Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Total Microbial Load”

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 199 records · Page 11Linked to original sources
PubMed2005

Tubular microbial fuel cells for efficient electricity generation.

A tubular, single-chambered, continuous microbial fuel cell (MFC) that generates high power outputs using a granular graphite matrix as the anode and a ferricyanide solution as the cathode is described. The maximal power outputs obtained were 90 and 66 W m(-3) net anodic compartment (NAC) (48 and 38 W m(-3) total anodic compartment (TAC)) for feed streams based on acetate and glucose, respectively, and 59 and 48 W m(-3) NAC for digester effluent and domestic wastewater, respectively. For acetate and glucose, the total Coulombic conversion efficiencies were 75 +/- 5% and 59 +/- 4%, respectively, at loading rates of 1.1 kg chemical oxygen demand m(-3) NAC volume day(-1). When wastewater was used, of the organic matter effectively removed (i.e., 22% at a loading of 2 kg organic matter m(-3) NAC day(-1)), up to 96% was converted to electricity on a Coulombic basis. The lower overall efficiency of the wastewater-treating reactors is related to the presence of nonreadily biodegradable organics and the interference of alternative electron acceptors such as sulfate present in the wastewater. To further improve MFCs, focus has to be placed on the enhanced conversion of nonrapidly biodegradable material and the better directing of the anode flow toward the electrode instead of to alternative electron acceptors. Also the use of sustainable, open-air cathodes is a critical issue for practical implementation.

Acetates↗
PubMed1997

Dynamic multidrug therapies for HIV: a control theoretic approach.

Motivated by the inability of current drug treatment to provide long-term benefit to HIV-infected individuals, we derive HIV therapeutic strategies by formulating and analyzing a mathematical control problem. The model tracks the dynamics of uninfected and infected CD4+ cells and free plasma virus, and allows the virus to mutate into various strains. At each point in time, several different therapeutic options are available, where each option corresponds to a combination of reverse transcriptase inhibitors. The controller observes the individual's current status and chooses among the therapeutic options in a dynamic fashion in order to minimize the total viral load. Our initial numerical results suggest that dynamic therapies have the potential to significantly outperform the static protocols that are currently in use; by anticipating and responding to the disease progression, the dynamic strategy reduces the total free virus, increases the uninfected CD4+ count, and delays the emergence of drug-resistant strains.

CD4-Positive T-Lymphocytes↗
PubMed2001

Effect of temperature increase from 55 to 65 degrees C on performance and microbial population dynamics of an anaerobic reactor treating cattle manure.

The effect of a temperature increase from 55 to 65 degrees C on process performance and microbial population dynamics were investigated in thermophilic, lab-scale, continuously stirred tank reactors. The reactors had a working volume of 31 and were fed with cattle manure at an organic loading rate of 3 g VS/l reactor volume/d. The hydraulic retention time in the reactors was 15 days. A stable reactor performance was obtained for periods of three retention times both at 55 degrees C and 65 degrees C. At 65 degrees C methane yield stabilized at approximately 165ml/g VS/d compared to 200 ml/g VS/d at 55 degrees C. Simultaneously, the level of total volatile fatty acids, VFA, increased from being below 0.3 g/l to 1.8-2.4 g acetate/l. The specific methanogenic activities (SMA) of biomass from the reactors were measured with acetate, propionate, butyrate, hydrogen, formate and glucose. At 65 degrees C. a decreased activity was found for glucose-, acetate-, butyrate- and formate-utilizers and no significant activity was measured with propionate. Only the hydrogen-consuming methanogens showed an enhanced activity at 65 degrees C. Numbers of cultivable methanogens, estimated by the most probable number (MPN) method, were significantly lower on glucose, acetate and butyrate at the increased operational temperature, while the numbers of hydrogenotrophic methanogens remained unchanged. No viable propionate-degrading bacteria were enriched at 65 C. Use of ribosomal oligonucleotide probes showed that an increase in temperature resulted in a decreased contribution of the rRNA of the domain bacteria from 74-79 to 57-62% of the universal probe, while the rRNA of the domain archaea, increased from 18-23 to 34-36%.

Anaerobiosis↗
PubMed2006

Comparison of different packing materials for the biofiltration of air toxics.

