Title: 0604 - Role of Oral Microbiota in the Severity of Chemotherapy-Induced Oral Mucositis


Kai Soo Tan (Presenter)
National University of Singapore

Nitasha Gupta, National University of Singapore
Samantha Yiling Quah, National University of Singapore
Jin Fei Yeo, National University of Singapore
Ferreira Joao, National University of Singapore
Catherine Hsu Ling Hong, National University of Singapore


Objectives: Oral mucositis (OM) is a painful and debilitating condition affecting patients receiving chemotherapy, and head and neck radiotherapy. OM treatment remains largely symptomatic and has not improved in years. The current understanding of OM pathophysiology comprises five stages namely initiation, damage response, signal amplification, ulceration and healing. Previously, preclinical and observational studies have shown a higher abundance of microbiota in OM, a shift from a largely gram positive to gram negative oral bacteria during cancer therapy, and the coincidence of the peak of bacterial colonization with increased severity of OM. However, this current OM model does not consider the role of oral microbiota. The aims of this study were, (i) to determine the potential role of oral bacteria in OM pathogenesis, and (ii) to investigate the therapeutic effect and safety of probiotics in OM.

Methods: For aim 1, specific pathogen free (SPF) and germ-free mice Swiss Webster mice were dosed with 5-florouracil (5-FU) to induce OM. For aim 2, C3H mice were dosed with 5-FU and fed with either regular drinking water or water with Lactobacillus reuteri. Body weight and diarrhea score were recorded daily. Oral mucosa tissues were harvested and histopathologic evaluation was carried out. For aim 2, blood and spleen were cultured.

Results: Germ-free mice exhibited significantly less severe weight loss and diarrhea compared to SPF mice. Oral mucosa tissues of germ-free mice showed reduced inflammation and atrophy compared to SPF mice. Mice fed with L. reuteri showed an improvement in the epithelial thickness in animals compared to animals not given L. reuteri. There was no bacterial growth in blood and spleen homogenates of mice fed with L. reuteri.

Conclusions: We have shown for the first time that oral microbiota exacerbates chemotherapy-induced OM severity. Administration of probiotics reduces the severity of OM.

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE