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PubMed1997

Isolation and overexpression of a gene encoding an extracellular beta-(1,3-1,4)-glucanase from Streptococcus bovis JB1.

Streptococcus bovis JB1 was found to produce a 25-kDa extracellular enzyme active against beta-(1,3-1,4)-glucans. A gene was isolated encoding a specific beta-(1,3-1,4)-glucanase that corresponds to this size and belongs to glycoside hydrolase family 16. A 4- to 10-fold increase in supernatant beta-glucanase activity was obtained when the cloned beta-glucanase gene was reintroduced into S. bovis JB1 by use of constructs based on the plasmid vector pTRW10 or pIL253. The beta-(1,3-1,4)-glucanase gene was also expressed upon introduction of the pTRW10 construct pTRWL1R into Lactococcus lactis IL2661 and Enterococcus faecalis JH2-SS, although extracellular activity was 8- to 50-fold lower than that in S. bovis JB1. The beta-(1,3-1,4)-glucanase purified from the culture supernatant of S. bovis JB1 carrying pTRWL1R showed a K(m) of 2.8 mg per ml and a Vmax of 338 mumol of glucose equivalents per min per mg of protein with barley beta-glucan as the substrate. The S. bovis beta-(1,3-1,4)-glucanase may contribute to the ability of this bacterium to utilize starch by degrading structural polysaccharides present in endosperm cell walls.

Amino Acid Sequence↗
PubMed1996

Inducer expulsion is not a determinant of diauxic growth in Streptococcus bovis.

When Streptococcus bovis JB1 was repeatedly transferred in a medium that contained the non-metabolizable glucose analog, 2-deoxyglucose, it lost its phosphotransferase system (PTS) for glucose but was still able to take up glucose via a facilitated diffusion mechanism. The wild type (JB1) had an inducible enzyme II lactose, but the mutant (JB1(2DG)) had a constitutive lactose PTS. JB1(2DG) was no longer able to exclude lactose when it was provided with glucose, but it retained its ability to expel a non-metabolizable lactose analog. Because JB1(2DG) could utilize glucose and lactose simultaneously and grow in a non-diauxic fashion, it appeared that inducer expulsion was not an important catabolite regulatory mechanism. Based on these results, inducer expulsion may be an artifact of non-metabolizable sugars.

Biological Transport, Active↗
PubMedDate not supplied

[The importance of Streptococcus bovis systemic infections].

Streptococcus bovis is relatively common cause of bacteremia and endocarditis, especially in older persons, or in patients that have some kind of chronic disease. These infections are frequently connected with malignant, potentially malignant, or benign colorectal neoplasia. Hematogenous dissemination of Streptococcus bovis could result with various clinical manifestations, namely purulent meningitis, brain abscess, osteomyelitis, spondylodiscitis, and many different kinds of infections in AIDS patients are reported. In this report, two patients hospitalized at the Departement of Infectious Diseases at the General Hospital "Dr. Josip Bencević" in Slavonski Brod are presented. The first patient was addmited to the hospital because of fever of unknown origin, and in his blood cultures, Streptococcus bovis was isolated. He was an older man, who had undergone prostatectomy due prostatic adenoma several years before. The other patient, previously completely healthy younger man, suffered purulent meningitis caused by the same microorganism. Colon endoscopy was performed in both patients and it revealed colon polyps. Histologically, in both cases, those were benign neoplasia. In Croatia, until this report, there have been no other reports about patients suffering systemic Streptococcus bovis infections. At the same time, this report describes Streptococcus bovis purulent meningitis in a previously healthy adult, which is also extremely rare in the medical literature. Since Streptococcus bovis infections are associated with colon carcinoma, it is imperative to perform colonoscopy in each patient suffering infection with this germ, and to consider him as a high risk patient for developing colon cancer.

Adult↗
PubMed1986

Infective endocarditis due to penicillin-tolerant Streptococcus bovis.

