Staphylococcus aureus endocarditis: The Grady Memorial Hospital Experience

Staphylococcus aureus is a common cause of endocarditis. Previous studies have shown that the mortality rate associated with S aureus endocarditis remains high, and methicillin resistance is becoming more prevalent.

Over the past 4 years, 283 patients with suspected endocarditis were referred to the cardiology department of Grady Memorial Hospital for echocardiography. Their clinical course and demographic information was entered into a database. Among these patients, 87 (30.6%) were confirmed to have endocarditis, with 41 (47.1%) of them culture positive for either methicillin-resistant (MRSA) or methicillin-sensitive S aureus (MSSA). Of these patients, 14 were MRSA culture positive, and 27 were MSSA culture positive. These two groups were compared with respect to demographic information and morbidity and mortality outcomes.

The MRSA and MSSA groups were found to be similar upon analysis in all baseline characteristics. There was a non-statistical trend among the two groups in origin of infection, as the MRSA group tended toward nosocomial infection more often. Outcomes, including surgery, death, and complications were also found to be similar between the two groups.

There does not seem to be difference in the outcome of MRSA versus MSSA endocarditis. Nosocomial infection may predispose patients to MRSA endocarditis, but a larger study with a greater sample size is necessary to evaluate these questions more accurately.