Streptococcus bovis Contributes to the Development of Colorectal Cancer via Recruiting CD11b⁺TLR-4⁺ Cells.

BACKGROUND An increasing number of studies have demonstrated that Streptococcus bovis and its concomitant inflammatory factors concentrate in the intestine in colorectal cancer (CRC). However, the molecular mechanism of S. bovis on colorectal tumorigenesis remains unclear. This study aimed to explore the role of S. bovis in carcinogenesis and its potential mechanism in CRC of mice orally pretreated with S. bovis. MATERIAL AND METHODS The colons of experimental mice were collected and evaluated for the extent of neoplasm. In addition, comparative feces DNA sequencing was adopted to verify the abundance change of S. bovis during the progression of CRC in patients. RESULTS The results of this study found that S. bovis is more likely to be present at higher levels in patients with progressive colorectal carcinoma compared to those adenoma patients and healthy volunteers (P<0.05). Pretreatment with S. bovis aggravated tumor formation in mice, resulting in more substantial and a higher number of tumor nodes (P<0.05). A cytokine expression pattern with increased levels of IL-6, Scyb1, Ptgs2, IL-1ß, TNF, and Ccl2 was detected in S. bovis pretreated CRC mice (all P<0.05). Furthermore, S. bovis recruited myeloid cells, especially CD11b⁺TLR-4⁺ cells, which could promote pro-tumor immunity in the tumor microenvironment (P<0.05). CONCLUSIONS Collectively, our study indicates that S. bovis may induce a suppressive immunity that is conducive to CRC by recruiting tumor-infiltrating CD11b⁺TLR-4⁺ cells. In conclusion, S. bovis contributes to colorectal tumorigenesis via recruiting CD11b⁺TLR-4⁺ cells.

Identification and pathogenicity analysis of Streptococcus equinus FMD1, a beta-hemolytic strain isolated from forest musk deer lung.

Streptococcus spp. cause a wide range of diseases in animals and humans. A Streptococcus strain (FMD1) was isolated from forest musk deer lung. To identify the bacterium at the species level and investigate its pathogenicity, whole genome sequencing and experimental infections of mice were performed. The genome had 97.63% average nucleotide identity with the S. equinus strain. Through virulence gene analysis, a beta-hemolysin/cytolysin genome island was found in the FMD1 genome, which contained 12 beta-hemolysin/cytolysin-related genes. Hemolytic reaction and histopathological analysis established the strain's pathogenicity in mice. This is the first report of a beta-hemolytic S. equinus strain in forest musk deer identified based on phenotypic and genotypic analyzes; this strategy could be useful for analyzing pathogens affecting rare animals.

Cloning and characterization of the glutamate dehydrogenase gene in Streptococcus bovis.

Streptococcus bovis, an etiologic agent of rumen acidosis in cattle, is a rumen bacterium that can grow in a chemically defined medium containing ammonia as a sole source of nitrogen. To understand its ability to assimilate inorganic ammonia, we focused on the function of glutamate dehydrogenase. In order to identify the gene encoding this enzyme, we first amplified an internal region of the gene by using degenerate primers corresponding to hexameric family I and NAD(P)+ binding motifs. Subsequently, inverse PCR was used to identify the whole gene, comprising an open reading frame of 1350 bp that encodes 449 amino acid residues that appear to have the substrate binding site of glutamate dehydrogenase observed in other organisms. Upon introduction of a recombinant plasmid harboring the gene into an Escherichia coli glutamate auxotroph lacking glutamate dehydrogenase and glutamate synthase, the transformants gained the ability to grow on minimal medium without glutamate supplementation. When cell extracts of the transformant were resolved by blue native polyacrylamide gel electrophoresis followed by activity staining, a single protein band appeared that corresponded to the size of S. bovis glutamate dehydrogenase. Based on these results, we concluded that the gene obtained encodes glutamate dehydrogenase in S. bovis.

