Epidemiology and bacteriological diagnosis of paediatric acute osteoarticular infections

Acute paediatric osteo-articular infections require a fast and sensitive diagnosis allowing a treatment directed to the causative pathogen. Many micro-organisms can be incriminated, but Staphylococcus aureus and Kingella kingae markedly prevail. K. kingae became the first bacterial species responsible for septic arthritis in children < 3 years. More rarely, (2)haemolytic Streptococci and Streptococcus pneumoniae are found. The incidence of community acquired S. aureus resistant to oxacillin in osteo-articular infections is still low in France. The microbiological diagnosis of septic arthritis relies upon analysis of articular fluid, which requires systematic inoculation of a blood culture vial to increase the recovery rate of K. kingae. If the culture is negative, it is recommended to carry out a universal PCR or a PCR targeted to the main germs responsible for septic arthritis. Indeed, PCR represents an undeniable benefice for the diagnosis of paediatric septic arthritis, particularly for the DNA detection of K. kingae. The diagnosis of acute osteomyelitis relies primarily upon blood cultures, since the bone puncture is not a systematic procedure in this setting. Their efficiency is low, and there is still a need to look for other arguments of diagnosis such as search of possible portals of entry or specific serologies.