Enterococcal Bacteremia: Clinical Features, the Risk of Endocarditis, and Management

The enterococci, members of the group D streptococci and the predominant aerobic streptococci of the gastrointestinal and female genital tracts, have long been recognized as significant pathogens in infective endocarditis. Over the past 2 decades, enterococci have become increasingly important nosocomial pathogens, related to their intrinsic resistance to many antibiotics, especially the cephalosporins, and the greatly increased use of antimicrobial therapy in hospitals. Recent reports have documented an alarming increase in the frequency of high-level resistance to aminoglyclosides, and strains resistant to ampicillin by production of a beta-lactamase and to vancomycin have now been encountered. We have reviewed the clinical features and course of 153 cases of enterococcal bacteremia occurring in a university hospital over the 14-year period, 1970 to 1983, 1) to understand better the importance of enterococci as human pathogens, 2) to identify the clinical features of enterococcal bacteremia, 3) to isolate those findings that help to identify associated endocarditis, and 4) to develop guidelines for more effective antimicrobial therapy of bacteremic enterococcal infections. The annual incidence of enterococcal bacteremia in our center rose three-fold over the period reviewed. In 65 cases (42%), bacteremia was polymicrobial, caused by Enterococcus and at least 1 other microorganism, usually an aerobic gram-negative bacillus. Most bacteremias were nosocomial and derived from infections of the urinary tract (29 cases), intravenous catheters (24 cases), intra-abdominal infections or surgical wounds (46 cases), burn wounds (25 cases), or cholangitis (21 cases); only 1 case originated from a pneumonia. Endocarditis was identified in association with 12 of 35 community-acquired bacteremias, but only 1 of 118 bacteremias acquired in the hospital (P less than .001). Endocarditis was also significantly associated with pre-existent valvular heart disease and cryptogenic bacteremia, and was negatively associated with polymicrobial enterococcal bacteremia (no endocarditis in 65 cases, P less than .001). Isolated enterococcal bacteremia produced an indolent infection rarely associated with shock (3 of 64 cases evaluated, all cases due to valve destruction by endocarditis); conversely, with polymicrobial enterococcal bacteremia, primarily with gram-negative bacilli, shock or disseminated intravascular coagulation developed in 50% of cases (P less than .001).(ABSTRACT TRUNCATED AT 400 WORDS)