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PubMed1993

Periodontopathic bacteria and salivary microbes before and after extraction of partly erupted third molars.

This study examines the effect of extraction of third molars on suspected periodontopathogenic microbes, salivary acidogenic bacteria, and yeasts. The subjects were 39 healthy conscripts aged 20.2 yr, with symptom-free, partly erupted mandibular third molars. Microbial samples were taken from the mandibular third molar pericoronal space and from the adjacent gingival pocket of the second molar. The samples were stained by Gram's and Giemsa's methods and studied under a light microscope. Stimulated saliva was collected for assessing mutans streptococci, lactobacilli, and yeast counts by chair-side kits. All partly erupted third molars were extracted from 20 test subjects; 19 control subjects were left untreated. Microbial samplings were repeated 2 and 5 months postoperatively. Results showed that at base line the total number of Gram-negative bacteria, Gram-negative rods, and spirochetes was significantly higher at the third molar than at the second molar sites. The extraction of the third molars caused a significant decrease in the percentage of these bacteria at the second molar sites. High counts of salivary mutans streptococci (CFU > or = 10(6)) and lactobacilli (CFU > or = 10(5)) were also significantly less frequent after the operations. Yeast counts were not affected by the extractions. Thus, partly erupted third molars may harbor a periodontally pathogenic microflora and increase the number of salivary acidogenic microbes.

Adult↗
PubMed2005

[Validation method for bacteria and fungi count in microbial limit test of drugs].

OBJECTIVE: To establish the validation method and criteria for counting bacteria and fungi in microbial limit test which is described in the Pharmacopeia of China (ChP) 2005. METHOD: According to the method set up for validation, the tested microorganisms with known counts were added to samples followed by the determination of the recovery. RESULT: With different preparing method for testing samples, the recoveries for the tested microorganisms in testing samples were found to be over 70%. CONCLUSION: Validation method for counting contaminated bacteria and fungi in drugs is recommended to follow the method established in this paper. The recovery for tested microorganisms should be not less than 70%.

Aspergillus niger↗
PubMed2003

Growth and survival of selected pathogens in margarine-style table spreads.

Although margarine-style table spreads can have a pH above 4.6 and a water activity greater than 0.85, there is some question if such products can support the growth of pathogenic bacteria. The objective of this study was to evaluate the growth and survival of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhi in 60-percent- and 70-percent-vegetable-oil, margarine-style, water-in-oil-emulsion table spreads stored at different temperatures. Samples of 25 grams of each table spread were inoculated with 1 x 10(3) cells of each bacterial mixture. The samples were stored at 5 degrees C, 7 degrees C, and 21 degrees C, and the microbial population in colony-forming units per gram (CFU/gram) was enumerated over time. In almost all storage conditions, bacterial levels were shown to decrease over time. Inactivation was observed in (listed from fastest to slowest, respectively) S. aureus, L. monocytogenes, E. coli O157:H7, and S. typhi. Growth was observed only for S. typhi in table spreads stored at 21 degrees C, but the rate of growth was extremely slow. Based on these findings, the table spreads evaluated in this study are not potentially hazardous foods, and cold temperature storage is not necessary from a food safety perspective.

Cold Temperature↗
PubMed1990

The effect of treatment with buffered lactic acid on microbial decontamination and on shelf life of poultry.

The use of buffered lactic acid systems compared with unbuffered lactic acid solutions enhances the decontaminating effect and increases shelf life of chicken legs. A reduction of about 2 pH units of the chicken skin is obtained by treatment with 10% lactic acid buffer. The buffer keeps the pH of the skin lower than that of untreated legs. Legs treated with 10% lactic acid buffer have a shelf life of 12 days at 6 degrees C, which means an increase of 6 days compared with the shelf life of untreated legs.

Animals↗
PubMed2002

Evolution of extracellular enzyme activities during manure composting.

