Emergence of endocarditis due to group D streptococci: findings derived from the merged database of the International Collaboration on Endocarditis.

The aim of the present study was to compare the epidemiological and clinical characteristics of Streptococcus bovis endocarditis with those of endocarditis caused by oral streptococci, using data obtained from a large international database of uniformly defined cases of infective endocarditis. S. bovis, a well-known cause of infective endocarditis, remains the common name used to designate group D nonenterococcal streptococci. In some countries, the frequency of S. bovis endocarditis has increased significantly in recent years. Data from the International Collaboration on Endocarditis merged database was used to identify the main characteristics of S. bovis endocarditis and compared them with those of infective endocarditis (IE) due to oral streptococci. The database contained 136 cases of S. bovis IE and 511 cases of IE due to oral streptococci. Patients with S. bovis IE were significantly older those with IE due to oral streptococci (63+/-16 vs. 55+/-18 years, P<0.00001). The proportion of streptococcal IE due to S. bovis increased from 10.9% before 1989 to 23.3% after 1989 (P=0.0007) and was 56.7% in France as compared with 9.4% in the rest of Europe and 6.0% in the USA (P<0.00001). Patients with S. bovis IE had more comorbidity and never used intravenous drugs. Complication rates, rates of valve replacement, and mortality rates were similar in the two groups. In conclusion, this study confirmed that S. bovis IE has unique characteristics when compared to endocarditis due to oral streptococci and that it emerged in the 1990s, mainly in France, a finding that is yet unexplained.