Prediction by surveillance cultures of bacteremia among neutropenic patients treated in a protective environment.

One hundred seventy-five consecutive marrow transplant patients who were treated in a protective environment for at least two weeks were studied to determine the usefulness of bacteriologic surveillance cultures for the prediction of bacteremia due to Staphylococcus aureus or aerobic gram-negative bacilli. Bacteremia with these organisms occurred in 15 patients (9%), and all patients were colonized with the respective organism before bacteremia occurred. Bacterial colonization was associated with a 17- to 174-fold increase in the relative risk of bacteremia. Negative predictive values were high, but positive predictive values were low owing to the infrequent occurrence of bacteremia. Surveillance cultures also predicted antibiotic sensitivities for all but one organism causing bacteremia. Bacteriologic surveillance cultures in the protective environment are thus useful both for the identification of patients at higher risk of bacteremia with certain types of organisms and for the identification of those who may fail to respond to antibiotic therapy as a result of infection with resistant organisms.