By Dean L. Winslow, MD, FACP, FIDSA
Professor of Medicine, Division of General Medical Disciplines, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine
Dr. Winslow reports no financial relationships relevant to this field of study.
SYNOPSIS: Non-β-hemolytic streptococci (NBHS) are the most common cause of infective endocarditis. In this retrospective study of 399 patients with NBHS bacteremia, 26 patients had endocarditis. HANDOC score (heart murmur, aetiology by specific species of NBHS, number of positive blood cultures, duration of symptoms, only one species in blood culture, and community-acquired infection) was predictive of endocarditis vs. non-endocarditis bacteremia.
SOURCE: Sunnerhagen T, Tornell A, Vikbrant M, et al. HANDOC: A handy score to determine the need for echocardiography in non-β-hemolytic streptococcal bacteremia. Clin Infect Dis 2018;66:693-698.
Researchers reviewed medical records from 399 patients with NBHS bacteremia in southern Sweden as part of an initial cohort. Of these 399, 26 patients ultimately were deemed to have infective endocarditis (IE). The following factors were identified that correlated with diagnosis of endocarditis: presence of heart murmur or valve disease; etiology with Streptococcus mutans, S. bovis, S. sanguinis, or S. anginosus; number of positive blood cultures ≥ 2; duration of symptoms ≥ 7 days; only one species growing in blood culture; and community-acquired infection. Using a cutoff between 2 and 3 points, HANDOC had a sensitivity of 100% and specificity of 73% in the first cohort. When these criteria were applied to a second validation cohort of 399 patients, the sensitivity was 100% and the specificity was 76%.
While NBHS and Staphylococcus aureus cause most cases of native valve endocarditis, the majority of patients who have bacteremia with either of these pathogens do not have IE. The Infectious Diseases Society of America currently has a panel of experts who are developing new guidelines to help clinicians manage S. aureus bacteremia, including when to order echocardiography. However, we do not have official guidelines in development to provide similar guidance for when to order echocardiography in the setting NBHS bacteremia. This is important since NBHS not only commonly cause IE, but also are seen commonly in neutropenic sepsis and are secondary only to coagulase-negative staphylococci as common contaminants seen in blood cultures.
I believe that for experienced clinicians, using the HANDOC criteria is something most of us have been doing all along (although we didn’t have that spiffy acronym). However, this retrospective study should provide important guidance for hospitalists and other doctors who commonly manage patients with NBHS bacteremia in the hospital setting.
Applying the criteria that came from this nice retrospective study should significantly reduce the inappropriate ordering of both transthoracic echocardiograms, which are expensive, and transesophageal echocardiograms, which are both expensive and can be associated with complications due the requirement for sedation as well as potential adverse consequences of passing a transducer into the esophagus, in patients with NBHS bacteremia.