Endocarditis due to coagulase-negative staphylococci. Microbiologic, epidemiologic, and clinical considerations.

Coagulase-negative staphylococci are the most frequently isolated pathogens in prosthetic valve endocarditis and cause 5% of infections involving native valves. Distinguishing contamination from bacteremia may be challenging. The presence of heteroresistance in many strains makes rigorous susceptibility testing a requirement for selecting appropriate antibiotic selection. Infection is frequently complicated by valvular insufficiency with congestive heart failure, local tissue invasion or synthetic embolization, making surgical intervention necessary in many cases.