[Interest of gene amplification by PCR for the diagnosis of Mycoplasma pneumoniae infections in the child].

Between december 1996 and february 1998, rhinopharyngeal and tracheal aspirates from 165 children exhibiting symptoms compatible with M. pneumoniae infection were tested by a PCR method using in the same tube primers specific for M. pneumoniae P1 adhesin gene and for a human control gene. The positive cases were controlled using culture and/or serology. PCR was positive in 22 out of 165 samples (13.3%); an evaluation of the clinical and biological data was possible in 20 of these infected children. From 17 PCR positive respiratory samples tested by culture, 13 (76.5%) grew M. pneumoniae. From 14 serum specimens tested by ELISA, 12 exhibited specific IgM (3 of them with low titers); cold agglutinins were detected in all 7 tested sera. Only one case was not confirmed by any of the 3 former markers. The mean age of patients was 8.1 years. The main clinical symptoms included fever > 38 degrees C, cough, clinical and radiological pneumonia in 90, 95, 50 and 85% of cases, respectively. Neurological symptoms were the main clinical manifestation in 3 patients; another child exhibited a pneumonia associated to an hemophagocytic syndrome and a bone marrow failure which needed a graft. These results emphasize the value of PCR for the rapid diagnosis of M. pneumoniae infection in children.