LACK OF UTILITY OF THE LYSIS-CENTRIFUGATION BLOOD CULTURE METHOD FOR DETECTION OF FUNGEMIA IN IMMUNOCOMPROMISED CANCER-PATIENTS

We retrospectively compared the utility of a fungal isolation device ( Isolator) versus conventional techniques for recovering fungal organis ms from blood cultures obtained from neutropenic cancer patients. Posi tive cultures were deemed true pathogens, possible pathogens, or conta minants according to laboratory and clinical criteria. Fifty-three pat ients had 66 positive blood cultures for fungi, nine on multiple occas ions. In 20 episodes true pathogens were recovered, 6 from broth mediu m alone, 4 from the Isolator system alone, and 10 from both systems. F alse-negative cultures were noted in 4 of 20 (20%) cases in which brot h medium was used and in 6 of 20 (30%) cases in which the Isolator sys tem was used. Possible pathogens were detected in 4 of 66 blood cultur e-positive cases. Forty-two positive cultures were considered contamin ants, 1 collected from standard medium and 41 of 42 (98%) which grew o nly in Isolators. Eleven of 18 patients with true fungal infections ex pired as a result of infection, while 4 of 33 patients with a contamin ant expired, none from a fungal cause. We do not advocate the routine use of Isolator tubes in the evaluation of the febrile, neutropenic pa tient due to the high rates of false positives and of contamination.