A Case of a Brain Abscess with Streptococcus intermedius Rapidly Diagnosed with the Melting Temperature Mapping Method

An 11-year-old boy, who had undergone repair of a total anomalous pulmonary venous connection (TAPVC) and double outlet right ventricle (DORV) during infancy, presented with a headache. Sinusitis and dental caries were also observed. Computed tomography (CT) scan revealed a mass on the left frontal lobe of his brain. He was diagnosed as having a brain abscess (BA) based on the magnetic resonance imaging (MRI) findings. The BA was drained, and the patient was treated with 300mg/kg cefotaxime and 40mg/kg metronidazole per day intravenously as empirical therapy. The melting temperature mapping method revealed Streptococcus intermedius in the intracranial pus 4.5 h after drainage. The echocardiogram showed no infective endocarditis. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDITOF MS) detected the same organism from the pus 3 days after drainage. The organism was pansusceptible, and treatment was continued because the presence of anaerobic, Gram-negative bacilli was suspected in the sinus cavity and dental plaque. The brain abscess, however, grew to 5cm 3 weeks after the drainage even under continued antibiotic therapy. A craniotomy was performed, and the entire abscess, including the abscess wall, was excised. Antibiotics were continued for 6 weeks, and the patient recovered completely. Rapid detection empirical therapy by administering appropriate antibiotics and total excision of the abscess successfully treated the patient. Thus, the use of rapid diagnostic tests and the melting temperature mapping method had significant impacts on effective antimicrobial stewardship.