A Case of Bordetella holmseii Endocarditis in an Asplenic Pediatric Patient

INTRODUCTION A 9-year-old male patient with congenital dextrocardia and congenital asplenia history was seen in the emergency room due to parental concern for dehydration as a result of gastritis of five day duration. Previously, in 2006, the patient had mitral valve replacement and a pace maker implanted. The patient was admitted as a result of the current emergency room visit when the physician suspected endocarditis due to the patient's asplenia, artificial heart valve, and fever. An echocardiogram was performed. The echocardiogram was negative and showed no vegetations. A CBC was ordered on the patient. Results showed an elevated WBC count of 19.4 x 10³/μL. (Table 1) Ten blood cultures were drawn during the patient's admission; three were positive. The first positive blood culture grew bacteria after three days incubation in the aerobic bottle. The second positive blood culture was drawn six days later and took 3.6 days for growth to occur. The third positive blood culture, drawn 4 days after the second, took 2.5 days to become positive. Blood culture Gram stain results showed presence of small to moderate sized gram negative rods. Subsequent plate growth indicated that the organism grew best on Chocolate agar, appearing after 72 hours and was catalase negative. No growth was observed on MacConkey agar at three days. bioMérieux automated VITEK® 2 identification of the organism, grown from the blood, suggested Bordetella species. Organism identification was also obtained using MALDI-TOF mass spectrometry (VITEK® MS) instrumentation, which was undergoing validation studies at the time, and was…