Association of Streptococcus bovis endocarditis and advanced colorectal neoplasia: a case-control study

Association of the Streptococcus bovis/Streptococcus equinus Complex With Colorectal Neoplasia: A Systematic Review and Meta-analysis

Background

Invasive infection with Streptococcus bovis/Streptococcus equinus complex (SBSEC) bacteria is associated with underlying colorectal neoplasia. However, the link between intestinal or fecal colonization with SBSEC isolates or antibody responses to SBSEC members and colorectal cancer is not thoroughly investigated in the literature.

Methods

We searched the PubMed, EMBASE, and Web of Science databases for case-control studies as well as retrospective or prospective cohort studies reporting an association between SBSEC bacteria and colorectal neoplasia.

Results

We identified 22 studies (15 case-control and 7 cohort) that met our inclusion criteria. Among the cohort studies, patients with SBSEC bacteremia were 3.73 times more likely to have underlying colorectal cancer compared with individuals with no bacteremia (relative risk [RR], 3.73; 95% CI, 2.79-5.01), whereas the risk of underlying colorectal adenoma in patients with SBSEC bacteremia was not significantly increased (RR, 5.00; 95% CI, 0.83-30.03). In case-control studies, patients with colorectal cancer were 2.27 times more likely to have evidence of intestinal or fecal colonization with SBSEC isolates (odds ratio [OR], 2.27; 95% CI, 1.11-4.62) and immunoglobulin G (IgG) antibody responses to SBSEC antigens (OR, 2.27; 95% CI, 1.06-4.86) compared with controls. Patients with colorectal adenoma were not more likely to be colonized with SBSEC isolates compared with controls (OR, 1.12; 95% CI, 0.55-2.25).

Conclusions

Apart from the well-established association of SBSEC bacteremia and underlying colorectal cancer, intestinal or fecal colonization with SBSEC isolates and IgG antibody responses to SBSEC antigens were higher in patients with colorectal cancer compared with controls. Neither bacteremia from SBSEC isolates nor colonization with SBSEC bacteria was associated with underlying colorectal adenoma.

Fusobacterium nucleatum and Bacteroides fragilis detection in colorectal tumours: Optimal target site and correlation with total bacterial load

Background

Mucosal infiltration by certain bacterial species may contribute to the development and progression of colorectal cancer (CRC). There is considerable variation in reported detection rates in human CRC samples and the extent to which bacterial infiltration varies across regions of the primary tumour is unknown. This study aimed to determine if there is an optimal site for bacterial detection within CRC tumours.

Methods

Presence of target bacterial species was assessed by quantitative real-time PCR (qPCR) in 42 human CRC tumours. Abundance in primary tumour regions, normal epithelium and at metastatic sites was investigated in an expanded cohort of 51 patients. Species presence/absence was confirmed by diversity profiling in five patients. Correlation with total bacterial load and clinicopathological features was assessed.

Results

Fusobacterium nucleatum and Bacteroides fragilis were detected in tumours from 43% and 24% of patients, respectively (17% positive for both species). The optimal detection site was the tumour luminal surface (TLS). Patients testing positive at the TLS frequently tested negative at other sites, including central tumour and invasive margin. F. nucleatum was detected at a higher frequency in tumour versus normal epithelium (p < 0.01) and was associated with more advanced disease (p = 0.01). Detection of both species correlated with total bacterial load. However, corroboration of qPCR results via diversity profiling suggests detection of these species may indicate a specific microbial signature.

Conclusions

This study supports a role for F. nucleatum in CRC development. Presence of F. nucleatum and B. fragilis varies across primary tumour regions, with the TLS representing the optimal site for bacterial detection.

First Case of Infective Endocarditis With Streptococcus equinus in an Immunocompetent Patient in North America: A Case Report and Review of Literature

Infective endocarditis (IE) can be caused by bacterial or fungal infections invading the endocardial surface of the heart, such as its valves and chambers. Staphylococcus and Streptococcus species are mainly responsible for IE. Streptococcus equinus (S. equinus) has been rarely noted to cause IE. We present a case of a 69-year-old white male with a past medical history of severe aortic regurgitation, who during an elective aortic heart valve replacement surgery was noted to have multiple plaque-like vegetations at the base of the mitral valve that were positive for S. equinus. To date, there are only four cases of S. equinus endocarditis reported worldwide, with a high possibility of our case being the first reported in North America.

