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PubMed1999

Salivary mutans streptococci and lactobacilli in 9- and 13-year-old Italian schoolchildren and the relation to oral health.

The prevalence and levels of mutans streptococci (MS) and lactobacilli (LB) in saliva and its possible correlation with dental caries and periodontal conditions was investigated in 473 Italian schoolchildren, 9 and 13 years of age. A clinical examination and sampling of stimulated whole saliva was carried out in the school and oral health was assessed as DMFT and CPITN using the WHO criteria. The saliva samples were frozen in liquid nitrogen and after thawing, cultivated on selective media. To test the influence of cryopreservation, fresh samples from 20 subjects were cultivated. Thirty-five percent of the children were caries-free with a mean DMFT of 1.9 at the age of 13. The majority exhibited healthy periodontal conditions. Salivary MS and LB were identified in 52% and 21% of the children, respectively. The prevalence of MS was higher among the 13-year-olds than the 9-year-olds while no such difference was found regarding LB. There was a statistically positive relationship (P < 0.01) between the levels of MS and LB and both were significantly correlated to caries (P < 0.01). The correlation coefficient of microbial recovery between frozen and unfrozen samples was 0.99. In conclusion, the data provided cross-sectional information of a clear positive relationship between selected micro-organisms in saliva and caries in 9- and 13-year-old children in spite of a relatively low prevalence of the disease. The findings are discussed in a risk selection perspective.

Adolescent↗
PubMed1991

Salivary Streptococcus mutans levels in patients before, during, and after orthodontic treatment.

The purpose of this study was to evaluate salivary Streptococcus mutans levels in patients before, during, and after orthodontic treatment. S. mutans levels were significantly elevated during active treatment. However, when sampled 6 to 15 weeks into the retention phase of treatment, the microbial levels decreased significantly to levels comparable to age-matched untreated controls. In addition, patients who were no longer wearing any retention appliances had S. mutans levels similar to those subjects sampled in the retention phase of treatment as well as to subjects in age-matched control groups. The findings of the study suggest that orthodontic treatment does not result in any long-term elevations of S. mutans levels.

Adolescent↗
PubMed1999

Effects of larval mosquitoes (Aedes triseriatus) and stemflow on microbial community dynamics in container habitats.

The dynamics of the microbial food sources for Aedes triseriatus larvae in microcosms were found to be strongly influenced by larval presence. The total abundance of bacteria in water samples generally increased in response to larvae, including populations of cultivable, facultatively anaerobic bacteria. Additionally, a portion of the community shifted from Pseudomonaceae to Enterobacteriaceae. Bacterial abundance on leaf material was significantly reduced in the presence of actively feeding larvae. Principle-component analysis of whole community fatty acid methyl ester (FAME) profiles showed that larvae changed the microbial community structure in both the water column and the leaf material. Cyclopropyl FAMEs, typically associated with bacteria, were reduced in microcosms containing larvae; however, other bacterial fatty acids showed no consistent response. Long-chain polyunsaturated fatty acids characteristic of microeukaryotes (protozoans and meiofauna) declined in abundance when larvae were present, indicating that larval feeding reduced the densities of these microorganisms. However, presumed fungal lipid markers either increased or were unchanged in response to larvae. Larval presence also affected microbial nitrogen metabolism through modification of the physiochemical conditions or by grazing on populations of bacteria involved in nitrification-denitrification. Stemflow primarily influenced inorganic ion and organic compound concentrations in the microcosms and had less-pronounced effects on microbial community parameters than did larval presence. Stemflow treatments diluted concentrations of all inorganic ions (chloride, sulfate, and ammonium) and organic compounds (total dissolved organic carbon, soluble carbohydrates, and total protein) measured, with the exceptions of nitrite and nitrate. Stemflow addition did not measurably affect larval biomass in the microcosms but did enhance development rates and early emergence patterns of adults.

Aedes↗
PubMed1996

Transmission of mother's microflora to the newborn at birth.

