[Quantitative study of bacteriological infections in dogs undergoing gunshot wound in seawater]

To investigate the changes in bacterial proliferation and the time of infection occurrence in dogs wounded by gunshot in seawater.

Fourteen canine models of gunshot wound in seawater were established, with another 2 dogs receiving the wound without seawater immersion serving as control. Gross observation and quantitative bacterial analysis were performed at 0, 6, 12 and 24 h after the injury respectively, and two dynamic models for the bacterial growth were set up on the basis of statistical analysis of the results.

Bacterial quantity in both of the two groups tended to increase with time, but at each time point after the injury, the seawater group had higher bacterial count than the other group. Within 6 h after the injury, the bacterial count reached the critical point for clinical infection in seawater group. The two bacterial growth dynamics models were (1) Y=9.12 x 10(3+0.247X) and (2) Y=1.35 x 10(3+0.227X) for the seawater group and land group respectively, with the variant X representing time after gunshot injury, and Y the bacterial count per gram tissue. Using the dynamic models, we found that to reach the same bacteria count, the land group needed 4 h more than the seawater group(4.2 h).

Bacterial proliferation is accelerated in the wounds in seawater to result in earlier infection onset with more severity, suggesting that early debridement within 4 h after the injury, complete washing of the wound and early administration of the antibiotics are necessary for the wound management.