Antibacterial Effect And Application Of Two Antimicrobial Peptide Products

This experiment was designed for the antibacterial effect and clinical application of antimicrobial peptides.,and try to explore theoretical basis for the popularization and application in the animal husbandry.In vitro,the Oxford Cup method was employed.The experiment results show that the high concentration and low concentration of antibacterial peptide produced by manufacturer A and high concentrations of antimicrobial peptides by B manufacturers forman antibacterial whileon the Salmonella,but little effects was seen from other group.The results show that the concentration of two kinds of antimicrobial peptides produced by the two manufacturers has no inhibitory effect on Staphylococcus aureus and Escherichia coli,whileon the Salmonella,the mechanism of function remains to be studied.In vivo the results of antibacterial test was gained First of all,through pre-test: intraperitoneal injection of 1.0�107 cfu / m L of Staphylococcus aureus 0.5m L can make mortality rate of the KM mice in experiment by 80%-100%;intraperitoneal injection of 1.0�108 cfu / m L of Escherichia coli 0.5m L by 80%-100%.The experimental mice was injected intragastrically antibacterial peptide with different concentration produced by manufacture B seven days later with 0.5 m L of Staphylococcus aureus intraperitoneally.Compared with the groups without antibacterial peptide injection,the groups with the high concentration of antibacterial peptide decrease the mortality of the mice by about 67%;the middle one by about 56%,low one by about 20%;compared with the groups without antibacterial peptide injection,with intraperitoneal injection of 0.5m L E.coli bacteria,the high the middle and the low concentration groups decreased the mortality rate of mice by about 100%(P<0.01),and the difference is very significant.Five days later,the mice were sacrificed and dissected.The livers were used to make the pathological section observation.The pathological changes of the liver in the group with E.coli bacteria injection were mainly manifested as hepatocellular degeneration and scattered hepatocyte necrosis.The pathological changes of the liver in the group with Staphylococcus aureus were mainly congestion,inflammatory cell infiltration and leukocytosis.The pathological changes of liver of mice with high concentration of antimicrobial peptides were mild or no pathological changes.The pathological changes of liver of mice were moderately inflammatory and partial hepatocellular degeneration.The low concentration of liver showed a large area of congestion as well as severe inflammation,and even necrosis.Analysis gained from in vitro antibacterial test results evince antimicrobial peptides from manufacturer B have a effect on mice infected with Staphylococcus aureus or Escherichia coli and reducing the mortality of mice,also a protective effect on mouse live.The experimental mice was injected intragastrically antibacterial peptide with different concentration produced by manufacture A seven days later with 0.5 ml of Staphylococcus aureus intraperitoneally.Compared with the groups without antibacterial peptide injection.the groups with he high concentration of antibacterial peptide decrease the mortality of the mice by about 20%(P<0.01);the middle one increased by about 20%(P<0.01),low one decreased by about 50%(P<0.01);compared with the groups without antibacterial peptide injection,with intraperitoneal injection of 0.5ml E.coli bacteria,the high concentration group decreased the mortality rate of mice by about 100%,the middle one increased by about 100%,low one decreased by about 100%.Similar to B antibacterial peptides,high concentrations and low concentrations of A antimicrobial peptides can effectively prevent the infection of Staphylococcus aureus or Escherichia coli,the middle dose of antimicrobial peptides,however,increase the mice mortality.Antibacterial peptide with high,middle and low concentrations produced by manufacturer A,conventional drug group and antimicrobial peptide concentration +0.5 times the dose of conventional drug group were applied to 50 piglets with bacillary yellow diarrhea of piglet to test their clinical efficacy.Results show that antibacterial peptides produced by manufacturers A have a moderate inhibition activity against on piglets infected bacillary yellow diarrhea,the inhibitor rate was positive correlation with concentration,and also reduce the mortality of infected pigs.With more antimicrobial peptides dose was applied,the better the effect was.But compared with the conventional drug group,the effect is far from enough.No better results were gained form the group of antibacterial peptide dose and half dose of conventional drug dose.