Investigation Of Bacterial Infections In Gunshot Wound Tract In The Seawater

Object: The infection of gunshot wound is one of the important problems in wound treating in modern war. The investigations about gunshot -wound-infection on the land have been reported quite many, but there is no research of gunshot - wound - infection in the seawater reported According to the needs of managing the gunshot wound on the sea, we established canine models with gunshot wound in the seawater to find the special rules of gunshot-wound-infection in the seawater.Method: Sixteen beagle canines were randomly divided into two groups: seawater group (fourteen canines) and land group (two canines). We threw the canines of seawater group into the seawater. After 2~8 minutes, we shot the canines in the seawater, keeping away from the vital part such as skull , thorax and abdominal et al. Then the canines were salvage out of the seawater , wrapped with aseptic dressing and transfused 5 00 ~ 1000ml 5% glucose solution at once.1. The bacteriological compose of seawater group: General observation and obtaining a piece of musculature from deep of the gunshot wound tract were performed at 0, 6, 12 and 24h after the injury respectively. These musculatures were used to smear over there kind of plates: blood agar, china -blue agar and TCBS agar, then put these plates to culture at 37℃ for 18 to 24 hours. We selected every different form isolated for bacteria identification.2. Quantitative bacteriological study on gunshot wound in the seawater: Quantitative bacterial analysis was performed at 0, 6, 12 and 24h after the gunshot injury respectively. We dealt the results with statistical method.3. Drug sensitivity test for identified bacteria: We tested every isolate the sensitivity to abomacetin, penicilinG, gentamicin, cefacidal, economycin and alficetin.Results:1. General observation: Tissue damage of gunshot wound tract was more serious in seawater group than land group at the same time points after the injury. Also seawater group had a higher mortality rate (ll/14)than land group (0/2) .2. Bacterial quantification of two groups tended to increase with the time, but the seawater group had higher count of bacteria than land group at the same time points after the injury .Within 6 hour, the bacterial count reached the critical point for clinical infection in seawater group.3. Two bacterial growth dynamics models were set up, i.e:Formula (1) (2) represent bacterial growth dynamics model of seawater group and land group respectively .X represents time after gunshot injury, and Y represents the bacterial count in per gram tissue.4. Using the dynamics model , we found that the bacterial count of seawater group would reached the critical point for clinical infection in 4.2h and the land group would reach the same bacteria count of seawater group 4 hours later.5. We found 17 species of bacteria in the tract of the gunshot wound in seawater group. They are Streptococcus, Escherichia coli, Staphylococcus aureus , Staphylococcus epidermidis, Proteus vulgaris , Pseudomonas aeruginosa, Micrococcus, Vibrio vulnificus, Vibrio damsela, Shigella, Salmonella, Serratia, Providencia, Enterobacter, Flavobacterium, Yersinia and Moraxella. Most of the species were gram-negative bacillus (44.16%) and gram-positive coccus (53.30%). The most frequently isolated organism was Streptococcus.6. The infectious rate of bacteria in seawater group from high to low: Streptococcus > Escherichia coli > Staphylococcus aureus > Staphylococcus epidermidis > Proteus vulgaris > Pseudomonas aeruginosa, Micrococcus>marine vibrios>other species.7. There were mixed infection in gunshot wound in all seawater group. Streptococcus, Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis mixed were most frequent to see.8 .The infectious rate of marine vibrios was 14.29% in seawater group.9. The sensitivity of the infection bacteria to antibiotic in seawater group in order: gentamicin > cefacidal > alficetin.> economycin> abomacetin > penicilin G.Conclusions:...