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At least 1,081 records · Page 60Linked to original sources
PubMed2001

Lactoferrin, amylase and mucin MUC5B and their relation to the oral microflora in hyposalivation of different origins.

There are several reasons for hyposalivation, each affecting the salivary composition in different ways. The aim of this study was to analyze and compare lactoferrin, amylase and mucin MUC5B in stimulated whole saliva collected from subjects with hyposalivation of different origins and to relate the results to the presence of some microbial species associated with oral disorders. Albumin was determined as a marker of serum leakage. The characteristic feature for subjects with radiation-induced hyposalivation was a large increase in lactoferrin, probably due to leakage through inflamed mucosal tissues, while it was a high albumin content for the group with primary Sjögren's syndrome, probably due to disruption of the fragile mucosa. The saliva composition in subjects with hyposalivation of unknown origin or due to medicines was close to that in the healthy controls. All three hyposalivation groups tended to display a decrease in the concentrations of MUC5B and amylase. None of the microbial species analyzed (streptococci, mutans streptococci, Lactobacillus spp., Fusobacterium nucleatum, Prevotella intermedia/Prevotella nigrescens, Candida albicans, Staphylococcus aureus and enterics) correlated with concentration of MUC5B in saliva. The RT group, having the highest concentration of lactoferrin, had the lowest median number of F. nucleatum and was the only group in which median number of P. intermedia/P. nigrescens was zero.

Adult↗
PubMed2000

Microbial aerosols in general dental practice.

OBJECTIVE: To measure the concentration of microbial aerosols in general dental practices and to use this information to carry out quantitative microbiological risk assessments. METHODOLOGY: Microbial air sampling was carried out continuously during 12 treatment sessions in 6 general dental practices in the South West of England. RESULTS: The microbial aerosol concentration in treatment rooms was generally less than 10(3) colony forming units per cubic metre of air (cfu x m(-3)). However, in 6 out of the 12 visits, at least one peak concentration with much higher numbers of bacteria was detected. The peak concentrations were associated with increased recoveries of presumptive oral streptococci suggesting these aerosols originated from the mouths of patients. These aerosol peaks dissipated within 30 minutes and no dissemination into waiting areas was detected. The peak concentrations were associated with mechanical scaling procedures (47% of procedures giving rise to a peak) and to a lesser extent by cavity preparation (11%). No aerosolised blood was detected. CONCLUSIONS: The data have been used to generate a framework for quantifying risk of exposure of staff to aerosolised microbial pathogens in general dental practice. For example, dentists and their assistants may have a slightly higher risk of exposure to Mycobacterium tuberculosis than the general public. The use of face seal masks that have been shown to protect against aerosolised micro-organisms may reduce this exposure.

Aerosols↗
PubMed1998

Effect of leavening microflora on pizza dough properties.

Fourteen different starter cultures containing one strain of Saccharomyces cerevisiae with and without individual or combinations of lactic acid bacteria (Lactobacillus plantarum, Lact. sanfrancisco, Enterococcus faecium, Leuconostoc mesenteroides) were employed to investigate the role of leavening microflora on the properties of pizza doughs. Microbiological, chemical and physical characteristics of doughs prepared with the same flour and under the same processing conditions were determined. Leavening times and acidification properties depended on the microbial association used. The proportions of lactic and acetic acid produced by lactic acid bacteria were consistent with the metabolic properties of the strains employed. The bacteria/yeast ratios arising from microbial counts at the end of the leavening process were always lower in comparison to sour- or bread-doughs. The size of the yeast population did not change much, while bacteria showed from one to four duplications. Rheologically, the fermented doughs could only be significantly distinguished from the control dough with regard to the elastic modulus. Principal Component Analysis was applied to the acidimetric data. The scattergram of the two principal components effectively discriminated 13 of the 14 pizza dough types.

Acetic Acid↗
PubMed1997

Elimination of adhering bacteria from surfaces by pulsed laser beams.

As an alternative to the use of chemicals for cleaning and disinfecting surfaces of equipment in food industry, the efficacy of pulsed laser beams for removal and killing of adherent bacteria from stainless steel surfaces was assessed. Escherichia coli biofilms were produced under dynamic conditions in diluted nutritive medium incubated at 37 degrees C for 24 h. Influence of energy density and number of shots were tested at three wavelengths (1064, 532 and 355 nm). With one 20 ns pulse, results range from 3.5 decimal reductions of the microbial load with < or = 50 MW cm-2 without visible alteration of the surface, to more than 6 decimal reductions with < or = 600 MW cm-2. The measured effect was largely attributed to removal of the micro-organisms and transfer to the surrounding air. The treatment could therefore be improved with respect to the numbers remaining associated with the surface by venting.

