Ostéomyélites à staphylocoque coagulase négative chez le prématuré : proposition de démarche diagnostique

Acute osteomyelitis, although a rare complication in neonates, is a diagnostic and therapeutic challenge. Successful treatment to avoid functional sequelae depends on early recognition of infection and rapid initiation of therapy. Although Staphylococcus aureus is the most common causative agent, coagulase-negative Staphylococcus (CONS), well known for bloodstream infection, can be involved in neonatal osteomyelitis. Risk factors of osteomyelitis include prematurity and invasive procedures, such as long-term central venous catheterization. We report on 3 cases of acute CONS osteomyelitis in preterm infants presenting with prolonged CONS bacteremia. Bacteremia persisted despite antibiotic treatment in accordance with antibiograms and despite removal of the intravascular device. All catheter cultures were negative and osteomyelitis was not located on the limb where the central catheter had been inserted in all cases. Osteomyelitis diagnosis may be difficult in neonates because of the paucity of clinical signs. In our observations, 99mTc scintigraphy was the key investigation for diagnosis and detection of multiple sites of bone infection. The place of this investigation is discussed in relation to other imaging techniques. These observations suggest that in the context of persisting CONS bacteremia, a secondary bone infection should be considered. Scintigraphy is a discriminating diagnostic tool.