AIMS: The objectives of this work were to determine the extracellular enzyme profiles during composting, relate the activities of these enzymes to the changes in microbial population and compare the enzyme profiles between two manures. METHODS AND RESULTS: API ZYM assay was used to monitor the activities of 19 extracellular enzymes during poultry and pig manure composting. Results showed an overall increase in diversity and relative abundance of enzymes present. The relative abundance and activities of enzymes were higher in poultry manure than in pig manure. Among the 19 enzymes tested, esterase, valine amino-peptidase and alpha-galactosidase were the most abundant enzymes in poultry manure, whereas it was N-acetyl-beta-glucosaminidase for the pig manure. A number of these enzymes correlated with change in numbers of different microbial groups during composting. CONCLUSIONS: The composting process represented a combined activity of a wide succession of environments, as one enzyme/microbial group overlapped the other and each emerged gradually due to the continual change in temperature and progressive breakdown of complex compounds to simpler ones. SIGNIFICANCE AND IMPACT OF THE STUDY: The results presented here show the applicability of the API ZYM test not only in monitoring the quantitative and qualitative fluctuation of the available substrate during composting, but also in revealing differences in composts and compost maturity.

Actinomycetales↗
PubMed2004

Low archaeal diversity linked to subseafloor geochemical processes at the Lost City Hydrothermal Field, Mid-Atlantic Ridge.

The recently discovered Lost City Hydrothermal Field (LCHF) represents a new type of submarine hydrothermal system driven primarily by exothermic serpentinization reactions in ultramafic oceanic crust. Highly reducing, alkaline hydrothermal environments at the LCHF produce considerable quantities of hydrogen, methane and organic molecules through chemo- and biosynthetic reactions. Here, we report the first analyses of microbial communities inhabiting carbonate chimneys awash in warm, high pH fluids at the LCHF and the predominance of a single group of methane-metabolizing Archaea. The predominant phylotype, related to the Methanosarcinales, formed tens of micrometre-thick biofilms in regions adjacent to hydrothermal flow. Exterior portions of active structures harboured a diverse microbial community composed primarily of filamentous Eubacteria that resembled sulphide-oxidizing species. Inactive samples, away from regions of hydrothermal flow, contained phylotypes related to pelagic microorganisms. The abundance of organisms linked to the volatile chemistry at the LCHF hints that similar metabolic processes may operate in the subseafloor. These results expand the range of known geological settings that support biological activity to include submarine hydrothermal systems that are not dependent upon magmatic heat sources.

Archaea↗
PubMed1998

Repeatability of the Petrifilm HEC test and agreement with a hydrophobic grid membrane filtration method for the enumeration of Escherichia coli O157:H7 on beef carcasses.

The Petrifilm HEC test (3M Canada Inc., London, Ontario), a quantitative microbiological test for Escherichia coli O157:H7, was evaluated for its performance as a beef-carcass monitoring test. Test repeatability and agreement and agreement with an E. coli O157:H7 detection method using a hydrophobic grid membrane filter (HGMF) overlaid onto cefixime-tellurite-sorbitol MacConkey agar (CT-SMAC) followed by a latex agglutination test for the O157 antigen were determined by using pure cultures of E. coli O157:H7, beef samples experimentally contaminated with bovine feces containing E. coli O157:H7, and naturally contaminated beef carcasses of unknown E. coli O157:H7 status from a local abattoir. The Petrifilm HEC test showed excellent repeatability and excellent agreement with the HGMF-CT-SMAC method when test samples were obtained from pure cultures and experimentally contaminated meat. All 125 naturally contaminated beef carcasses surveyed were negative for E. coli O157:H7 with both microbial methods. The Petrifilm HEC test, however, demonstrated a significantly lower proportion of cross-reactive organisms (false-positive reactions) than the HGMF-CT-SMAC method. Given the performance of this test coupled with its ease of use and compact size, it shows considerable promise for carcass testing where abattoir laboratory facilities are limited and as a substitute for more complex laboratory testing methods used in established laboratories.

Abattoirs↗
PubMedDate not supplied

[Guidelines on water and solutions for dialysis. Italian Society of Nephrology].

