Prospective evaluation of the risk of bacteremia associated with transesophageal echocardiography

BACKGROUND. Transient bacteremia may lead to endocarditis in patients with significant valvular lesions. METHODS AND RESULTS. Because transesophageal echocardiography selects a patient population with a high prevalence of valvular lesions, we prospectively evaluated the risk of transient bacteremia associated with transesophageal echocardiography in 49 patients. Blood cultures were obtained immediately before transesophageal echocardiography and at 5, 10, and 20 minutes after the start of the procedure. For each culture, 30 ml venous blood was obtained and 10 ml was inoculated into each of an Isolator tube, Septi-chek bottle, and a nonvented Trypticase soy broth bottle. Broth cultures were incubated for 14 days. Blood from the Isolator tube was plated onto appropriate media for recovery of bacteria and fungi. Two patients were excluded from analysis because the final two sets of blood cultures could not be obtained. Among the remaining 47 study patients, two preprocedure control blood cultures were positive, and two of 141 subsequent cultures were positive. All isolates were considered contaminants. Thus, we found no significant bacteremia due to pathogenic oral flora during transesophageal echocardiography (0%; 95% CI, 0.0-7.5%). CONCLUSIONS. Although recommendations for antimicrobial prophylaxis for transesophageal echocardiography should be individualized for each patient, many patients may not require antimicrobial prophylaxis.