Presencia de Streptococcus bovis en muestras de orina de sujetos con síntomas de infección del aparato urinario / Presence of Streptococcus bovis in urine samples from patients experiencing symptoms of urinary tract

Dada la importancia de la correcta validación clínica de los aislamientos de Streptococcus bovis, nos planteamos la revisión de su presencia en muestras de orina con el objetivo de conocer su frecuencia relativa y su patrón de sensibilidad antibiótica. Se revisó retrospectivamente la sensibilidad a los antibióticos de 91 aislados de S. bovis recuperados de muestras de orina durante un período de 4 años (2012-2015). La media de la edad de los pacientes fue de 55 años y en su mayoría fueron mujeres (81%). El 37,4% eran pacientes hospitalizados con enfermedades urológicas (61%). La sensibilidad a penicilina, vancomicina y teicoplanina fue del 97,8%. Aunque S. bovis puede ser poco común en los aislamientos de orina, su presencia en sujetos con enfermedades de base justifica la realización de estudios de patogenicidad que demuestren la verdadera capacidad de producir enfermedad de este grupo de bacterias.

Given the relevance of proper clinical validation of Streptococcus bovis, we here consider revising its presence in urine samples in order to determine its relative frequency and the pattern of antibiotic susceptibility. The susceptibility to antibiotics of 91 isolates of S. bovis from urine samples was retrospectively reviewed over a period of 4 years (2012-2015). The mean age of patients was 55 years, 81% of whom were women and 37.4% were hospitalized patients suffering from urological diseases (61%). Susceptibility to penicillin, vancomycin and teicoplanin was 97.8%. Due to the fact that S. bovis can be infrequent in urine isolates and given its presence in patients suffering from urological diseases, further pathogenic studies, showing the true ability of this group of bacteria to produce disease, are required.

[Presence of Streptococcus bovis in urine samples from patients experiencing symptoms of urinary tract]. / Presencia de Streptococcus bovis en muestras de orina de sujetos con síntomas de infección del aparato urinario.

Given the relevance of proper clinical validation of Streptococcus bovis, we here consider revising its presence in urine samples in order to determine its relative frequency and the pattern of antibiotic susceptibility. The susceptibility to antibiotics of 91 isolates of S. bovis from urine samples was retrospectively reviewed over a period of 4 years (2012-2015). The mean age of patients was 55 years, 81% of whom were women and 37.4% were hospitalized patients suffering from urological diseases (61%). Susceptibility to penicillin, vancomycin and teicoplanin was 97.8%. Due to the fact that S. bovis can be infrequent in urine isolates and given its presence in patients suffering from urological diseases, further pathogenic studies, showing the true ability of this group of bacteria to produce disease, are required.

[Streptococcus gallolyticus (ex S. bovis) bacteremia and its relationship with colonic or hepatobiliary disease and endocarditis]. / Bacteriemias por Streptococcus gallolyticus (ex S. bovis) y su relación con patología colónica o hepatobiliar y endocarditis.

BACKGROUND: Bacteremia due to Streptococcus bovis (now S. gallolyticus) has been traditionally associated to colon or hepatobiliar disease and endocarditis but there is no information on this matter in Chile. AIMS: To describe clinical features of adult patients suffering bacteremia by S. bovis/S. gallolyticus, identify the source of the bacteremia and the frequency of endocarditis. METHODS: Retrospective-descriptive study using laboratory records. RESULTS: Between January 2003 and August 2014, 23 S. bovis/S. gallolyticus bacteremic events were identified among 22 patients. Mean age was 72.7 years (range 46-96). Co-morbidities were frequent (9.1 to 47.6%). The primary source of bacteremia was intestinal in 52.2%; hepatobiliar in 17.4% and in 34.8% it was not elucidated. Six patients had infective endocarditis (26.1%) and one patient had espondylodiscitis (4.3%). S. bovis represented 39.1% of isolates (all until 2008), S. gallolyticus subsp pasteurianus 39.1% and, S. gallolyticus subsp infantarius and S. gallolyticus subsp gallolyticus 8.7% each one, respectively. Association studies between the bacteremic source or endocarditis with specific S. gallolyticus subspecies were limited by the small number of isolates. Seven patients (30.4%) underwent surgical interventions. In-hospital mortality reached 21.7% (n=5). CONCLUSIONS: Although infrequent, bacteremic events by S. gallolyticus/S. bovis have increased in-hospital mortality, require surgical intervention and affect older patients with co-morbidities. Near two-thirds suffer from colonic or hepatobiliary disease that act as the primary source of bacteremia. In addition, near one fourth is affected by infective endocarditis. Detection of S. gallolyticus/S. bovis in blood cultures prompts a thorough clinical evaluation in order to clarify the source of the bloodstream infection and the presence of complications.

