Isolation,Identification And Traceability Of Mastitis Pathogenic Bacteria In Cow Milk

As the economy continues to develop and the quality of life continues to improve,people’s demand for milk and dairy products is increasing,and the quality and safety of milk and dairy products are facing a great test.Dairy cow mastitis is one of the most common diseases of dairy cows,and the incidence is high,which has a large impact on milk production and milk quality.Mastitis treatment will lead to safety hazards such as antibiotic residues in milk.There are many incentives for dairy cow mastitis.One of the main factors is that pathogenic bacteria in the environment invade the dairy mammary glands,and there are many pathogens that can affect milk quality and even threaten human health and safety,so we studied the bacterial diversity in mastitic milk,feces,skin,cups and environmental samples,and then traced the dominant bacteria in mastitis using Source Tracker.We used the California Mastitis Test(CMT)method to screen of 6 cows with mastitis(somatic cell number > 1.5million cell / ml),and collected 6 mastitic milk samples,6 corresponding skin,cup and fecal samples each,and 54 other samples collected from the farming environment of mastitic cow,including 3 drinking water,1 spray water,6(new)litter,3 air,2 feeds,18 bath medicine(9 a-bath medicine,9 b-bath medicine),18 bath medicine cup(9a-bath medicine cup,9 b-bath medicine cup)samples.We used separation and culture technology,Polymerase Chain Reaction(PCR)technology,16 S r DNA amplicon sequencing and source Tracker software to detect and analyze the types and diversity of microorganisms in mastitic milk and different environmental samples,and the source of the pathogenic bacteria of mastitic milk.After separation and purification using selective medium,4 strains identified as Staphylococcus and 1 strain as Escherichia coli(E.coli)were isolated from mastitic milk.The dominant bacteria isolated from other environmental samples were Bacillus,followed by Enterobacter,Staphylococcus,Acinetobacter bacteria.The 16 S r DNA amplicon sequencing was used to analyze the types and diversity of bacteria in the samples,and all samples were found to contained high levels of Ruminococcaceae,Moraxellaceae,Burkholderiaceae,Lachnospiraceae,Flavobacteriaceae,Pseudomonadaceae,and Bacillaceae bacteria.It was found that skin,air,medicine bath cups and feces contributed the most to the microbes in mastitis milk by using Source Tracker software.In this study,we initially obtained the environmental source of the pathogenic bacteria of mastitis in a dairy farm in Tianjin by using 16 S r DNA amplicon sequencing and Source Tracker software.It is proposed that nipple skin and milk cups in milk parlors are the key points of weak cow production management control.Therefore,this study provides beneficial data support for further improving the production welfare of dairy cows and it is great significant to find reasonable methods for mastitis prevention and to improve the quality of milk and dairy products.