Endocarditis: impact of methicillin-resistant Staphylococcus aureus in hemodialysis patients and community-acquired infection.

BACKGROUND AND PURPOSE: Staphylococcus aureus endocarditis showed an increase in the 1990s compared to the 1980s. In order to characterize the clinical and laboratory features of S. aureus endocarditis, we retrospectively reviewed the medical charts of patients diagnosed with endocarditis in the 5-year-period between 2000 and 2005.

METHODS: From August 2000 to August 2005, 22 patients with a definite diagnosis of infective endocarditis (IE) caused by S. aureus were reviewed.

RESULTS: Of the 22 patients reviewed, 16 cases were caused by methicillin-resistant S. aureus (MRSA) while the causative agent in the other 6 cases was methicillin-susceptible S. aureus (MSSA). Patients with MRSA infections were more likely to show hospital-acquired infections, hemodialysis and ventilator dependence, septic shock, impaired initial renal function, persistent bacteremia, and a higher 3-month mortality rate. MSSA infections in patients were more likely to be community-acquired, and show intravenous drug use and longer days of fever prior to admission. Three patients with MRSA endocarditis, however, presented community-acquired infections. The mortality rate of MRSA endocarditis in hemodialysis patients was 90% (9/10).

CONCLUSIONS: MRSA IE is more common than MSSA IE and is associated with a significantly poorer prognosis, especially in patients undergoing hemodialysis. Although most cases of MRSA IE are hospital acquired, we noticed 3 cases of community-acquired MRSA IE. As MRSA IE has been noticed in the community and hemodialysis patients in recent years, and is associated with higher mortalities, strategies for its prevention and management are warranted.