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PubMed1995

A comparison of the microbial flora in carious dentine of clinically detectable and undetectable occlusal lesions.

It is not known whether the aetiology of occlusal hidden caries lesions (HCL) is identical to that of small visible lesions (SVL). Previous studies of the microflora of HCL suggest that relatively few species can be isolated. The aim of the present study was to compare the bacterial composition of dentine from 10 HCL and 17 SVL in a population of children aged 8-18 years. The following bacteria were identified: Actinomyces spp., mutans streptococci, Streptococcus sanguis, Streptococcus oralis, Streptococcus gordonii. Streptococcus mitis, and Lactobacillus spp. Streptococcus mutans was found more often in the HCL group (p = 0.03), while Streptococcus sobrinus was found more often in the SVL group (p = 0.05). However, proportions of both species were lower in the SVL group as compared with the HCL group (S. mutans p = 0.07; S. sobrinus p = 0.03). Lactobacilli and Actinomyces spp. were found at similar levels in both groups. A more diverse range of streptococcal species and Veillonella was found in the SVL group (p = 0.001). These results show a less complex microflora in HCL as compared with SVL, indicating that the aetiology of hidden caries might be different from that of open caries.

Actinomyces↗
PubMed1989

Molecular analysis of viridans and nutritionally deficient (variant) streptococci causing sequential episodes of endocarditis in a patient.

Clinical blood isolates from sequential episodes of endocarditis occurring over a six-month period of time in an addict were investigated. The pathogens were Streptococcus sanguis II, Streptococcus mitis, and a nutritionally deficient (variant) streptococcus. The authors determined the DNA relatedness of these isolates by antibiograms, plasmid profiles, chromosomal endonuclease restriction digestions, and dot blot DNA-DNA hybridization analyses. The S. sanguis II and nutritionally deficient streptococcal strain had similar antibiograms being resistant to penicillin; neither produced beta-lactamase. No plasmids were found. The restriction endonuclease chromosomal digestion patterns of these isolates were unique and epidemiologically unrelated to each other. Dot blot DNA-DNA hybridizations, using the nutritionally deficient streptococcal DNA as the probe, showed homology to the preceding clinical isolates, S. sanguis II and S. mitis, at 15.4% and 45.1% hybridization levels, respectively. The nutritionally deficient streptococcus was only 4.2% homologous to a S. mitis ATCC strain and another nutritionally deficient streptococci isolate. Therefore, this patient had endocarditis with three distinct streptococcal strains.

Adult↗
PubMed1985

Characterization of nutritionally variant streptococci by biochemical tests and penicillin-binding proteins.

A comparative study of 60 strains of nutritionally variant streptococci (NVS) with 34 strains of Streptococcus mitis and 37 strains of Streptococcus sanguis II showed the presence of a red chromophore which was absent in the other streptococcal species. By using the conventional microbiological tests, only small differences were found between the NVS and the two other related species. In contrast a clear-cut delineation was found by the API 20 Strep system of identification. All NVS contained pyrrolidonylarylamidase, an enzyme which was absent in S. mitis and S. sanguis II strains, and lacked the alkaline phosphatase enzyme which was present in 56% of S. mitis strains and 62% of S. sanguis II strains. According to the additional enzymatic and biochemical tests of the API 20 Strep system, there were three biotypes among NVS. The major biotype included 33 of 60 strains which were characterized by the presence of both alpha- and beta-galactosidases and the capacity to hydrolyze trehalose. This biotype also showed a specific pattern of penicillin-binding proteins. These results show that NVS are recognized as a separate variety distinct from S. mitis and S. sanguis II species, despite some common biochemical properties. Moreover, the delineation of 33 strains with a specific biotype and a specific penicillin-binding protein pattern strongly suggests that a large part of NVS strains belong to an individual species.

Bacterial Proteins↗
PubMed2000

Taxonomic study of "tufted mitior" strains of streptococci (Streptococcus sanguinis biotype 11); recognition of a new genospecies.

