[An experimental study on pyogenic osteomyelitis with special reference to polymicrobial infections].

The author used the following method to successfully devise a model of experimental osteomyelitis caused by two different bacteria. A 3-mm silk thread (No. 5) soaked in Staphylococcus aureus (1.0 X 10(4) CFU) and Pseudomonas aeruginosa (1.0 X 10(5) CFU) suspensions was dried under reduced pressure. The silk thread was inserted into the metaphysis of the right tibia of mice. Experimental osteomyelitis caused by these two species of bacteria was successfully produced in all the mice, and this infection was similar to osteomyelitis in man. After prior infection with S. aureus, P. aeruginosa (1.0 X 10(3) CFU) was inoculated directly into the tibia of mice during the acute and chronic stages of the S. aureus infection, and secondary infection by P. aeruginosa was confirmed in all the mice. Using this experimental model of osteomyelitis, the author administered an antibiotic that is effective against only S. aureus in mice and observed abrupt growth of P. aeruginosa to elucidate certain aspects of the bacterial replacement phenomena.