Our aim was to study the initial microbial colonization of the newborns by comparing it with their mothers' vaginal microflora. Nineteen mother-newborn pairs were examined at delivery. We found a close association, both qualitative and quantitative, between the individually different microflora of a mother's vagina and that of her newborn. The degree of contamination of the newborn significantly correlated with the counts of microorganisms found in the vagina of mothers. In 85% of investigated individual mother-newborn pairs we revealed similar predominant microorganisms. There were no cases of the mothers and their newborns harbouring similar potentially pathogenic prevailing microorganisms.

Bacteria↗
PubMed2001

Internal contamination of a 2-component implant system after occlusal loading and provisionally luted reconstruction with or without a washer device.

BACKGROUND: Microbial internal contamination of oral implants has been suggested as being responsible for inflammatory infiltration of peri-implant tissues at the fixture-abutment interface of 2-stage and 2-component implant systems; it is also considered as a potential source of pathogens. The present in vivo study evaluated contamination of the inner abutment-implant retaining screw, after occlusal loading and provisionally-luted reconstruction with or without a washer device. METHODS: Eight 2-component oral implants sealed with an o-ring silicon washer device and 9 without a seal were placed in 7 patients with high oral hygiene standards. Two months after prosthetic reconstruction, crowns and internal screws were removed, and organic and inorganic screw contamination was examined by scanning electron microscopy and energy dispersive x-ray spectroscopy (EDS) analysis. RESULTS: An amorphous and crystalline contamination, suggestive of calcium and phosphate compounds, was seen on all screw surfaces. Microbial contamination was more frequently observed in the unsealed group. No differences in bacterial morphotypes were observed between the sealed and unsealed implants. Cocci were the most representative morphotypes, while rods were seldom seen. CONCLUSIONS: In clinical situations, leakage occurs at the implant-abutment interface, although bacterial contamination is limited in patients with high oral hygiene standards. Contamination may be reduced by using a washer device.

Analysis of Variance↗
PubMed1988

Microbiological and physico-chemical aspects in dry-salted Spanish ham.

The main microbiological and physico-chemical parameters in dry-salted ham previously selected were determined during the elaboration process. All determinations were performed at 2 levels: surface and internal. The selected microbiological parameters were: total aerobes, halotolerant, lactic acid bacteria, yeasts and hazardous microorganisms. NaCl, nitrate, nitrite, water activity, moisture, pH, temperature and loss of weight were selected for the physico-chemical study. All microbial groups showed a similar behaviour, increasing along the first stages up to the third month of drying, then decreasing to numbers similar to the initial ones. Only the halotolerants maintained fairly high numbers during the last stages. Some groups were almost absent at internal levels. The hazardous bacteria showed different behaviour: whereas the faecal streptococci were fairly abundant during the whole study, coliforms almost disappeared at the final stages.

Animals↗
PubMed2004

Pathogen growth in herbal teas used in clinical settings: a possible source of nosocomial infection?

In some clinical settings, herbal tea is used in patient care (eg, for oral hygiene). Teabags containing herbal tea were therefore tested with regard to the presence of microbial contamination before and after brewing. In addition, pathogen growth in intentionally contaminated brewed tea was investigated over time. Teabags and brewed tea were highly contaminated (maximum mean values of 1.9 x 10(8) CFU/g raw tea), and it was found that the pathogen load of intentionally contaminated tea increased significantly (by a maximum of 10(5) colony-forming units/mL brewed tea) over time, suggesting a possible risk of patients developing a nosocomial infection when used in patient care.

Bacteria↗
PubMed1998

Identification of contamination sources of Bacillus cereus in pasteurized milk.