The National Society of Nephrology has promoted the development of specific Italian Guidelines for dialysis fluids. Two previous national inquiries showed a wide variety in the type and frequency of both microbiological and chemical controls concerning dialysis water, reinforcing the need for specific standards and recommendations. An optimal water treatment system should include tap water pre-treatment and a double reverse osmosis process. Every component of the system, including the delivery of the treated water to the dialysis machines, should prevent microbiological contamination of the fluid. Regular chemical and microbiological tests and regular disinfection of the system are necessary. 1. Chemical quality (Table: see text). Treated tap water used to prepare dialysis fluid should be within European Pharmacopoeia limits at the water treatment system inlet and at the reverse osmosis outlet. In addition dialysate, concentrate and infusion fluids must comply with specific Pharmacopoeia limits. The physician in charge of the dialysis unit is advised to institute a multidisciplinary team to evaluate the requirement for added chemical controls in the presence of local hazards. 2. Microbiological quality (Table: see text). High microbiological purity of dialysis fluid--regularly verified--is a fundamental prerequisite for dialysis quality and every dialysis unit should aim as a matter of course to obtain "ultra-pure" dialysate (microbial count <0.1 UFC/mL, endotoxins <0.03 U/mL). On-line dialysate ultrafiltration and regular disinfection of dialysis machines greatly enhance microbiological purity. On-line dialysate reinfusion requires specific devices used according to corresponding instructions and to more frequent microbiological tests. Dialysis fluids for home dialysis should comply with the same chemical and bacteriological quality. The appendix reports the water treatment system's technical characteristics, sampling and analytical methods, monitoring time-tables, as well as the origin and effects of the main toxic substances. Suggestions and questions concerning these guidelines are welcome to nefrologia@sin-italy.org.

Colony Count, Microbial↗
PubMed1989

[Comparison of subgingival plaque buccally and interdentally localized during 3-week experimental gingivitis in humans].

During 21 days of abolished oral hygiene and developing gingivitis the microbial changes were studied in buccal and interdental sites. The subgingival plaque of 6 dental students was analyzed by darkfield microscopy. The microbiota found in interdental sulci showed a higher complexity than that of buccal sites. Buccally and interdentally there was a significant increase in the total number of microorganisms between days 0 and 21. Yet, the development of gingivitis was slower in the buccal than in the interproximal sites. For all bacteria, but specially for more disease-associated morphotypes the accumulation rate was higher interdentally than buccally.

Adult↗
PubMedDate not supplied

Application of triphenyltetrazolium chloride in microbial limit test of pharmaceuticals and cosmetics.

An alternative method was developed for counting viable microbial contaminants in pharmaceuticals and cosmetics with insoluble materials and low bioburden. The method uses triphenyltetrazolium chloride (TTC). The inhibitory effect of TTC on microbial growth observed by others was eliminated by adding it as an overlay, after incubation of sample in culture medium for 48 h. Six samples of pharmaceutical suspensions and 6 samples of cosmetics were evaluated by most-probable number (MPN) and pour-plate techniques with TTC in comparison with MPN with subculturing. The equivalence between MPN technique with TTC and subculturing was demonstrated for all samples and between pour-plate and subculturing for 10 samples. The differences were probably due to some error inherent in both techniques and not from application of TTC. Comparison of coefficients of variation showed that plate countings were more precise than the MPN method, as expected.

Bacteriological Techniques↗
PubMed2004

Protective effect of salivary nitrate and microbial nitrate reductase activity against caries.

To test the hypothesis that a combination of high salivary nitrate and high nitrate-reducing capacity are protective against dental caries, 209 children attending the Dental Institute, Barts and The London NHS Trust were examined. Salivary nitrate and nitrite levels, counts of Streptococcus mutans and Lactobacillus spp., and caries experience were recorded. Compared with control subjects, a significant reduction in caries experience was found in patients with high salivary nitrate and high nitrate-reducing ability. Production of nitrite from salivary nitrate by commensal nitrate-reducing bacteria may limit the growth of cariogenic bacteria as a result of the production of antimicrobial oxides of nitrogen, including nitric oxide.

Adolescent↗
PubMed2002

Review of the treatment strategies for oral malodour.

