Lasting profile changes characterized hematological cancer patients who developed oral mucositis following conditioning therapy.

Oral mucositis (OM) is a common side effect of conditioning therapy implemented before hematopoietic stem cell transplantation (HSCT). The role of oral microbiome in OM is not fully elucidated. To determine oral microbiome profile changes post-conditioning in HSCT patients who developed moderate OM, or mild to no OM. Patient groups were: Muc0-1 with OM-score = 0-1 (43 paired samples) and Muc2 with WHO OM-score = 2 (36 paired samples). Bacterial DNA was isolated from oral samples (saliva, swabs of buccal mucosa, tongue, and supragingival plaque) at pre-conditioning (T ), post-conditioning mucositis onset (T ), and one-year post-conditioning (T ). gene next-generation sequencing was used to determine the relative abundance (RA) of >700 oral species. -diversity, -diversity and linear discriminant analyses (LDA) were performed Muc2 Muc0-1. Muc2 oral microbiome - and -diversity differed between T and T . Muc2 -diversity and Muc0-1 diversity did not differ between T and T . T to T LDA scores were significant in Muc2 for . For Muc2 patients, the average RA decreased for , a species known as mucosal surfaces protector, but increased for genera. Post-conditioning OM might contribute to long-term oral microbiome changes affecting , in HSCT patients.