What is the most common pathogen causing endocarditis in intravenous drug users?

Endocarditis in intravenous drug users is most commonly associated with Staphylococcus aureus. This pathogen is a highly virulent bacterium that can easily enter the bloodstream through breaks in the skin or mucosal barriers, which are often present in individuals who use intravenous drugs. The nature of intravenous drug use often involves the use of non-sterile techniques, which can introduce bacteria directly into the bloodstream, increasing the risk of infections such as endocarditis.

Staphylococcus aureus is particularly aggressive in causing damage to heart valves, leading to acute endocarditis. It tends to infect previously normal heart valves, in contrast to other pathogens that more commonly affect damaged valves. Factors such as the presence of foreign bodies, such as catheters, also elevate the risk for this pathogen.

In contrast, while other options like Streptococcus, Enterococcus, and Acinetobacter can cause endocarditis, they are not as commonly associated with intravenous drug users. Streptococcus may be more prevalent in cases involving underlying heart disease, Enterococcus is typically linked with urinary tract infections and often infects prosthetic valves, and Acinetobacter infections are more common in intensive care settings rather than related to drug usage. Therefore, the association of Staphylococcus