Infective endocarditis, 1970-1979. A study of culture-positive cases in St. Thomas' Hospital.

Ninety-three episodes of culture-positive endocarditis occurred in 88 patients in the years 1970 to 1979. Streptococci caused two-thirds of the cases, with Streptococcus mitior and Streptococcus sanguis most common. Among the Group D streptococci, Streptococcus bovis was much more common than Streptococcus faecalis. Staphylococci accounted for a quarter of the episodes. Streptococcal endocarditis was commonest in the elderly, whereas staphylococcal endocarditis occurred at all ages. Degenerative heart disease was the underlying cardiac factor in nearly half the streptococcal cases, but staphylococci most often affected normal heart valves. When prosthetic valves were infected endocarditis of early onset was staphylococcal but that of late onset was streptococcal. Narcotic abuse was a common cause of staphylococcal endocarditis, second only to surgical wound infection following valve replacement. Streptococci affected the mitral and aortic valves equally but the staphylococci more usually involved mitral or tricuspid valves. The overall mortality was 36 per cent but was much higher for staphylococcal than streptococcal endocarditis.