Biofilms↗
PubMed2006

Toll-like receptor triggering of a vitamin D-mediated human antimicrobial response.

In innate immune responses, activation of Toll-like receptors (TLRs) triggers direct antimicrobial activity against intracellular bacteria, which in murine, but not human, monocytes and macrophages is mediated principally by nitric oxide. We report here that TLR activation of human macrophages up-regulated expression of the vitamin D receptor and the vitamin D-1-hydroxylase genes, leading to induction of the antimicrobial peptide cathelicidin and killing of intracellular Mycobacterium tuberculosis. We also observed that sera from African-American individuals, known to have increased susceptibility to tuberculosis, had low 25-hydroxyvitamin D and were inefficient in supporting cathelicidin messenger RNA induction. These data support a link between TLRs and vitamin D-mediated innate immunity and suggest that differences in ability of human populations to produce vitamin D may contribute to susceptibility to microbial infection.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2005

Quantum dots as fluorescent labels for quantitative detection of Salmonella typhimurium in chicken carcass wash water.

Fluorescent semiconductor quantum dots have recently emerged as a novel and promising class of fluorescent labels for biological detection. In this study, quantum dots were used as fluorescent labels in immunoassays for quantitative detection of foodborne pathogenic bacteria. Salmonella Typhimurium cells were separated from chicken carcass wash water using anti-Salmonella antibody coated magnetic beads and reacted to secondary biotin-labeled anti-Salmonella antibody. Quantum dots coated with streptavidin were added to react with biotin on the secondary antibody. Measurement of the intensity of fluorescence produced by quantum dots provided a quantitative method for microbial detection. A linear relationship between Salmonella Typhimurium cell number (log N) in the samples of chicken carcass wash water and the fluorescence intensity (FI) was found for the cell numbers ranging from 10(3) to 10(7) CFU/ml. The regression model can be expressed as FI = 198.6 Log N - 639.03 with R2 = 0.96. The detection limit of this method was 10(3) CFU/ml.

Animals↗
PubMedDate not supplied

[Physicochemical and biological factors affecting atmospheric methane oxidation in gray forest soils].

The decline of methane oxidizing activities in gray forest soil upon its conversion into arable land was shown to be caused by major changes in biotic and physicochemical properties of soil. Using the method of immune serums, methane-oxidizing bacteria were detected in both forest and agricultural soils, but their populations differed significantly in both abundance and composition. In the forest soil, the number of methanotrophs was an order of magnitude higher than in arable soil, amounting to 3.5 x 10(8) and 0.24 x 10(8) cells/g soil, respectively. All methane-oxidizing bacteria identified in the forest soil belonged to the genus Methylocystis, and 94% of these were represented by a single species, M. parvus. The arable soil was dominated by type I methanotrophs (Methylobacter and Methylomonas, 67.6%), occurring along with bacteria of the genus Methylocystis. In addition, arable soil is characterized by a low content of microbial biomass, lower porosity and water permeability of soil aggregates, and the predominance of nitrogen mineralization processes over those of nitrogen immobilization. These factors can also contribute to lower rates of methane oxidation in arable soil as compared to forest soil.

Agriculture↗
PubMedDate not supplied

[The role of persistence factors in the forming of a microbial biocenosis in the nasal mucosa in staphylococcal bacteria carriers].

The microbial biocenosis of the nasal mucosa under normal conditions and in cases of Staphylococcus aureus carriership was studied, taking into account the biological properties of symbionts in 159 persons. In S. aureus carriers the dysbiotic state of the intranasal microflora was established: the decrease of the index of total microbial contamination, the index of contamination with obligate coccal microflora and the index of specific diversity. The factors of the persistence and antagonism of dysbiotic microflora contribute to the mechanism of the development of dysbiosis. In the biocenosis of the carriers obligate microflora strains (Corynebacterium, Micrococcus and coagulase-negative staphylococci) with more pronounced interspecific antagonism or bacteriocinogeny were dominant.

Adult↗
PubMed2002

Enumeration of thermophilic Bacillus species in composts and identification with a Random Amplification Polymorphic DNA (RAPD) protocol.

