The research about the virulence and wound infection of the Shewanella putrefaciens from some coastal area

Objective: To study the pathogenicity of the Shewanella putrefaciens separated from the coastal seawater.Methods: Virulence experiment groups: 22 mice were divided into four groups in random: The Shewanella putrefaciens groups were treated by intraperitioneal injection with Shewanella putrefaciens.The positive control groups were treated with standard S.aureus and E.coli were respectively in the same way,and negative control group were with stroke-physiogical saline solution.wound infection groups: 22 SPF mice were divided into four groups in random after their legs were injured: the test group（dipped in artificial seawater with the Shewanella putrefaciens）;the positive control group（with standard S.aureus and E.coli）;the negative control group（dipped in aseptic artificial seawater）.To observe the general condition,leucocyte,blood culture,viscera and wound culture of the mice,the viscera and the pathologic changes of viscera and injured extremities were examined with light microscope wound limbs were examined with pathological optical microscope.Results: Virulence experiment: among 7 mice of the experimental group,bacterial growing was found in the blood of 2 mice after injection,the positive ratio was 28.6%,the positive rate of viscera culture was 42.9%.Wound infection experiment: positive rate of the wound infection was 100%,the positive culture rate of the organ culture（of the sacriced mice） was 28.6%,pathological examination showed there were obvious dropsy in the muscular layer and widespread neutrophile granulocytes in the cross striated muscle of the injured extremity.Conclusion: The Shewanella putrefaciens isolated from the brine has transmissibility,which can cause wound（and riscera） infection and septicaemia when the concentration reached 106CFU·mL^-1.