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At least 199 records · Page 11Linked to original sources
PubMed1995

Development of a flow method for susceptibility testing of oral biofilms in vitro.

Bacteria in biofilms are known to be more resistant than bacteria in batch cultures to antimicrobial agents. The purpose of the present study was to develop a flow method for formation of oral biofilms permitting susceptibility testing of plaque bacteria. A brain heart infusion (BHI) Streptococcus sanguis 804 culture was pumped through a modified Robbins Device (MRD) with 25 exchangeable silicone disks at 40 ml/h. After 24-48 h disks were removed and biofilm cells dispersed by vortex mixing and low-output ultrasonication. Colony forming units (cfu)/cm2 were determined after aerobic incubation on blood agar plates. Optimal biofilm formation was found after growth for 48 h at 37 degrees C in BHI + 1% sucrose, using saliva-coated silicone disks in inverted MRDs, yielding on average 4.4 x 10(5) cfu/cm2. Similar results were obtained for S. sanguis ATCC 10556 and five clinical isolates. Testing the susceptibility of S. sanguis to chlorhexidine gluconate showed increased resistance of biofilms compared to batch culture. Thus an appropriate biofilm model for susceptibility testing of oral microorganisms has been established.

Biofilms↗
PubMed1998

Effects of mouth cleansing on the levels of exhaled nitrous oxide in young and older adults.

Nitrous oxide (N2O) is produced by denitrification, i.e. by microbial reduction of nitrate (NO3-). Our previous studies have established an analytical method for demonstrating the existence of N2O in exhaled air, and we showed that levels of N2O in exhaled air increase with age after puberty. However, the source of this change and its biological significance are still unclear. The purpose of this study was to examine whether the oral microorganisms are the main source of N2O. We measured exhaled N2O in 35 young adults (aged 19-29 years) and 34 older adults (aged 61-79 years) before and after mouth cleansing. N2O was measured using an infrared-photoacoustic analyzer equipped with an optical filter (UA0985, 2215 cm-1). Participants were classified as producers and non-producers according to the levels of exhaled N2O relative to the level in the atmosphere. N2O production differed significantly between the young adult producers and the older adult producers. Mouth cleansing resulted in an immediate reduction in exhaled N2O in both groups. We only found seven (20.0%) producers in the young, and 32 (94.1%) producers in the older after mouth washing. The differences before and after mouth cleansing were significant in both groups (P < 0.01 in the young and P < 0.05 in the older). The oral cavity is a major source of N2O. However, since approximately half-levels of N2O were still observed in exhaled air after mouth, cleansing, there may exist another N2O source in the human body.

Adolescent↗
PubMed1990

[Rare cases of prostatitis caused by invasion of Trichomonas vaginalis with Candida albicans].

Three cases of prostatitis caused by the invasion of T. vaginalis and C. albicans which has been found in different biological materials were described. After per rectum examination perineum biopsy of prostata was performed in all patients; in histopathological preparations pointing at the inflammation reaction of that gland the fungi were detected. Also, the same microorganisms were proved in sexual partners of those patients but multifocal invasion of C. albicans--including genital and urinary organs, mouth and alimentary tract--also in members of their family.

Adult↗
PubMed1976

[Swimming plastic toy-animals as biotopes of microorganisms and possible source of infant infections (author's transl)].

Infants are particularly jeopardized as regards oral infection, because they like to put all kinds of things in their mouth. In swimming plastic toy-animals, which are mainly used in bathtubs and from which children might suck water into their mouths, more than 4 million germs/ml (when rinsed with 5 ml tryptone/NaCl solution) were found. In addition thereto, the liquid contained various types of enterobacteriaceae such as Serratia marcescens (up to 150000/ml) as well as P. aeruginosa (up to 80000/ml). 19 of the toys from seven different households were "commodities" as defined by the German Food Law. If these items are used according to purpose, however, the concentration and dissemination of pathogens or facultative pathogens is unavoidable.

Bacterial Infections↗
PubMed1989

[Clinical study of the correlation between bad breath and subgingival microflora].