Breath malodour, a significant social and/or psychological handicap, may be caused by several intra- and extraoral factors. Malodour of intraoral origin is the result of microbial putrefaction, during which volatile sulphur compounds (VSC) and other volatile compounds are produced. The treatment of oral malodour can therefore be focused on the reduction of the intraoral bacterial load and/or the conversion of VSC to nonvolatile substrates. This article outlines the efficacy and mechanisms of different antimalodour approaches. Most approaches were found to be inefficient and/or short lasting. The most successful treatment involves mechanical debridement (including toothbrushing, flossing, and tongue cleaning), possibly combined with the use of an antimicrobial mouthrinse.

Anti-Infective Agents, Local↗
PubMed2001

Differential effects of the herbicides bensulfuron and cinosulfuron on soil microorganisms.

Bensulfuron toxicity on soil microbes was evaluated by the methods used in a previous study on cinosulfuron; the effects of the two sulfonylureas were compared. Cinosulfuron and bensulfuron, at the normal field application rate and 100 times higher, had no effect on the total number of bacteria and nitrifiers, or on the respiration activity in the soil, but they did decrease the nitrification activity. In vitro toxicity tests carried out on representative soil microbial strains using bensulfuron at 50 mg l(-1) showed some inhibition of three of the 17 bacterial strains and strong inhibition of almost all the 12 fungal strains; cinosulfuron had had no effect on any of these strains in the previous study. It is concluded that, compared with cinosulfuron, bensulfuron is potentially more toxic on soil heterotrophic microorganisms, but only at very high concentrations that are nearly impossible to reach with the usual agricultural use of the herbicides. However, autotrophic nitrifiers were more sensitive to both sulfonylureas than the other microorganisms.

Bacteria↗
PubMed2001

Effects of triclosan on the cytotoxicity and fungal growth on a soft denture liner.

STATEMENT OF PROBLEM: Contamination of removable prostheses with microorganisms, particularly Candida albicans, is a common clinical problem. Microban, a broad-spectrum antimicrobial containing triclosan, recently has been proposed to inhibit microbial growth. PURPOSE: This study aimed to determine whether the addition of Microban to PermaSoft denture liner prevents the growth of C albicans and affects the cytotoxicity of the PermaSoft material. MATERIAL AND METHODS: Experimental specimen disks (5 x 1 mm each) with and without incorporated Microban were fabricated aseptically (n = 6) against polyester film to produce a smooth surface. To assess the cytotoxic effect of Microban, the MTT assay was used. To determine the effect of Microban on the growth of C albicans, disks were placed in Transwell dishes, covered with Sabouraud's broth containing an ATCC strain of C albicans, and incubated at 37 degrees C for 24 hours. Wells containing fluorocarbon resin disks or broth alone served as controls. The disks were rinsed to remove unattached C albicans and then sonicated in sterile water to remove surface organisms. Serial dilutions of the water extracts were plated on Sabouraud's agar and returned to the incubator for 24 hours. Colonies were counted with a Brunswick Colony Counter. Growth of C albicans in the internal aspects of the specimens was determined in a manner as previously described, with the exception that the specimens were sonicated to remove surface organisms, minced, and sonicated once more before making serial dilutions. The results were compared with ANOVA and Tukey intervals (alpha=.05). RESULTS: The number of colonies formed ranged from 17 to 31 x 10(5) (mean = 23 +/- 4 x 10(5)) and 14 to 69 x 10(5) (mean = 32 +/- 20 x 10(5)) for the PermaSoft with and without Microban groups, respectively. There was no statistically significant difference between PermaSoft with and without Microban. CONCLUSION: The addition of Microban did not significantly alter the cytotoxicity of the PermaSoft denture lining material or reduce the adherence of viable C albicans to the surface of PermaSoft material after 24 hours.

Analysis of Variance↗
PubMed1997

Antibacterial effects of Nd:YAG laser irradiation within root canal dentin.