The taxonomic position of tufted strains of streptococci, phenotypically resembling Streptococcus mitis and previously referred to as 'tufted mitior' was investigated. By 16S rRNA sequence analysis, it was clear that the "tufted mitior" strains belonged to the mitis group of species within the genus Streptococcus. It was confirmed that these strains were taxonomically independent at the species level, sharing less than 43%, DNA-DNA similarity with all established species of the mitis group. However biochemical test data obtained, using three commercial identification kits (Rapid ID32 Strep, STREPTOGRAM, and Biolog GP-plate) together with in-house biochemical tests employing 4-MUF-linked fluorogenic substrates did not reveal sufficient differential tests with which to identify the "tufted mitior" strains unequivocally. From these data, we conclude that these "tufted mitior" strains represent a new taxon within the mitis group of the genus Streptococcus, and propose that they should be considered as a genospecies until differential phenotypic characteristics are found for their identification.

Bacterial Typing Techniques↗
PubMed1999

Systemic doxycycline administration in the treatment of periodontal infections (II). Effect on antibiotic resistance of subgingival species.

The purpose of this investigation was to determine the proportion and prevalence of doxycycline resistant species in subgingival plaque samples taken during and after doxycycline administration. 20 subjects with adult periodontitis were randomly assigned to test (n = 10) or control groups (n = 10). Saliva samples as well as subgingival plaque samples taken from the distal surface of 6 posterior teeth were collected at baseline. All subjects received full mouth SRP and the test group systemic doxycycline at the dosage of 100 mg/day for 14 days. Saliva samples and plaque samples from the distal surface of 2 randomly selected teeth were taken at 3, 7 and 14 days during and after antibiotic administration. Control subjects were sampled at the same time points. Samples were anaerobically dispersed and serially diluted in PRAS Ringer's solution and plated on enriched Trypticase soy blood agar plates with or without 4 microg/ml doxycycline. After 7 days of anaerobic incubation, colonies were counted on both sets of plates. Microbial growth was washed from the doxycycline-containing media and the species identified using 40 DNA probes and checkerboard DNA-DNA hybridization. Differences in proportions of resistant species between test and control groups were tested for significance at each time point using the Mann Whitney test and over time within each group using the Quade test. The mean % (+/-SEM) of isolates resistant to 4 microg/ml doxycycline in the plaque samples of the test subjects increased from 6+/-2 to 48+/-9% during doxycycline administration, decreasing to 25+/-6% 2 weeks later and 9+/-2% at 90 days. In saliva, the % of resistant isolates rose from 13+/-1% to 81+/-10% during doxycycline administration falling to 46+/-8% 2 weeks later and 22+/-5% at 90 days. The % of resistant isolates did not change significantly in plaque or saliva samples of the control subjects at the same time points. For all subject visits combined, the most prevalent resistant species were: Streptococcus anginosus, Streptococcus oralis, Streptococcus intermedius, Streptococcus sanguis, Streptococcus mitis, Veillonella parvula, Actinomyces gerencseriae, Streptococcus constellatus, Actinomyces naeslundii genospecies 2, Streptococcus gordonii, Eikenella corrodens and Actinomyces naeslundii genospecies 1. Doxycycline resistant strains of these species were detected in both plaque and saliva samples prior to therapy and in the control group. Despite the finding of increased resistance, approximately 50% of the organisms present at periodontal sites at the end of 14 days of doxycycline administration tested sensitive to the agent.

Adult↗
PubMedDate not supplied

Non-mutans streptococci in patients receiving radiotherapy in the head and neck area.

OBJECTIVE: To study mutans and non-mutans streptococci in patients after radiotherapy of the head and neck. METHODS: Oral rinse samples collected from nasopharyngeal carcinoma patients before and after radiotherapy were diluted and cultured on nonselective and selective media for enumeration of total cultivable plaque flora, mutans and non-mutans streptococci and lactobacilli. Non-mutans streptococci were identified biochemically and by 16S rDNA sequence homology analysis. RESULTS: After irradiation, mutans streptococci were not isolated; the levels of Streptococcus mitis and lactobacilli increased significantly. The level of Streptococcus salivarius increased, but the significance was the borderline. The level of Streptococcus sanguis decreased significantly after irradiation. The abundance of other oral streptococci species showed no significant changes. CONCLUSIONS: S. mitis and S. salivarius are the predominant non-mutans streptococci in the high-caries-risk oral flora following radiotherapy.