A dark field microscopic examination of subgingival microorganisms and gas chromatographic analysis of volatile sulphur compounds were employed to investigate the role of subgingival microflora in the production of bad breath. Subjects (11 female, 13 male; aged 24 to 61) were divided into the following 2 groups on the basis of apparent bad breath by the olfactory judgement; bad breath group (group B, n = 13), and no bad breath group (group N, n = 11). A gas tight syringe was employed to withdraw 5 ml mouth air samples, which were injected directly into the gas chromatograph. Volatile sulphur compounds produced in mouth air were analyzed by gas chromatograph to determine volumes of CH3SH. Subgingival plaque samples were taken with sterilized paper points from the deepest site of probing depth in each subjects. The samples were examined by means of dark field microscopy and 100 bacteria in randomly selected fields were classified on a percentage basis into one of the following morphological categories: (1) spirochetes, (2) motile rods, (3) filaments, (4) fusiforms, (5) straight rods, and (6) coccoid cells. Total cell counts per 1 ml were calculated from bacterial counts of each categories. Comparison of 2 independent means from each groups were carried out by Wilcoxon's rank sum test for nonparametric values. Correlations of bacterial data with CH3SH values in mouth air were determined by means of Spearman rank correlation cofficient. Results were as follows; 1. Significant differences existed in the microbial flora between the 2 groups: percentage of spirochetes and motile rods in group B were significantly higher than those in group N (p less than 0.01). Total cell counts of group B were significantly greater than group N, and there were statistically significant differences (p less than 0.01). 2. CH3SH values in mouth air had positive correlations with the percentage of spirochetes, the percentage of motile rods, and total cell counts. These results are consistent with the view that subgingival microorganisms play a certain role in the production of bad breath. Moreover, it was suggested that spirochetes and motile rods are related to the mechanism of bad breath production.

Adult↗
PubMed1982

Adsorption of lysozyme from human whole saliva by Streptococcus sanguis 903 and other oral microorganisms.

Several strains of Streptococcus sanguis, Streptococcus mutans, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii plus fresh isolates of Streptococcus salivarius were surveyed for their abilities to deplete lysozyme from human-whole-saliva supernatant. Bacteria were incubated in saliva for 60 min at 37 degrees C and then removed by centrifugation, and the recovered supernatant solutions were assayed for lysozyme activity by using whole cells of Micrococcus lysodeikticus as the substrate. Mean lysozyme depletions by bacterial strains varied over a wide (eightfold) range. The greatest mean depletion of lysozyme (60 to 70%) was observed with S. sanguis (biotype I), serotype b of S. mutans, and the fresh S. salivarius isolates. The lowest mean depletion was noted with S. mitis (15%) and biotype II S. sanguis (ca. 30%). The remaining species and strains exhibited an intermediate degree of depletion. In studies with S. sanguis 903, lysozyme was depleted by normal or heated (90 degrees C, 30 min) bacteria and could be recovered from the organism. Furthermore, under appropriate conditions, lysozyme depletion by cells at 0 and 37 degrees C was very similar. On the basis of these observations, we concluded that depletion was due to the adsorption of lysozyme by the organism. With S. sanguis 903, lysozyme adsorption depended on the concentration of bacteria, time of incubation, and the ionic strength of the medium. The extent of adsorption, however, was independent of pH's of 3.9 to 8.3. When a low concentration of S. sanguis 903 was used, lysozyme adsorption reached saturation (4 mug of adsorbed lysozyme per 10(7) cells) at 20 mug of lysozyme added per ml. Salivary lysozyme adsorption by several other oral microorganisms (A. viscosus WVU 626 and WVU 627, S. sanguis 73x11, S. mutans BHT, and S. salivarius NG) was similar to that of S. sanguis 903 in sensitivity to ionic strength. Lysozyme adsorption by S. sanguis 903 from either a buffer solution or a saliva supernatant was more sensitive to ionic strength at 0 than at 37 degrees C. On the basis of results from experiments in saliva versus buffer, we concluded that saliva had no major effect on the extent of lysozyme adsorption by S. sanguis 903 other than providing a source of ionic strength. A comparison of pH and ionic strength effects on lysozyme adsorption by S. sanguis 903 with literature reports of lysozyme lysis of whole cells and hydrolysis of cell walls, peptidoglycan, and (GlcNAc)(4) suggested that adsorption by S. sanguis 903 was more dependent on electrostatic interactions than was lysozyme catalysis. The possibility is discussed that anionic bacterial surface components mediate lysozyme adsorption and temper the potential effects of lysozyme on the microorganisms.

Actinomyces↗