brain tissue on Mac agar culture 37?cultured for 12 h, have red colony growth. Microscopic examination after gram stain, accord with Escherichia coli characteristics. Biochemical tests showed that isolated bacterias were Escherichia coli, while the 5 minks of control group were all survival, prove of 27 strains isolated strains were pathogenic Escherichia coli.Results indicated that serotype of Escherichia coli from mink is very complex, The phenomenon of antibiotic resistance is serious. and have cross-resistance, heavily pathogenicity. This study provides a theoretical basis for prevention and treatment of mink from Shandong province and also the rational use of drugs.