Adult↗
PubMed2003

The presence of bacteria in the synovial fluid of the temporomandibular joint and clinical significance: preliminary study.

PURPOSE: The objective of this study was to find any relation between the presence of specific bacterial species in the synovial fluid of the temporomandibular joint (TMJ) and clinical parameters. PATIENTS AND METHODS: We studied 43 patients (male-to-female ratio, 1:1.69; average age, 34.37 +/- 14.55 years). Thirty-three patients had a displaced disc in the TMJ (DD group), and 10 patients did not have a displaced disc of the TMJ or any symptom related to TMJ disorders (NDD group). Clinical examinations were made to determine maximum mouth opening, joint sounds, previous trauma history, systemic disease, and TMJ pain. Six bacterial species that were reported in other studies were chosen to evaluate the presence of bacteria in the TMJ for this study. RESULTS: Mycoplasma genitalium was most frequently detected in synovial fluid (86.0%). Staphylococcus aureus, Mycoplasma fermentans/orale, Actinobacillus actinomycetemcomitans, and Streptococcus mitis were detected in 51.2%, 37.2%, 25.6%, and 7.0% of samples, respectively. beta-Hemolytic Streptococcus was not detected. The prevalence of S aureus was significantly higher in the DD group than in the NDD group (P <.05). The patients who had M. fermentans/orale were 5.40 times more likely to be younger than 30 years than were those without M. fermentans/orale (P <.05). Those with M. genitalium were 5.81 times more likely to be female than were those without M. genitalium (P <.05). CONCLUSION: The presence of S. aureus in TMJ synovial fluid was related to TMJ disorder symptoms and clinical parameters seemed to be influenced by bacterial presence in TMJ synovial fluid.

Adult↗
PubMed1989

A double-blinded comparative evaluation of three media for chromophore testing with viridans and nutritionally variant (deficient) streptococci.

A double-blinded prospective comparison of chromophore testing among 109 clinical isolates of alpha-hemolytic gram-positive cocci and 48 strains of nutritionally variant (deficient) streptococci (NVS) for its sensitivity, specificity, and predictive value under stimulated clinical laboratory conditions was performed after growth in three different media--Todd-Hewitt broth supplemented with 10 micrograms/mL of pyridoxal (THBP), THBP with 0.8% (w/v) yeast-extract (THBP + YE), and a semisynthetic chemically defined medium with Todd-Hewitt dialyzate (CDMT). The chromophore detection rates of Streptococcus mitis were 60.7, 67.9, and 78.6% after growth in THBP, THBP + YE, and CDMT, respectively. After growth in THBP there was significantly lower chromophore detection than either THBP + YE or CDMT for NVS (P less than 0.001), with a trend toward significantly less detection for S. mitis (0.15 greater than P). For Streptococcus sanguis II the detection rates were 45.7, 57.1, and 54.3%, respectively, for each medium. There was no significant difference between the detection rates after growth in THBP + YE or CDMT. One NVS was persistently chromophore negative, the first so described. There was a similar number of presumably false positive chromophore S. sanguis I strains (3 of 12) detected after growth in THBP + YE or CDMT. The sensitivity of chromophore detection for NVS (pooling results in THBP + YE and CDMT) was 95.8% and specificity was 59.6%. For a nonvariant streptococcus, the sensitivity was 61.9% and specificity was 93.5% for an isolate to be either S. mitis or S. sanguis II.

Chromogenic Compounds↗
PubMed2003

A unique variant of streptococcal group O-antigen (C-polysaccharide) that lacks phosphocholine.