Bacteriemias por Streptococcus gallolyticus (ex S. bovis) y su relación con patología colónica o hepatobiliar y endocarditis / Streptococcus gallolyticus (ex S. bovis) bacteremia and its relationship with colonic or hepatobiliary disease and endocarditis

Background: Bacteremia due to Streptococcus bovis (now S. gallolyticus) has been traditionally associated to colon or hepatobiliar disease and endocarditis but there is no information on this matter in Chile. Aims: To describe clinical features of adult patients suffering bacteremia by S. bovis/S. gallolyticus, identify the source of the bacteremia and the frequency of endocarditis. Methods: Retrospective-descriptive study using laboratory records. Results: Between January 2003 and August 2014, 23 S. bovis/S. gallolyticus bacteremic events were identified among 22 patients. Mean age was 72.7 years (range 46-96). Co-morbidities were frequent (9.1 to 47.6%). The primary source of bacteremia was intestinal in 52.2%; hepatobiliar in 17.4% and in 34.8% it was not elucidated. Six patients had infective endocarditis (26.1%) and one patient had espondylodiscitis (4.3%). S. bovis represented 39.1% of isolates (all until 2008), S. gallolyticus subsp pasteurianus 39.1% and, S. gallolyticus subsp infantarius and S. gallolyticus subsp gallolyticus 8.7% each one, respectively. Association studies between the bacteremic source or endocarditis with specific S. gallolyticus subspecies were limited by the small number of isolates. Seven patients (30.4%) underwent surgical interventions. In-hospital mortality reached 21.7% (n = 5). Conclusions: Although infrequent, bacteremic events by S. gallolyticus/S. bovis have increased in-hospital mortality, require surgical intervention and affect older patients with co-morbidities. Near two-thirds suffer from colonic or hepatobiliary disease that act as the primary source of bacteremia. In addition, near one fourth is affected by infective endocarditis. Detection of S. gallolyticus/S. bovis in blood cultures prompts a thorough clinical evaluation in order to clarify the source of the bloodstream infection and the presence of complications.

Antecedentes: Los cuadros de bacteriemia por Streptococcus bovis (actualmente S. gallolyticus) han sido tradicionalmente asociados a patología colónica o hepatobiliar y endocarditis pero no se conoce de estudios en Chile que hayan abordado este tema. Objetivos: Describir aspectos clínicos de pacientes adultos afectados por bacteriemias por S. bovis/S. gallolyticus, identificar la fuente de la bacteriemia y la frecuencia de endocarditis. Métodos: Diseño de tipo retrospectivo, descriptivo, con el registro de casos bacteriemia. Resultados: Entre enero de 2003 y agosto de 2014 se identificaron 23 eventos de bacteriemia por S. bovis/S. gallolyticus en 22 pacientes. La edad promedio fue de 72,7 años (rango 46-96). La prevalencia de diferentes co-morbilidades fue elevada (9,1 a 47,6%). El foco primario de la bacteriemia fue intestinal en 52,2%, hepatobiliar en 17,4% y, en 34,8% no se aclaró el foco. Seis pacientes presentaron endocarditis infecciosa (26,1%) y uno espondilodiscitis (4,3%). S. bovis representó 39,1% de los aislados (todos hasta el 2008), S. gallolyticus subsp pasteurianus 39,1%, S. gallolyticus subsp infantarius y S. gallolyticus subsp gallolyticus 8,7%, respectivamente. Los estudios de asociación estuvieron limitados por el bajo número de aislados. Siete pacientes (30,4%) debieron ser intervenidos quirúrgicamente. La mortalidad hospitalaria fue de 21,7% (n: 5). Conclusiones: Aunque infrecuentes, los eventos de bacteriemia por S. gallolyticus/S. bovis tienen una elevada mortalidad hospitalaria, requieren con frecuencia procedimientos quirúrgicos y afectan a pacientes mayores con co-morbilidades. Cerca de dos tercios padecen de una patología colónica o hepatobiliar que actúa como foco primario y cerca de un cuarto presenta endocarditis infecciosa. La detección de este grupo bacteriano en los hemocultivos requiere una evaluación para establecer el origen de la bacteriemia y la presencia de complicaciones.