The thermophilic microbial flora of general garden and domestic wastes composts, derived from thermogenic, post-thermogenic and maturation phases, was analysed using spore and total plate counts in combination with an optimised RAPD protocol. A total of 459 isolates were recovered obtained at 55 degrees C, and another 56 at 70 degrees C using tryptic soy-starch agar plates, with near-equal numbers being derived from total plate counts or spore preparations. The isolates were obtained from 11 compost samples and were assigned to eighteen different RAPD fingerprint types, with 76.1% of these ultimately being positively assigned by their RAPD profiles to just 2 species including Bacillus thermodenitrificans and B. licheniformis. Viable cell numbers ranged from 1.4 to 150 x 10(6) colony forming units per gram compost (wet weight), with the highest two counts being from 2 week and 4 week old compost samples with temperatures of 70 degrees C and 55 degrees C, respectively. B. thermodenitrificans was a dominant isolate (representing more than 50% of isolates from total plate counts) in 7 of the 11 individual compost total plate count samples between 30 degrees C to 73 degrees C, and accounted for 68.9% of all isolates overall. Another relatively common Bacillus species that was identified with RAPDs in significant numbers included B. licheniformis (7.2% of all isolates and dominant isolate in 1 sample). Three other relatively common RAPD profiles could not be identified by comparison with known species in a RAPD profile database but were tentatively identified using 16S rDNA sequence comparisons. These were B. sporothermodurans (4.9% of all isolates and dominant in 1 sample), B. thermosphaericus (7.4% and dominant in 1 sample) and Terrabacter tumescens (5.0%). Overall, based on the vegetative and spore count results and the subsequent RAPD-based identification, the data strongly support a significant role for B. thermodenitrificans in the composting process, and casts doubt on the notion that B. stearothermophilus sensu strictu (DSMZ 22) is a prominent member within compost ecology.

Bacillus↗
PubMed2000

A survey on the microbiological changes during the manufacture of dry-cured lacón, a Spanish traditional meat product.

This article describes a microbiological study carried out on lacón, a dry-cured meat product made in the north-west of Spain from the fore extremity of pig. Using classical methods, aerobic mesophilic flora, salt-tolerant flora, lactic acid bacteria, Enterobacteriaceae, enterococci, moulds and yeasts were enumerated, some physicochemical parameters (pH, aw and moisture and NaCl contents) were determined and a representative number of isolates of the salt-tolerant flora (the main microbial group) were identified during the manufacture of five batches. All the microbial groups, with the exception of Enterobacteriaceae and enterococci, reached maximum counts both on the surface and in the interior of the pieces at the end of the post-salting stage and afterwards progressively dropped during the drying-ripening stage. Staphylococcus xylosus, Staph. saprophyticus, Staph. simulans, Staph. sciuri and Micrococcus luteus were the main species isolated throughout manufacturing. This study will significantly increase knowledge of the microbiology of cured meat products made from entire pieces.

Animals↗
PubMedDate not supplied

Role of interleukin-8 in community-acquired pneumonia: relation to microbial load and pulmonary function.

In pneumonia local phagocyte activation is crucial for clearing of pathogenic microorganisms. In this context alveolar macrophage interleukin-8 secretion, phagocyte oxidative response and concentrations of lavage proteins were quantified, including interleukin-8, in 31 patients with pneumonia, 13 age matched patients with peripheral lung consolidation and six healthy volunteers; these findings were related to the impairment of gas exchange and the bacterial load in the alveolar space. Increased interleukin-8 levels were found in bronchoalveolar lavage fluid (BALF) and in alveolar macrophage supernatants from patients with pneumonia (214 ng/10(5) AM +/- 121 vs 71 ng/10(5) AM +/- 35 and 66 ng/10(5) AM +/- 30, p < 0.05). Interleukin-8 release from alveolar macrophages correlated with the upregulated spontaneous luminol enhanced oxidative response of pulmonary phagocytes but not with the neutrophil count in BALF. In pneumonia patients a significant difference was found between patients with 10(4) or more colony forming units (CFU)/ml BALF of one pathogen and patients with less CFU or nonspecific microbiological results (261 ng/10(5) AM +/- 89 vs 179 ng/10(5) AM +/- 81 and 7.5 ng/ml BALF +/- 17 vs 0.44 ng/ml BALF +/- 1, p < 0.05). Further, a negative correlation between interleukin-8 release of alveolar macrophages and the arterial pO2 at the time of BALF could be demonstrated (r = -0.47, p < 0.05). The results demonstrate local cellular activation in community-acquired pneumonia, which is related to the bacterial load in the alveolar space and to impairment of gas exchange. This is consistent with the hypothesis that pulmonary phagocytes play a central role in the pathogenesis of bacterial pneumonia, contributing not only to bacterial clearing but also to local tissue damage.