Streptococcus mitis strain SK598, which represents a subgroup of biovar 1, possesses a unique variant of the C-polysaccharide found in the cell wall of all strains of Streptococcus pneumoniae and in some strains of S. mitis. This new variant lacks the choline methyl groups in contrast to the previously characterized forms of C-polysaccharide, which all contain one or two choline residues per repeat. The following structure of the repeating unit of the SK598 polysaccharide was established: where AAT is 2-acetamido-4-amino-2,4,6-trideoxy-d-galactose. This structure is identical to the double choline-substituted form of C-polysaccharide, except that it is substituted with ethanolamine instead of choline. This extends the number of recognized C-polysaccharide variants to four.

Carbohydrate Sequence↗
PubMed2004

The influence of biosurfactants released by S. mitis BMS on the adhesion of pioneer strains and cariogenic bacteria.

The influence of Streptococcus mitis BMS biosurfactants on the adhesion of eight pioneer and four cariogenic oral bacterial strains was, for a first screening, examined in a microtiter plate assay. The adhesion to pellicle-coated wells of three cariogenic strains was inhibited >70% by the biosurfactants, while only one pioneer strain showed >70% reduction. The reduction for the other strains did not exceed 50%. Subsequently, adhesion of Streptococcus mutans ATCC 25175 and Streptococcus sobrinus HG 1025, both cariogenic strains, and Actinomyces naeslundii T14V-J1 and Streptococcus oralis J22, two pioneer strains, to biosurfactants-coated enamel with and without a salivary pellicle was studied in a parallel plate flow chamber. A biosurfactants coating to enamel with or without a pellicle caused a reduction in the number of adhering cariogenic organisms, although no such reduction was observed for the pioneer strains. Consequently, it is concluded that S. mitis BMS biosurfactants may play a protective role against adhesion of cariogenic bacteria.

Bacterial Adhesion↗
PubMed1995

Detection of binding of denatured salivary alpha-amylase to Streptococcus sanguis.

Native alpha-amylase, either solubilized, or immobilized and tested with an overlay immunotechnique, was bound in a species-specific manner to Streptococcus mitis and to one of the Streptococcus gordonii strains. However, only insignificant amounts of alpha-amylase were bound to Streptococcus sanguis and all other strains tested. When alpha-amylase was denatured before immobilization, Streptococcus sanguis bound strongly to the protein while binding of other strains was insignificant.

Bacterial Adhesion↗
PubMed1992

Enumeration of subgingival species on primary isolation plates using colony lifts.

This study evaluated the feasibility of using a colony lift method and DNA probes to enumerate bacterial species cultured on primary isolation plates. Fourteen digoxigenin-labeled whole chromosomal DNA probes representing 12 subgingival species were validated by hybridization with colony lifts prepared from 249 reference strains of 51 species grown on Trypticase soy agar plates supplemented with 5% sheep blood. Colonies of reference strains were lifted onto Nytran filters from plates and treated to lyse cells, remove cellular proteins, denature and fix microbial DNA to the filters. Positive reactions were detected with an anti-digoxigenin antibody conjugated to alkaline phosphatase and revealed by bromo-chloro-indolyl phosphate and nitroblue tetrazolium. Cross-reactions were not observed for 13/14 probes, but 2 strains of Streptococcus mitis reacted with the probe to Streptococcus sanguis II. Subgingival plaque samples were taken by means of a sterile curette from mesiobuccal surfaces of teeth present in each of 26 subjects with differing periodontal disease states. Samples were dispersed, diluted, plated and incubated anaerobically for 7 d at 35 degrees C. Colonies were lifted as described above. Filters were cut into sections and hybridized with the 14 digoxigenin-labeled DNA probes. The probes were used to enumerate the test species and the total number of isolates was determined in 711 plaque samples. The colony lift method and DNA probes provided a sensitive, economical and quantitative method for enumerating cultivable microbial species in subgingival plaque samples. In addition, the amplification provided by growing the organisms on agar plates facilitated determination of numbers of organisms in small plaque samples, such as those from healthy sites.

Actinomyces↗
PubMed1987

Binding of laminin to oral and endocarditis strains of viridans streptococci.

