Cephalosporins as risk factor for nosocomial Enterococcus faecalis bacteremia. A matched case-control study

Nosocomial enterococcal infections have increased in various institutions, and patients with these infections had often been treated with cephalosporins during the previous weeks. The objective of this study was to determine whether the use of second- and third-generation cephalosporins is a risk factor for nosocomial enterococcal bacteremia (NEB), by means of a matched case-control study design.

Two hundred seven cases of NEB were studied. A control was matched to each case by sex, age (+/- 10 years), date of admission (+/- 2 years), hospital service, days of hospitalization, primary diagnosis, and operative procedures.

One hundred fifty-six cases had an appropriate matched control. The univariate analysis of unmatched variables showed that the presence of a urinary catheter (odds ratio [OR], 3.8), mechanical ventilation (OR = 2.6), and cephalosporin use (OR = 5.1) were associated with NEB. Using a conditional logistic regression model, cephalosporin use (adjusted OR = 4.8, 95% confidence interval, 2.3 to 9.8) and urinary catheter use (adjusted OR = 3.6, 95% confidence interval, 1.7 to 7.4) remained significantly associated with NEB after controlling for other unmatched variables.

These data show that the use of second- and third-generation cephalosporins may be a major risk factor for NEB. It may explain, at least partially, the steadily increasing number of enterococcal infections observed in some hospitals.