28. IS THE SWAB USEFUL AS AN ALTERNATIVE METHOD OF COLLECTING MICROBIOTA SAMPLES IN PATIENTS WITH COLON CANCER?

Abstract

Abstract Introduction This study aims to investigate the intestinal microbiota in rectal samples obtained by swab, comparing them with stool samples, tumor, and non-tumor tissue in patients who underwent colorectal cancer surgery at our hospital. Methods Eight patients (3 women and 5 men) who underwent surgery at our center between 2021 and 2022 were included in the study. The anatomopathological stage was evenly distributed, with 50% in stage II and 50% in stage III. Tumor location was also varied, with 37.5% of patients having neoplasms in the left side colon and 62.5% in the right side. During the preoperative period, stool samples were collected from the patients. Additionally, a rectal exudate was obtained with a swab, and samples of tumor and non-tumor tissue were collected during the procedure. The composition of the intestinal microbiota in all samples was analyzed using rRNA sequencing. Results The analysis of all samples identified the phyla Firmicutes, Bacteroidota, Actinobacteriota, Fusobacteriota, and Proteobacteria. No significant differences were observed in terms of alpha and beta diversity when analyzing the different types of samples (feces, exudate, tumor, and non-tumor tissue). Stage II patients showed a greater abundance of Pasteurellacea, Magasphera, Citrobaceter, and Clostridium in the exudate, while Velillonella and Blautia were more prominent in feces. All the genera were different from those of stage III. The composition did not vary depending on the location of the tumor. Conclusion Swabs are a reliable alternative to stool collection for obtaining microbiota samples in patients with colon cancer.