Experimental polymicrobial osteomyelitis produced by both aerobic and anaerobic opportunistic pathogens

Experimental models of polymicrobial osteomyelitis were prepared using clinical isolates of Staphylococcus epidermidis and Enterococcus faecalis as aerobes and Bacteroides fragilis and Bacteroides bivius as anaerobes. These pathogens were used because of their opportunistic properties. Two 8 mm long silk threads with the microorganism were inserted into the bone marrow of a rat. The microorganism inoculated was about 10(5) c.f.u. for aerobes and 10(6) c.f.u. for anaerobes. Infected parts observed in the roentgenograms, histopathological changes, and bacterial counts all showed the evolution of osteomyelitis. It was found that our models caused osteomyelitis both when each of S. epidermidis, E. faecalis, B. fragilis, and B. bivius was implanted individually and in their combinations. The patterns of the radiological and the histological observations were almost similar in all cases examined, but their characteristics differed depending on the kinds and combinations of the pathogens.