The microbial flora of the root canal dentin can cause failures in the conventional treatment of infected root canals if it cannot be sufficiently removed by preparation and chemical disinfection of the root canal. The aim of this study is to examine the bactericidal effects of neodymium:yttriumaluminum garnet (Nd:YAG) laser irradiation in the depth of the root canal dentin. Following sterilization, longitudinal section dentin slices of different thicknesses (100-1000 microns) were inoculated on one side with 4 microliters of a Streptococcus mutans suspension. The opposite sides of the dentin slices were then irradiated four times for 10-20 sec (according to the sample area) using the Nd:YAG laser at a setting of 1.5 W, 15 pps with a 200 microns glass fiber from an angle of about 5 degrees. The bacteria were then removed from the dentin using vibration and plated out on culture dishes that were selective for Streptococcus mutans. When compared with untreated control slices, counting of the colonies revealed a highly significant elimination of bacteria for all thicknesses following laser irradiation. Although the intensity of the laser irradiation decreased after penetration of a 1000-micron dentin slice, the bactericidal mode of action was still effective.

Colony Count, Microbial↗
PubMed1995

Bacteriological quality of ready to eat meals.

Microbial investigation of 30 samples of roasted liver and 30 samples of meat sandwiches, collected randomly from different peddlers and restaurants in Alexandria city, was conducted to evaluate their sanitary status. The average count/gm of total aerobic bacterial count thermophilic, total coliform and faecal coliform counts isolated from liver sandwiches were 8.11 x 10(6), 1.05 x 10(5) and 9.04 x 10(3), but from meat sandwiches (shawerma) were 7.06 x 10(4), 6.24 x 10(3), 2.26 x 10(3) and 1.09 x 10(3) respectively. E. coli, Shigella, Staph. aureus could be isolated in varying percentages, but Salmonella failed to be isolated. The public health importance of the isolated microorganisms as well as suggested hygienic measures to improve the quality of such products are discussed.

Animals↗
PubMed1995

Environmental microbial contamination. Pilot study in a dental surgery.

Environmental contamination by bacterial aerosols occurs every day in the dental surgery. The aim of this study was to determine bacterial levels in five different areas of a dental surgery during ultrasonic scaling procedures using bacterial cultures. Two areas with markedly different amounts of infective aerosols were identified. The role of the air conditioning system was also assessed. There was evidence that the air conditioning system could act as a vehicle for the transmission of microorganisms.

Aerosols↗
PubMed2003

Biogenic amines in dry fermented sausages: a review.

Biogenic amines are compounds commonly present in living organisms in which they are responsible for many essential functions. They can be naturally present in many foods such as fruits and vegetables, meat, fish, chocolate and milk, but they can also be produced in high amounts by microorganisms through the activity of amino acid decarboxylases. Excessive consumption of these amines can be of health concern because their not equilibrate assumption in human organism can generate different degrees of diseases determined by their action on nervous, gastric and intestinal systems and blood pressure. High microbial counts, which characterise fermented foods, often unavoidably lead to considerable accumulation of biogenic amines, especially tyramine, 2-phenylethylamine, tryptamine, cadaverine, putrescine and histamine. However, great fluctuations of amine content are reported in the same type of product. These differences depend on many variables: the quali-quantitative composition of microbial microflora, the chemico-physical variables, the hygienic procedure adopted during production, and the availability of precursors. Dry fermented sausages are worldwide diffused fermented meat products that can be a source of biogenic amines. Even in the absence of specific rules and regulations regarding the presence of these compounds in sausages and other fermented products, an increasing attention is given to biogenic amines, especially in relation to the higher number of consumers with enhanced sensitivity to biogenic amines determined by the inhibition of the action of amino oxidases, the enzymes involved in the detoxification of these substances. The aim of this paper is to give an overview on the presence of these compounds in dry fermented sausages and to discuss the most important factors influencing their accumulation. These include process and implicit factors as well as the role of starter and nonstarter microflora growing in the different steps of sausage production. Moreover, the role of microorganisms with amino oxidase activity as starter cultures to control or reduce the accumulation of biogenic amines during ripening and storage of sausages is discussed.

Amine Oxidase (Copper-Containing)↗