Gut Microbiota Imbalance is Related to Sporadic Colorectal Neoplasms. A Pilot Study

(1) Background: Colorectal cancer (CRC) development is sustained by multiple factors including the gut microbiota, as suggested by a growing body of evidence. Most CRCs have a sporadic (non-hereditary) onset and develop from sporadic colorectal adenomas/polyp (SCA/P). In the present study, we investigated the characteristic of anaerobic microorganisms in stool samples obtained from 20 patients with SCA/P and 20 subjects without evidence of proliferative lesions at colonoscopy (Controls). (2) Material and Methods: We designed this clinical trial using adaptive randomization by minimization. Selective culture media and Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) mass spectrometry techniques were used to identify the components of microbiota. The data obtained revealed a different variability of gut microbiota in stool samples of controls and SCA/P subjects. (3) Results: The most interesting difference was observed for Bacteroides species, which represent the 50% of all bacterial species identified in the stool samples: two species, Bacteroides stercoris and Parabacteroides distasonis, were found only in the feces from control group, whereas Bacteroides fragilis and Prevotella melaningenica species were presents only in SCA/P patients. Among Gram+ bacteria also, specific species were found in the two groups of feces: Clostridium clostridioforme, Propionibacterium avidum and Pediococcus pentasaceus were identified only in controls, while Eubacterium limosum, Clostridium innocuum and Corybebacterium xerosus were identified in SCA/P stool samples only. (4) Conclusions: Our findings suggest that, compared to control stool samples, a different intestinal microbiota is present in SCA/P stool samples, that may create a micro-environment predisposing for the development of proliferative phenomena. As a consequence, gut microbiota manipulation could be a future target for personalized treatments.