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At least 289 records · Page 16Linked to original sources
PubMed2004

Establishment of an animal model using recombinant NOD.B10.D2 mice to study initial adhesion of oral streptococci.

An oral biofilm is a community of surface-attached microorganisms that coats the oral cavity, including the teeth, and provides a protective reservoir for oral microbial pathogens, which are the primary cause of persistent and chronic infectious diseases in patients with dry mouth or Sjögren's syndrome (SS). The purpose of this study was to establish an animal model for studying the initial adhesion of oral streptococci that cause biofilm formation in patients with dry mouth and SS in an attempt to decrease the influence of cariogenic organisms and their substrates. In nonobese diabetogenic (NOD) mice that spontaneously develop insulin-dependent diabetes mellitus (IDDM) and SS, we replaced major histocompatibility complex (MHC) class II (A(g7) E(g7)) and class I D(b) with MHC class II (A(d) E(d)) and class I D(d) from nondiabetic B10.D2 mice to produce an animal model that inhibited IDDM without affecting SS. The adhesion of oral streptococci, including Streptococcus mutans, onto tooth surfaces was then investigated and quantified in homologous recombinant N5 (NOD.B10.D2) and N9 (NOD.B10.D2) mice. We found that a higher number of oral streptococci adhered to the tooth surfaces of N5 (NOD.B10.D2) and N9 (NOD.B10.D2) mice than to those of the control C57BL/6 and B10.D2 mice. On the basis of our observation, we concluded that these mouse models might be useful as animal models of dry mouth and SS for in vivo biological studies of oral biofilm formation on the tooth surfaces.

Animals↗
PubMed1990

Genetic approaches to the study of oral microflora: a review.

As the study of oral microorganisms intensified almost 2 decades ago, the application of genetic techniques resulted in important contributions to the understanding of this clinically and ecologically important group of bacteria. The isolation and characterization of mutants of cariogenic streptococci helped to focus attention on traits that were important in colonization and virulence. Such classic genetic approaches gave way to molecular genetic techniques, including recombinant DNA methodology in the late 1970s. Gene cloning systems and methods to move DNA into cells have been developed for oral streptococci. Many streptococcal genes thought to be important in colonization and virulence have since been cloned and their nucleotide sequence determined. Mutant strains have been constructed using defective copies of cloned genes in order to create specific genetic lesions on the bacterial chromosome. By testing such mutants in animal models, a picture of the cellular and molecular basis of dental caries is beginning to emerge. These modern genetic methodologies also are being employed to develop novel and efficacious cell-free or whole cell vaccines against this infection. Genetic approaches and analyses are now being used to dissect microorganisms important in periodontal disease as well. Such systems should be able to exploit advances made in genetically manipulating related anaerobes, such as the intestinal Bacteroides. Gene cloning techniques in oral anaerobes, Actinomyces and Actinobacillus, are already beginning to pay dividends in helping understand gene structure and expression. Additional effort is needed to develop facile systems for genetic manipulation of these important groups of microorganisms.

Bacteria↗
PubMed1987

Strict protective isolation in allogenic bone marrow transplantation: effect on infectious complications, fever and graft versus host disease.

Complete microbial decontamination (laminar air flow room, sterile nursing and oral administration of cefamandole, gentamicin and nystatin) was carried out in 65 consecutive patients prior to allogeneic BMT for leukaemia (n = 58) or aplastic anaemia (n = 7). Very few microorganisms persisted during the post-transplant treatment period, and the gut became sterile in all except for Candida in 11 patients. Six uncomplicated septicaemias, all with persistent organisms simultaneously present in the mouth (Pseudomonas 3, Serratia 1, Candida 2) occurred during a total of 1,360 days with granulocyte counts less than 0.5 X 10(9)/l. Post-transplant fever occurred in 52 patients, exceeding 40 degrees C in 25. Guided by the surveillance cultures only 46% of 43 unexplained febrile reactions were treated with systemic antimicrobials. Significant acute graft versus host disease (AGVHD) occurred in 14 (27%) of 52 patients receiving standard prophylaxis and HLA-matched grafts; immunosuppressive treatment was needed in 8 cases (16%). Thus, the additional costs of total microbial decontamination appear partially regained by a decreased morbidity and a reduced need for antimicrobial and immunosuppressive treatment, although neither fever nor AGVHD could be prevented.

