Gastrointestinal disturbances are a side-effect frequently associated with haematological
malignancies due to the intensive cytotoxic treatment given in connection with
bone marrow transplantation (BMT). However, intestinal microbiota changes during
chemotherapy remain poorly described, probably due to the use of culture-based and low-resolution molecular methods in previous studies. The objective of our study was to apply a next generation
DNA sequencing technology to analyse
chemotherapy-induced changes in faecal microbiota. We included eight patients with
non-Hodgkin's lymphoma undergoing one course of BMT conditioning
chemotherapy. We collected a prechemotherapy faecal sample, the day before
chemotherapy was initiated, and a postchemotherapy sample, collected 1 week after the initiation of
chemotherapy. Total
DNA was extracted from faecal samples, denaturing high-performance liquid chromatography based on amplification of the V6 to V8 region of the
16S ribosomal RNA (rRNA) gene, and 454-pyrosequencing of the 16 S rRNA gene, using PCR primers targeting the V5 and V6 hypervariable
16S rRNA gene regions were performed. Raw sequence data were screened, trimmed, and filtered using the QIIME pipeline. We observed a steep reduction in alpha diversity and significant differences in the composition of the intestinal microbiota in response to
chemotherapy.
Chemotherapy was associated with a drastic drop in Faecalibacterium and accompanied by an increase of Escherichia. The
chemotherapy-induced shift in the intestinal microbiota could induce severe side effects in immunocompromised
cancer patients. Our study is a first step in identifying patients at risk for gastrointestinal disturbances and to promote strategies to prevent this drastic shift in intestinal microbiota.