| Bovine mastitis is one of the most important diseases affecting the dairy industry,but also one of the frequent disease in dairy cow.Which caused huge economic losses to dairy production and dairy farming industry.Different types of pathogen infection are the most important reason of dairy cow mastitis.In order to discover the epidemiology of dairy cow and the status quo of pathogenic microbial infection in Jiangsu province,this study isolate the pathogens from five large-scale dairy farms in four regions of Jiangsu Province.Detect and analysis the sensitivity and tetracycline-related drug resistance gene of the isolated pathogens.Research ?.The epidemiological investigation of bovine mastitis in Jiangsu provinceUse the BMT method to detect bovine mastitis carried out on dairy cows in four dairy farms in four areas of Jiangsu Province.The milk samples of recessiveness and clinical bovine mastitis were collected according to the test results.Isolation and purification of these milky pathogens were carried out and use the MALID-TOF-MS method to identificate the Streptococcus.From October 30,2014 to August 17,2016,a total of 536 milk samples of clinical and recessiveness bovine mastitis were collected from cattle(A,B,C,D)in four cities in Jiangsu Province.Staphylococcus 382(47.75%),Streptococcus 207(25.88%),and Bacilli 211(26.38%)were isolated from the milk samples.By the method of MALDI,165(79.71%)strains of Streptococcus agalactiae,3(1.45%)strains of Streptococcus dysgalactiae and Streptococcus uberis were identified in 207 strains of Streptococcus.The results show that streptococcus,which is caused by dairy cow mastitis in Jiangsu province,is mainly Streptococcus agalactiae.Research ?.The sensitivity detection of streptococcus isolated from mastitisThe drug sensitivity test was carried out on 256 strains of Streptococcus with 20 kinds of 8 categories of drug according to the KB disc method stipulated by CLSI.The results showed that streptococcal to tetracycline,oxacillin,spectinomycin and polymyxin B Showing a very seriousresistance,to the phenomenon of penicillin,norfloxacin,ciprofloxacin and other drugs have a higher medium.The main multiple drug resistance showed triple,quadruple,five and six drug resistance,among which the highest number of quadruple resistant(19.92%),more than ten kinds of drug resistance accounted for the rate of 10.33%.The detected strains show a high rate sensitive to Vancomycin,cephalosporins,erythromycin,clarithromycin and clindamycin and nitrofurantoin.The research show severe status of streptococcal resistance of dairy cows in Jiangsu Province,macrolide drugs and vancomycin and nitrofurantoin can still be used as clinical medication.Research ?.The detection of Tetracycline resistance genes in Streptococcus isolated from mastitisIn this study,tetracycline resistance genes(tetM,tetO,tetK,tetL)were amplified by PCR.The resistance genes of tetM,tetO,tetK,tetL were amplified from the genome of Streptococcus,and BLAST analysis showed that the amplified fragments were more than 99%homologous to GenBank.The detection rate of tetM gene was 39.06%,the detection rate of tetO gene was 15.63%,the detection rate of tetK gene was 0.78%,tetL gene was not found in this test.The results showed that the severe resistance of tetracycline was mainly caused by the tetM and tetO genes.At the same time tetracycline resistance rate is higher than the detection rate of drug resistance genes.The reason of this result might with other mechanisms of drug resistance or other drug resistance gene.This study shows that tetracycline resistance is serious,drug resistance mechanism is very complex,clinical management and treatment is very difficult. |
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