Microbiota's role in health and diseases

The microbiome is a term that usually refers to the community of various microorganisms that inhabit/live inside human/animal bodies or on their skin. It forms a complex ecosystem that includes trillions of commensals, symbiotics, and even pathogenic microorganisms. The external environment, diet, and lifestyle are the major determinants influencing the microbiome's composition and vitality. Recent studies have indicated the tremendous influence of the microbiome on health and disease. Their number, constitution, variation, and viability are dynamic. All these elements are responsible for the induction, development, and treatment of many health disorders. Serious diseases such as cancer, metabolic disorders, cardiovascular diseases, and even psychological disorders such as schizophrenia are influenced directly or indirectly by microbiota. In addition, in the last few weeks, accumulating data about the link between COVID-19 and the microbiota were published. In the present work, the role of the microbiome in health and disease is discussed. A deep understanding of the exact role of microbiota in disease induction enables the prevention of diseases and the development of new therapeutic concepts for most diseases through the correction of diet and lifestyle. The present review brings together evidence from the most recent works and discusses suggested nutraceutical approaches for the management of COVID-19 pandemic.

Is Echocardiography Mandatory for All Streptococcus gallolyticus Subsp. pasteurianus Bacteremia?

Background

Streptococcus gallolyticus, formerly known as one of the Streptococcus bovis group, is frequently associated with endocarditis. Current guidelines recommended diagnostic work-up for endocarditis among patients with S. gallolyticus bacteremia. However, S. gallolyticus subsp. pasteurianus, was found to be associated with neonatal sepsis and liver diseases and is less commonly associated with endocarditis compared with S. gallolyticus subsp. gallolyticus. Our study aimed to identify the risk factors for S. gallolyticus subsp. pasteurianus endocarditis to help select the patients for echocardiography.

Methods

In this retrospective cohort study, medical records from all adult patients with S. gallolyticus subsp. pasteurianus isolated from blood cultures at Phramongkutklao Hospital from 2009 to 2015 were reviewed. Patients who had mixed bacteremia or missing records were excluded from the study.

Results

During the study period, S. gallolyticus subsp. pasteurianus was isolated among 106 individuals. Mean age was 66.9±15.6 years. Most patients (61.3%) were male, with cirrhosis as the most common underlying diseases (46.2%), followed by malignancy and chronic kidney disease. Most common manifestations included primary bacteremia (44.3%), followed by spontaneous bacterial peritonitis (23.6%). Infective endocarditis was found among 9 patients. No patients with cirrhosis or single blood specimen of bacteremia had endocarditis (RR 0; p-value 0.003, and RR 1.35; p-value 0.079). The common complications associated with endocarditis were acute respiratory failure (RR 4.32; p-value 0.05), whereas acute kidney injury was a protective factor (RR 0; p-value 0.01). Among 76 patients who had records of 2-year follow-up, no new diagnosis of endocarditis or malignancy was observed.

Conclusion

Among patients with S. gallolyticus subsp. pasteurianus bacteremia, echocardiography might not be needed among patients with cirrhosis and without sustained bacteremia.

How to manage patients in whom malignancy and infective endocarditis are associated: a review

Objective. Infective endocarditis (IE) is a potentially short-term lethal condition. An association with malignancy could complicate diagnostic and therapeutic decisions. The questions to be answered are: (1) which type of malignancies are encountered; (2) how often has the association between malignancy and IE been described, and (3) what are thus far the diagnostic and treatment strategies for patients with both conditions. Methods. A literature search from 2010 to 2018 has been performed with the focus on IE and cancer/malignancy/neoplasm, as well as with risk factors for adverse outcome, when cancer was included in the analysis. Results. An association between digestive, respiratory and hematologic malignancy with IE has been observed in four large databases. The most important mechanisms for this association are a "port of entry" and immune suppression. Sixteen studies dealt with the effect of short and mid-term cancer on the outcome of surgery of IE in these patients. No uniform management strategy could be identified. It seems that a malignancy does not alter the short-term outcome for IE, although referral to a tertiary cardiac center and surgical treatment are less common for patients with known malignancy. Conclusions. Although there is an association between malignancy and IE, no treatment strategy has yet been developed for these patients. Short-term outcome of IE is unaltered by cancer. In most papers, the effect of cancer on mid-term survival is only significant in a univariate analysis, without being a predictor. The results indicate that cardiac surgery for IE should not be withheld in patients in whom a treatable malignancy has been found.