Four different biofilter packing materials (two porous ceramics, perlite, and open pore polyurethane foam) were compared for the removal of toluene vapors. The focus was on evaluating performance at relatively short gas retention time (13.5 and 27 sec). The reactors were initially operated as biotrickling filters with continuous feeding and trickling of a nutrient solution. After significant plugging of the biotrickling filter beds with biomass was observed, the operation mode was switched to biofiltration with only periodic supply of mineral nutrients. This resulted in stable conditions, which allowed detailed investigations over > 6 months. The reactor packed with cattle bone Porcelite (CBP), a ceramic material containing some macronutrients and micronutrients, exhibited the highest performance. The critical load (i.e., load at which 95% removal occurred) was 29 g m(-3) hr(-1) at a gas retention time of 13.5 sec and 66 g m(-3) hr(-1) at a gas retention time of 27 sec. After the long-term experiment, the packing materials were taken from the reactors and examined. The reactors were divided into three sections, top, middle, and bottom, to determine whether spatial differentiation of biomass occurred. The assays included a double-staining technique to count total and live microorganisms and determination of moisture, protein, and dry weight contents. Microbial community analysis was also conducted by denaturing gradient gel electrophoresis. The results showed that most reactors had a significant fraction of inactive biomass. Comparatively, the CBP biofilter held significantly higher densities of active biomass, which may be the reason for the higher toluene removal performance. The analyses suggest that favorable material properties and the nutrients slowly released by the CBP provided better environmental conditions for the process culture.

Air Pollutants↗
PubMed1988

Antibiotic resistance of coagulase-negative staphylococci in an orthopaedic department.

Coagulase-negative staphylococci (CNS) were cultured from the anterior nares of surgeons, theatre and ward staff, and from patients before and 2 weeks after a total hip replacement. The CNS found in ward staff were more resistant to antibiotics than those in surgeons and theatre staff. Methicillin resistance of CNS in patients increased from 4 to 31% following surgery. Gentamicin-resistant CNS were only found postoperatively, in 20% of patients, in most of whom gentamicin-loaded acrylic bone cement was used.

Anti-Bacterial Agents↗
PubMedDate not supplied

Isolation and identification of fungal communities in compost and vermicompost.

This research illustrates the qualitative and quantitative composition of the mycoflora of both a green compost (thermophilically produced from plant debris) and a vermicompost (mesophilically produced by the action of earthworms on plant and animal wastes after thermophilic preconditioning). Fungi were isolated using three media (PDA, CMC, PDA plus cycloheximide), incubated at three temperatures (24, 37 and 45 C). Substantial qualiquantitative differences in the species composition of the two composts were observed. The total fungal load was up to 8.2 X 10(5) CFU/g dwt in compost and 4.0 x 10(5) CFU/g dwt in vermicompost. A total of 194 entities were isolated: 118 from green compost, 142 from vermicompost; 66 were common to both. Structural characterization of this kind is necessary to determine the most appropriate application of a compost and its hygienic quality.

Agriculture↗
PubMed2005

Multiple exposures to swine barn air induce lung inflammation and airway hyper-responsiveness.

BACKGROUND: Swine farmers repeatedly exposed to the barn air suffer from respiratory diseases. However the mechanisms of lung dysfunction following repeated exposures to the barn air are still largely unknown. Therefore, we tested a hypothesis in a rat model that multiple interrupted exposures to the barn air will cause chronic lung inflammation and decline in lung function. METHODS: Rats were exposed either to swine barn (8 hours/day for either one or five or 20 days) or ambient air. After the exposure periods, airway hyper-responsiveness (AHR) to methacholine (Mch) was measured and rats were euthanized to collect bronchoalveolar lavage fluid (BALF), blood and lung tissues. Barn air was sampled to determine endotoxin levels and microbial load. RESULTS: The air in the barn used in this study had a very high concentration of endotoxin (15361.75 +/- 7712.16 EU/m3). Rats exposed to barn air for one and five days showed increase in AHR compared to the 20-day exposed and controls. Lungs from the exposed groups were inflamed as indicated by recruitment of neutrophils in all three exposed groups and eosinophils and an increase in numbers of airway epithelial goblet cells in 5- and 20-day exposure groups. Rats exposed to the barn air for one day or 20 days had more total leukocytes in the BALF and 20-day exposed rats had more airway epithelial goblet cells compared to the controls and those subjected to 1 and 5 exposures (P < 0.05). Bronchus-associated lymphoid tissue (BALT) in the lungs of rats exposed for 20 days contained germinal centers and mitotic cells suggesting activation. There were no differences in the airway smooth muscle cell volume or septal macrophage recruitment among the groups. CONCLUSION: We conclude that multiple exposures to endotoxin-containing swine barn air induce AHR, increase in mucus-containing airway epithelial cells and lung inflammation. The data also show that prolonged multiple exposures may also induce adaptation in AHR response in the exposed subjects.