[Streptococcus bovis endocarditis as a sign of colon cancer: case report].

INTRODUCTION: Streptococcus bovis is labeled in the literature as a cause of bacteremia and endocarditis, which are often associated with gastrointestinal malignancy. CASE OUTLINE: In our paper we present a patient with endocarditis induced by Streptococcus bovis who was also, after completed cardiologic examination and treatment, diagnosed colon cancer in situ by targeted endoscopy. Owing to the timely diagnosis, and after successful cardiologic surgery with implantation of an artificial aortic valve, patient underwent surgery of the colon, and is now asymptomatic and in good health. CONCLUSION: Complete and detailed endoscopic examination of the colon must be done in patients with endocarditis caused by Streptococcus bovis, even if the patient is asymptomatic. By following these recommendations, it is possible to detect precancerosis or cancer at an early stage and save the patient's life.

Aislamiento de Streptococcus bovis en paciente con cáncer de colon no diagnosticado: presentación de un caso / Isolation of streptococcus bovis in a patient with undiagnosed colon cancer: a case report

Uno de los agentes bacterianos que ha sido regularmente asociado con el cáncer colorectal es el Streptococcus bovis. Del 25 al 80 por ciento de los pacientes con bacteremia por Streptococcus bovis tienen tumores colorrectales y la incidencia de asociación de neoplasia de colon con endocarditis por S. bovis ha sido mostrada del 18 al 62 por ciento. Por tales razones se decidió la presentación del caso de un paciente de 57 años, de procedencia urbana, con antecedentes de alcoholismo y diabetes mellitus tipo I, desde hacía seis años, que ingresó en el Hospital de Cienfuegos con sangrado digestivo alto y fiebre de 39 a 40 o C. En hemocultivo se aisló Streptococcus bovis. El paciente falleció a las 72 hora de ingresado. Los resultados de la necropsia mostraron adenocarcinoma de colon derecho, moderadamente diferenciado(AU)

One of the bacterial agents commonly associated with colorectal cancer is Streptococcus bovis. Twenty five to 80 percent of patients with Streptococcus bovis bacteremia develop colorectal tumors and the incidence of colonic neoplasia associated with S. bovis endocarditis has been shown to be 18 to 62 percent. Hence, it was decided to present the case of a 57-year-old patient from an urban area with a 6-year history of diabetes mellitus type I and alcoholism, who was admitted to the hospital in Cienfuegos because of significant gastrointestinal bleeding and fever (39-40 o C). Streptococcus bovis was isolated from the blood culture. The patient died 72 hours after his admission. Autopsy results showed a moderately differentiated adenocarcinoma of the right colon

The itinerary of Streptococcus gallolyticus infection in patients with colonic malignant disease.

Bacteria constitute about 90% of all cells in the human body. The densest and most complex bacterial community is in the large intestine. This population is quite stable in healthy intestines, but intestinal disease distorts the ecological balance and induces dysbiosis. Results of studies have indicated that the epithelial and metabolic changes that occur with colorectal cancer provide a competitive advantage to a subset of intestinal bacteria. Strikingly, however, Streptococcus gallolyticus gallolyticus (previously known as Streptococcus bovis biotype I) is one of the very few opportunistic pathogens that has been clinically linked to colonic malignant diseases. In this Personal View we describe how S. gallolyticus gallolyticus exploits its unique range of virulence features to cause infections in patients with colorectal cancer. We postulate that distinct virulence factors on one hand enable this bacterium to establish a symptomatic infection in susceptible individuals, and on the other hand make its ability to do this dependent on pre-existing colonic abnormalities. We believe that our current reconstruction of this route of infection aids understanding of how S. gallolyticus gallolyticus infections can be best exploited for early detection of colorectal cancer.