Diet, Microbiome, and Epigenetics in the Era of Precision Medicine

Precision medicine is a revolutionary approach to disease prevention and treatment that takes into account individual differences in lifestyle, environment, and biology. The US National Institutes of Health has recently launched The All of Us Research Program (2016) to extend precision medicine to all diseases by building a national research cohort of one million or more US participants. This review is limited to how the human microbiome factors into precision medicine from the applied aspect of preventing and managing cancer. The Precision Medicine Initiative was established in an effort to address particular characteristics of each person with the aim to increase the effectiveness of medical interventions in terms of prevention and treatment of multiple diseases including cancer. Many factors contribute to the response to an intervention. The microbiome and microbially produced metabolites are capable of epigenetic modulation of gene activity, and can influence the response through these mechanisms. The fact that diet has an impact on microbiome implies that it will also affect the epigenetic mechanisms involving microbiota. In this chapter, we review some major epigenetic mechanisms, notably DNA methylation, chromatin remodeling and histone modification, and noncoding RNA, implicated in cancer prevention and treatment. Several examples of how microbially produced metabolites from food influence cancer risk and treatment response through epigenetic mechanisms will be discussed. Some challenges include the limited understanding of how diet shapes the microbiome and how to best evaluate those changes since both, diet and the microbiota, exhibit daily and seasonal variations. Ongoing research seeks to understand the relationship between the human microbiome and multiple diseases including cancer.

The presence of bacteria varies between colorectal adenocarcinomas, precursor lesions and non-malignant tissue

BACKGROUND

A causal association has been suggested between certain bacteria and colorectal cancer (CRC). Only a few studies have, however, investigated the presence of these bacteria directly in colon tissue with conflicting results. It is thus uncertain which role they may have in prognosis and carcinogenesis of CRC.

METHODS

Formalin-fixed and paraffin-embedded (FFPE) colorectal tissue samples from patients diagnosed with colorectal cancer (CRC)(tumor and paired normal tissue, n = 99), adenomas (n = 96), or diverticular disease (n = 104) were tested for the presence and bacterial load of Streptococcus gallolyticus (S. gallolyticus), Fusobacterium nucleatum (F. nucleatum), and Bacteroides fragilis (B. fragilis) using quantitative PCR. A subsequent broader search was conducted on a subset of samples using 16S ribosomal RNA gene sequencing. Finally, to evaluate the prognostic value, the bacterial status was compared to patient outcome.

RESULTS

S. gallolyticus was not detected by qPCR in any of the investigated tissue samples and F. nucleatum and B. fragilis were found to be equally distributed in tumors, paired normal tissue, and diverticula, but significantly less present in adenomas compared to both tumors and diverticula. Neither, F. nucleatum nor B. fragilis status affected the five-year prognosis of the patients. The 16S rRNA gene sequencing data revealed that tumors were associated with the Prevotella genus while conversely adenomas and diverticula were associated with Acinetobacter genus.

CONCLUSION

These findings do not support a role of F. nucleatum or B. fragilis during colorectal beginning, while S. gallolyticus was not implicated in the colorectal tissue of a Danish population. A potential role of the bacterial genera Prevotella and Acinetobacter was indicated, and requires further investigations.

Gut microbiota, inflammation and colorectal cancer

Although genes contribute to colorectal cancer, the gut microbiota are an important player. Accumulating evidence suggests that chronic infection and the ensuing inflammation contributes to tumor initiation and tumor progression. A variety of bacterial species and tumor-promoting virulence mechanisms have been investigated. Significant advances have been made in understanding the composition and functional capabilities of the gut microbiota and its roles in cancer. In the current review, we discuss the novel roles of microbiota in the progression of colon cancer. Although microbiota technically include organisms other than bacteria e.g., viruses and fungi, this review will primarily focus on bacteria. We summarize epidemiological studies of human microbiome and colon cancer. We discuss the progress in the scientific understanding of the interplay between the gut microbiota, barrier function, and host responses in experimental models. Further, we discuss the potential application in prevention, diagnosis, and therapy of colon cancer by targeting microbiota. We discuss the challenges lie ahead and the future direction in studying gut microbiome in colon cancer to close the gap between the basic sciences and clinical application.

