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PubMed2000

Lack of association between Streptococcus oralis and recurrent aphthous stomatitis.

In the present study, the potential involvement of Streptococcus oralis in the aetiology of recurrent aphthous stomatitis (RAS) was investigated using the polymerase chain reaction (PCR). Biopsies from 28 RAS patients were analysed, in addition to 20 oral lichen planus (OLP) and 13 normal biopsies that were used as controls. PCR was carried out using a primer pair that targets the D-alanine:D-alanine ligase gene and detects DNA from both S. oralis and the closely related species Streptococcus mitis. Discrimination between these two species was achieved by digestion of PCR products with the restriction endonucleases HaeIII and HindIII, which both give distinct restriction profiles for each species. S. oralis DNA was detected in 8 of 28 (29%) RAS samples, 10 of 20 (50%) OLP samples and 6 of 13 (46%) normal samples. These results suggest that S. oralis is not of primary aetiological significance in RAS.

Adult↗

PubMed1997

Antimicrobial susceptibility of 278 streptococcal blood isolates to seven antimicrobial agents.

A total of 278 streptococci isolated from blood (including 66 strains of Streptococcus pneumoniae) were tested for their MIC to penicillin G, gentamicin, rifampicin, clindamycin, erythromycin, vancomycin and teicoplanin to determine the current state of resistance among streptococci isolated from blood at a University Hospital in Copenhagen, Denmark, and thereby to assess alternative treatment for patients who are infected with a penicillin-resistant streptococcal strain or allergic to penicillin. Danish Blood Sensitivity Agar and the Etest were used. Overall, resistance to penicillin among Streptococcus mitis strains was 44.4% (37% intermediately susceptible and 7.4% resistant). As penicillin resistance in S. mitis may be an early indication of emerging penicillin resistance among other streptococcal species, this finding is a matter of concern. Except for this observation, penicillin remains the best and a safe choice for treatment of streptococcal infection. For alternative treatment when the patient is allergic to penicillin and for prophylaxis, the usual recommendation is macrolide antibiotics or clindamycin. The majority of non-enterococcal groups of streptococci remain sensitive to erthromycin and clindamycin, but the antibiotic susceptibility pattern is unpredictable without testing the isolates, so empirical therapy or prophylaxis may fail.

Bacteremia↗

PubMed1992

Infectious crystalline keratopathy with ring opacity.

A 41-year-old physician was treated for 3 months with antiviral medications, antibiotics, and steroids for presumed herpetic keratitis. When seen by us, an annular infiltrate was observed, along with crystalline-like opacities in the superficial one third of the stroma. Cultures of scrapings and of subsequent biopsies were positive for Streptococcus mitis of the viridans group; histopathology demonstrated large aggregates of cocci between the stroma lamellae. Tapering of topical corticosteroids and treatment with topical penicillin resulted in resolution of the infiltrates. The clinical appearance and findings in this patient suggest that infectious crystalline keratitis can produce an annular infiltrate. Injection of the organism into rabbit corneas produced a crystalline infiltrate, but no annular opacity was observed. Corticosteroids altered the clinical and histopathologic appearance of the lesions in rabbits.

Adult↗

PubMedDate not supplied

Septicaemia caused by viridans streptococci in neutropenic patients with leukaemia.

10 neutropenic leukaemic patients had septicaemia caused by viridans streptococci, organisms not commonly recognised as opportunist pathogens. 1 patient died; in the remainder recovery was generally dependent on an adequate circulating granulocyte count (seven patients) rather than specific antimicrobial therapy. Seven of the infections were caused by Streptococcus mitis, and seven of the eight strains tested were resistant to cotrimoxazole, which the patients had received as prophylaxis against infection. It is suggested that oral ulceration caused by cytotoxic chemotherapy provided a portal of entry for cotrimoxazole-resistant viridans streptococci. The increasing incidence of infections with gram-positive organisms as a complication of neutropenia prompts a reconsideration of current empirical antimicrobial therapy.

Administration, Oral↗

PubMed1991

Antibacterial and antifungal properties of propylene glycol, hexylene glycol, and 1,3-butylene glycol in vitro.

