The value of surveillance cultures in neutropenic patients receiving selective intestinal decontamination

230 neutropenic episodes in 84 patients with acute myeloid leukemia receiving selective intestinal decontamination were studied to evaluate the ability of surveillance cultures to monitor the efficacy of microbial suppression, to identify causative organisms in case of fever, and to predict infection due to potential pathogens (i.e. Staphylococcus aureus and aerobic Gram-negative bacteria). Most cultures became negative soon after the administration of prophylactic antibiotics and there were only few persistent colonizations. 14 potential pathogens resistant to the intestinal decontamination regimen were isolated in surveillance cultures, none of which caused infection. Of the 212 febrile episodes, only 22 were caused by a microbiologically documented infection with potential pathogens. Most microbiologically documented infections were caused by organisms not routinely identified by surveillance cultures, indicating efficient selective intestinal decontamination. Only 9 (41%) of the 22 infections with potential pathogens were predicted by surveillance cultures. We conclude that surveillance cultures are of limited use in predicting infection or identifying causative organisms of fever in neutropenic patients receiving selective intestinal decontamination. However, they are useful in monitoring the efficacy of microbial suppression. One set of surveillance cultures each week after the disappearance of potential pathogens would be sufficient.