Adult↗
PubMed2006

Modelling Yersinia enterocolitica inactivation in coculture experiments with Lactobacillus sakei as based on pH and lactic acid profiles.

In food processing and preservation technology, models describing microbial proliferation in food products are a helpful tool to predict the microbial food safety and shelf life. In general, the available models consider microorganisms in pure culture. Thus, microbial interactions are ignored, which may lead to a discrepancy between model predictions and the actual microbial evolution, particularly for fermented and minimally processed food products in which a background flora is often present. In this study, the lactic acid mediated negative microbial interaction between the lactic acid bacterium Lactobacillus sakei and the psychrotrophic food pathogen Yersinia enterocolitica was examined. A model describing the lactic acid induced inhibition (i.e., early induction of the stationary phase) of the pathogen [Vereecken, K.M., Devlieghere, F., Bockstaele, A., Debevere, J., Van Impe, J.F., 2003. A model for lactic acid induced inhibition of Yersinia enterocolitica in mono- and coculture with Lactobacillus sakei. Food Microbiology 20, 701-713.] was extended to describe the subsequent inactivation (i.e., decrease of the cell concentration to values below the detection limit). In the development of a suitable model structure to describe the inactivation process, critical points in the variation of the specific evolution rate mu [1/h] with the dynamic (time-varying) pH and undissociated lactic acid profiles were taken into account. Thus, biological knowledge, namely, both pH and undissociated lactic acid have an influence on the microbial evolution, was incorporated. The extended model was carefully validated on new data. As a result, the newly developed model is able to accurately predict the growth, inhibition and subsequent inactivation of Y. enterocolitica in coculture as based on the dynamic pH and lactic acid profiles of the medium.

Antibiosis↗
PubMed1997

A surface swab method for culturing Foley catheters assays the pericatheter (urethral) but not the urine (luminal) microbial population.

Assessment of the urethral flora in patients with indwelling bladder catheters is problematic in the presence of urinary tract infection (UTI). A new surface swab method that samples the external catheter surface without interference from contaminated luminal contents is described. In vitro, recovery of adherent bacteria from the external catheter surface by the surface swab method was proportional to the bacterial density as measured by a comparison scrape method. In a prospective longitudinal assessment of three chronically catheterized subjects with polymicrobial catheter-associated UTI, a conventional roll plate catheter culture method suggested substantial overlap between the urethral and urine microbial populations, possibly a result of contamination of catheter cultures by infected urine. In contrast, the surface swab method revealed little overlap between these floras, evidence suggesting a predominantly luminal (rather than meatal) route of UTI acquisition. The new surface swab method should prove useful in future studies of the pathogenesis and prevention of catheter-associated UTI.

Bacteriological Techniques↗
PubMed1998

[Airborne molds and their metabolites at workplaces in composting plants].

Airborne fungal contaminants in composting facilities gain more and more importance in regard to health hazards for workers and an emission of spores and microbial metabolites in the environment. Possible health impacts of bioaerosols are widely discussed from both an allergological and a toxicological point of view. The present study investigates in detail the exposure to airborne fungal spores at working places in compost plants. These fungal spores are compared to the spectrum of microbial volatile metabolites with regard to the physiological properties of each fungal species. The results indicate, that the spectrum of microbial volatile organic compounds (MVOC) as well as the production of mycotoxins can be specific for certain species. In addition to the pathogenic and allergological relevance, the fungi may have different toxicological health impacts. However, an evaluation of health effects caused by the great variety of volatile organic compounds remains difficult, since information on their toxicological impact is lacking.

Air Microbiology↗
PubMed2001

The effects of toothpastes on the residual microbial contamination of toothbrushes.