[Diseases associated with bloodstream infections caused by the new species included in the old Streptococcus bovis group]. / Cuadros clínicos asociados a bacteriemia causada por las nuevas especies incluidas en el antiguo grupo Streptococcus bovis.

OBJECTIVE: We sought to identify possible diseases associated with bloodstream infections caused by new species of S. bovis group isolated in blood cultures and by studying patient records METHODS: Forty-four consecutive blood culture isolates initially designated S. bovis were further characterised using phenotypic methods Patient records were examined. RESULTS: We identified 15 Streptococcus gallolyticus subsp. gallolyticus, 24 Streptococcus gallolyticus subsp. pasteurianus, and 5 Streptococcus infantarius isolates in 44 BSI episodes. CONCLUSIONS: The association between S. bovis bacteraemia and endocarditis and/or colon carcinoma is highly dependent on the causative species. Streptococcus gallolyticus subsp. gallolyticus is a surrogate for endocarditis and/or bowel disease, whereas Streptococcus gallolyticus subsp. pasteurianus is a surrogate for hepato-biliary disease.

Two weeks of postsurgical therapy may be enough for high-risk cases of endocarditis caused by Streptococcus viridans or Streptococcus bovis.

The duration of antimicrobial therapy after surgery for infective endocarditis (IE) is controversial. A short course of postsurgical therapy is currently accepted only for patients with negative valve culture. We performed a retrospective (1994-2008) analysis of patients who underwent surgery for IE in our hospital and had a high risk of complications ( one of more of the following: <2 weeks of antibiotic treatment before surgery; embolism; perivalvular extension; and positive valve culture) to compare outcomes of patients who received short-course antimicrobial therapy (SAT) (median 15 days) or long-course antimicrobial therapy (LAT) (median 32 days), irrespective of the results of valve culture. Our endpoints included length of hospital stay, renal and hepatic failure, relapse, re-infection, and mortality rates 1 year after surgery. During the study period, 140 patients underwent surgery for IE (valve replacement, 87.9%). Of these, 133 fulfilled the high-risk group criteria and 92 completed the antimicrobial schedule. Comparison of patients receiving SAT (37) and LAT (55) showed that the SAT group had a shorter length of hospital stay (29 vs. 40 days, p 0.01), and a trend towards lower frequency of renal failure (5.4% vs. 18.2%, p 0.11) and hepatic failure (5.4% vs. 9.1%, p 0.69), whereas mortality (5.4% vs. 3.6%, p 1), relapse (0% vs. 1.8%, p 1) and re-infection (5.4% vs. 3.6%, p 1) rates were similar between both groups. Multivariate analysis showed that IE caused by Streptococcus viridans or Streptococcus bovis was independently associated with SAT. Postsurgical SAT is safe, especially when IE is caused by Streptococcus viridans or Streptococcus bovis, even in patients at high risk of complications.

Análisis descriptivo de las enfermedades asociadas a bacteriemia por Streptococcus bovis / Descriptive analysis of diseases associated with Streptococcus bovis bacteremia

