Streptococcus bovis/Streptococcus equinus complex fecal carriage, colorectal carcinoma, and infective endocarditis: a new appraisal of a complex connection

Abstract

The proportion of group D streptococcal infective endocarditis (IE) (predominantly due to Streptococcus gallolyticus) and the incidence of colorectal cancer are higher in France than in most European countries. We assumed that this could be explained by a high group D streptococci (GDS) fecal carriage rate. The aims of this study were to re-assess the GDS fecal carriage rate in France and its relationship with colorectal cancer. Consecutive adult subjects who were to undergo a complete colonoscopy were invited to participate. GDS were searched in subjects' stools before their colonoscopy using biomolecular techniques. Colonoscopic findings were sorted into four subgroups: normal colonoscopy, non-tumoral lesions, benign tumors, and premalignant/malignant tumors. GDS fecal carriages were calculated overall and in each subgroup and compared. The data from 259 subjects were analyzed. GDS were identified in the feces of 12 subjects, with the following distribution: S. lutetiensis (n = 9), S. pasteurianus (n = 2), and S. gallolyticus (n = 1). This accounted for an overall GDS fecal carriage rate of 4.6 %. The GDS fecal carriage rate was 6 % in case of normal colonoscopy, 1.3 % in case of non-tumoral lesions, 3.2 % in case of benign tumors, and 11 % in case of premalignant/malignant tumors. These four percentages were not statistically different. The GDS fecal carriage rate was lower than expected, which did not confirm our working hypothesis. Most strains belonged to S. bovis biotype II, while S. gallolyticus was found only once. These findings suggest that different GDS play different roles in the etiopathogenesis of IE and colorectal cancer.

Novel Real-Time PCR Assays Using TaqMan Minor Groove Binder Probes for Identification of Fecal Carriage of Streptococcus bovis/Streptococcus equinus Complex from Rectal Swab Specimens

“…pasteurianus, n ϭ 2; and S. gallolyticus subsp. gallolyticus, n ϭ 1 (14). Our results were in agreement with theirs, with S. infantarius subsp.…”

“…This fecal carriage rate is higher than those observed in prior studies (3,12,13). Notably, a recently published study (14) showed that the fecal carriage rate of SBEC subspecies was 4.6% among adult subjects with tumorous lesions, nontumorous lesions, and normal colonoscopy results. Those authors used a biomolecular technique and identified SBEC subspecies in the feces of 12 of 259 subjects, with the following distribution: S. lutetiensis (S. infantarius subsp.…”

The clinical epidemiology and malignancies associated with Streptococcus bovis biotypes in 506 cases of bloodstream infections

“…31,32 Consequently in settings with high rates of CRN an increased rates of Sb bacteraemia might be expected, which is the case of France presenting high incidence of CRN. 33 We do not know the incidence of CRN in our areas, but we know the incidence of mortality due to CRN, which was significantly higher in the cattle area than in the other two areas (Fig. 2), 34,35 Interestingly, some studies have shown an association of long-term consumption of red meat with increased risk of CRN, 36 and although the causality for this association is unknown it should be noted down that Sb could be isolated from meat.…”

Genomics, evolution, and molecular epidemiology of the Streptococcus bovis / Streptococcus equinus complex (SBSEC)

“…SBSEC colonize the GI-tract of humans where they are commensal and potentially opportunistic pathogenic bacteria. The faecal carriage rate of SBSEC is estimated around 23.8% in neonates and 5% in adults (Noble, 1978) with more precise recent estimations for SBSEC around 4.6% comprising S. lutetiensis as predominant member (Chirouze et al, 2013). However, in countries where live SBSEC members are consumed in large amounts via fermented food (Jans et al, 2013b;Tsakalidou et al, 1998), the faecal load might be higher.…”