Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Colony Count, Microbial”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,207 records · Page 67Linked to original sources
PubMed2002

Microbial profile on metallic and ceramic bracket materials.

The placement of orthodontic appliances creates a favorable environment for the accumulation of a microbiota and food residues, which, in time, may cause caries or exacerbate any pre-existing periodontal disease. The purpose of the present study was to compare the total bacterial counts present on metallic and ceramic orthodontic brackets in order to clarify which bracket type has a higher plaque retaining capacity and to determine the levels of Streptococcus mutans and Lactobacillus spp on both types of brackets. Thirty-two metallic brackets and 24 ceramic brackets were collected from orthodontic patients at the day of debonding. Two brackets were collected from each patient; one from a maxillary central incisor and another from a maxillary second premolar. Sixteen patients who used metallic brackets and 12 patients who used ceramic brackets were sampled. Bacterial populations were studied using "checkerboard" DNA-DNA hybridization, which uses DNA probes to identify species in complex microbial samples. The significance of differences between groups was determined using the Mann-Whitney U-test. Results showed no significant differences between metallic and ceramic brackets with respect to the caries-inducing S mutans and L acidophilus spp counts. Mean counts of 8 of 35 additional species differed significantly between metallic and ceramic brackets with no obvious pattern favoring one bracket type over the other. This study showed higher mean counts of Treponema denticola, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum ss vincentii, Streptococcus anginosus, and Eubacterium nodatum on metallic brackets while higher counts of Eikenella corrodens, Campylobacter showae, and Selenomonas noxia were found on ceramic brackets.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Microbiological and chemical quality of raw milk in New York State.

Between December 1993 and January 1996, samples of raw milk from bulk tanks were collected by licensed milk haulers at the time of pick-up from 855 randomly selected farms in New York State (representing approximately 10% of all dairy farms in the state). The milk was examined for microbial and chemical qualities. Bacterial numbers were determined by standard plate count, laboratory-pasteurized count, coliform count, heat-resistant spore-forming psychrotroph count, aerobic spore count (mesophilic), rapid psychrotrophic count, and preliminary incubation count. The frequency distributions for these counts are presented. Paired correlation analyses between the microbiological parameters showed low correlations between test results; no correlation coefficients were > 0.8. The four highest positive correlation coefficients were found between standard plate count and rapid psychrotrophic count (0.7685), rapid psychrotrophic count and preliminary incubation count (0.6648), standard plate count and preliminary incubation count (0.5800), and aerobic spore count and laboratory-pasteurized count (0.5393). All other correlation coefficients were < 0.5. Milk freezing points and acid degree values were determined for all samples. Frequency distributions for these results are also presented.

Animals↗
PubMed2002

Influence of starter and nonstarter on the formation of biogenic amine in goat cheese during ripening.

Two commercial starters were investigated for their potential ability to decarboxylate amino acids during goat cheese ripening. Two batches of goat cheese were produced with identical pasteurized milk but different starter cultures. One of them contained Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris and the other Lactococcus lactis subsp. lactis. The amine contents, microbial counts, proteolysis-related parameters, pH, total solids and salt content were studied in raw materials and cheeses. In raw materials, polyamines were the prevailing amines, whereas the main amines in cheeses were putrescine, tryptamine and, in particular, tyramine (94.59 mg/kg). Aerobic mesophilic microorganisms and Lactococcus counts increased throughout ripening, while Enterobacteriaceae were no longer detectable in cheese after 30 days of ripening. Amine concentration rose during cheese ripening in both batches. Moreover, the decarboxylase activity of microorganisms isolated from samples during cheese ripening was assayed and discussed.

Animals↗
PubMedDate not supplied

A method for the rapid detection of microbial contaminants in animal cell culture processes.

