Isolation,Identification And Drug Resistance Analysis Of Pathogenic Bacteria In Fresh Milk In Some Areas Of Xinjiang

The pathogenic bacteria in raw milk affect the quality and safety of raw milk.The quality and safety of raw milk is closely related to people’s health.In order to understand the contamination and drug resistance of main pathogens in fresh milk of large-scale dairy farms in some areas of Xinjiang,and to provide reference for rational use of drugs for dairy farms.110 fresh milk samples were randomly collected from large-scale dairy farms in the South and north of Xinjiang.The bacteria were isolated and purified according to the bacterial morphology and Gram’s staining,and then identified by biochemical and molecular biological methods.The drug resistance of 16 kinds of antibiotics were detected by broth dilution method.In this experiment,110 samples were collected from large-scale dairy farms in the South and north of Xinjiang,18 strains of Staphylococcus aureus were isolated,the isolation rate was 16.36%;no Streptococcus agalactiae was isolated;3 strains of Streptococcus dysgalactiae were isolated,the isolation rate was 2.73%;20 strains of Enterococcus faecalis were isolated,the isolation rate was 18.18%;48 strains of Escherichia coli were isolated,the isolation rate was 43.64%;16 strains of Klebsiella were isolated,The isolation rate was 14.54%.Staphylococcus aureus isolates were highly sensitive to oxacillin,cefalotin,ceftiofur,gentamycin,rifaximin,vancomycin,ciprofloxacin and cotrimoxazole,with sensitivity rates of 94.44%,94.44%,94.44%,83.33%,94.44%,100%,94.44%and 100%,respectively.It was highly resistant to penicillin,ampicillin and sulfisoxazole,with drug resistance rates of 83.33%,100%and 77.78%,respectively.It was not sensitive to amoxicillin/clavulanic acid.The multiple drug resistance rate was 77.78%.Streptococcus dysgalactiae was sensitive to penicillins and cephalosporins,erythromycin,clindamycin,gentamicin,florfenicol,rifaximin,vancomycin,ciprofloxacin,cotrimoxazole.It was moderately sensitive to sulfisoxazole.It was moderately resistant to doxycycline.Enterococcus faecalis was highly resistant to penicillin,ampicillin,oxacillin,cefothiophene and ceftiofur,with resistance rates of 90%,95%,100%,90%and 85%,respectively;but highly sensitive to amoxicillin/clavulanic acid,with sensitivity rate of 70%;It was highly resistance to clindamycin and sulfisoxazole,and the drug resistance rate were 95%and 70%.The multiple drug resistance rate of enterococcus faecalis was 100%,all of which were above 4 drug resistance.Escherichia coli strains was not sensitive to amoxicillin/clavulanic acid.It was highly resistant to cefalotin,and the drug resistance rate was 79.17%.It were sensitive to sensitive to amoxicillin/clavulanic acid,ceftiofur and meropenem,with sensitivity rates of 93.75%,91.67%and 89.58%respectively.It was sensitive to kanamycin,gentamicin,polymyxin,ciprofloxacin,and the drug sensitive rate were 87.5%,87.5%,85.42%,89.58%,respectively.It was highly resistant rate of rifaximin and sulfisoxazole was 97.9%and 77.1%.Thirty five of the 48 E.coli strains was multidrug-resistant,with the multidrug resistance rate of 72.62%.Klebsiella was not sensitive to ampicillin.The sensitivity to amoxicillin/clavulanic acid was 100%.It was sensitive to ceftiofur and meropenem,the drug resistance rate were 100%and 87.5%;It was sensitive to streptomycin,kanamycin,gentamycin,tetracyclin,doxycycline,ciprofloxacin and cotrimoxazole,and the sensitivity rates were 87.5%,87.5%,93.75%,87.5%,93.75%,93.75%and 100%.The resistance of rifaximin and sulfamethoxazole were 93.75%and 81.25%,respectively.The multiple drug resistance rate was 87.5%.There are five pathogenic bacteria in the fresh milk of large-scale dairy farms in Xinjiang,including Staphylococcus aureus,Streptococcus dysgalactiae,Enterococcus faecalis,Escherichia coli and Klebsiella.No Streptococcus agalactiae was isolated,and the pollution of Escherichia coli in the fresh milk was serious.Staphylococcus aureus,Enterococcus faecalis,Escherichia coli and Klebsiella,with serious multi drug resistance.For the diseases caused by gram-positive pathogenic bacteria,oxacillin,cefalotin,ceftiofur and florfenicol can be used for treatment;for the diseases caused by gramnegative pathogenic bacteria,amoxicillin/clavulanic acid,ceftiofur,meropenem,streptomycin,kanamycin,gentamicin,tetracycline,doxycycline,polymyxin,ciprofloxacin and cotrimoxazole can be used for treatment.The dairy farm can take preventive and control measures for the quality and safety of fresh milk according to the actual situation of the dairy farm,and provide drug reference for dairy diseases.