The ability of several species of streptococcus and staphylococcus to adhere to human buccal epithelial cells was studied in vitro by using bacteria and epithelial cells isolated from human buccal cavity. Viridans streptococci were found adhering in highest numbers(65 +/- 8 bacteria per epithelial cell) to epithelial cells. Streptococcus pyogenes adhered in great numbers (44 +/- 4), whereas Streptococcus pneumoniae (26 +/- 2), Staphylococcus aureus (21 +/- 2), Staphylococcus epidermidis (14 +/- 2) adhered poorly. These data showed that bacteria differed in their ability to adhere to human buccal epithelial cells. This difference in adhesive ability between bacterial species may correlate with the ability of the bacteria to colonize oral surface of human.
Bacterial Physiology* ; Cheek ; Epithelial Cells ; Human ; In Vitro ; Mouth/microbiology* ; Staphylococcus/physiology ; Streptococcus/physiology

Pneumococcal resistance has become a global issue during the past three decades. One of the major foci of pneumococcal resistance worldwide is the Asian region including Korea, Japan, and Hong Kong. Korea had not been recognized as a focus of pneumococcal resistance until 1995, when serial reports documented the alarmingly high prevalence of penicillin resistance among clinical isolates. Serial reports on penicillin resistance among pneumococcal isolates in Korea ranged from 68% to 77% as of 1995. Multidrug resistance was also noted in 34% of Korean isolates. Penicillin-binding protein profile analysis, pulsed-field gel electrophoresis, ribotyping, and fingerprinting analysis of pbp genes showed that antibiotic-resistant pneumococci isolated in Korea were genetically related. Data documented the extensive spread of a resistant clone within Korea and between different countries. Besides the injudicious use of antimicrobial agents or the high prevalence of serotypes 23 and 19, the spread of a resistant clone may play an important role in the rapid increase of penicillin resistance in Korea.
Asia ; Drug Resistance, Microbial/physiology* ; Drug Resistance, Multiple/physiology ; Epidemiologic Methods ; Human ; Korea ; Streptococcus pneumoniae/physiology*

Similar to multicellular animals, single-cell organisms, such as bacteria show the phenomenon of programmed cell death (PCD). The PCD not only can play an important role in various physiological procedures, but also can eliminate bacteria with irreversible injuries. The PCD of single cell in a colony is for the benefits of other bacteria in the same colony to achieve the development and reproduction of the whole colony. Disturbing or destroying such PCD may provide a new way for antibiotic drug research and development.
Autophagy ; physiology ; Bacteria ; cytology ; Staphylococcus aureus ; cytology ; physiology ; Streptococcus pneumoniae ; cytology ; physiology

OBJECTIVETo investigate the inhibition of Streptococcus oligofermentans (So) on Streptococcus mutans (Sm) and the producibility of hydrogen peroxide by So under the influence of glucose concentration environment.

METHODSThe inhibition between So and Sm was observed by plating method under the different glucose concentration environment. The initial synthesis rates and production of hydrogen peroxide by So were determined under the different glucose concentration environment by 4-aminoantipyine-horseradish peroxidase method at A(510).

RESULTSUnder 0, 10 and 50 mmol/L glucose environment, the inhibition of So on Sm was evident. When both Sm and So were inoculated at the same time, the ratio of inhibition area by bacterial membrane area was 0.202 ± 0.005, 0.467 ± 0.025, 0.468 ± 0.028 under 0, 10, 50 mmol/L glucose environment. When So was cultivated first and then Sm applied, the ratio was 0.394 ± 0.004, 0.811 ± 0.075 and 0.816 ± 0.007 under 0, 10 and 50 mmol/L glucose environment respectively. The inhibition under 10 and 50 mmol/L glucose environment were more significant than that under non-glucose environment. There was no significant difference between these two glucose concentrations (P > 0.05). The initial synthesis rates of H2O2 by So under the 10 mmol/L [(23.573 ± 0.263) µmo×L(-1)×min(-1)] and 50 mmol/L [(23.337 ± 0.473) µmol×L(-1)×min(-1)] glucose were higher than without glucose[(10.513 ± 0.516) µmol×L(-1)×min(-1)], P < 0.05. H2O2 was not detected in 1000 mmol/L glucose. However, the production of H2O2 by So under 0 mmol/L glucose was higher than other glucose concentrations (P < 0.05).

CONCLUSIONSThe capability of the inhibition of So on Sm was affected by glucose environment and was much stronger under certain glucose concentrations (10, 50 mmol/L).

