Bacterial DNA was detected directly in the serum of a patient with endocarditis by broad-range 16S rRNA PCR followed by sequencing and analysis of the results by the BLAST search. Using these methods, Cardiobacterium hominis was identified in 2 days from the date of serum collection. The microorganism was also isolated and identified using conventional methods (bacterial culture and biochemical tests) 17 days from the date of sample collection. This is the first report showing the direct detection of C. hominis in a patient's serum using molecular-based methods, emphasizing their potential usefulness as additional and rapid diagnostic tools for the detection and identification of fastidious bacteria.
CASE REPORTA 62-year-old man with a past history of arterial hypertension was admitted to our department because of a 3-week history of poor dietary intake, fatigue, weakness, diffuse abdominal discomfort, chills, and night sweats. His symptoms began after a short period of diarrhea and fever. He also reported a history of toothache and gum bleeding 4 weeks prior to admission. One week prior to his admission he was seen by his primary physician, who diagnosed viral infection. He had no previous history of cardiac murmur, heart disease, intravenous drug use, recent dental work, skin injury, or previous hospitalizations.On admission, physical examination revealed a temperature of 39°C, a heart rate of 105 beats per minute, 25 respirations per minute, and blood pressure of 160/70 mm Hg. He appeared pale and moderately ill but was not in acute distress. He had no subconjunctival, palatal, or subungual splinter hemorrhages, and his ocular fundi were normal. Dental caries was noted. There was no palpable peripheral adenopathy, but a spleen tip and a palpable liver were felt. Auscultation of the heart revealed a grade 2 of 6 at the apex of heart, without S3 sound or signs of heart failure. The remainder of the physical examination was unremarkable.A complete blood count revealed a white-blood-cell count of 14,400 cells/mm 3 , with 87% neutrophils, 5.5% lymphocytes, and 7.5% monocytes. Hemoglobin was 11.5 g/dl, and the platelet count was 262,000/mm 3 . Renal function testing revealed normal creatinine and blood urea levels. At that time, the erythrocyte sedimentation rate (ESR) was 62 mm in the first hour, C-reactive protein was 14.33 mg/dl, and fibrinogen was 597 mg/dl. Arterial blood gas analysis showed respiratory alkalosis with pH 7.503, 69 mm Hg PaO 2 , 26.2 mm Hg PaCO 2 , and 20.8 mmol/liter HCO 3 . A urine specimen was positive for hemoglobin (ϩϩϩ) and protein (ϩ); the sediment contained 4 to 6 red blood cells, 1 to 2 white cells per high-power field, and granular casts. Mild proteinuria (636 mg/24 h) was also present. His electrocardiogram showed sinus tachycardia. At entry, a two-dimensional trans-thoracic echocardiography showed normal valves without any obvious sign of valve vegetations and a left ventricular ejection fraction of 65 to 70%. Additional investigation included an abdominal ultrasonography, which con...