Association between colorectal cancer and Streptococcus gallolyticus subsp. pasteuranus (former S. bovis) endocarditis: clinical relevance and cues for microbiota science. Case report and review of the literature.

OBJECTIVE: The purpose of this paper is to contextualize the case of a patient with a synchronous diagnosis of colorectal cancer (CRC) and endocarditis from S. gallolyticus subsp. pasteuranus (former S. Bovis) within the current evidence, in order to determine if this condition is indicative of an underlying CRC and if it has any pathophysiologic significance. PATIENTS AND METHODS: First, we describe the clinical case. Then, we review the literature focused on the association between infections from the former S. Bovis group and CRC and on the possible role of certain microbiota species on the occurrence of CRC. At last, we discuss the implications of this case considering the current evidence. RESULTS: There is a strong association between all the species of the former S. Bovis group and CRC. There is initial evidence that these bacteria may contribute to CRC by a genomic passenger mechanism. CONCLUSIONS: There are two main conclusions for this paper. The first one is that CRC neoplasms and endocarditis from all species of the former S. bovis group have a strong association. Any case of infection by these subspecies should prompt to a diagnostic completion by colonoscopy. The second one is that there is an increased need for detailed reports/series and original articles based on the evaluation of gut microbiota in patients with CRC, with the aim to clarify if the association between bacteria and CRC is causative or sporadic and to better understand the possible causative mechanism of specific bacteria in initiating and promoting CRC.