Antibiosis ; Dose-Response Relationship, Drug ; Glucose ; metabolism ; Hydrogen Peroxide ; metabolism ; Streptococcus ; growth & development ; metabolism ; physiology ; Streptococcus mutans ; growth & development ; metabolism

OBJECTIVETo determine the physicochemical properties of the mutanase of Trichoderma harzianum isolated from China and to study the influence of mutanase on the adherence of oral Streptococci and the structure of oral biofilms.

METHODSSix fungal strains belonging to Trichoderma were tested for mutanase production in the same cultural condition, the strain producing the highest mutanase activity was studied further and the pH and temperature optimum of the enzyme was determined. The RT-PCR method was used to obtain the gene coding for mutanase and the product was cloned to pMD18-T simple vector for sequencing. Inhibition effects of mutanase on the adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 were studied by adherence test. The optical sectioning of biofilms with or without mutanase supplementation were analyzed by confocal laser scanning microscopy (CLSM).

RESULTSThe highest enzymatic activity was achieved by Trichoderma harzianum Th1, the maximum activity was at pH 5.5 and at 40 degrees C. The nucleotide sequence was 92% homology with that of a known gene coding a mutanase (GenBank accession No. AJ243799). The adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 was significantly inhibited by mutanase. Compared with control, the biofilms with mutanase supplementation had lower height and sparser structure.

CONCLUSIONSThe mutanase from Trichoderma harzianum Th1 can inhibit the adherence of oral Streptococci and had an influence on the structure of oral biofilms.

Bacterial Adhesion ; drug effects ; Biofilms ; Glycoside Hydrolases ; chemistry ; physiology ; Streptococcus mutans ; drug effects ; Streptococcus sobrinus ; drug effects ; Trichoderma ; enzymology ; pathogenicity

OBJECTIVEThis study compared the roughness of porcelain polished or glazed surfaces and the adhesion of oral streptococcus mutans to them in vitro.

METHODS30 porcelain samples were made. Porcelain samples in group A were polished with diamond paste. Porcelain samples were glazed in group B and were polished with Al2O3 (240#) bur in group C. Their roughness values were measured by profilometer. Standardized cell suspensions were incubated with test samples for one hour at 37 degrees C, then retained cells were counted by image analysis (percentage area of a microscopic field covered by cells).

RESULTSRoughness values of group A, B, C were respectively (0.1987 +/- 0.057) microm, (0.1990 +/- 0.091) microm, (0.4260 +/- 0.174) microm. There was no significantly difference between group A and group B. The roughness samples in group C were significantly rougher than that in the other groups. The amount of retained cells in group A, group B, group C was respectively (15.92 +/- 4.37)%, (16.39 +/- 6.31)% and (41.48 +/- 12.1)%. There was no significant difference between the cell adhesion on porcelain surface glazed and polished, but more bacteria adhered on the porcelain surface in group C.

CONCLUSIONSPorcelain surface polished treatment was clinically acceptable compared with its glazed. They all exhibited the least amount of bacteria adhesion. The more porcelain surface was rough, the more bacteria adhered on it.

Bacterial Adhesion ; Dental Polishing ; Dental Porcelain ; Humans ; Streptococcus mutans ; physiology ; Tooth ; microbiology

OBJECTIVETo investigate the effects of compounds of Galla chinensis extract (GCE) and Nidus vespae extract-1 (WVE1) on oral bacteria biofilm structure and activity and to determine the possibility of caries prevention by the compounds.

METHODSThe morphology and activity of treated-oral bacterial biofilm and untreated-oral bacterial biofilm were observed by using fluorescence microscope in combination of idio-fluorochrome to label the died and living bacteria. The visible light semiquantitative method was used to measure biomass glucosyltransferase (GTF, A620) values and to determine the effects of active compounds of GCE and NVE1 on GTF of oral bacteria biofilm.

RESULTSThe living bacteria in the untreated 24 h bacterial biofilm was dominant, and only a small number of died bacteria were found, the biofilm structure was regular and clear. GCE, GCE-B and NVE1 could inhibit the bacteria in the dental biofilm, which showed significant difference with the negative control. GCE and NVE1 could also inhibit GTF activity of 24 h bacterial biofilm in comparison with the negative control.

CONCLUSIONSThe traditional Chinese medicine Galla chinensis and Nidus vespae could not only inhibit bacteria growth on oral bacterial biofilm, but also function by adjusting biofilm structure, composition and GTF activity of 24 h bacterial biofilm.

