Micro-organisms responsible for osteo-articular infections.

Identification of the aetiological agents responsible for bone and joint infections requires either hard to obtain specimens that are easy to interpret, or easy to obtain specimens of difficult interpretation. Isolates obtained by blood cultures, arthrocentesis, or trephine or surgical biopsy bone samples are usually clinically significant. In contrast, samples obtained from sinus tracts or through open wounds are very often easy to obtain but difficult to interpret. Micro-organisms such as Staphylococcus epidermidis are the most common cause of infections around prosthetic joint materials but are usually of little significance when obtained from the sinus tract of a patient with chronic osteomyelitis of the tibia without osteosynthesis. Other micro-organisms to be interpreted with caution include Corynebacterium spp. and Enterococcus spp. The most important families of antimicrobial agents and their utility in bone and joint infections are briefly reviewed at the end of the chapter. Bone and joint infections require long-term antimicrobial therapy based on the correct diagnosis and the appropriate selection of antimicrobial treatment.