Microbial Epidemiology of Infectious Endocarditis in the Intravenous Drug Abuse Population: A Retrospective Study

INTRODUCTION: The microbial epidemiology differs between infective endocarditis (IE) patients with and without a history of injection drug use. We set out to determine the prevalence and microbial epidemiology of infective endocarditis in our region, the Southeastern USA, to determine if any changes need to be made in empiric antimicrobial treatment. METHODS: The electronic medical record was reviewed for patients with IE between January 2013 and July 2017, which revealed 299 cases. The cases were then sorted between patients with and without a history of injection drug use. The growth of their initial set of blood cultures and side of cardiac involvement were then recorded. Statistical analyses were run on the data sets. RESULTS: There were statistically significant effects associated with both methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas species infections occurring more often in individuals with active injection drug use, while streptococcus and enterococcus infections were more likely to occur in the population of individuals who do not inject drugs. CONCLUSION: In IE patients who use or are suspected of injection drug use, first-line broad-spectrum antibiotics with excellent MRSA and Pseudomonas coverage are essential.