[Bacillus Calmette-Guérin osteomyelitis. A case report in a former preterm baby].

Postvaccination osteo-articular mycobacterial infectious disease is a rare and potentially serious complication after Bacillus Calmette-Guérin (BCG) vaccine. We report on a case of a former preterm baby born at 30 weeks of gestation who was vaccinated with BCG Copenhagen strain at 2 months of age. He presented 6 months later with a painful limp, which was found to be a mono-articular osteitis of the right ankle. Histology of the biopsy showed signs of mycobacterial infection and molecular analysis confirmed a BCG infection. Blood tests did not reveal any immunodeficiency associated with the disease (IFN-gamma levels were normal). The course of the disease was favorable with 9 months of antibiotic therapy against mycobacteria. BCG complications should lead to screening for immunodeficiency. The prognosis of BCG osteitis is excellent if the disease is localized. No link between prematurity and BCG complications has been found to date. BCG vaccination of premature infant should be the same as for the general population.