Case-control study of risk factors for the development of enterococcal bacteremia

To determine the risk factors involved in the development of enterococcal bacteremia, a prospective, observational, case-control study was carried out over 18 months. All episodes of enterococcal bacteremia with clinical significance detected in adults were included. A control matched by sex, age and hospitalization ward (medical, surgical or intensive care unit) was selected randomly for each patient with enterococcal bacteremia. Uni- and multivariate analyses of the epidemiological characteristics of both groups were performed. Etiologic fractions of every risk factor were also determined. One hundred twenty-two pairs were included. The severity of the chronic underlying diseases was similar in both groups. Neutropenia, cirrhosis, organ transplantation, intravascular catheter, urinary catheter, nasogastric tube, parenteral nutrition and previous administration of cephalosporins and imipenem were the factors associated with enterococcal bacteremia in the univariate analysis. The factors independently associated with enterococcal bacteremia in the multivariate analysis were neutropenia (odds ratio [OR] = 8), urinary catheter (OR = 3) and previous administration of cephalosporins (OR = 4) and imipenem (OR = 10). Their respective etiologic fractions were 9%, 44%, 11% and 29%. Efforts to reduce the occurrence of enterococcal bacteremia should be focused on appropriate use of cephalosporins, imipenem and external devices.