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At least 667 records · Page 37Linked to original sources
PubMed1994

Detection of caries-inducing microorganisms in hyposalivated rats without infection of mutans streptococci.

Rampant dental caries was induced in hyposalivated rats fed a high sucrose diet without infection of mutans streptococci, in which increased numbers of lactobacilli and S. aureus were demonstrated in the oral flora. Administration of either penicillin or piperacillin, effective against all isolates of lactobacilli, markedly inhibited the caries induction in these rats, while severe dental caries was induced in hyposalivated rats given vancomycin that is inhibitory against S. aureus. These results suggested that certain lactobacilli might induce dental caries in hyposalivated rats fed a sucrose diet. Three strains of Lactobacillus species isolated from the hyposalivated rats were made resistant to erythromycin. The caries-inducing activity of these erythromycin-resistant lactobacilli was studied in hyposalivated rats giving erythromycin in the drinking water at a concentration of 500 micrograms/ml. After a 61-day experimental period, severe dental caries was induced in hyposalivated rats infected with L. fermentum TY1R. On the other hand, low caries incidence was found in hyposalivated rats infected with either L. acidophilus TY7R or L. plantarum TY3R. These results indicate that L. fermentum may be one of causative agents of dental caries in hyposalivated rats fed a sucrose diet.

Animals↗
PubMed2003

Ecological and immunopathological implications of oral bacteria in Helicobacter pylori-infected disease.

Increasing evidence has linked colonization by Helicobacter pylori with the development of gastritis and peptic ulcer disease. H. pylori resides primarily in the gastric mucosa without invading the gastric epithelium, causing persistent mild gastric inflammation. There are many reports examining the relationship between colonization by microorganisms in the stomach and oral cavity. We found that some oral bacteria are able to trap H. pylori cells, but oral bacteria inhibit H. pylori growth in vitro. In cases where H. pylori was detected in oral cavity samples, including oral cancer surface samples, we suggested that this species had colonized the stomach and were present in the oral cavity only as a transient organism. We demonstrated that periodontopathic Campylobacter rectus strains posses proteinaceous antigens, including heat shock proteins that share antigenicity with antigens of H. pylori strains. These cross-reactive antigens between H. pylori and C. rectus may be related to the induction of immunopathological responses in periodontal tissues and the stomach. We concluded that H. pylori could not survive in the human oral cavity; however, there would be an interrelationship between periodontal disease due to C rectus and stomach diseases due to H. pylori.

Antibiosis↗
PubMed2005

Effectiveness evaluation of different suction systems.

Microorganisms of the patient's oral cavity and his/her blood and saliva may cause different air-borne and blood-borne infectious diseases among odontologists and their assistants who work with patients. Quantitative analysis and spatial distribution analysis of the environmental spread of oral liquid and cooling liquid mixture were performed during this study. Effectiveness of suction systems of four types was evaluated: without suction, using a small-size suction pump alone, using a small-size and large-size suction pumps, using a small-size suction pump together with an experimental extra-oral aspirator. Quantitative changes of the water aerosol, which enters the environment during the preparation of teeth, were determined in respect of the used suction systems. The small-size pump system together with an experimental extra-oral suction system eliminated best the aerosol formed during the preparation.

Aerosols↗
PubMed2000

Detection of herpes simplex virus and varicella-zoster virus in clinical swabs: frequent inhibition of PCR as determined by internal controls.

BACKGROUND: PCR-based detection of microorganisms is widely used for diagnostic purposes. Most routine PCR applications do not control for inhibition of PCR, thus leading to false-negative results. METHODS AND RESULTS: One hundred eighteen swab samples obtained from skin and mucosa were investigated for the presence of herpes simplex virus (HSV), varicella-zoster virus (VZV), and the control gene betaglobin by internally controlled PCR with purified and unpurified DNA in parallel. With unpurified DNA, inhibition of PCR was detected in 23% of betaglobin PCRs, 25% of VZV PCRs, and 16% of HSV PCRs versus 3% each for purified DNA. Approximately 20% of the samples with positive results for HSV or VZV had negative or inhibited results using unpurified DNA. CONCLUSION: These results indicate that PCR from clinical swab specimens should be performed exclusively with internal controls because the positive control alone cannot exclude PCR inhibition in individual samples. Purification of DNA will decrease, but not exclude, PCR inhibition.

Conjunctiva↗
PubMed1976

Torulopsis glabrata infection in the oral cavity.