BACKGROUND: Contaminated toothbrushes have been shown to harbor and transmit viruses and bacteria. The authors conducted a study to evaluate the effect of a triclosan-containing toothpaste on the residual anaerobic microbial contamination of toothbrushes. METHODS: Twenty patients who had Type III or Type IV periodontitis participated in this study. One side of each of their mouths served as a control (no toothpaste). The teeth on the other side were brushed with a regular toothpaste or a triclosan-containing toothpaste. After the toothbrushes were allowed to dry in air for four hours, the authors placed the toothbrush heads in solution, dislodged the microbes from the brushes by vortexing and plated them in culture dishes. The authors anerobically incubated the culture dishes and determined the presence or absence of Prevotella species or Ps; Porphyromonas gingivalis, or Pg; and Actinobacillus actinomycetemcomitans, or Aa. RESULTS: The authors detected Aa and Pg on the control toothbrushes more frequently than they did Ps. This variation in isolation frequency was statistically significant by chi 2 analysis (P < .001). The authors compared the isolation frequency of the three test organisms between the control and regular-toothpaste groups, between the control and triclosan-containing--toothpaste groups, and between the triclosan-containing--toothpaste and regular-toothpaste groups. They found no significant intergroup differences in the isolation frequencies after using chi 2 analysis. CONCLUSIONS: Toothpaste use reduced the residual microbial contamination for two of three test organisms, but the lower isolation frequencies were not statistically significant. Further study in this area is indicated. CLINICAL IMPLICATIONS: Dental professionals should advise patients who have systemic, localized or oral inflammatory diseases to disinfect or frequently replace their toothbrushes.

Aggregatibacter actinomycetemcomitans↗
PubMed2005

Dental caries experience and salivary levels of Streptococcus mutans and Lactobacilli in 13-15 years old children of Belgaum city, Karnataka.

The present cross-sectional study was carried out in 372 school going children of Belgaum aged 13-15 years. The sample was selected by two stage random sampling method. The aim of the study was to estimate the salivary levels of Streptococcus mutans and Lactobacilli and to study the relationship between these microorganisms and dental caries experience. The DMFT was recorded according to the WHO criteria(1997).The microbial load was estimated from a single saliva sample obtained from the children. The mean DMFT recorded was 2.41. Streptococcus mutans was detected in 87.37% and Lactobacilli in only 36.71% of the sample. Statistically, highly significant relation was found between Streptococcus mutans and DMFT categories (chi2=125.36, P<0.001), while Lactobacilli was not statistically related to DMFT categories (chi2=8.78, P>0.05).

Adolescent↗
PubMed2005

Inactivation of Salmonella enterica serovar Enteritidis on shell eggs by ozone and UV radiation.

The presence of Salmonella enterica serovar Enteritidis in shell eggs has serious public health implications. Several treatments have been developed to control Salmonella on eggs with mixed results. Currently, there is a need for time-saving, economical, and effective egg sanitization treatments. In this study, shell eggs externally contaminated with Salmonella (8.0 x 10(5) to 4.0 x 10(6) CFU/g of eggshell) were treated with gaseous ozone (O3) at 0 to 15 lb/in2 gauge for 0 to 20 min. In other experiments, contaminated shell eggs were exposed to UV radiation at 100 to 2,500 microW/cm2 for 0 to 5 min. Treatment combination included exposing contaminated eggs to UV (1,500 to 2,500 microW/cm2) for 1 min, followed by ozone at 5 lb/in2 gauge for 1 min. Eggs that were (i) noncontaminated and untreated, (ii) contaminated and untreated, and (iii) contaminated and treated with air were used as controls. Results indicated that treating shell eggs with ozone or UV, separately or in combination, significantly (P < 0.05) reduced Salmonella on shell eggs. For example, contaminated eggs treated with ozone at 4 to 8 degrees C and 15 lb/in2 gauge for 10 min or with UV (1,500 to 2,500 microW/cm2) at 22 to 25 degrees C for 5 min produced 5.9- or 4.3-log microbial reductions or more, respectively, when compared with contaminated untreated controls. Combinations including UV followed by ozone treatment resulted in synergistic inactivation of Salmonella by 4.6 log units or more in about 2 min of total treatment time. Salmonella was effectively inactivated on shell eggs in a short time and at low temperature with the use of a combination of UV radiation and ozone.

Animals↗
PubMed2004

[Studies on the changes in rice straw composition in relay treatment of chemical-microbial process by FTIR spectroscopy].

Direct burning of crop straw in the field has given or is giving rise to a serious pollution of atmosphere. The difficult decomposing of the crop straw by soil microorganisms is one of the reasons the crop straw is not popularly used in agriculture. Fourier transform infrared spectroscopy (FTIR) was used to study the changes in straw composition during the relay treatment of chemical-microbial process. The results showed that the method of FTIR spectra could indicate the changes in straw composition during the treatment processes. After the relay treatment of chemical-microbial process, the contents of cellulose, semi-cellulose, and silicon, and C/N ratio were decreased significantly, while the water soluble substances were increased, which was in accordance with the results of chemical analysis. The method to treat crop straw proposed in this paper could provide a practicable way in agricultural utilization of crop straw.

Agriculture↗