Associated factors in Streptococcus bovis bacteremia and colorectal cancer

Reports suggest that between 25% and 80% of patients with Streptococcus bovis/gallolyticus bacteremia have concomitant colorectal tumors. This retrospective study was aimed to identify associations between clinical characteristics and a finding of colorectal neoplasm in patients with S. bovis bacteremia who had colonoscopy examination. We retrospectively reviewed the records of patients with S. bovis bacteremia from Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, between January 2004 and January 2014. Clinical data including age, sex, comorbidities, blood culture, and colonoscopy findings were collected and their relationship to a finding of colorectal cancer was examined. A total of 107 patients with S. bovis bacteremia were identified, of whom 49 (72% male; age 65 ± 12 years) were investigated with colonoscopy; 15 of these patients (30.6%) had colorectal adenocarcinoma. Female sex (p = 0.014) and a history of noncolorectal malignancy (p = 0.004) were associated with a finding of colorectal adenocarcinoma. There were no associations with age, percentage of blood cultures, or the presence of diabetes mellitus, chronic liver disease, heart disease, or end-stage renal disease. Our results show that S. bovis bacteremia is associated with the presence of colorectal adenocarcinoma, especially in female patients, and concomitant existence of other malignancies.

Infective endocarditis and cancer in the elderly

Little is known about the magnitude of the association between infective endocarditis and cancer, and about the natural history of cancer patients with concomitant diagnosis of infective endocarditis. We used the SEER-Medicare linked database to identify individuals aged 65 years or more diagnosed with colorectal, lung, breast, or prostate cancer, and without any cancer diagnosis (5% random Medicare sample from SEER areas) between 1992 and 2009. We identified infective endocarditis from the ICD-9 diagnosis of each admission recorded in the Medpar file and its incidence rate 90 days around cancer diagnosis. We also estimated the overall survival and CRC-specific survival after a concomitant diagnosis of infective endocarditis. The peri-diagnostic incidence of infective endocarditis was 19.8 cases per 100,000 person-months for CRC, 5.7 cases per 100,000 person-months for lung cancer, 1.9 cases per 100,000 person-months for breast cancer, 4.1 cases per 100,000 person-months for prostate cancer and 2.4 cases per 100,000 person-months for individuals without cancer. Two-year overall survival was 46.4% (95% CI 39.5, 54.5%) for stage I-III CRC patients with concomitant endocarditis and 73.1% (95 % CI 72.9, 73.3%) for those without it. In this elderly population, the incidence of infective endocarditis around CRC diagnosis was substantially higher than around the diagnosis of lung, breast and prostate cancers. A concomitant diagnosis of infective endocarditis in patients with CRC diagnosis is associated with shorter survival.

Streptococcus bovis Bacteremia in Neonates in a Predominantly Hispanic Population

BACKGROUND

Streptococcus bovis bacteremia has been associated with gastrointestinal diseases, especially colon cancer, neoplastic colon polyps, and other malignancies of the GI tract in adults. Sporadic cases of S. bovis disease have also been reported in neonates and young infants. Although uncommon, S. bovis infection can cause fulminant neonatal sepsis and meningitis.

OBJECTIVES

We report a series of pediatric patients with S. bovis bacteremia in a county hospital in a United States-Mexico border city in order to examine the demographic and clinical associations.

METHODS

We characterized the demographic and clinical features in all pediatric patients with blood cultures positive for S. bovis at University Medical Center in El Paso, TX, USA between January 2000 and December 2010. Hospital records were systematically reviewed by using a standardized protocol.

RESULTS

A total of seven episodes of S. bovis bacteremia were documented in seven pediatric patients (four female and three male). Mean age was 1.2 days (range 1-3 days), all were Hispanic, average birth weight (3.25 kg). Mode of delivery was spontaneous vaginal delivery (five) and Caesarian section (two). All of our patients developed early (<1 week) onset disease and presented with signs of respiratory distress. Five out of seven babies presented with abdominal distention and diarrhea. Six had clinical evidence of sepsis at presentation. Respiratory distress was the most common manifestation of sepsis (seven). Aspiration pneumonia was diagnosed in two of them. Most patients were treated with a combination of antibiotics (six), either ampicillin and gentamicin or ampicillin and cefotaxime, and one with ampicillin alone. None of the pediatric patients had endoscopy and none of them died.

