Left-sided endocarditis in parenteral drug abusers: recent experience at a large community hospital

Endocarditis in IV drug abusers involves the right side of the heart with much higher incidence than in the general population, being limited to the left in 30% to 40% of cases. The infecting organism is Staphylococcus aureus approximately 50% of the time, followed by Streptococcus (all groups), which accounts for 15% of all cases. In a retrospective study of infective endocarditis in IV drug abusers treated at Charity Hospital over a 5-year period, 67 patients had vegetations documented by two-dimensional echocardiogram. Left-sided involvement was present in 38 (57%) of these patients, a higher prevalence than reported in the literature in such populations. Right-sided involvement was limited to only 27 (40%). A total of 55 patients had positive blood cultures, most of which yielded Staphylococcus aureus (32 [58%]), with the next largest group being Streptococcus species (14 [25%]). This distribution of isolates was consistent with that found in the literature. From these data we conclude that the prevalence of left ventricular endocarditis in our population is higher than expected. With the known increase in morbidity and mortality of left-sided endocarditis as compared to right, it is imperative that careful consideration be given this entity often encountered in IV drug abusers.