[Pericarditis caused by Gemella morbillorum. Description of a case].

Pericardial diseases, in the pediatric age group are rare, and are usually due to viral infection or collagen diseases. Since the advent of the antibiotic era, bacterial pericardial has rarely been reported, and the bacteria most commonly involved are Staphylococcus aureus, Streptococcus pneumoniae, Haemophylus influenzae and Neisseria meningitidis; other pyogenic agents have rarely been isolated in pericarditis. Gemella morbillorum, also known as Streptococcus morbillorum, is a Gram-positive pyogen, usually a saprophite agent of the human gastrointestinal tract, rarely associated with human infections such as arthritis, endocarditis and meningitidis; to our knowledge, it has never been isolated in pericarditis. We report a case of pyogenic pericarditis in an 11-year-old boy, suffering from substernal chest pain for about one year, in which the clinical symptoms, the presence of acute phase proteins, the large amount of fluid within the pericardial space (echocardiographically estimated to be approximately 18 mm), the lack of improvement in clinical conditions and in laboratory values after therapy (diuretics, broad spectrum antibiotics and steroids) led to the indication for a pericardial drainage with the isolation of Gemella morbillorum. Antimicrobial therapy was then modified according to in vitro susceptibility of the Gemella morbillorum, with a decisive contribution to the recovery of the patient, although long-term steroid therapy (5 months) was necessary because of one recurrence of pericardial effusion. This case report shows how Gemella morbillorum, usually a saprophit microorganism, can become pathogenic and also underlines the importance of a correct etiologic diagnosis of pericarditis resistent to classical antibiotic therapy.