In order to determine the sources of Bacillus cereus in pasteurized milk, a total of 232 milk samples from various sampling points along milk processing lines and 122 environmental swabs were collected in two dairy plants between March and September, 1996. The incidence of B. cereus vegetative cells in raw milk from the plants was low (< or = 10%). However, the incidence and the average counts of B. cereus spores in the raw milk were very high and similar to those of B. cereus vegetative cells in pasteurized milk or final products after enrichment (> 80% and 1.1 x 10(5) cfu ml(-1), respectively). The incidence and average count of both vegetative cells and spores of B. cereus in environmental swabs was low. Using the microbial identification system (MIDI), a library of B. cereus fatty acid profiles comprising 229 B. cereus isolates from milk samples and environmental swabs was constructed using a critical Euclidian distance of 6.0 units as the cut-off value. Using this library, the relationship between 546 B. cereus isolates from the different sampling points along the milk processing lines and the environmental swabs was determined. Most B. cereus isolates obtained from the pasteurized milk and final products belonged to the same sub-groups as the B. cereus strains germinated from spores in raw milk. Furthermore, specific sub-groups were found in pasteurized milk, different dairy plants and at different sampling times. The results suggested that B. cereus spores in raw milk were the major source of B. cereus in pasteurized milk and that post-pasteurization contamination along the milk processing lines was possibly a minor source of B. cereus in pasteurized milk.

Animals↗
PubMed1995

Is hand washing really needed in an intensive care unit?

OBJECTIVES: To determine whether a rigorous antiseptic hand washing of bare hands with 4% chlorhexidine and alcohol reduced fingertip microbial colonization as compared with the use of boxed, clean, nonsterile latex gloves. In addition, to investigate if aseptic donning technique and/or a prior hand washing would reduce the level of glove contamination. DESIGN: Prospective, randomized, crossover design, with each subject serving as his/her own control. SETTING: University intensive care unit. SUBJECTS: Forty-three intensive care nurses. INTERVENTIONS: The fingertips of 20 nurses were cultured before and after a strict antiseptic hand washing and before and after the routine and aseptic donning of sterile gloves. Subsequently, the fingertips of 43 nurses were cultured before and after the casual donning of nonsterile gloves over unwashed hands and before and after a strict antiseptic hand washing. Fingertip cultures were plated directly on agar, incubated for 24 hrs, and counted and recorded as the number of colony-forming units (cfu) for each hand. Different colony types were then subcultured. MEASUREMENTS AND MAIN RESULTS: Hand washing with antiseptic reduced colonization from 84 to 2 cfu (p < .001). The proportion of cases with > or = 200 cfu/hand was reduced from 30% to 9%. Aseptic or casual donning of sterile gloves, with or without prior antiseptic hand washing, resulted in consistently low glove counts between 0 and 1.25 cfu. Nonsterile gloves casually donned over washed or unwashed bare hands diminished the bioburden to 2.17 and 1.34 cfu, respectively. No qualitative difference was found in the microorganisms recovered from gloved or bare hands. CONCLUSIONS: Antiseptic hand washing and the use of nonsterile gloves over unwashed hands confer similar reductions in the number of microorganisms. There is no additional benefit with the use of aseptic donning technique, prior antiseptic hand washing, or the use of individually packaged sterile gloves.

Asepsis↗
PubMed2000

Microbial study of farmhouse ewe cheese during storage in olive oil.

The effect of storing farmhouse ewe cheese in oil and in vacuo over long periods of time on physicochemical properties (water activity and pH) and the microbiota of the cheese was investigated. The storage conditions were found to scarcely influence the sample pH. Also, the initial water activity (a(w) = 0.961) and its value after 9 months of storage (0.927) were both very similar to those for naturally ripened cheese. The incidence of pathogenic microbial groups was found to decrease with storage time (counts fell below 1 log CFU/g). The flora that effects proteolytic changes in cheese consisted of lactic microorganisms (viz. lactococci and lactobacilli), in addition, after 6 months of storage, of enterococci. The last are responsible for the formation of large amounts of soluble nitrogen (SN), non-protein nitrogen (NPN) and aminoacid nitrogen (NH2-N), which provide this type of cheese with very special sensory features while preventing dehydration and thus lengthening its shelf life.

Animals↗
PubMedDate not supplied

New methods for microbial contamination monitoring: an experiment on board the MIR orbital station.