Attachment of bacteria to the host tissue is regarded as a crucial step in the development of many types of infections. Recent studies by us and others have shown that matrix proteins which serve as adhesion proteins for eucaryotic cells may also be recognized by some bacteria. In the present communication, we report that several strains of viridans streptococci are able to bind to laminin. Most strains isolated from blood and heart valves of patients with endocarditis expressed laminin receptors, whereas only a few of the strains isolated from the oral cavity recognized this protein. This observation indicates that laminin binding might be an important factor in the pathogenesis of viridans endocarditis. Laminin binding to two strains (Streptococcus mitis UAB594 and UAB597) isolated from patients with endocarditis was characterized further. The bacterial cells expressed a limited number of laminin receptors (4 X 10(2) to 1 X 10(3) per cell) which bound the protein in a high-affinity interaction (Kd, 40 to 80 nM). This receptor of S. mitis UAB594 was heat labile and could be solubilized from bacteria by brief digestion with trypsin. Solubilized receptors which competed with cell-bound receptors for 125I-laminin could be adsorbed on laminin-Sepharose but not on Sepharose substituted with fibrinogen or fibronectin. Comparison of laminin receptors from S. mitis with those previously described for Streptococcus pyogenes suggest that different sites in the laminin molecule are recognized by the two bacteria and hence that the corresponding receptor molecules are not identical.

Animals↗
PubMed1990

Ability to bind salivary alpha-amylase discriminates certain viridans group streptococcal species.

A collection of 144 viridans group streptococcal strains recently characterized as part of a taxonomic study was examined for the ability to bind salivary alpha-amylase. This property was found in most strains of Streptococcus gordonii and Streptococcus mitis and in occasional strains of Streptococcus anginosus and Streptococcus salivarius. In contrast, all strains of Streptococcus sanguis, Streptococcus oralis, Streptococcus vestibularis, and Streptococcus mutans lacked alpha-amylase-binding capacity. A rapid and easy assay described in this paper may be an important supplementary test for identification of oral streptococci.

Bacteriological Techniques↗
PubMedDate not supplied

[The isolation of Streptococcus morbillorum from vaginal exudates].

We have tested 195 vaginal secretions sent by Gynecology Service of this hospital between the years 1988-1990. We achieved positive culture for streptococci in 58 (30%) of these cultures, 26 (44.8%) corresponding to Streptococcus morbillorum 9 (15.5%), to Gardnerella vaginalis 5 (8.6%), to Enterococcus faecalis-durans and to Streptococcus agalactiae, 3 (5.1%) to Streptococcus mitis and milleri 2 (3.4%), to Streptococcus bovis and cremoris, and 1 (1.7%) to Streptococcus salivarius, equinus and sanguis II respectively. We previously found that 52.8% of these patients were positive for vaginal candidiasis. The bacteriological identification done by the API 20 STREP System (bioMerieux GmbH, Nútingen, Germany) provides a typical pattern ("good identification") for the Streptococcus morbillorum.

Adolescent↗
PubMed1984

Inhibition of Neisseria gonorrhoeae growth due to hydrogen peroxide production by urogenital streptococci.

Seven streptococci isolated from the normal urogenital flora were selected for the production of an inhibitory activity toward Neisseria gonorrhoeae on solid medium. This activity was abolished when catalase was added to the medium in the case of Streptococcus mitis isolates 22, 25, 74 and Streptococcus sanguis II isolate 70 suggesting the involvement of hydrogen peroxide. The inhibitory activities produced by the other isolates (Streptococcus faecalis) were trypsin sensitive (isolates 12 and 14) or stable (isolate 59). Hydrogen peroxide production by S. sanguis II was quantitatively evaluated by reference to a standard curve representing the inhibitory effect of various concentrations of commercial H2O2 on N. gonorrhoeae growth. After 22 h of incubation a yield of 5.3 m mol H2O2 I-1 was reached on solid medium while in liquid medium values of 2.8 and 7.3 m mol H2O2 I-1 were obtained, respectively, in non-agitated and agitated cultures after 8 h of incubation.

Humans↗