The early detection of microbial contamination is an important issue in the production of biopharmaceuticals using animal cell culture systems. A new method, based on the ChemScan RDI analyser, was evaluated for the rapid detection and enumeration of low concentrations of microorganisms within a large population of animal cells and in cell culture media. The method was tested with suspension cell cultures and is applicable to adherent cell cultures. In both cases, the method uses an initial step to eliminate the animal cells followed by collection and fluorescent labelling of the viable microbial contaminants on a filter membrane. Total counts of the viable microorganisms were obtained after analysis of the membrane by the ChemScan RDI analyser. The results showed that the ChemScan RDI detected individual bacterial cells after filtration of the pre-treated animal cell culture. The detection limit of the ChemScan RDI was less than 10 bacteria/ml in cell culture containing 10(6) mammalian cells/ml and one bacterium in 500 ml of cell culture medium. A strong correlation between the standard plate count and the ChemScan RDI was observed, even at low bacterial concentrations. The total time for each analysis was less than two hours.

Animals↗
PubMed2001

Contamination and survival of Pseudomonas aeruginosa in hospital used sponges.

The microbial contamination of in-use sponges was investigated. Of the sixty sponges examined, 51 (85%) were contaminated with 10(3)-10(9) colony forming units (CFU) per sponge. Pseudomonas aeruginosa was isolated from sixteen (26.7%) of the sixty sponges. P. aeruginosa survived for 2 months in contaminated sponges which were left at room temperature and became dry to the touch. The susceptibility of sponges to P. aeruginosa contamination should be recognized. Once sponges are contaminated with P. aeruginosa, eradication of this organism is difficult even if the sponges are dried.

Cell Division↗
PubMed1996

[Dust and microorganism count at delivery, sorting and composting of home refuse and home refuse-like industrial waste].

The exposure of employees to airborne dust and microorganisms was assessed in a waste processing plant established to recover reusable materials from unsorted domestic and industrial waste. Exposure criteria considered relevant were the quantity of the individual size-selected particle fractions, the morphological properties of the particles, their heavy metal content, and the degree of their contamination with various microorganisms and mold. In addition, separate microbiological analyses to determine potential pathogen concentrations in the air were made. The highest concentrations of total and fine dust were measured in the waste delivery area. A close correlation between the frequency of deliveries and the level of dust exposure was observed. In this area, fine dust concentrations exceeded the threshold limit value of 6 mg/m3 repeatedly for shorter periods. The average fine dust concentration during an entire work-shift, however, was considerably lower than this value. Particles with an aerodynamic diameter of 2 to 7 microns predominated both in the waste delivery and the processing areas. Fibrous dust particles were present in smaller numbers than spherical particles and consisted mainly of organic materials. Natural and artificial inorganic fibers were found only occasionally. The concentrations of lead, cadmium, nickel and mercury were considerably lower than the corresponding MAK and TRK values, and were--with the exception of lead--in the range of the respective metal concentrations in the atmosphere of urban areas. Microscopical examinations of used protective masks (protection category P2) revealed that dust particles were deposited even on the inner side of the masks. Most of the particles on this side were very small and carried nickel or titanium. Microorganism concentrations measured in air from the highly dust-exposed areas of the plant showed values up to 6.9 x 10(5) cfu/m3, with a mold content of 6.6 x 10(4) cfu/m3. Approximately 90% of the microorganisms were deposited on particles of the fine dust fraction (particle size < 7 microns), and more than 50% contaminated particles with an aerodynamic diameter of 2 to 4.7 microns. In the compost facility, mold concentrations of up to 8.4 x 10(5) cfu/m3 were measured. In contrast, the level of microbial contamination in the filtered air from the compost facility did not exceed the concentration measured in air outside the plant. The data which were obtained during the winter months are probably at the lower end of the average exposure range over the entire year. In regard to exposure assessment, it should be mentioned that particles with a size of 4 to 7 microns are not really "inert" particles, since they are preferential carriers for heavy metals and microorganisms. More studies in the future should be performed to establish, whether the level of exposure to microorganisms can be estimated indirectly by the determination of dust exposure.

Air Microbiology↗
PubMed2006

Quantification of methanogens by fluorescence in situ hybridization with oligonucleotide probe.