Two Streptococcus bovis isolates obtained from patients with endocarditis were found to be tolerant to penicillin and other cell wall active agents. By time-kill analysis, penicillin and streptomycin acted synergistically against these strains. The existence of tolerant S. bovis strains should be considered when initially choosing antibiotics for the treatment of serious S. bovis infections.

Adult↗
PubMed1996

Purification and properties of extracellular glucosyltransferase from Streptococcus bovis.

Eight Streptococcus bovis strains were classified into 3 types on the basis of isoelectric point (pI) and molecular mass (M(r)) of extracellular glucosyltransferase. Strains ATCC 9809, 35034 and 43143 produced glucosyltransferase of pI 3.7 and M(r) 165 kDa; strains ATCC 15351, 27960 and 33317 produced glucosyltransferase of pI 4.1 and M(r) 140 kDa; strains ATCC 43085 and 43144 did not produce any glucosyltransferase. The glucosyltransferase form S. bovis 9809 was purified by Bio-Gel hydroxyapatite chromatography and DEAE-Toyopearl chromatography. The S. bovis 9809 glucosyltransferase was immunologically identical with the other 5 S. bovis glucosyltransferases and not related to mutants streptococcal glucosyltransferases. The specific activity, the optimum pH and the Km value for sucrose were 17.9 U/mg protein, 6.0 and 5.0 mM, respectively. The first 11 N-terminal amino acid residues of the glucosyltransferases were DETSAVTLTRE, and the region was hydrophilic. The glucosyltransferases from S. bovis 9809 and 3317 synthesized from sucrose 1, 6-alpha-D-glucan with 9 and 2 mol%, 1, 3, 6-alpha-branched glucose, respectively.

Amino Acid Sequence↗
PubMed1981

Polyposis coli presenting with Streptococcus bovis endocarditis.

Streptococcus bovis bacteremia is an important early clue to the presence of serious and clinically unexpected gastrointestinal disease, particularly carcinoma of the colon. S. bovis bacteremia has also been associated with carcinoma of the esophagus and stomach, gastric lymphoma, pancreatic adenocarcinoma, intestinal diverticulosis and single adenomatous polyps and villous polyps of the colon. We report a patient with S. bovis endocarditis as the initial clinical manifestation of extensive polyposis of the colon and rectum. All patients with S. bovis bacteremia need thorough investigation of their gastrointestinal tract even in the absence of symptoms, signs, or positive laboratory tests suggestive of gastrointestinal pathology.

Adenoma↗
PubMed2003

Continuous ambulatory peritoneal dialysis-related peritonitis caused by Streptococcus bovis.

The first case of Streptococcus bovis peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD) in a 40-year-old Chinese woman suffering from systemic lupus erythematosus is reported. Streptococcus bovis is part of the normal flora in the human intestine and, less commonly, the female genital tract. Being a rare cause of peritonitis, the possible link between genital tract colonization by Streptococcus bovis and retrograde invasion of the peritoneal cavity is postulated to be the cause of continuous ambulatory peritoneal dialysis peritonitis in this patient. Since invasive Streptococcus bovis infection is associated with gastrointestinal pathology (Streptococcus bovis biotype I) and chronic liver diseases (Streptococcus bovis biotype II), identifying the biotype of Streptococcus bovis could guide treatment by indicating that further investigation of these underlying diseases is required.

Adult↗
PubMed1993

Diversity of chromosomal genetic elements and gene identification in antibiotic-resistant strains of Streptococcus pneumoniae and Streptococcus bovis.

Antibiotic-resistant Streptococcus pneumoniae (26 strains) and Streptococcus bovis (28 strains), devoid of R plasmids, were examined for DNA-DNA homology to Tn916 and Tn3701. Tn916-like structures were found in 17 S. pneumoniae and 21 S. bovis strains. Tn916-modified structures were present in 6 S. pneumoniae and 2 S. bovis strains. Two strains of each species carried elements having a Tn3701-like composite structure. All these elements were chromosome-borne. No chromosomal elements were detected in 1 S. pneumoniae and 3 S. bovis strains.

