Detection of bacteria in blood circulation in patients receiving cancer chemotherapy

Introduction: Bacterial translocation, in which intestinal bacteria pass through the intestinal wall, enter the blood circulation, and spread to other sites of the body, is thought to cause bacteremia and sometimes febrile neutropenia (FN) in patients who receive cancer chemotherapy. Materials and methods: We collected blood samples from 39 patients with various cancers at baseline and after chemotherapy began (during chemotherapy) and explored how frequently bacteria could be detected in the blood using a highly-sensitive, bacterial rRNA-targeted reverse transcription quantitative polymerase chain reaction (PCR) assay. Results: Bacterial traces, typically Escherichia coli and Enterobacter spp., were detected in 10 patients (25.6%) at baseline and 11 patients (28.2%) during chemotherapy. The bacterial traces were positive either at baseline or during chemotherapy in 3 (60%) of 5 patients who had FN, and 6 (46%) of 13 patients aged 65 years or older. Conclusion: These findings support the notion that bacterial translocation occurs in patients with cancer regardless of whether they receive chemotherapy and can lead to the development of FN and other treatment-related infections.