The Separation and Identification of Dairy Cow Mastitis and Drug Resistance Analysis in Coagulase Negative Staphylococcus
In order to reduce the practical application of veterinary antibiotics,a precise medication program for cows with CNS mastitis suitable for pasture characteristics is established to promote the production practice of a cattle farm in Inner Mongolia.In this study,262 samples of mastitis were collected from a large-scale cattle farm in Hohhot,Inner Mongolia,and the pathogenic bacteria of mastitis were studied and analyzed by means of differential chromogenic medium separation,traditional culture and 16S rRNA based nucleic acid sequence identification.Subsequently,53 isolated CNS strains were tested for MIC of 6 commonly used drugs(micro-broth dilution method)and their drug resistance was analyzed.The results show that the pathogenic bacteria isolated and identified from 262 mastitis samples has a large number of species,with a total of 20 genera and 54 species.Staphylococcus is the dominant genus of 262 isolates and also the dominant genus of Staphylococcus in the identification medium.The analysis described that CNS is the most likely long-term cause of mastitis in cows on the farm.Drug sensitivity test results show that among the 6 antibacterial drugs,cephalexin and mbofloxacin have the highest drug resistance rate(47.17%and 49.06%,respectively),and cefuroxime have the lowest drug resistance rate(16.98%).Among the four β-lactams,the sensitivity to cefotirome is the highest,reaching 83.02%,and cefotirome has better CNS antibacterial activity than cefquinme.Among the CNS obtained by isolation technology in this study,Staphylococcus epidermidis is the most isolated strain,and its drug resistance rate to penicillin and ceftioire is low.Staphylococcus Simulans has the lowest resistance rate to ceftiodom.Staphylococcus haemolyticus has low drug resistance to ceftiofuroxime and cefquinoxime.Staphylococcus sciuri has low resistance rates to cefalexin,penicillin and ceftioxime.This study proved that different CNS strains have different sensitivity to different antibiotics,which largely provides scientific basis for the management and prevention of dairy cow mastitis in this area.
MastitisCoagulase-negative staphylococciSeparation and identificationDrug resistance16S rDNA
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