To monitor anaerobic environmental engineering system, new method of quantification for methanogens was tested. It is based on the measurement of specific binding (hybridization) of 16S rRNA-targeted oligonucleotide probe Arc915, performed by fluorescence in situ hybridization (FISH) and quantified by fluorescence spectrometry. Average specific binding of Arc915 probe was 13.4+/-0.5 amol/cell of autofluorescent methanogens. It was 14.3, 13.3, and 12.9 amol/cell at the log phase, at stationary phase and at the period of cell lysis of batch culture, respectively. Specific binding of Arc915 probe per 1 ml of microbial sludge suspension from anaerobic digester linearly correlated with concentration of autofluorescent cells of methanogens. Coefficient of correlation was 0.95. Specific binding of oligonucleotide probe Arc915 can be used for the comparative estimation of methanogens during anaerobic digestion of organic waste. Specific binding of Arc915 probe was linear function of anaerobic sludge concentration when it was between 1.4 and 14.0 mg/ml. Accuracy of the measurements in this region was from 5 to 12%.

Anaerobiosis↗
PubMed1995

[Microbial contamination of immersed massage devices].

Investigations in the District of Schaumburg. On the occasion of the inspection of a hospital we became aware of the problem of contamination of underwater-massage tubs with microorganisms. Hence, investigations according to the German DIN standard 19,643 were performed on 41 tubs. Very often we found a high count of microorganisms. If Pseudomonas aeruginosa was detected, the use of the respective tub was prohibited because of the risk of infection (about 70% of all tubs). The reasons are the design of the pumps and different procedures of cleaning and disinfection. During the investigations the suppliers of the apparatus were queried. In some cases, technical improvements have already been effected. Reliable standard disinfection procedures must be developed.

Colony Count, Microbial↗
PubMed1996

Effect of an antiseptic mouthrinse on salivary microbiota.

PURPOSE: To evaluate the effect of rinsing with original formulation Listerine Antiseptic (LA) on the level of viable salivary bacteria for periods up to 1 hour. MATERIALS AND METHODS: In this double-blind, controlled, cross-over study, unstimulated saliva was collected from 25 subjects, serially diluted, and cultured on selective and non-selective media under aerobic and anaerobic conditions. Streptococci, Veillonella sp., and total aerobic and anaerobic flora were enumerated just prior to and 2, 15, 30, and 60 minutes after rinsing for 30 seconds with either 20 ml of LA or a 5% hydroalcohol control rinse. RESULTS: After the control rinse, total flora cultivated on MM10 agar exhibited a non-significant (P > 0.05) 10%-20% decrease relative to baseline. In contrast, rinsing with LA resulted in a significant (P < 0.05) 60%-65% decrease from baseline in all four microbial groups at 2 minutes; except in the case of Veillonella, the significant decreases were sustained up to 60 minutes. Total Listerine group aerobic, anaerobic and streptococcal counts were significantly lower than placebo (P < 0.05). The significant reduction in salivary bacterial levels seen in the Listerine group for up to 60 minutes suggests that this antiseptic mouthrinse may have use clinically as a pre-procedural rinse to decrease the level of viable microorganisms in aerosols generated during dental procedures.

Adult↗
PubMedDate not supplied

[Simplified model of increase in colony diameter during growth of unicellular microorganisms and its use in evaluating the effect of biocides on microbial cells].

A simplified model of increase in colony diameter is proposed. The model uses the size of single cells and several measurements of colony diameter during linear growth for calculating with good approximation the growth curve for the culture from the moment of inoculation. The parameter mu(m)', which is approximately 10% lower than the maximum specific growth rate of the colony biomass, could be also calculated. The effect of copper sulfate on the colony growth of Pseudomonas sp. G-1 was studied using the model. A high concentration of Cu2+ ions was found to result in decreases in the value of mu(m)', colony diameter, and the rate of increase in the colony diameter.

Bacteria↗
PubMed1979

Microbiological flora as a function of ice depth in central Antarctica.

A technique has been developed for obtaining ice samples under sterile conditions for microbiological analyses as a function of ice thicknesses and with a view to clarifying the possibility of long term microbial anabiosis under permafrost conditions. For the first time microbiological studies from the surface down to 312 meters in the Vostok station region have been carried out and the distribution of microorganisms in the strata studied has been clarified. Microorganisms occur rather rarely, and their distribution is of a random character, independent of the depth of sampling. Viable microorganisms have been found in the ice horizons approximately as old as 8-13 thousand years.