Adolescent↗
PubMedDate not supplied

[Study of the effectiveness of amine fluoride and stannous fluoride containing toothpaste and mouthwash].

AmF and SnF2 containing toothpastes (equally 750 ppm F-) and mouthrinses (equally 125 ppm F-) from the GABA International Agency were tested. After a five month treatment period (daily two times tooth cleaning), in the saliva of the examined persons the germ counts of the S. mutans and Lactobacillus showed a decreasing tendency, though the change was not statistically significant. The control group used NaF containing cleaners (toothpaste; 1500 ppm F-, mouthrinse; 250 ppm F-) for also a five month treatment period. Within this group the germ counts of the microorganisms of the examined saliva did not change markedly.

Amines↗
PubMed1989

An in vitro study of the antibacterial and antifungal properties of an irreversible hydrocolloid impression material impregnated with disinfectant.

The difficulties associated with the disinfection of alginate (irreversible hydrocolloid) materials have resulted in the development of an irreversible hydrocolloid impression material impregnated with an antimicrobial compound, didecyldimethyl ammonium chloride. This investigation assessed the antibacterial and antifungal properties in vitro of this innovative irreversible hydrocolloid material by using the agar well technique. The microorganisms used were Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sanguis, Lactobacillus odontolyticus rodriguez, Actinomyces odontolyticus, mixed salivary organisms, and Candida albicans. The results showed an absence of activity against Pseudomonas aeruginosa. Varying degrees of antibacterial activity were exhibited against the other microorganisms. It is concluded that it is not know whether the limited antibacterial and antifungal effect demonstrated in this study is sufficient to prevent bacterial and fungal colonization of the impression surface in the mouth during clinical practice.

Actinomyces↗
PubMed1996

Clinical and microbiologic evaluation of a resin modified glass ionomer cement for orthodontic bonding.

This study evaluated the clinical performance of a new resin modified glass ionomer cement, Geristore (Den-Mat Corp., Santa Maria, Calif.), for the bonding of orthodontic brackets and its effect on certain caries-associated microorganisms. This cement has been shown to possess increased mechanical properties and long-term fluoride release. There were 716 brackets bonded in 40 patients (17 males and 23 females), with a split-mouth technique and a composite resin, Phase II (Reliance, Itasca, III.), as a control. Bond failures were recorded up to 1 year. Plaque scores and plaque samples were taken from the area of the bonding adhesive in 20 patients, before, at 1 week, and 5 months after the placement of brackets. The plaque samples were investigated for the presence of Streptococcus mutans and lactobacilli. The overall bond failure rate was found to be 8.9% for Geristore and 3.1% for Phase II (p < 0.05). Labially, there was no significant difference (p > 0.05) in bond failure rate: 3.8% for Geristore and 1.7% for Phase II. The proportions of S. mutans and lactobacilli in plaque taken from around Geristore cement were reduced at 1 week and 5 months, when compared with Phase II resin, and this reduction was statistically significant (p < 0.05) at 1 week. Results of this study suggest that Geristore may be of use in the labial segments, especially in caries prone patients, in whom demineralization at debond may present an esthetic and restorative problem several years after treatment.

Adolescent↗
PubMed1990

Eikenella corrodens infection of the oral cavity as a cause of bacterial endocarditis.

The authors describe the case of a 24-year-old woman with valve disease. After a bout of respiratory tract infection, she was diagnosed to have bacterial endocarditis associated with mitral valve disease. The causative agents isolated included Eikenella corrodens, Streptococcus intermedius, Bacteroides oralis and Bacteroides bivius. At the same time, the patient was found to have developed IgA immunodeficiency. A complication accompanying the cardiac disease was spontaneous pneumothorax. Since antibiotic therapy had failed, the mitral valve was replaced by a prosthetic one. After the procedure, the patient had her teeth examined. The examination revealed complete destruction of tooth 36, thick layers of calculus and chronic gingivitis. E. corrodens was isolated also after microbiological examination of the patient's oral cavity. The reason for reporting on what we regard as an interesting case is that bacterial endocarditis with E. corrodens implicated as the causative agent is relatively rare; to date, polymicrobial endocarditis due to E. corrodens and other microorganisms has been described in intravenous drug addicts only.

Adult↗