Chromosomes, Bacterial↗
PubMed1998

The diversion of lactose carbon through the tagatose pathway reduces the intracellular fructose 1,6-bisphosphate and growth rate of Streptococcus bovis.

Twenty strains of Streptococcus bovis grew more slowly on lactose (1.21 +/- 0.12 h-1) then than on glucose (1.67 +/- 0.12 h-1), and repeated transfers or prolonged growth in continuous culture (more than 200 generations each) did not enhance the growth rate on lactose. Lactose transport activity was poorly correlated with growth rate, and slow growth could not be explained by the ATP production rate (catabolic rate). Batch cultures growing on lactose always had less intracellular fructose 1,6-bisphosphate (Frul,6P2) than cells growing on glucose (6.6 mM compared to 16.7 mM), and this difference could be explained by the pathway of carbon metabolism. Glucose and the glucose moiety of lactose were metabolized by the Embden-Meyerhoff-Parnas (EMP) pathway, but the galactose moiety of lactose was catabolized by the tagatose pathway, a scheme that by-passed Frul,6P2. A mutant capable of co-metabolizing lactose and glucose grew more rapidly when glucose was added, even though the total rate of hexose fermentation did not change. Wild-type S. bovis grew rapidly with galactose and melibiose, but these galactose-containing sugars were activated by galactokinase and catabolized via EMP. On the basis of these results, rapid glycolytic flux through the EMP pathway is needed for the rapid growth (more than 1.2 h-1) of S. bovis.

Adenosine Triphosphate↗
PubMed1994

Alternative strategies of 2-deoxyglucose resistance and low affinity glucose transport in the ruminal bacteria, Streptococcus bovis and Selenomonas ruminantium.

Streptococcus bovis and Selenomonas ruminantium grew in the presence of the glucose analog, 2-deoxyglucose (2-DG), but the cells no longer had high affinity glucose transport. In S. bovis, 2-DG resistance was correlated with a decrease in phosphoenolpyruvate (PEP)-dependent glucose phosphotransferase (PTS) activity. The 2-DG-selected S. bovis cells relied solely upon a low affinity, facilitated diffusion mechanism of glucose transport and a 2-DG-resistant glucokinase (ATP-dependent). The glucokinase activity of S. ruminantium was competitively inhibited by 2-DG, and the 2-DG selected cells continued to use PEP-dependent PTS as a mechanism of glucose transport. In this latter case, the 2-DG selected cells switched from a mannosephosphotransferase (enzyme II) that phosphorylated glucose, mannose, and 2-DG, but not alpha-methylglucose to a glucosephosphotransferase (enzyme II) that phosphorylated glucose and alpha-methylglucoside but not 2-DG or mannose. The glucosephosphotransferase (enzyme II) had a very low affinity for glucose and the transport kinetics were similar to the facilitated diffusion system of S. bovis.

Animals↗
PubMed1998

Streptococcus bovis bacteremia: unusual complications.

Streptococcus bovis bacteremia is known to be related to neoplastic lesions of the colon. We describe a patient with several complications of S bovis bacteremia and adenocarcinoma of the colon--endocarditis, spondylodiskitis, and splenic abscess. We believe this is the eighth known case of endocarditis and diskitis caused by S bovis and the third case of endocarditis and splenic abscess by S bovis in a patient with adenocarcinoma of the colon.

Abscess↗
PubMed2001

Nisin resistance of Streptococcus bovis.