The antimicrobial properties of three glycols, - propylene glycol, hexylene glycol, and 1,3-butylene glycol - against Candida albicans, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes A, Streptococcus mitis, and E. coli were studied in vitro. Within 20 h, 10% and 30% hexylene glycol in fresh tryptic soy broth were able to kill all the micro-organisms listed above. Five percent hexylene glycol showed some antimicrobial properties but the 1% agent had no effect. Thirty percent 1,3-butylene glycol and 30% propylene glycol were approximately as effective as 10% HG. The results speak in favour of using hexylene glycol in cosmetic and dermatological vehicles instead of propylene glycol and 1,3-butylene glycol.

Anti-Bacterial Agents↗

PubMed2006

Relationship between the ability of oral streptococci to interact with platelet glycoprotein Ibalpha and with the salivary low-molecular-weight mucin, MG2.

The oral streptococci Streptococcus sanguinis, Streptococcus gordonii and Streptococcus oralis are common aetiological agents of infective endocarditis, and their ability to adhere to and induce the aggregation of platelets is thought to be a virulence trait. The platelet glycoprotein GPIbalpha has been implicated as the adhesion receptor for S. sanguinis and S. gordonii, but it is not known if this is the case for S. oralis and other species. The aim of this study was to determine the GPIbalpha-interactive capability of a range of oral streptococci and to determine the relationship between this capability and their ability to interact with the salivary constituents that they would encounter in their normal habitat. All platelet-adhesive S. sanguinis strains and most S. gordonii strains adhered in a GPIbalpha-dependent manner, but strains of S. oralis, Streptococcus cristatus, Streptococcus parasanguinis and Streptococcus mitis had no direct affinity for platelets. Those strains that were able to bind GPIbalpha also bound to the low-molecular-weight submandibular salivary mucin, MG2, and this interaction was sialic acid-dependent. The data suggest that S. sanguinis and S. gordonii may be efficient colonizers of platelet vegetations because of their adaptation to recognize sialylated salivary mucins. In contrast, S. oralis does not interact with platelets and so is likely to colonize vegetations through an as yet unidentified mechanism.

Bacterial Adhesion↗

PubMed1995

In vitro activities of 22 beta-lactam antibiotics against penicillin-resistant and penicillin-susceptible viridans group streptococci isolated from blood.

A total of 410 strains of viridans group streptococci isolated consecutively from blood were tested by the microdilution method for in vitro susceptibility to 22 beta-lactam antibiotics. One hundred thirty-eight strains (33.6%) were resistant to penicillin with a MIC range of 0.25 to 8 micrograms/ml. MICs of all beta-lactam agents tested were higher for penicillin-resistant strains than for susceptible strains. These antibiotics were classified into three groups according to their in vitro activities (MICs at which 50 and 90% of the isolates are inhibited). Beta-Lactams of the first group (these included imipenem, cefpirome, FK-037, cefditoren, cefotaxime, ceftriaxone, and cefepime) showed activities higher than or similar to that of penicillin against penicillin-resistant viridans group streptococci. However, 80% of highly penicillin-resistant Streptococcus mitis organisms required cefotaxime and ceftriaxone MICs of > or = 2 micrograms/ml (range, 2 to 16 micrograms/ml). Beta-Lactams of the second group (cefpodoxime, ampicillin, amoxicillin-clavulanate, piperacillin, and cefuroxime) showed lower activities than penicillin. Finally, antibiotics of the third group (cephalothin, oxacillin, ceftazidime, cefixime, cefaclor, cefetamet, cefadroxil, cephalexin, and ceftibuten) showed poor in vitro activities. Therefore, some of the beta-lactam agents included in the first group could be an acceptable alternative in the treatment of serious infections due to strains highly resistant to penicillin, although clinical experience is needed.

Anti-Bacterial Agents↗

PubMed1991

Subclass distribution of salivary secretory immunoglobulin A antibodies to oral streptococci.

