Significance of Streptococcus gallolyticus subsp. gallolyticus Association With Colorectal Cancer

Abstract

Streptococcus gallolyticus subsp. gallolyticus Sgg (formerly known as S. bovis type I) is the main causative agent of septicemia and infective endocarditis (IE) in elderly and immunocompromised persons. It belongs to the few opportunistic bacteria, which have been strongly associated to colorectal cancer (CRC). A literature survey covering a period of 40 years (1970–2010) revealed that 65% of patients diagnosed with an invasive Sgg infection had a concomitant colorectal neoplasia. Sgg is associated mainly with early adenomas and may thus constitute an early marker for CRC screening. Sgg has been described as a normal inhabitant of the rumen of herbivores and in the digestive tract of birds. It is more rarely detected in human intestinal tract (2.5–15%). Recent molecular analyses indicate possible zoonotic transmission of Sgg. Thanks to the development of a genetic toolbox and to comparative genomics, a number of factors that are important for Sgg pathogenicity have been identified. This review will highlight the role of Sgg pili in host colonization and how their phase-variable expression contributes to mitigate the host immune responses and finally their use as serological diagnostic tool. We will then present experimental data addressing the core question whether Sgg is a cause or consequence of CRC. We will discuss a few recent studies examining the etiological versus non-etiological participation of Sgg in colorectal cancer with the underlying mechanisms.

Tumour Microbiome-Based Subtypes of Colorectal Cancer Correlate with Clinical Variables

“…Some of the tumour genera of (possible) oral origin identi ed in our study, were associated with tumour mucosa previously, namely Fusobacterium, Campylobacter, Leptotrichia, Parvimonas, Gemella, Granulicatella, Eikenella, Selenomonas, Neisseria, Streptococcus, Alloprevotella, Veilonella, Haemophilus [8,31,32,[61][62][63][64][65][66][67][68]. In contrast, Solobacterium was reported increased [31], while Slackia and Pseudomonas were shown to be decreased [12,19] in fecal samples of CRC patients compared to healthy donors, and, in one epidemiological study, the presence of Treponema in the oral cavity was associated with increased risk of CRC [29], but none of these were previously associated with tumour mucosa.…”

Streptococcus gallolyticus abrogates anti-carcinogenic properties of tannic acid on low-passage colorectal carcinomas

“…Whether Sgg is a passenger or a driver bacterium has not been completely elucidated, but is just beginning to become clear. Pasquereau-Kotula described a two-hypothesis model, by which Sgg either contributes to CRC development as a consequence of local microbial imbalance or actively accelerates transformation due to high colonization in pre-malignant epithelium along with specific inflammatory responses and increased cell proliferation 46 . Growing evidence supports the former with Sgg not being a bona fide pathogen, but likely benefits www.nature.com/scientificreports www.nature.com/scientificreports/ from the microenvironment created by preneoplastic glands in the gut 9 .…”

Colon cancer of Peutz-Jeghers syndrome with gallolyticus endocarditis

“…The nature and the etiological role of S. gallolyticus with colon neoplasm have been extensively studied in mice. It is suggested that S. gallolyticus might be passengers and cancer-promoting bacteria [11]. The underlying mechanisms remain to be clarified further.…”