The first case report of an oral infection due to Torulopsis glabrata is presented. This microorganism is a yeast-like fungus grouped in a similar family to the Candida species. It has been isolated with increasing frequency from the oral cavity but, surprisingly, has not been reported as a pathogen in this site. In other anatomical sites, including the urinary tract, lung and gastrointestinal tract, Torulopsis glabrata has been reported as a pathogen, at times resulting in a fatal outcome. However, there has usually been some modifying factor, e.g. malignancy, cytotoxic drug therapy, diabetes or broad spectrum antibiotics, which caused this marginal pathogen to assume a pathogenic role. No such modifying factors could be elicited in this case. The history of the case including the management is presented. A brief outline of the microbiologic grouping of Torulopsis glabrata is given, as well as the diagnostic test used in its identification. The histopathology is described and the necessity for combining special tests in establishing a positive diagnosis is exemplified, as the histology alone is not pathognomonic of the infection.

Candida↗
PubMed1998

The relationship between the cell length, adhesion to acrylic and relative cell surface hydrophobicity of Candida parapsilosis.

Candida parapsilosis is an emerging opportunistic pathogen which causes systemic and superficial infections in immunocompromised hosts. Successful colonization and subsequent infection of the host by a microorganism depends upon its ability to adhere to host surfaces, and its relative cell surface hydrophobicity (CSH) is a contributory physical force involved in the process. During a comprehensive study of a battery of C. parapsilosis isolates, we noted wide variations in their cell size. Hence we examined the relationship between the cell length, in vitro adhesion to acrylic surfaces and relative CSH of 24 isolates of C. parapsilosis from superficial and systemic sources. A strong positive correlation was observed between the cell length and adhesion of Candida to acrylic surfaces (r=0.56; P=0.004) as well as the cell length and the relative CSH, as measured by a hydrocarbon assay method (r=0.72, P=0.0001). Further, the cell length of both the superficial and systemic isolates correlated well with their CSH (r=0.63, P=0.01; r=0.63, P=0.03 for superficial and systemic isolates, respectively). These data provide a tantalizing glimpse of the structural and functional dynamics of the candidal cell surface.

Acrylic Resins↗
PubMed1989

[Anticaries vaccination: present and future prospects].

Despite the encouraging decline in dental caries observed in recent years in many populations, millions of children still risk tooth decay. Along with established methods of prevention, caries vaccines have the potential of making a highly valuable contribution to disease control. Compelling evidence has shown that Streptococcus mutans is the principal etiologic agent of dental caries, therefore a vaccine directed to this microorganism could significantly reduce the caries incidence. In experimental models with rodents, both peroral and parenteral immunization have provided protection against S. mutans infection and dental caries. In primates only parenteral immunization has given positive results, and there have been conflicting results in studies on human peroral immunization. Presently there is no conclusive evidence which shows that antibodies to S. mutans can protect against dental caries in humans. Among the S. mutans antigens that could be used as a vaccine, only some protein antigens have given protection in primates. One of these has been produced in large amounts and is ready for testing in humans. Another antigen, the enzyme complex glucosyltransferase, has shown protection in rodents and the effect of peroral administration of this antigen is now being tested in humans. While awaiting results of clinical trials with available vaccines, much additional experimental work is needed to understand the complex phenomenon of caries. New information will permit the development of more efficacious vaccines against the caries.

Bacterial Vaccines↗
PubMed2002

Antimicrobial action of Nitens mouthwash (cetyltrimethylammonium naproxenate) on multiple isolates of pharyngeal microbes: a controlled study against chlorhexidine, benzydamine, hexetidine, amoxicillin, amoxicillin-clavulanate, clarithromycin, and cefaclor.

BACKGROUND: Acute oropharyngeal and respiratory tract infections are due to a wide spectrum of microorganisms. The aim of this study was to compare and evaluate the in vitro activity of four antiseptics (cetyltrimethylammonium naproxenate, chlorhexidine, benzydamine, hexetidine) to four antibiotics (amoxicillin, amoxicillin-clavulanate, clarithromycin, cefaclor) on strains of Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pyogenes and Streptococcus pneumoniae. METHODS: Susceptibility tests were performed on 90, aerobic and anaerobic, bacterial strains, isolated from nasopharyngeal swabs and sputum. Minimum inhibitory concentrations (by microdilution) and minimum bactericidal concentrations were determined and compared. RESULTS: Our selected panel of bacteria was highly susceptible to the antiseptics, particularly to chlorhexidine and naproxenate, even more so than two of the most frequently used antibiotics. Data were statistically significant (p < 0.005). CONCLUSIONS: In view of their bactericidal and anti-inflammatory properties, these antiseptics may be effective in controlling the transitory colonization of the oral cavity by microbes that cause or worsen disease in patients with mild infections.