The ability of specific secretory immunoglobulin A (S-IgA) antibodies to inhibit bacterial colonization of mucosal surfaces may be neutralized by the activity of bacterial IgA1 proteases. Because of the resistance of the IgA2 subclass to these enzymes, the biological effect of IgA1 proteases in vivo may depend on the subclass distribution of the bacterium-specific antibodies. We have estimated the subclass distribution of S-IgA antibodies in saliva samples from 13 individuals against IgA1 protease-producing (Streptococcus sanguis and Streptococcus oralis) and nonproducing (Streptococcus gordonii and Streptococcus mitis bv. 2) oral streptococci. IgA1 was found to be the predominant subclass of antibodies against these four bacteria in most of the saliva samples, corroborating previous data suggesting a role of IgA1 proteases in plaque formation. However, variation in the subclass distribution of S-IgA antibodies against the same strain was observed. In one individual, IgA2 was the predominant subclass of antibodies against all four streptococci and of total salivary S-IgA, pointing to the possible significance of genetic variations. The study also addresses methodological problems related to the quantitation of salivary antibodies by solid-phase immunoassays.

Antibodies, Bacterial↗

PubMedDate not supplied

[Calcified aortic stenosis due to healed experimental bacterial endocarditis].

We studied the role of bacterial endocarditis in the development of aortic valve stenosis. A femoral arterio venous shunt was performed in nine dogs with the method previously proposed by Lillehei. We induced bacteremic infection with the administration of streptococcus mitis (1 x 10(10)) 10 ml once a day for 15 days these bacterium were sensible to penicillin. All dogs were treated with 1,000,000 U of benzatinic penicillin and sacrificed between 28-102 days after the bacterial inoculation ended. In one dog we observed bacterial endocarditis in the mitral and aortic valves and in other three dogs there was an aortic valve stenosis with calcium deposits in the body and in the free edges of the aortic valve with evident irregular stenosis as seen in man.

Animals↗

PubMed1998

Measurement of long-range carbon-carbon coupling constants in a uniformly enriched complex polysaccharide.

A quantitative coherence transfer scheme for 1H-detected measurement of long-range carbon-carbon coupling constants in NMR spectra of complex carbohydrates is described. It is applied to a uniformly highly 13C-enriched monosaccharide and to a complex cell wall polysaccharide from Streptococcus mitis J22 having seven distinct sugars in the repeating subunit. Coupling values within the ring were compared to published values for monosaccharides to demonstrate the validity of the method. An attempt was made to relate coupling constants between carbon atoms across the glycosidic linkage to the dihedral angles of a recently published flexible model for the polysaccharide which is based on 3JCH data. The experimental coupling constants do not agree with any single conformation demonstrating that the repeating subunit of the polysaccharide must be flexible. This conclusion is in accord with results of molecular modeling nuclear Overhauser effect and 3JCH data.

Carbohydrate Sequence↗

PubMed1984

Regulation of glucose metabolism in oral streptococci through independent pathways of glucose 6-phosphate and glucose 1-phosphate formation.

In vivo rates of glucose uptake and acid production by oral streptococci grown in glucose- or nitrogen-limited continuous culture and batch culture were compared with the glucose phosphorylation activities of harvested, decryptified cells. The strains examined contained significant phosphoenolpyruvate-phosphotransferase system (PTS) activity, measured by a glucose 6-phosphate (G6P) dehydrogenase-linked assay procedure, but this activity was insufficient to account for the in vivo glucose uptake rates. However, ATP was a superior phosphoryl donor to phosphoenolpyruvate, and unlike the PTS, phosphoryl transfer with ATP was insensitive to bacteriostatic concentrations of chlorhexidine, suggesting glucokinase-mediated G6P formation. Again, G6P formation from the PTS and glucokinase reactions was not commensurate with some of the glucose uptake rates observed, implying that other phosphorylation reactions must be occurring. Two novel reactions involving carbamyl phosphate and acetyl phosphate were identified in some of the strains. No G6P formation was detected with these potential phosphoryl donors, but in the presence of phosphoglucomutase, glucose 1-phosphate (G1P) formation was evident, which was insensitive to chlorhexidine. G1P is a precursor of glycogen, and good correlation was obtained between G1P formation activity and endogenous metabolism of washed cells measured either as a rate of acid production at a constant pH 7 or as a decrease in pH with time in the absence of titrant. A "league table" of abilities to synthesize G1P and produce acid from endogenous metabolism was compiled for oral streptococci grown in batch culture. This indicated that Streptococcus mutans Ingbritt and Streptococcus sanguis Challis were unable to form G1P or produce much acid endogenously, whereas increasing activities were obtained with Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mitis. In particular, S. mitis had the highest G1P formation activities and was able to decrease the pH to less than 5 in 15 min by endogenous metabolism alone. The data are consistent with the intracellular accumulation of free glucose driven by proton motive force when PTS activities are low and the subsequent phosphorylation to either G6P for metabolism via glycolysis or G1P for glycogen biosynthesis. The accumulation of acetyl phosphate during glucose-limited growth and the availability of arginine for catabolism to carbamyl phosphate provide an explanation as to why some glucose-limited oral streptococci continue to synthesize glycogen under these conditions, which might prevail in plaque.