Experiment T2, carried out during the Euromir'95 mission, was an important step toward innovative methods for spacecraft microbial contamination monitoring. A new standard sampling technique permitted samples to be analysed by different means. On board, two analysis methods were tested in parallel: Bioluminescence and Miniculture. In turn, downloaded samples are being analysed by polymerase chain reaction (PCR), a powerful and promising method for the rapid detection, identification and quantification of pathogens and biofouling agents in closed manned habitats.

Bacteria↗
PubMed2005

Detection of Helicobacter pylori DNA in human faeces and water with different levels of faecal pollution in the north-east of Spain.

AIMS: To assess the role of water in the faecal transmission of Helicobacter pylori by detecting the DNA of this pathogen in human faecal samples and environmental water samples with a range of faecal pollution from the north-east of Spain. METHODS AND RESULTS: Semi-nested PCR was used to detect H. pylori in stools and water, both matrices with a complex biota. DNA was detected using highly specific primers of an ureA gene fragment. In addition, antigens were used to detect the bacteria in stools. Helicobacter pylori was detected in 33% of 36 human faecal samples and in 66% of wastewater samples, and 11% of river samples, but in none of the spring waters samples. Faecal pollution of the aquatic environment was tested analysing the presence of microbial indicators. CONCLUSIONS: We report the presence of H. pylori DNA in stools and in aquatic environments with different levels of faecal pollution, from the north-east of Spain. In this study a higher number of positive results were obtained in the more faecally polluted waters. SIGNIFICANCE AND IMPACT OF THE STUDY: These data indicate that water may be a vector of H. pylori in its faecal-oral route.

Adolescent↗
PubMed2002

Microflora of date fruits and production of aflatoxins at various stages of maturation.

Twenty-five varieties of dates (Phoenix dactylifera) were examined at different maturation stages for total microbial counts, aflatoxins and aflatoxigenic Aspergillus sp. and lactic acid bacteria. The samples were examined as fresh and under simulated storage condition of high humidity. Microbial counts were high at the first stage of maturation (Kimri) and increased sharply at the second stage (Rutab), then decrease significantly at the final dried stage of maturation (Tamr). Aflatoxins were detected in 12% of the samples although aflatoxigenic Aspergillus were detected in 40% of the varieties examined, all at Kimri stage only. Lactic acid bacteria were present only at the Rutab stage in some varieties including all varieties in which aflatoxins or aflatoxigenic Aspergillus were detected. No aflatoxins or aflatoxigenic Aspergillus were detected at the final edible stage of maturation.

Aflatoxins↗
PubMed1994

Atmospheric contamination during dental procedures.

The aim of this study was to evaluate the level of aerosol pollution following dental procedures performed in 15 sessions with an ultrasound scaler and a bicarbonate cleaner. The air contamination was measured by means of the Surface Air System method and the "plate" method (Air Microbial Index). Each colony-forming unit per cubic meter of air was allotted a unit value for statistical analysis. The data were then compared with the hygienic assessments made in previous studies. The results showed that the initial environmental conditions in a dental office initiated at the level of mediocre, then became very bad during dental procedures, and fell between mediocre and very bad at the end of the procedures.

Aerosols↗
PubMed1998

The effect of prosthesis disinfection on salivary microbial levels.

The aim of this study was to evaluate how the soaking of dentures in a disinfection solution affects salivary microbe counts and stomatitis of partially dentate patients. Patients soaked their dentures for 4 weeks randomly both in a disinfection solution and in a placebo solution. Mutans streptococci, lactobacilli and yeast counts were measured before and after each test period and also the flow rate, buffer capacity and pH of saliva were registered. Disinfection decreased all microbe levels investigated, but only lactobacilli counts decreased significantly. Placebo treatment had either no effect on salivary microbe counts or they increased slightly. Disinfection caused some reduction of the mucosal inflammation under the denture base, but could not completely remove stomatitis during the 4-week test period.

Adult↗
PubMed2004

Partitioning of the variance in the growth parameters of Erwinia carotovora on vegetable products.