Antarctic Regions↗
PubMed2006

Microbial contamination of endodontic files received from the manufacturer.

This study was conducted to test the sterility of new unused endodontic files received from manufacturers. Fifteen types of hand and rotary files from five manufacturers were tested. Positive microbial cultures were obtained from 13% of the 150 files tested. Autoclaved files were intentionally contaminated with bacterial species recovered from the positive cultures to evaluate a chairside sterilization method. Immersion of contaminated files in 5.25% sodium hypochlorite for five minutes sterilized the files. The results of this study indicate that endodontic files should be sterilized before clinical use. It is also suggested that manufacturers list the sterility state of their endodontic files on their packaging.

Bacillaceae↗
PubMed2003

Persistence of biofilm-associated Escherichia coli and Pseudomonas aeruginosa in groundwater and treated effluent in a laboratory model system.

This study was based on the hypothesis that groundwater-derived biofilms may provide a reservoir for coliform or pathogenic bacteria as has been observed in drinking water distribution systems. Escherichia coli, labelled with green fluorescent protein, was found to colonize all layers of mixed-population biofilms developed in association with indigenous groundwater micro-organisms in a laboratory-scale reactor. Biofilm-associated E. coli was removed at a slower rate from the reactor flasks than planktonic E. coli under a continuous flow regime. During flow-through of groundwater, planktonic E. coli removal was slower in flasks containing coverslips for enhanced biofilm development compared to a control flask without coverslips. Conversely, during flow-through of treated effluent, planktonic E. coli removal was faster in flasks with coverslips compared to without. Removal of attached E. coli was also fastest in the coverslip-containing flasks with effluent flow-through. This suggests that an increase in available nutrients may reduce E. coli survival potential due to either enhanced competition for nutrients or enhanced antagonism by the indigenous microbial population. Under identical conditions, GFP-labelled Pseudomonas aeruginosa was found to persist in the biofilms for longer than E. coli, most notably when exposed to flow-through of treated effluent. However, prolonged persistence of P. aeruginosa in the effluent could not be attributed to an association with the biofilms. This study has shown that under certain conditions the presence of mixed-population biofilms may limit the survival potential of enteric bacterial pathogens introduced into groundwater.

Biofilms↗
PubMed1998

Microbial stability and fate of Salmonella enteritidis in halva, a low-moisture confection.

A traditional low-moisture confectionery, halva, was studied with respect to microbial stability over prolonged storage. It was kept under refrigeration or at room temperature in air-sealed or vacuum packaging in moisture-proof material. Microbial stability of commercial samples was evaluated with regard to the following groups of microorganisms: aerobic plate count, Enterobacteriaceae, enterococci, sulfite-reducing clostridia, aerobic mesophilic and thermophilic sporeformers, staphylococci, Staphylococcus aureus, Salmonella spp., lipolytic microorganisms, yeasts and molds. In all samples tested the above microorganisms were in acceptable levels, while sulfite-reducing clostridia, Salmonella spp., and molds were not detected. The potential for survival of Salmonella Enteritidis in the product was evaluated by artificial contamination. Inoculum surviving after the immediate significant decrease was still recovered after 8 months of storage. The reduction of salmonellae during storage cannot be predicted on the basis of the aw alone.

Candy↗
PubMed2005

Inhibition of Listeria monocytogenes and Salmonella by natural antimicrobials and high hydrostatic pressure in sliced cooked ham.

The effectiveness of nisin, lactate salts, and high hydrostatic pressure to inhibit the growth of Listeria monocytogenes and Salmonella in sliced cooked ham was studied through a combination of PCR-based detection methods, most probable number, and classical microbial enumeration techniques (International Organization for Standardization protocols). A synergistic effect to inhibit a cocktail of Listeria monocytogenes CTC1010, CTC1011, and CTC1034 was observed between potassium lactate, high hydrostatic pressure (400 MPa, 17 degrees C, 10 min), and low storage temperature when sliced cooked ham was stored for 84 days at 1 degrees C. The high hydrostatic pressure treatment also proved to be useful to inhibit a cocktail of Salmonella enterica serotypes London CTC1003, Schwarzengrund CTC1015, and Derby CTC1022.

