We describe a case of primary purulent culture-negative pericarditis caused by Neisseria meningitidis serogroup C occurring in an 8-month-old previously healthy boy, which was detected in pericardial fluid by broad-spectrum PCR amplification.
CASE REPORTA previously healthy infant aged 8 months was admitted to the Emergency Department of Louis Mourier Hospital (Paris, France) with a 10-day history of several daily feverish peaks of between 39 and 40°C. On examination, the patient had normal hemodynamic parameters, and his temperature was 36.6°C. He was pale, with neither spots nor purpura. The examination of the ears and nose was unremarkable. There was no hepatosplenomegaly or local pain. Neurologic and pulmonary clinical examinations revealed no abnormalities. Heart sounds were diminished in intensity. A chest radiograph showed considerable cardiomegaly, with a cardiothoracic index of 0.6. The cardiac echography revealed a pericardial effusion and thickened pericardium. There was no sign of cardiac tamponade. Blood and urine samples were taken for culture. Laboratory studies showed a white blood cell (WBC) count of 21.10 9 /mm 3 , with 45% polymorphonuclear neutrophils, 11% monocytes, and 44% lymphocytes. The C-reactive protein level was 167 mg/liter, and the erythrocyte sedimentation rate was 92 mm/h. The creatine kinase level was 126 UI/liter (range, 30 to 180 UI/liter). Despite the absence of neurologic signs, cerebrospinal fluid was collected. It was clear, with no WBCs, 2 red blood cells/mm 3 , and normal glucose and protein levels. The patient was transferred to the cardiac surgery care unit of NeckerEnfants Malades hospital (Paris, France) for management of pericarditis. He had an emergency pericardiocentesis and was then started on a probabilistic intravenous antibiotic therapy including cefotaxime (200 mg/kg of body weight/24 h), gentamicin (30 mg/kg/24 h), and ciprofloxacin (30 mg/kg/24 h).Pericardiocentesis yielded a moderate fluid with 1,800 red blood cells/mm 3 and 270 WBC/mm 3 , with 82% polymorphonuclear neutrophils and 18% lymphocytes. No microorganism was observed by Gram and Ziehl-Nielsen stain. The cultures of pericardial fluid on blood and chocolate agar (BioMérieux, Marcy l'Etoile, France) and in BacT/Alert (BioMérieux) blood culture bottles incubated under aerobic and anaerobic conditions were negative. The culture for mycobacteria was negative. The standard culture of cerebrospinal fluid, blood, and urine remained sterile. A PCR for detection of Mycoplasma pneumoniae and Chlamydia pneumoniae from bronchoalveolar liquid (BAL) was negative. Immunofluorescence microscopy of BAL was negative for respiratory syncitial virus, adenovirus, and herpes simplex virus. No cytomegalovirus was detected by PCR from BAL. Serological investigations for human immunodeficiency virus, cytomegalovirus, and Epstein-Barr virus were negative.In the absence of microbial cultures, we performed a universal 16S rRNA PCR amplification from the pericardial fluid.