Anti-Bacterial Agents↗
PubMed2005

Candida albicans-infected oral epithelial cells augment the anti-fungal activity of human neutrophils in vitro.

Oropharyngeal candidiasis (OPC) is the most common opportunistic infection in immunosuppressed patients. In OPC, Candida albicans persists intraepithelially triggering inflammatory events, without generally causing invasive infection. Since neutrophils play an important role in preventing invasive infection and since they establish contact with the microorganisms only within the epithelial cell layer, we examined the ability of Candida-infected oral epithelial cells to augment neutrophil-mediated hyphal damage in vitro. We found that challenge of neutrophils with hyphal organisms in the presence of C. albicans-infected oral epithelial cell supernatants resulted in a significantly greater suppression of hyphal cell metabolic activity compared to basal neutrophil anti-fungal function. Anti-hyphal activity in response to these supernatants was partly inhibited by neutralizing anti-IL-1alpha antibody and IL-1 receptor antagonist. Control supernatants from uninfected oral epithelial cells, as well as C. albicans conditioned-medium had a much less pronounced effect on neutrophil anti-fungal activity, which was not inhibited by these cytokine antagonists. We conclude that oral epithelial cells can act as activators of neutrophil anti-hyphal function, an effect that can be partly attributed to the generation of immunomodulatory cytokines during the interaction of oral mucosal cells with the pathogen.

Candida albicans↗
PubMed1992

Changes with time in the oral microflora and dental caries induction in hyposalivated rats fed on sucrose diet.

The effects of hyposalivation on the induction of dental caries and the change in oral microflora were examined at weekly intervals in Sprague-Dawley rats fed on diet 2000 containing 56% sucrose. In hyposalivated rats, significant dental caries was induced within one week and its severity increased with the experimental period. Bacteriological examinations demonstrated that the number of total cultivable microorganisms, lactobacilli and Staphylococcus aureus increased significantly shortly after surgical induction of hyposalivation, while the number of streptococci and yeasts did not increase significantly until the 7th week, beyond which time remarkable gross caries developed. A positive correlation was found between the caries score and the recovery of lactobacilli from mandibles of hyposalivated rats, while there was no statistically significant correlation between the caries score and the recoveries of S. aureus. On the other hand, dental caries was not induced in control rats fed on sucrose diet with no surgically-induced hyposalivation. It was also found that the number of lactobacilli increased significantly shortly after diet 2000 was given to control rats, but S. aureus was rarely recovered from the mandibles of control rats throughout the experiments. The roles of lactobacilli and S. aureus in the induction of dental caries under the hyposalivated condition were discussed and it was suggested that lactobacilli may play some significant role in the induction of dental caries in hyposalivated rats.

Animals↗
PubMed2006

Antimicrobial effect of acidified nitrate and nitrite on six common oral pathogens in vitro.

BACKGROUND: Salivary nitrate is positively correlated with plasma nitrate and its level is 9 times the plasma level after nitrate loading. Nitrate in saliva is known to be reduced to nitrite by oral bacteria. Nitrate and nitrite levels in saliva are 3 - 5 times those in serum in physiological conditions respectively in our previous study. The biological functions of high salivary nitrate and nitrite are still not well understood. The aim of this in vitro study was to investigate the antimicrobial effects of nitrate and nitrite on main oral pathogens under acidic conditions. METHODS: Six common oral pathogens including Streptococcus mutans NCTC 10449, Lactobacillus acidophilus ATCC 4646, Porphyromonas gingivalis ATCC 33277, Capnocytophaga gingivalis ATCC 33624, Fusobacterium nucleatum ATCC 10953, and Candida albicans ATCC 10231 were cultured in liquid medium. Sodium nitrate or sodium nitrite was added to the medium to final concentrations of 0, 0.5, 1, 2, and 10 mmol/L. All of the microorganisms were incubated for 24 to 48 hours. The optical densities (OD) of cell suspensions were determined and the cultures were transferred to solid nutrient broth medium to observe the minimum inhibitory concentration and minimum bactericidal/fungicidal concentration for the six tested pathogens. RESULTS: Nitrite at concentrations of 0.5 to 10 mmol/L had an inhibitory effect on all tested organisms at low pH values. The antimicrobial effect of nitrite increased with the acidity of the medium. Streptococcus mutans NCTC 10449 was highly sensitive to nitrite at low pH values. Lactobacillus acidophilus ATCC 4646 and Candida albicans ATCC 10231 were relatively resistant to acidified nitrite. Nitrate at the given concentrations and under acidic conditions had no inhibitory effect on the growth of any of the tested pathogens. CONCLUSION: Nitrite, at a concentration equal to that in human saliva, is both cytocidal and cytostatic to six principal oral pathogens in vitro, whereas nitrate at a similar concentration has no antimicrobial effect on these organisms.