Air Microbiology↗
PubMed2000

The role of dentistry in palliative care of the head and neck cancer patient.

Although palliative care for the terminally ill is based on a multidimensional philosophy to provide whole-person comfort care while maintaining optimal function, it does not usually include dentistry in its team approach. Dentists can have a significant role in the care of these patients by providing total, active comfort care of the oral cavity. The function of the oral cavity is essential to the patient's ability to thrive. Therefore, alleviation of pain and prevention of infection in the oral cavity should be a priority in providing total, active comfort for the patient. The oral problems experienced by the hospice head and neck patient clearly affect the quality of his or her remaining life. Through routine assessments and interventions by a dentist on the palliative care team (Figure 4), comfort care for the patient may be improved by the maintenance of oral hygiene and procedures to hydrate the oral mucosa. In addition, routine dental assessments may identify dental disease and facilitate dental interventions for caries, periodontal disease, oral mucosal problems or prosthetic needs. Attention to such detail may reduce not only the microbial load of the mouth but the risk for pain and oral infection as well. This multidisciplinary approach to palliative care, including a dentist, may reduce the oral debilities that influence the patient's ability to speak, eat or swallow. Not only does maintenance of oral health have impact on the quality of life, which is already challenged by the disease, but it also aids in the ability of patients to thrive for whatever precious time is left to them.

Bacterial Infections↗
PubMed2004

Chemical and toxic evaluation of a biological treatment for olive-oil mill wastewater using commercial microbial formulations.

Olive-oil-mill wastewater (OMW) has significant polluting properties due to its high levels of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and phenols. In the present study, different commercial bacterial formulations were used in the biological treatment of OMW. COD and toxicity testing using primary consumers of the aquatic food chain (the rotifer Brachionus calyciflorus and the crustacean Daphnia magna) were employed to evaluate abatement of the organic load and reduction of the toxic potential. In addition, the four most active formulations were tested mixed pair-wise on the basis of their unique characteristics in order to evaluate the improvement of treatment. The effect of treatment was assessed by measuring COD removal, reduction of total phenols, and decreased toxicity. The results obtained with the mixed formulations showed that the maximum removal of the organic load was about 85%, whereas phenols were reduced by about 67%. The toxicity for rotifers decreased by 43% and for crustaceans by about 83%.

Animals↗
PubMed2006

Microbial succession in a compost-packed biofilter treating benzene-contaminated air.

Air artificially contaminated with increasing concentrations of benzene was treated in a laboratory scale compost-packed biofilter for 240 days with a removal efficiency of 81-100%. The bacterial community in the packing material (PM) at different heights of the biofilter was analysed every 60 days. Bacterial plate counts and ribosomal intergenic spacer analysis (RISA) of the isolated strains showed that the number of cultivable aerobic heterotrophic bacteria and the species diversity increased with benzene availability. Identification of the isolated species and the main bands in denaturing gradient gel electrophoresis (DGGE) profiles from total compost DNA during the treatment revealed that, at a relatively low volumetric benzene load (1.2< or =VBL< or =6.4 g m(-3) (PM) h(-1)), besides low G+C Gram positive bacteria, originally present in the packing compost, bacteroidetes and beta- and gamma-proteobacteria became detectable in the colonising population. At the VBL value (24.8 g m(-3) (PM) h(-1)) ensuring the maximum elimination capacity of the biofilter (20.1 g m(-3) (PM) h(-1)), strains affiliated to the genus Rhodococcus dominated the microflora, followed by beta-proteobacteria comprising the genera Bordetella and Neisseria. Under these conditions, more than 35% of the isolated strains were able to grow on benzene as the sole carbon source. Comparison of DGGE and automated RISA profiles of the total community and isolated strains showed that a complex bacterial succession occurred in the reactor in response to the increasing concentrations of the pollutant and that cultivable bacteria played a major role in benzene degradation under the adopted conditions.

Air Pollutants↗
PubMed1995

Extending the storage life of chilled beef: microwave processing.

This study investigates whether it is possible to use microwave technology to reduce the bacterial load of meat to such an extent that shelf-life is extended while the product retains the appearance of fresh meat. It investigates the use of microwaves in raising the surface temperature of vacuum-packed beef steak, recording the total aerobic and anaerobic bacterial count, the appearance of the meat and the amount of purging of meat juices within the package.

Animals↗
PubMed2004

[Continuous operation of hydrogen bio-production reactor with ethanol-type fermentation].

