Clinical Utility of Molecular Diagnosis of Blood Stream Infections in Allogeneic Hematopoietic Stem Cell Transplantation Recipients with Hematologic Malignancies

Blood stream infections (BSIs) are a serious problem in patients with hematologic malignancies receiving allogeneic hematopoietic stem cell transplantation (ASCT). We evaluated the clinical utility of molecular diagnosis for the management of BSIs in such patients. We prospectively performed a polymerase chain reaction (PCR) analysis of microbial DNA in blood samples from 10 consecutive patients with hematological malignancies at least once a week for one month after ASCT. In total, 51 and 54 samples were analyzed by bacterial and fungal PCR assays, respectively. Bacteria were detected in 24 samples from 8 patients by PCR, but in only 2 samples from one patient by blood culture. Notably, the bacteria detected in at least half of the 24 samples were considered to have originated from the oral cavity. Fungi were detected in 5 samples from 3 patients by PCR, but not by blood culture. Most cases with positive PCR results were manageable with empirical antimicrobial therapy without disclosure of DNA data. Our DNA analyses did not directly contribute to management of BSIs, but did provide valuable microbiological evidence for the patients. Additionally, oral management appears to require a critical re-evaluation to reduce the occurrence of BSIs in ASCT recipients.