The Study Of Treatment Effect For Cows’ Mastitis Based On Bacteirophage And Bacteriophage Lysins

Cows’ mastitis is one of the most multiple diseases for cows. Cows’ mastitis has a seriousinfluence on milk production and quality, and it causes huge pecuniary cost to aquacultureevery year. Tried to treat cow’s mastitis by the mixed formulation that was made of somephages:1. Sampling, we collected untreated sewage sample from different locations, and isolatedthe bacteria from sick cows’ milk of farms. With these indicators we had isolated from thesewage several bacteriophages, including two lytic phages: IME-SA1and IME-SA2. BothIME-SA1and IME-SA2could lyse many Staphylococcus aureus strains, indicating IME-SA1and IME-SA2were broad spectrum phages, and it could have potential applications in cowmastitis treatment.2. Identification, BLAST the results online in NCBI of digested fragment clones showedthat IME-SA1was Staphylococcus phage. According to the studies of the biologicalcharacteristics, it showed that the MOI of Staphylococcus phage IME-SA1and IME-SA2were both0.01. According to the phage infect and growth dynamics, the latent period was20min, and the burst period was30min.3. Analysis, the genomic DNA of Staphylococcus aureus phage IME-SA1and IME-SA2were sequenced by Ion Torrent, we also found that phage IME-SA2had three high-frequencysequence in its reverse, and it speculated that the features of the end of genome was that theleft was fixed, the right was random, and there was a certain redundancy.4. Amplification, the lysine gene of phage IME-SA1(LySA1) was cloned into the coldshock impression vector pCold-I and expressed in BM M15successfully. The result of turbidmetric method proved that the LySA1had a very good activity.5. Effect determination, we tested the antibacterial effect of phage IME-SA1andIME-SA2under the room temperature, both of two phages had a good antibacterial affection.6. Clinical trials, we used the mixed formulation of phage preparation to act on treatingsick cows of acute mastitis that without antibiotics or other drugs treatment. After treatment,the symptoms were improved, and the milk had recovered normal standards, with swellingcured. We achieved the goal of treatment.Phage preparations for treating bacterial infection have a broad space for development.We can predict that when people turn their attention from antibacterial drugs to phage, it willnot only be a major breakthrough in the medicine undoubtedly, but also has a very importantsignificance to save the lives of critically infected patients.