CONCLUSION

Streptococcus bovis is considered as an uncommon pathogen in the newborn, but can be associated with substantial morbidity and mortality if not identified and treated early. Physicians should be alert to the less common presentation of neonatal bacteremia due to S. bovis.

Streptococcus bovis infection and colorectal neoplasia: a meta-analysis

AIM

A meta-analysis was conducted to determine the risk associated with Streptococcus bovis infection and the occurrence of colorectal neoplasia (CRN). The level of risk remains unknown.

METHOD

We conducted a search of MEDLINE, PubMed and EMBASE up to January 2014. We used a random-effects model to analyse the data.

RESULTS

We identified 48 studies concerning three main topics: S. bovis septicaemia, S. bovis endocarditis and S. bovis faecal carriage. The total sample sizes were 1729, 807 and 1145, respectively; the 48 studies included 9 case-control studies and 39 case series. Overall, the presence of S. bovis infection was found to be significantly associated with the presence of CRN. Streptococcus bovis endocarditis showed the strongest association in analyses of case-control studies and case series (OR 14.54, 95% CI 5.66-37.35, test for heterogeneity I2 = 43.53; event rate of 0.53, 95% CI 0.45-0.61, test for heterogeneity I2 = 53.50). Similarly, S. bovis septicaemia was also associated with a high level of concurrence with CRN (OR 7.48, 95% CI 3.10-18.06, test for heterogeneity I(2) = 43.32; event rate 0.49, 95% CI 0.42-0.56, test for heterogeneity I2 = 69.97). Patients with CRN were found to have a higher incidence of S. bovis in faeces upon stool culture (OR 2.52, 95% CI 1.14-5.58, test for heterogeneity I2 = 69.17).

CONCLUSION

The meta-analysis showed a statistically significant association between the presence of S. bovis endocarditis or S. bovis septicaemia and CRN. Furthermore, there is a statistically significant increase in likelihood of finding S. bovis in the stool of individuals with CRN.

Streptococcus gallolyticus bacteraemia in hepatobiliary-pancreatic and colonic pathologies

BACKGROUND

Streptococcus gallolyticus bacteraemia has been associated with several pathologies, including bacterial endocarditis and colorectal cancer.

AIMS

In this study, we have analysed whether Streptococcus gallolyticus bacteraemia is associated with an increased risk of hepatobiliary and colonic pathology. The association with other pathologies and the antibiotic sensitivities of Streptococcus gallolyticus were also analysed.

DESIGN

Observational retrospective study.

METHODS

The case notes of patients with documented Streptococcus gallolyticus bacteraemia between 2007 and 2012 at Mater Dei hospital (Malta) were reviewed. Demographic and clinical data, including co-morbidities, clinical investigations, antibiotic sensitivities and mortality were analysed.

RESULTS

A total of 42 patients (33 males, 9 females) were recruited. Two patients were pre-term infants and were therefore excluded from the study. Mean age of the cohort population studied was 72 years (SD ± 14). One-year survival rate was 62%. Gastrointestinal (colonic and hepatobiliary-pancreatic) pathologies were present in 59.5% of patients with 16% of this group having more than one gastrointestinal pathology. High incidence rates of underlying diabetes mellitus (28.6%), valvular heart disease (21.4%) and malignancies (21.4%) were noted in this study. Furthermore, we observed that 14.3% of patients had an underlying respiratory pathology. Streptococcus gallolyticus was 100% sensitive to cefotaxime and vancomycin but was highly resistant to clindamycin, erythromycin and tetracycline.

CONCLUSION

Streptococcus gallolyticus bacteraemia is commoner in the elderly and in those with multiple underlying co-morbidities. The high incidence of gastrointestinal pathologies among patients with Streptococcus gallolyticus bacteraemia (59.5%) suggests that a thorough work-up for colonic and hepatobiliary/pancreatic pathology should be carried out in these patients.

