Epidemiology in bone and joint infection.

The studies of community-acquired infection indicate the importance of the environment in which the host-pathogen interaction takes place. Whereas the high incidence rates at the extremes of life are compatible with a hypothesis of diminished immune competence, the varying rates of acute osteomyelitis during growth, and its predominantly metaphyseal site, suggest that further studies of the molecular biology of this rather specific infection would be revealing. Molecular biology has a role, too, in improving understanding of the epidemiology of resistance and pathogenicity in hospital-acquired infections. Although antibiotic prescription and other medical practices influence the environment profoundly, we should remember that we may be experiencing long-term trends beyond our present understanding. As more and more reconstructive bone and joint surgery is carried out, careful observational epidemiology remains a vital tool.