Chlorhexidine↗

PubMed1990

Effectiveness of ultrasonic files in the disruption of root canal bacteria.

The physical mechanisms of ultrasound, namely cavitation and acoustic streaming, generated by the Enac-Osada ultrasonic unit were investigated for effectiveness in disrupting Streptococcus mitis. In addition, the bactericidal effect of ultrasound in the presence of 2.5% sodium hypochlorite was examined. Bacterial suspensions were irradiated directly with ultrasound in simulated root canals, and the viability of bacteria was examined after growth on a blood agar medium under anaerobic conditions at 37 degrees C for 5 days. The results indicated that ultrasound per se failed to disrupt bacteria but resulted in increases in the viable counts; the former was considered to be because of the lack of cavitation and the latter because of the dispersal effects of acoustic streaming. The 2.5% sodium hypochlorite solution demonstrated powerful bactericidal activity.

Colony Count, Microbial↗

PubMed1997

Changes in the oral streptococcal flora of children undergoing allogeneic bone marrow transplantation.

The changes in the oral streptococcal flora of twenty children undergoing allogeneic bone marrow transplant are described. Saliva was collected from each child on four separate occasions: (i) before the conditioning regimen; (ii) 7 days post-transplantation; (iii) when the neutrophil count had risen above 0.5 x 10(9)/l; (iv) 119 days post-transplantation. Indices for dental caries, plaque, gingivitis, herpetic stomatitis and mucositis were also recorded. There was a significant decrease in the total aerobic (P<0.001) and anaerobic counts (P<0.0002) between baseline and 7 days post-transplantation. The proportion of the 'Streptococcus oralis group' (Streptococcus mitis and S. oralis) increased significantly from baseline 12.1% to 48.4% at 7 days post-transplantation (P<0.003). The plaque and gingivitis indices increased significantly from baseline to 7 days post-transplantation (P<0.001). Twenty percent of the children had either positive blood cultures or Hickman line cultures for the 'S. oralis group', and it is possible that the inflamed gingival tissues are a further site of entry for these streptococci. There were no differences in the total anaerobic counts or the proportion of the 'S. oralis group' between baseline and the end of the study in the transplant children, or between the transplant and control children.

Bone Marrow Transplantation↗

PubMed1996

Disruption of the gene encoding penicillin-binding protein 2b (pbp2b) causes altered cell morphology and cease in exopolysaccharide production in Streptococcus thermophilus Sfi6.

Genetic and biochemical analysis of exopolysaccharide (EPS) production in lactic acid bacteria has been a growing field of interest in the food industry. We previously identified and characterized a gene cluster composed of 13 genes (epsA to epsM) responsible for EPS production in Streptococcus thermophilus Sfi6. Here we report one further gene, pbp2b, that is connected to EPS production. Mutants with a gene disruption in pbp2b were no longer able to produce EPS, exhibited a reduced growth-rate, and their cell morphology was altered. The predicted gene product showed significant homology to the class B penicillin-binding proteins 2b of Streptococcus pneumoniae, Streptococcus sanguis and Streptococcus mitis involved in peptidoglycan synthesis. Upstream of pbp2b, we further identified two genes which showed significant homology to the E. coli folD and urfl, which is an unidentified open reading frame presumed to be involved in DNA repair. Downstream of pbp2b, we identified a gene that showed homology to the Bacillus subtilis and the Escherichia coli recM or recR which, respectively, are involved in the methyl-dependent DNA mismatch repair. In S. thermophilus, pbp2b and recM were transcribed from their own promoters as monocistronic mRNAs and are therefore organized as independent transcriptional units.

Amino Acid Sequence↗

PubMed1987

High-level aminoglycoside resistance mediated by aminoglycoside-modifying enzymes among viridans streptococci: implications for the therapy for endocarditis.

