Drug abuse is a widespread public health problem because many of its medical complications are infectious due to the transmission of bloodborne, environmental, and respiratory infectious agents. Availability of highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV)-infected substance abusers has reduced the severity and frequency of opportunistic infections seen in the intravenous drug users (IVDUs) and other drug users (DUs). That said DUs/IDUs remain the groups least likely to access care and to maintain adherence for optimal benefit. Recent studies find social and access factors related to criminalization are major barriers to care including HAART for these individuals. Increasing treatment options and societal acceptance of harm reduction efforts have been demonstrated to improve outcomes in countries that have undertaken them.

Endocarditis

Endocarditis, a life-threatening infection of the heart valves and/or endocardium, is associated with septic parenteral injections. Right-sided valvular infections are very frequent in IDUs because of septic inoculations. Intravenous injection with low-pressure venous return increases the susceptibility of right-sided valvular and other structures to infection. Concurrent pulmonary hypertension from drug adulterants, such as talc, may also predispose to right-sided disease.

Despite the high prevalence of endocarditis, the offending pathogens are not specific to injectors. Staphylococcus aureus, often methicillin-resistant S. aureus (MRSA), is the most commonly identified organism, but other pathogens are seen. These include Pseudomonas, Serratia, enterococci, Streptococcus groups A and B, and Streptococcus viridans. Increasingly, fungal pathogens are seen with and without immunodeficiency.