Actinomyces viscosus ; drug effects ; enzymology ; physiology ; Bacteriological Techniques ; Biofilms ; drug effects ; Dental Caries ; microbiology ; Drugs, Chinese Herbal ; pharmacology ; Glucosyltransferases ; metabolism ; Medicine, Chinese Traditional ; Microbial Sensitivity Tests ; Streptococcus mutans ; drug effects ; enzymology ; physiology ; Streptococcus sanguis ; drug effects ; enzymology ; physiology

OBJECTIVETo evaluate the in vitro cario-static effect of Galla chinesis with biofilm model.

METHODSA four-organism bacterial consortium was cultured in a biofilm model on hydroxyapatite (HA) discs in a continuous culture system and exposed to repeated solution pulsing. There were three groups with different solution pulsed in the model: negative control group was pulsed with distilled water, positive control group was pulsed with 100 mmol/L sucrose solution and experimental group was pulsed with 100 mmol/L sucrose solution containing 4.0 g/L Galla chinensis. During the experiment, the dynamic changes of pH were recorded. After 6 pulses, surface structure of the biofilm was observed with a scanning electron microscope and the population on the biofilm was enumerated.

RESULTSGalla chinesis significantly inhibited the adherence of Actinomyces naelundii to HA disc compared with the control group and facilitated the removal of acid products. It was also found that the extra-cellular polysaccharide was reduced with the pulsing of Galla chinesis.

CONCLUSIONGalla chinesis in the biofilm model can partially reduce the cario-genic response of sucrose solution.

Actinomyces ; drug effects ; physiology ; Bacterial Adhesion ; drug effects ; Biofilms ; growth & development ; Cariostatic Agents ; pharmacology ; Dental Caries ; microbiology ; Drugs, Chinese Herbal ; pharmacology ; Durapatite ; Humans ; Models, Biological ; Streptococcus mutans ; drug effects ; physiology ; Streptococcus sanguis ; drug effects ; physiology ; Sucrose ; pharmacology

In order to confirm whether the migrating larvae of parasites could carry pathogenic organisms into liver and cause hepatitis, a series of experiments has been carried out. The summary of the results is as follows: 1. Clonorchis sinensis A few of the excysted larvae of Clonorchis sinensis penetrated into the peritoneal cavity, but they could not penetrate the liver tissues. The artificially introduced Clonorchis sinensis in the tissues were all destroyed within 3-5 days. There was no manifestation of diffuse inflammatory changes due to the inoculation of the parasites, though the sampled micro-organisms, Staphylococcus aureus, were confirmed from the surrounding area. 2. Hookworm The larvae carried pathogenic organisms to liver tissues either by cutaneous or oral infection, but there was no manifestation of hepatitis due to the micro-organisms: In conclusion, it is indicated that liverfluke and hookworm may transmit pathogenic organisms to the liver during their migration.
Ancylostoma/*physiology ; Animals ; Larva/physiology ; Liver Diseases, Parasitic/*etiology ; Male ; Mice ; Opisthorchis/*physiology ; Rabbits ; Staphylococcus/*growth & development ; Streptococcus pneumoniae/growth & development

Cholesterol-lowering effect of lactic acid bacteria (LAB: Streptococcus, Lactobacillus and Bifidobacterium) is well-known. Thus, we investigated LAB isolated from human intestine on the cholesterol-lowering effect in vitro. Seven Streptococcus (61.1%), 11 Lactobacillus (71.8%) and 7 Bifidobacterium (27.9%) were isolated as acid (pH 2.5 and 3.0) and bile (0.3% oxgall) tolerant strains. Streptococcus HJS-1, Lactobacillus HJL-37 and Bifidobacterium HJB-4 were finally selected as probiotic strains to use through the bile salt hydrolase (BSH) activity assay by using MRS media added taurodeoxycholic acid (TDCA) and the cholesterol-lowering test by using soluble cholesterol containing MRS broth. These studies suggested that the isolated LAB had an excellent hypocholesterolemic effect.
Amidohydrolases/metabolism ; Bifidobacterium/*isolation&purification/physiology ; Cholesterol/*metabolism ; Feces/microbiology ; Female ; Humans ; Intestines/*microbiology ; Lactobacillus/*isolation&purification/physiology ; Male ; Probiotics/*therapeutic use ; Streptococcus/*isolation&purification/physiology ; Taurodeoxycholic Acid