Objective:To investigate the antibacterial effects of the antibacterial substances on Enterobacter cloacae infection of wound in mice.Methods:Antibacterial substances of the larvae of housefly were induced by ultrasonic treatment

and its antibacterial activity was investigated with inhibition experiment in vitro.Thirty ICR mice were enrolled in the study

and the Enterobacter cloacae infection model was re-produced by excision of the full layer of dorsal skin with anarea of 1 cm×1 cm.Then they were randomly divided into group C(control

n=10

with wet compress of isotonic saline)

group M(with hydropathic compress of 100 g/L mafenide)and group A(with wet compress of 0.1 g/L antibacterial peptide).The changes of white blood cell counts in each group were determined before and 3 days after injury.Bacterial growth in muscular tissue of the wounds and the survival of the mice were observed at 3 days after injury.Results:The purified peptide was highly potent against Enterobacter cloacae in vitro.The number of leucocytes in each group was decreased after operation

with significantly less number in group C than in group M and A.Bacterial growth in muscle demonstrated a difference between treated groups and group C at 3 days [group M:(87±31)×102 CFU/g;group A:(99±32)×102 CFU/g;group C:(504±338)×103 CFU/g(]P<0.01).The survival after 3 days in group C(60%)was evidently smaller than that in group A(90%)and M(90%)(P<0.05).Conclusion:The antibacterial peptide of housefly which is induced by ultrasonic treatment possesses obvious anti-bacterial effect on the Enterobacter cloacae infected wounds of ICR mice.