The objective of this paper was to estimate and partition the variability in the microbial growth model parameters describing the growth of Erwinia carotovora on pasteurised and non-pasteurised vegetable juice from laboratory experiments performed under different temperature-varying conditions. We partitioned the model parameter variance and covariance components into effects due to temperature profile and replicate using a maximum likelihood technique. Temperature profile and replicate were treated as random effects and the food substrate was treated as a fixed effect. The replicate variance component was small indicating a high level of control in this experiment. Our analysis of the combined E. carotovora growth data sets used the Baranyi primary microbial growth model along with the Ratkowsky secondary growth model. The variability in the microbial growth parameters estimated from these microbial growth experiments is essential for predicting the mean and variance through time of the E. carotovora population size in a product supply chain and is the basis for microbiological risk assessment and food product shelf-life estimation. The variance partitioning made here also assists in the management of optimal product distribution networks by identifying elements of the supply chain contributing most to product variability.

Beverages↗
PubMed2002

Microbial activity in soils following steam treatment.

Steam enhanced extraction (SEE) is an aquifer remediation technique that can be effective at removing the bulk of non-aqueous phase liquid (NAPL) contamination from the subsurface, particularly highly volatile contaminants. However, low volatility compounds such as polynuclear aromatic hydrocarbons (PAHs) are less efficiently removed by this process. This research evaluated the effects of steam injection on soil microbial activity, community structure, and the potential for biodegradation of contaminants following steam treatment. Three different soils were evaluated: a laboratory-prepared microbially-enriched soil, soil from a creosote contaminated field site, and soil from a chlorinated solvent and waste oil contaminated field site. Results from field-scale steaming are also presented. Microbial activity before and after steam treatment was evaluated using direct epifluorescent microscopy (DEM) using the respiratory activity dye 5-cyano-2,3, ditolyl tetrazolium chloride (CTC) in conjunction with the fluorochrome 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF) to yield a quantitative assessment of active and total microbial numbers. DEM results indicate that steamed soils that were analyzed while still hot exhibited microbial activity levels that were below detection. However, soil samples that were slowly cooled, more closely reflecting the conditions of applied SEE, exhibited microbial activity levels that were comparable to presteamed soils. Samples from a field-site where steam was applied continuously for 6 weeks also showed high levels of microbial activity following cooling. The metabolic capabilities of the steamed communities were investigated by measuring cell growth in enrichment cultures on various substrates. These studies provided evidence that organisms capable of biodegradation were among the mesophilic populations that survived steam treatment. Fluorescent in situ hybridization (FISH) analysis of the soils with domain-level rRNA probes suggest that both Archaea and Bacteria survived steam exposure.

Archaea↗
PubMed2003

Effects of the soluble fibre pectin on intestinal cell proliferation, fecal short chain fatty acid production and microbial population.

AIM: Although pectin, a dietary fibre, has been suggested to possess some trophic effects on the intestine, the mechanisms involved remain unclear. This study aimed to evaluate the effects of pectin on rat intestinal cell proliferation and the intraluminal environment. METHODS: Control and pectin-fed rats were given a fibre-free elemental diet (ED) and an ED containing 2.5% pectin, respectively. On the 15th day, the length, weight and number of Ki-67-positive cells from each intestinal segment, and the short chain fatty acids (SCFAs) and microbial population in the caecum were measured. Plasma glucagon-like peptide-2 (GLP-2) concentration and GLP-2 receptor (GLP-2R) mRNA levels in the epithelium were also determined. RESULTS: Pectin supplementation resulted in significant increases in the length, weight, and number of Ki-67-positive cells in the ileum, caecum and colon. Although pectin supplementation did not affect the caecal microbial flora that produced SCFAs, the caecal SCFA content was significantly increased. Pectin supplementation also induced an increase in the plasma GLP-2 concentration, but did not affect the GLP-2R mRNA levels in the small intestine. CONCLUSIONS: The increases in the caecal SCFAs and plasma GLP-2 levels induced by pectin supplementation may cause mucosal proliferation in the lower intestinal tract.

Animals↗