Two strains of Streptococcus mitis with high-level resistance to streptomycin and kanamycin were identified from a collection of multiple-resistant streptococci. The strains were resistant to penicillin-streptomycin and penicillin-kanamycin synergy but were synergistically killed by penicillin-gentamicin. Both strains adenylylated streptomycin at the 3'' position. Neither strain could be cured of its streptomycin resistance by novobiocin, acridine orange, or ethidium bromide. Attempts to pass the resistance into two recipients were unsuccessful. Agarose gel electrophoresis and cesium chloride gradients failed to reveal plasmid bands. This is the first report of high-level streptomycin resistance mediated by modifying enzymes among viridans streptococci. It is possible that endemic streptomycin resistance among viridans streptococci will develop.

Drug Synergism↗

PubMed1996

In vitro activities of eight macrolide antibiotics and RP-59500 (quinupristin-dalfopristin) against viridans group streptococci isolated from blood of neutropenic cancer patients.

From January 1988 to December 1994, 66 consecutive blood culture isolates of viridans group streptococci collected from febrile neutropenic cancer patients were tested for antimicrobial susceptibilities by the agar dilution method. The antibiotics studied were erythromycin, clarithromycin, roxithromycin, dirithromycin, azithromycin, josamycin, diacetyl-midecamycin, spiramycin, and quinupristin-dalfopristin. A total of 26 (39.4%) strains were resistant to erythromycin with an MIC range of 0.5 to > 128 micrograms/ml. The strains were classified into three groups according to their penicillin susceptibility: 42 (63.6%) were susceptible, 8 (12.1%) were intermediately resistant, and 16 (24.3%) were highly resistant. The percentages of erythromycin-resistant strains in each group were 23.8, 62.5, and 68.8%, respectively. Streptococcus mitis was the species most frequently isolated (83.3%) and showed the highest rates of penicillin (40%) and erythromycin (43.6%) resistance. MICs of all macrolide antibiotics tested and of quinupristin-dalfopristin were higher for penicillin-resistant strains than for penicillin-susceptible strains. All macrolide antibiotics tested had cross-resistance to erythromycin, which was not observed with quinupristin-dalfopristin. Our study shows a high rate of macrolide resistance among viridans group streptococci isolated from blood samples of neutropenic cancer patients, especially those infected with penicillin-resistant strains. These findings make macrolides unsuitable prophylactic agents against viridans group streptococcal bacteremia in this patient population.

Anti-Bacterial Agents↗

PubMed1992

Immunoglobulin A antibody activity to mutans streptococci in parotid, submandibular and whole saliva.

Antigen extracts of 9 strains of Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius and Streptococcus mitis were separated in acrylamide gels by electrophoresis. Strains of the same genotype of mutans streptococci were found to have virtually identical sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns but differed clearly from other genotypes of mutans or with the reference strains S. salivarius and S. mitis. Immunoglobulin A (IgA) antibody activity to antigens of S. mutans, S. sobrinus and S. mitis in the parotid, submandibular and whole saliva of 12 people was detected by Western blotting. IgA antibodies reacted with several of the antigens, and the reaction pattern was unique for each of the individuals. To certain antigens, all the salivas blotted bands if both clear and questionable bands were counted. Significantly more blotted bands were revealed with antigens from S. mutans than S. sobrinus. The results of the 3 different salivas of the same individual had a high degree of resemblance but in a few individuals, more blotted bands were obtained with parotid saliva to S. mutans and S. sobrinus antigens.

Adult↗

PubMed1996

The interference of gingival cell cultures with growth of selected bacteria.

The aim of the present study was to analyze the interference of oral tissue cells or cell lines (effector cells) with growth of reference bacteria, and furthermore to investigate whether cells derived from different individuals differ in such activity. The reference bacteria were Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mitis, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum. The effector cells used were gingival fibroblasts (GF) from 21 periodontally involved persons, gingival epithelial cells (E) from 2 such persons, HeLa cells (HeLa), and an amnion cell line (Amnion). The cells were cultivated and their supernatants tested for antibacterial activity in a Bioscreen robot analyzer (Labsystems, Finland). Results suggest that the antibacterial activity of each tested primary cell line of tissue had its own profile depending on cell type and donor, and that the composition of oral microbiota was influenced by oral cells, which might, in turn, contribute to the variations in the pathogenesis of periodontal diseases.

Aggregatibacter actinomycetemcomitans↗