Anti-Infective Agents↗
PubMed1999

[Gastrointestinal microecology of humans and Candida].

Microecology looks for the relationships between microorganisms and their natural environment in definite sites and their physiological and pathological effects. From birth Candida spp. are often but not always detectable in the human gastrointestinal tract. In cases of reduced defense the tract may be a source of infection to the macroorganism. In healthy subjects the incidence of Candida is between 23% and 76% in quantities between 10(2)-10(4) CFU/ml or g dependent on site. Evidence is most frequent in oral cavity and faeces. Tolerance for Candida spp. is different in the stomach and duodenum due to differences in acidity. Changes in the occurrence of Candida spp. are possible depending on age, different diseases and exogenous influences as nutrition, stress and drugs. In an endocrine stress model we found no yeasts in the duodenal juices of 7 subjects before and after stress situation, but a clear decrease of yeasts in the faeces. The formation of metabolic products by Candida is secondary to the whole of microbial fermentation in the human orointestinal tract. Colonizing strains of C. albicans are normally present in small or moderate numbers and only they are regarded as part of the resident gastrointestinal microflora.

Candida↗
PubMed1995

The epithelium of canine palatine tonsils.

The palatine tonsil is positioned to play a key role in protecting the body against ingested microorganisms. These microorganisms must traverse the tonsillar epithelium to initiate immune reactions, but no information is available from dogs on the structure of this epithelium. In this study, the morphology and ultrastructure of the epithelium of the palatine tonsil of dogs was examined using light and electron microscopy. The epithelium is of two types: reticular and non-reticular. Reticular epithelium, which is invaded by lymphoid cells, is located over the apices of nodules, separated indistinctly by islands of non-reticular squamous epithelium. The reticular epithelium contains M cells which are more abundant towards the periphery of lymphoid nodules. The apical membrane of the M cells forms folds from which microvilli extend into the lumen of the oropharynx. Abluminally, cytoplasmic processes enfold clusters of lymphocytes. Numerous desmosomes secure the marginal plasma membrane and lateral membranous interdigitations to adjacent epithelial cells, thereby maintaining the integrity of the tonsillar epithelium. Epithelial discontinuities, which are few, occupy similar positions to M cells and appear to contain migrating lymphocytes. A fenestrated basement membrane allows cell transport between the intraepithelial passageways of the reticular epithelium and the subepithelial lymphoid tissues.

Animals↗
PubMedDate not supplied

Bacteriocin production by Actinobacillus actinomycetemcomitans isolated from the oral cavity of humans with periodontal disease, periodontally healthy subjects and marmosets.

The ability of Actinobacillus actinomycetemcomitans to produce bacteriocin has rarely been reported. Antagonistic substance production may confer an important ecological advantage for the producer microorganisms, especially in a competitive ecosystem such as the oral cavity. In the present study, 75 A. actinomycetemcomitans strains isolated from the oral cavity of human patients with periodontal disease, periodontally healthy subjects and marmosets, as well as two reference strains (A. actinomycetemcomitans ATCC 29523 and FDC Y4) were evaluated for auto-, iso-, and heteroantagonistic activity. Fifty-one (68.00%) strains exhibited antagonistic activity; heteroantagonism was observed more often than isoantagonism. Isolated strains antagonized 17 different species of gram-positive and gram-negative bacteria from the oral and nonoral microbiota. Sensitivity to heat and to proteolytic enzymes constituted strong evidence that the antagonistic substance has a proteic nature. Taken together, our data enabled us to confirm that the antagonistic substance detected was a bacteriocin. The wide spectrum of activity indicates the possibility that more than one antagonistic substance is produced and that these substances play an important role in the ecological balance of the oral ecosystem.

Actinobacillus Infections↗
PubMed1984

The effect of selective decontamination of the digestive tract on colonisation and infection rate in multiple trauma patients.

