[Role of the bacteriology laboratory in the diagnosis and treatment of osteoarthritis].

The etiological diagnosis of bone and joint infections, the choice of antibiotics adapted to the responsible bacteria and the supervision of their efficacy depend mainly on the bacteriology laboratory. A routine search for the causal bacteria in various samples, e.g. synovial fluid, blood cultures, synovial biopsy, inter-vertebral disc puncture, permit etiological diagnosis in about 80% of cases. The choice of antibiotics, limited to those whose synovial and bony diffusion is known, depends on the results of in vitro studies of sensitivity of the isolated bacteria (CMI and CMB) and of the bactericidal power of the associations. The measurement of the inhibitory power or concentrations of antibiotic in synovial fluid and serum give an indication of the efficacy of the treatment.