The growth of Streptococcus bovis JB1 was initially inhibited by nisin (1 microM), and nisin caused a more than 3-log decrease in viability. However, some of the cells survived, and these nisin-resistant cells grew as rapidly as untreated ones. To see if the nisin resistance was merely a selection, nisin-sensitive cells were obtained from agar plates lacking nisin. Results indicated that virtually any nisin-sensitive cell could become nisin-resistant if the ratio of nisin to cells was not too high and the incubation period was long enough. Isolates obtained from the rumen were initially nisin sensitive, but they also developed nisin resistance. Nisin-resistant cultures remained nisin resistant even if nisin was not present, but competition studies indicated that nisin-sensitive cells could eventually displace the resistant ones if nisin was not present. Nisin-sensitive, glucose-energized cells lost virtually all of their intracellular potassium if 1 microM nisin was added, but resistant cells retained potassium even after addition of 10 microM nisin. Nisin-resistant cells were less hydrophobic and more lysozyme-resistant than nisin-sensitive cells. Because the nisin-resistant cells bound less cytochrome c, it appeared that nisin was being excluded by a net positive (i.e., less negative) charge. Nisin-resistant cells had more lipoteichoic acid than nisin-sensitive cells, and deesterified lipoteichoic acids from nisin-resistant cells migrated more slowly through a polyacrylamide gel than those from nisin-sensitive cells. These results indicated that lipoteichoic acids could be modified to increase the resistance of S. bovis to nisin. S. bovis JB1 cultures were still sensitive to monensin, tetracycline, vancomycin, and bacitracin, but ampicillin resistance was 1,000-fold greater.

Anti-Bacterial Agents↗
PubMed2000

Promotion of intestinal carcinogenesis by Streptococcus bovis.

The involvement of Streptococcus bovis, an member of the human gut flora, in colorectal neoplastic diseases is an object of controversy. The aim of this study was to determine the effects of S.bovis and of antigens extracted from the bacterial cell wall on early preneoplastic changes in the intestinal tract. Adult rats received i. p. injections of azoxymethane (15 mg/kg body weight) once per week for 2 weeks. Fifteen days (week 4) after the last injection of the carcinogen, the rats received, by gavage twice per week during 5 weeks, either S.bovis (10(10) bacteria) or wall-extracted antigens (100 microg). One week after the last gavage (week 10), we found that administration of either S.bovis or of antigens from this bacterium promoted the progression of preneoplastic lesions through the increased formation of hyperproliferative aberrant colonic crypts, enhanced the expression of proliferation markers and increased the production of IL-8 in the colonic mucosa. Our study suggests that S.bovis acts as a promoter of early preneoplastic lesions in the colon of rats. The fact that bacterial wall proteins are more potent inducers of neoplastic transformation than the intact bacteria may have important implications in colon cancer prevention.

Adenoma↗
PubMed2001

Prevalence of liver disease in patients with Streptococcus bovis bacteraemia.

BACKGROUND: The relationship between Streptococcus bovis bacteraemia and gastrointestinal disease (mainly colon cancer) is well known. Patients with advanced liver disease are prone to bacteraemia. Less attention has been paid to the association between liver disease and Streptococcus bovis bacteraemia in the literature. AIMS: To evaluate the prevalence of liver disease in patients with S. bovis bacteraemia. PATIENTS AND METHODS: Twenty-two episodes of S. bovis bacteraemia in 20 adults (13 males and seven females, with a median age of 61 years, range 32-94 years) were detected in a single hospital over a 7-year period. Ten of them had endocarditis. Patients' clinical records were reviewed, with special focus on underlying liver and gastrointestinal disease. RESULTS: Eleven patients (55%) had a chronic liver disease. Nine of them were cirrhotics. Ten patients had a history of chronic alcohol abuse, and four patients had hepatitis C virus antibodies (associated with alcohol abuse in three cases). Large bowel disease was present in six out of 13 evaluable patients (adenocarcinoma in three cases). Patients with liver disease were younger than patients without it. Mortality related to S. bovis bacteraemia was particularly high among patients with advanced liver disease (Child-Pugh state C). Bacteraemia recurred two times in one alcoholic cirrhotic, who was diagnosed as having a Dukes-B colon cancer 4.5 years after the first episode of S. bovis bacteraemia. CONCLUSIONS: In our area, S. bovis bacteraemia is frequently associated with chronic liver disease. Liver disease may be a predisposing factor for S. bovis bacteraemia.

Adult↗