Rat polyvinyl sponge model for the study of infections: initial investigations.

Polyvinyl sponges were implanted subcutaneously on both sides of young female rats. One sponge was infected with 10(8) of either Escherichia coli K-12 F-, Staphylococcus aureus ATCC 25923, or Pseudomonas aeruginosa CDC 7725. P. aeruginosa remained at the inoculum level and S. aureus declined by 1 log, whereas E. coli was reduced 1,000-fold. Only P. aeruginosa was recovered from the blood in 36% of the animals in 24 h and in 20% of the rats in 48 h. The nutrient potential of rat inflammatory fluid was compared to nutrient broth by growth of each bacterium in untreated and heat-inactivated sponge fluids and Trypticase soy broth.