122 multiple trauma patients staying in the ICU for 5 or more days and needing mechanical ventilation were investigated to determine the effect of selective decontamination of the digestive tract on prevention of infection. The (retrospectively studied) control group of 59 patients received no antibiotic prophylaxis. The infection rate during ICU-stay was 81%. Most infections were caused by potentially pathogenic microorganisms (PPM) from the oral cavity or the intestines (i.e. endogenous infections). The oropharynx and the intestines were rapidly colonised with ICU-associated gram-negative bacilli. After 2 weeks more than 80% of patients were found colonised. This secondary colonisation of the digestive tract is a very important stage in the pathogenesis of infections. Sixty-three patients were selectively decontaminated with nonabsorbable antibiotics, administered through the gastric tube even if peristalsis was absent. Emphasis was laid on the selective decontamination of the oral cavity, using topical application of an antibiotic paste. With this technique the oral cavity was free of PPM within 3 days in most patients. No secondary colonisation was found. Rectal colonisation decreased significantly after 5 days. Secondary colonisation occurred in 9 patients with PPM sensitive to the antibiotics used. The prophylactic regimen included systemic cefotaxim, directed against early endogenous infection. The suppression and after some time the absence of the endogenous source of PPM resulted in a significant reduction of colonisation and infection. The total infection rate decreased to 16%.

Administration, Topical↗
PubMed2005

Neutrophil and lymphocyte responses to oral Streptococcus in Adamantiades-Behçet's disease.

Immune reactions against microorganisms play an important pathogenic role in Adamantiades-Behçet's disease. We had previously obtained Streptococcus sanguinis (strain BD113-20), isolated from the oral cavity of patients with Adamantiades-Behçet's syndrome. To investigate the pathogenesis of this isolate, we examined neutrophil reactions and levels of cytokine production by lymphocytes after stimulation with the strain. The reactions of neutrophils were examined by chemiluminescence assay using whole blood. The amounts of interferon gamma (IFN-gamma) and interleukin (IL)-4, IL-8, IL-10 and IL-12, produced by peripheral blood mononuclear cells, were measured by ELISA. Strain BD113-20 activated neutrophils from Adamantiades-Behçet's patients and healthy volunteers, and, in addition it increased the IFN-gamma production by lymphocytes. Lymphocytes from Adamantiades-Behçet's patients showed a dominant T helper-1 immune response. Results indicated that both bacterial stimulation and host hypersensitivity might be involved in the symptoms and pathogenesis of Adamantiades-Behçet's disease.

Adult↗
PubMed1994

Criteria for the assessment of adverse effects of chemotherapy on the oral microflora.

Any assessment of an antimicrobial agent for the prevention of dental caries must include a consideration of its possible adverse effects on the oral flora. It must include an examination of the resistance developed by the target pathogens and either developed by, or inherently present in, microorganisms that are known to cause opportunistic infections (yeasts, enteric organisms, Pseudomonas, clostridia, and Staphylococcus aureus). Streptococcus pyogenes should also be included. Insofar as possible, these assessments should be done in preliminary experiments, both in vitro and clinical, rather than in caries trials, so that the large numbers of subjects will not be submitted to unnecessary exposure to the formulation. It must be recognized that some combinations of agent, vehicle, and frequency are more prone than others to cause adverse effects on the oral flora, and will also influence the length of the test period that should be utilized. The microbial assessments should be done on subjects prior to use of the agent, at appropriate frequencies during therapy, and approximately 2 months after the cessation of therapy. Currently, requirements to assess the state of gingival or periodontal health by microbiological examination seem unjustified, because of the relative lack of strong evidence for their diagnostic or predictive value (Ranney, 1989) and because of the ease with which direct measurements of clinical signs and symptoms can be made. Consequently, only the latter should be required.

Age Factors↗
PubMed1976

Dextran degrading bacteria in human oral cavity and their activity against insoluble glucan from Streptococcus mutants.

The distribution of dextran-degrading microorganisms in the saliva and plaque samples from the human oral cavity was assayed on 9 subjects. Approximately 2/3 of the saliva samples degraded Dextran T-150 (Pharmacia, M.W. 150,000) and 1/10 the Blue Dextran (Pharmacia), while 2/5 and 1/8 of the plaque samples degraded Dextran T-150 and Blue Dextran, respectively. Thirty-seven strains of the Blue Dextran degrading bacteria were isolated from the saliva and plaque samples and were classified into 6 groups by their morphology, gram staining and oxygen tolerance. The 24 strains from the 37 isolates, more or less, were shown to degrade the insoluble glucan extracted from Streptococcus mutans FA-1 on the agar plate. The 8 strains, selected from each group, were tested for their activity against the insoluble glucan extracted from Str. mutans (FA-1, HS-6, BHT, CHT, GS-5, LM-7 and PK-1) and Str. salivarius (HHT). The strains belonging to Groups I, II, IV and V showed activity against the insoluble glucan used. Among them, the strains of Group IV (gram negative facultative cocci) and Group V (gram negative strict anaerobic rod) were the most active against the insoluble glucan.

Adult↗