Anaerobic bacteria in bone and joint infections.

Anaerobic bacteria were discovered more than a century ago. However; they still remain difficult to cultivate, and their role in bone and joint infections is underestimated The ability to bring them out depends on the availability of adequate samples and the use in the laboratory of bacteriologic methods appropriate to overcome the difficulties of growth. Bacteriologic results are easy to interpret in the case of abundant growth and pure culture. They are more questionable when low numbers of a slow-growing pathogen are isolated. The situation is even more ambiguous in the case of isolation of more than one aerobic or anaerobic bacteria. Multiple bacteriologic samples are useful in overcoming these difficulties. The anaerobic or microaerophilic organisms that may cause bone and joint infections, either acquired by direct inoculation (traumatic or surgical wound) or by local extension of a contiguous infection or by hematogenous transmission are numerous. The careful search for anaerobic bacteria in appropriate samples is required to reduce the number of falsely negative results, too quickly issued as 'sterile after 48 hours'. It is a condition for a better therapeutic management of these infections that occur much more frequently than usually thought. (C) 2000 Editions scientifiques et medicales Elsevier SAS.