High-level gentamicin resistance in enterococcal bacteremia

Enterococci are facultatively anaerobic, catalase-negative, gram positive cocci. The bacteria most frequently cause urinary tract infection, and less commonly bacteremia and endocarditis. Enterococcus faecalis is most commonly isolated (80% to 90% of enterococcal bacteremias), followed by Enterococcus faecium. Enterococcal bacteremia is associated with a high mortality (30% to 60%). The organisms are frequently characterized by high-level resistance to the aminoglycoside gentamicin. Attention to laboratory susceptibility results, clinical manifestations, and appropriate antibiotic treatment of high-level gentamicin resistance are crucial for management of these difficult-to-treat infections.