Investigating corollaries between Streptococcus gallolyticus subsp. gallolyticus virulence and colorectal cancer

Streptococcus gallolyticus subsp. gallolyticus (Sgg) is a gram-positive, non-beta-hemolytic bacterium that belongs to the Lancefield group D of streptococcal pathogens. For the past several decades, associations between Sgg bacteremia and colorectal cancer (CRC) have been apparent, with gastroenterologists routinely recommending colonoscopies for positive cases of Sgg in either blood or stool samples. However, current research has not wholly established whether Sgg acts as a causative agent of CRC or if pre-existing cancers make the lumen of the colon more hospitable to its colonization. Regardless, Sgg has been implicated in the modulation of host inflammatory pathways and subsequent remodeling of gut microbial communities, both of which may constitute predispositions for the formation of colorectal neoplasias. This literature review seeks to define and characterize molecular mechanisms unique to Sgg that not only assist in colonizing environments where cancerous tissue abounds but also perpetuate cancerous phenotypes. In addition, this review seeks to not only understand how these mechanisms are internally regulated but also intends to probe host pathways influenced by Sgg colonization.