Fundamento y objetivo: Aunque se conoce la relación entre la bacteriemia por Streptococcus bovis (S. bovis) y el cáncer de colon, cirrosis hepática u otras neoplasias, no se ha establecido un protocolo de estudio para descartar estas enfermedades subyacentes a la bacteriemia. Nuestro objetivo fue describir la bacteriemia por S. bovis y las enfermedades asociadas.Pacientes y método: Estudio multicéntrico, retrospectivo de cohortes. Se incluyeron las bacteriemias por S. bovis entre 2001 y 2009. Las variables principales fueron: neoplasia colónica, neoplasias en otras localizaciones o cirrosis hepática. Se recogieron variables epidemiológicas, relacionadas con la bacteriemia, antecedentes personales, familiares, datos clínicos y analíticos. Resultados: Se incluyeron 93 pacientes. Un 25% de los individuos tuvo neoplasia de colon. Un 57% de ellos fueron casos concomitantes con la bacteriemia y 6 fueron diagnósticos posteriores a ella (mediana [Q1-Q3] de tiempo bacteriemia-diagnóstico neoplasia de 2,6 meses [1-11]), con un máximo de 15,4 meses. Catorce (15%) pacientes padecían alguna neoplasia no colónica (mayoritariamente biliopancreática [6 casos] y esofagogástrica [3 casos]). Hubo 3 (21%) casos concomitantes con la bacteriemia y 2 posteriores a ella (a 1,2 y 10,4 meses). Veintiún (23%) enfermos tenían cirrosis hepática.Conclusiones: A los pacientes con bacteriemia por S. bovis es necesario realizarles un estudio encaminado a descartar enfermedades subyacentes. Sugerimos que se incluyan, al menos: una prueba de imagen colónica, preferentemente colonoscopia; un estudio hepático mediante analítica, ecografía abdominal o un método de medición de fibrosis hepática; una endoscopia digestiva alta; y una prueba de imagen del área biliopancreática como la colangiorresonancia magnética

Background and objective: It is well-known the relationship between Streptococcus bovis (S. bovis) bacteremia and colon cancer, liver cirrhosis and others neoplasms. However, a study protocol to rule out these underlying diseases has not been carried out yet. Our objective was to describe S. bovis bacteremia and associated diseases. Patients and method: Multicenter, retrospective cohort study. S. bovis bacteremias episodes between 2001 and 2009 were included. Mean variables: colon neoplasm, non-colonic neoplasm or liver cirrhosis. Epidemiologist aspects, bacteremia related variables, personal and familiar history and clinical and analytical data were collected.Results: Ninety three patients were included. One out of four individuals had a colon neoplasm. Fifty seven per cent were concomitant cases with bacteremia and six cases were diagnosed after bacteremia (time bacteremia-diagnosis of neoplasm [months], median [Q1-Q3], 2.6 [1-11]). Fourteen (15%) patients were diagnosed with any non-colonic neoplasm (mainly biliary and pancreatic [6 cases] or esophagus-gastric [3 cases]). There were three patients (21%) with concomitant bacteremia non-colonic neoplasm and two after it (1.2 and 10.4 months). Twenty-one (23%) patients suffered from liver cirrhosis. Conclusions: Patients with S. bovis bacteremia must undergo a study designed to rule out underlying diseases. We suggest that this study should include: a colonic evaluation, ideally by colonoscopy, a liver evaluation by serum chemistry, an abdominal ultrasound scan or a method of liver fibrosis assessment, a gastroscopy and an evaluation of biliary and pancreatic areas by magnetic resonance imaging

Actitud diagnóstica ante la bacteriemia por Streptococcus bovis, o los límites de la medicina basada en la evidencia / Diagnostic approach to Streptococcus bovis bacteremia, or the limits of the evidence-based medicine

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Clinical Importance of Streptococcus gallolyticus infection among colorectal cancer patients: systematic review and meta-analysis.

BACKGROUND: Streptococcus bovis has long been associated with colorectal cancer (CRC). However, not all genospecies are as closely related to CRC. With this systematic review, we aim to increase the awareness of the association between S. bovis biotype I (Streptococcus gallolyticus) and CRC and urge for uniform molecular microbiological classification. METHODS: In January 2011, the PubMed database was searched for all studies that investigated the association between S. bovis, infective endocarditis (IE), and CRC. A total of 191 studies were screened for eligibility and yielded 52 case reports and 31 case series, of which 11 were used for meta-analysis on the association between S. bovis biotype, IE, and adenomas/carcinomas (CRC). RESULTS: Among the S. bovis-infected patients who underwent colonic evaluation, the median percentage of patients who had concomitant adenomas/carcinomas was 60% (interquartile range, 22%), which largely exceeds the disease rate reported in the general asymptomatic population. Meta-analysis showed that patients with S. bovis biotype I infection had a strongly increased risk of having CRC (pooled odds ratio [OR], 7.26; 95% confidence interval [CI], 3.94-13.36) and IE (pooled OR, 16.61; 95% CI, 8.85-31.16), compared with S. bovis biotype II-infected patients. Notably, CRC occurred more often among patients with S. bovis IE than among patients with S. bovis infection at other sites (pooled OR, 3.72; 95% CI, 2.03-6.81). CONCLUSIONS: Our meta-analysis clearly indicates that S. bovis should no longer be regarded as a single species in clinical practice, because S. gallolyticus (S. bovis biotype I) infection, in particular, has an unambiguous association with CRC.