Fusobacterium nucleatum associates with stages of colorectal neoplasia development, colorectal cancer and disease outcome

Commensal bacteria in the colon may play a role in colorectal cancer (CRC) development. Recent studies from North America showed that Fusobacterium nucleatum (Fn) infection is over-represented in disease tissue versus matched normal tissue in CRC patients. Using quantitative real-time polymerase chain reaction (qPCR) of DNA extracted from colorectal tissue biopsies and surgical resections of three European cohorts totalling 122 CRC patients, we found an over-abundance of Fn in cancerous compared to matched normal tissue (p < 0.0001). To determine whether Fn infection is an early event in CRC development, we assayed Fn in colorectal adenoma (CRA) tissue from 52 Irish patients. While for all CRAs the Fn level was not statistically significantly higher in disease versus normal tissue (p = 0.06), it was significantly higher for high-grade dysplasia (p = 0.015). As a secondary objective, we determined that CRC patients with low Fn levels had a significantly longer overall survival time than patients with moderate and high levels of the bacterium (p = 0.008). The investigation of Fn as a potential non-invasive biomarker for CRC screening showed that, while Fn was more abundant in stool samples from CRC patients compared to adenomas or controls, the levels in stool did not correlate with cancer or adenoma tissue levels from the same individuals. This is the first study examining Fn in the colonic tissue and stool of European CRC and CRA patients, and suggests Fn as a novel risk factor for disease progression from adenoma to cancer, possibly affecting patient survival outcomes. Our results highlight the potential of Fn detection as a diagnostic and prognostic determinant in CRC patients.

Streptococcus bovis group and biliary tract infections: an analysis of 51 cases

Streptococcus bovis is a well-known cause of endocarditis, but its role in other infections has not been well described. We analysed prospectively all patients with biliary tract infections caused by S. bovis group during the period 1988-2011. We selected those cases associated with cholangitis and cholecystitis, defined according to Tokyo guidelines. Identification of the strains was performed using the API 20 Strep and the GP card of the Vitek 2 system, and was confirmed by molecular methods. Our series included 51 cases (30 cholangitis and 21 cholecystitis). The associated microorganisms were: Streptococcus infantarius (biotype II/1) 29 cases (57%), Streptococcus gallolyticus subsp. pasteurianus (biotype II/2) 20 cases (39%) and Streptococcus gallolyticus subsp. gallolyticus (biotype I) two cases (4%). The only difference found between S. infantarius and S. gallolyticus subsp. pasteurianus was a greater association of the first with malignant strictures of the bile ducts: 48% (14/29) versus 5% (1/20), p <0.001. Thirty-seven of the cases also had bacteraemia, causing 20% (37/185) of all S. bovis bacteraemia, with differences between S. gallolyticus subsp. gallolyticus (2/112; 2%) and the other two microorganisms: S. infantarius and S. gallolyticus subsp. pasteurianus (35/73; 48%; p <0.001). The vast majority of biliary tract infections due to S. bovis group are caused by S. infantarius and S. gallolyticus subsp. pasteurianus (S. bovis biotype II), and nearly half of the bacteraemia due to these two species has a biliary source (43% of the S. infantarius and 56% of S. gallolyticus subsp. pasteurianus).

Correlation among Streptococcus bovis, endocarditis and septicemia in a patient with advanced colon cancer: a case report

INTRODUCTION

One of the bacterial agents that has been found to be associated with colorectal cancer is Streptococcus bovis, with 13% of infective endocarditis cases caused by this pathogenic species.

CASE PRESENTATION

We describe the case of a 57-year-old Caucasian man with infiltrating and ulcerating metastatic adenocarcinoma of the sigmoid colon. The patient was receiving second-line chemotherapy treatment and, on the eighth day of the second cycle, he developed a grade IV pancytopenia. We diagnosed a severe sepsis with positive blood cultures for Streptococcus bovis/gallolyticus with a secondary endocarditis.

CONCLUSIONS

A recent study suggests that the majority of patients affected by colonic cancer have a Streptococcus bovis/gallolyticus colonization that becomes apparent as an overt infection only when immunosystem disorders or cardiac valve lesions occur. This correlation is important for involving more specialists in a correct and early diagnosis of this rare, but potentially fatal, complication.