Animals↗
PubMed1992

Aerosol generation by two ultrasonic scalers and one sonic scaler. A comparative study.

The purposes of this study were to compare the amount of aerosols generated from ultrasonic and sonic scalers and to measure the potential depth of respiratory tract penetration. Forty subjects were randomly assigned to receive instrumentation with the magnetostrictive, piezoelectric, or air turbine scaler. The Anderson Air Sampler collected total baseline airborne microbes for 20 minutes prior to treatment and for 20 minutes during instrumentation. This cascade impactor system measures the degree of microbial penetration in a simulated respiratory system. Blood agar plates from the sampler were incubated for 24 hours at 37 degrees C. Colony forming units per cubic foot of air (CFUs/cu. ft.) were enumerated by one blind examiner using a Lab Line Colony Counter. Data for total microbial CFUs/cu.ft. and CFUs/cu.ft. by sampler level were analyzed on the log-transformed data using ANCOVA. Baseline values of airborne bacteria served as the covariate. Results showed no significant difference in mean combined total CFUs/cu.ft. for the magnetostrictive, piezoelectric, or air turbine sonic scalers. The magnetostrictive scaler generated the lowest CFUs/cu.ft. at the deepest level of penetration; however, no significant difference in level of penetration was found among the three scalers.

Aerosols↗
PubMed1998

Effect of high hydrostatic pressure on Pacific whiting surimi.

The effects of high hydrostatic pressure (HHP) on gel strength, microbial numbers, proteolytic activity, color and pH of Pacific whiting surimi gels were investigated. Strong gels without the use of protease inhibitors were formed with HHP treatments from 1-4 kBars. Gel strength was not affected by holding time. Total plate counts showed that destruction of vegetative cells was accomplished with 4 kBar. Proteolytic activity was diminished but not eliminated with pressure treatments. The color of the surimi gels treated were translucent while the heat-treated gels were opaque. The pH was increased slightly with HHP treatment. HHP was an effective processing method for making high quality surimi gels from Pacific whiting.

Animals↗
PubMed2004

Cutaneous bacterial colonization, modalities of chemotherapeutic infusion, and catheter-related bloodstream infection in totally implanted venous access devices.

GOALS OF WORK: Prospective clinical study to evaluate patients suffering from solid tumor using a totally implanted venous access device (TIVAD) to determine: (1) if there is a relationship between cutaneous contamination at port insertion site and catheter-related bloodstream infection (CRBI); (2) development modalities of CRBI; (3) if there is a relationship between chemotherapy administration modalities by push/ bolus versus continuous infusion and CRBI. PATIENTS AND METHODS: We studied 41 consecutive patients who needed a TIVAD positioned for chemotherapy administration by bolus/ push or continuous infusion. In every patient, we performed blood cultures from blood samples from port catheters and cutaneous cultures from cutaneous tampons of the skin surrounding the implant area on the first (T0) and eight day (T1) postoperatively, after 1 month (T2), and after 3 months (T3) from insertion. MAIN RESULTS: The study was completed on 40 patients; in one case, the port was removed at T2 for septic complications. We obtained four positive blood cultures (two, 5%), two in the same patient, all caused by staphylococcus. Positive cutaneous tampons were 21 (13%) in 11 patients (27%); the four CRBI occurred in this group of patients with none in the remaining 30 patients (73%) for a total number of 120 tampons (p<0.01). In two cases, the same germ was isolated from both the skin and blood. None of the patients presented a local infection of the subcutaneous pocket. Positive cutaneous cultures decrease over time: T0-T2; 24-5%; T1-T3, 20-5% (p<0.04). There were no differences in CRBI incidence and positive cutaneous tampons between the two chemotherapy administration modalities. CONCLUSIONS: Cutaneous microbial flora has a primary role in CRBI development within TIVADs; there is a relationship between cutaneous colonization and CRBI; colonization reaches its maximum during the first days after catheterization in which the use of the system is at high risk; colonization occurs both via extraluminal and endoluminal routes; there is no difference in CRBI incidence between bolus and continuous infusion administration.

Aged↗