Streptococcus bovis meningitis associated with colonic diverticulosis and hearing impairment: a case report.

A 75-year-old woman presented to the Tropical Diseases Hospital, Goiania, Brazil, with a two-day history of fever and chills followed by headache and vomiting over the last 24 hours. The cerebrospinal fluid (CSF) showed 270 leukocytes/mmc (30 percent neutrophils); 20 red cells/mmc; undetectable levels of glucose and 232 mg/dL of protein. The Gram stain revealed several Gram-positive cocci, and CSF culture yielded Streptococcus bovis. A colonoscopy showed diverticula in descendent and transverse colon. After a 14-day course of penicillin G, the patient was discharged in a good state of health, with only mild hearing impairment.

Streptococcus bovis bacteraemia revisited: clinical and microbiological correlates in a contemporary series of 59 patients.

OBJECTIVE: To characterise the clinical features, associations and outcome in a contemporary series of patients with Streptococcus bovis bacteraemia (SBB). METHODS: Retrospective analysis of all episodes of SBB at the University Hospital 12 de Octubre (Madrid, Spain) between January 1997 and November 2008 was performed. Patient data were reviewed, focusing on clinical and microbiological associations with the different biotypes of S. bovis. RESULTS: Fifty-nine episodes of SBB were documented in 59 adult patients (30 males; mean age: 70.9 ± 15.0 years). Chronic liver disease was identified in 20 patients (33.9%). Sixteen patients (27.1%) presented infective endocarditis (IE) and 14 (23.7%) had a biliary source of bacteraemia. Thirty-three patients (55.9%) underwent colonic evaluation, adenomatous polyps being the most common finding (21 patients). Malignancy was diagnosed following SBB in 9 cases, including 6 patients with colorectal carcinoma (18.2% of those who underwent colonic evaluation). Of 22 isolates biotyped, 12 were S. bovis biotype I and 10 were S. bovis biotype II. IE was more frequent among patients with S. bovis biotype I (P =0.010), whereas bacteraemia due to biotype II species was more likely to be of biliary origin (P=0.078). CONCLUSIONS: S. bovis biotyping identifies some clinically relevant associations.

Prevalence of colorectal cancer associated with Streptococcus bovis among inflammatory bowel and chronic gastrointestinal tract disease patients.

Colorectal cancer (CRC) is the second most common cause of cancer mortality among men and women worldwide; the risk of its occurrence has been shown to be increased by chronic bacterial infections. A case control study was therefore carried out at Hospital Universiti Sains Malaysia (HUSM) to determine the incidence of colorectal cancer associated with S. bovis infection. A total of 166 stool specimens were collected from diseased patients and healthy individuals and S. bovis isolates were identified. Suspected colon tumor and cancer cases were diagnosed and confirmed. It was found that overall prevalence of S. bovis was 41 (24.7%) out of 166 cases studied. Some 41(48.6%) of these S. bovis isolates was found in patients with colonic polyps, adenocarcinomas, inflammatory bowel disease (IBD) and chronic gastrointestinal tract (GIT). It was also found that colorectal cancer incidence was 24.7%, adenocarinomas accounting for 51% with the highest incidence in the sigmoid part of the colon. Among the IBD and chronic GIT cases, ulcerative colitis featured in the majority of cases (41.4%). In conclusion, there is a high incidence of colorectal cancer associated with S. bovis.