The natural response of a continuous stirred tank reactor (CSTR) for hydrogen bio-production using molasses wastewater as substrate was investigated. Emphasis was placed on assessing the operational controlling strategy on the stable operation of CSTR with high efficiency. It was found that at an initial biomass of 15g/L, an equilibrial microbial community in the ethanol-type fermentation and efficient stable operation of CSTR could be established with following conditions: temperature of 35 degrees C +/- 1 degrees C, COD organic loading rate (OLR) of 40kg/(m3 x d), hydraulic retention time (HRT) of 4h, pH value of 4.6 - 4.9 and oxidation reduction potential (ORP) of -450 - -470mV. Following that, hydrogen production in the reactor was relatively stable. The observed maximal hydrogen bio-production rate was 7.63m3/(m3 x d). The content of hydrogen in the biogas was about 40% - 58%. COD removal rate was between 22% - 26%. The total content of ethanol and acetic acid in the fermentative end products was above 80%.

Bacteria, Anaerobic↗
PubMed2006

Land spreading of olive mill wastewater: effects on soil microbial activity and potential phytotoxicity.

Extremely high organic load and the toxic nature of olive mill wastewater (OMW) prevent their direct discharge into domestic wastewater treatment systems. In addition to the various treatment schemes designed for such wastewater, controlled land spreading of untreated OMW has been suggested as an alternative mean of disposal. A field study was conducted between October 2004 and September 2005 to assess possible effects of OMW on soil microbial activity and potential phytotoxicity. The experiment was carried out in an organic orchard located on a Vertisol-type soil (Jezre'el Valley, Israel) and included two application levels of OMW (36 and 72m(3)ha(-1)). Total microbial counts, and to less extent the hydrolytic activity and soil respiration were increased following the high OMW application level. A bench-scale lab experiment showed that the rate of OMW mineralization was mainly dependent on the general status of soil activity and was not related to previous acclimatization of the soil microflora to OMW. Soil phytotoxicity (% germination and root elongation) was assessed in soil extracts of samples collected before and after each OMW application, using germinating cress (Lepidium sativum L.) seeds. We found direct short-term effect of OMW application on soil phytotoxicity. However, the soil was partly or completely recovered between successive applications. No further phytotoxicity was observed in treated soils as compared with control soil, 3 months after OMW application. Such short-term phytotoxicity was not in correlation with measured EC and total polyphenols in the soil extracts. Overall, the results of this study further support a safe controlled OMW spreading on lands that are not associated with sensitive aquifers.

Biodegradation, Environmental↗
PubMed2005

Alteration of pharmacokinetics of oxytetracycline following oral administration of Piper longum in hens.

The pharmacokinetic profile of orally administered oxytetracycline (10 mg/kg body weight) was studied 7 days post oral treatment of Piper longum (15 mg equivalent/kg) in White Leghorn hens (2-2.8 kg). On the day 8, oxytetracycline (OTC) was administered orally and blood samples were collected from the wing vein in heparinised vials for plasma separation at 0 (pre-treatment), 15, 30, 60, 120, 240, 360, 480 and 600 minutes post OTC administration. Plasma OTC concentrations were determined by microbial assay technique using Bacillus cereus var. mycoides (ATCC 11778) as test organism. The plasma levels of OTC against time were adequately described by one compartment open model. The pharmacokinetic data revealed that P.longum treated animals had significantly higher area under curve (AUC), area under the first moment of plasma drug concentration-time curve (AUMC) and mean residential time (MRT). Prior treatment of P.longum significantly reduced elimination rate constant(beta)and increased elimination half life (t(1/2beta)). The total body clearance (Cl(B)) reduced by 21%whereas total duration of pharmacological effect (t(d)) increased by 29%. The treatment with P. longum reduced loading and maintenance dose by 33.3 and 39%, respectively.

Administration, Oral↗
PubMed2002

Integration of aquatic fate and ecological responses to linear alkyl benzene sulfonate (LAS) in model stream ecosystems.

An integrated model stream ecosystem fate and effect study of dodecyl linear alkylbenzene sulfonate (C(12)LAS) was performed in the summer and fall of 1996. The study addressed responses of periphytic microbes, immature benthic fauna including abundance, drift, and emergence of adult insects in a 56-day exposure. Exposures ranged from 126 to 2978 microg/L and were continuously presented in a single-pass, flow-through test system. Microbial heterotrophs acclimated to C(12)LAS exposure quickly (14 days) and biodegraded C(12)LAS at all concentrations. Blue-green algae responded by increasing in abundance with increasing C(12)LAS concentration. Invertebrates responded by increased drift and reduced benthic abundances at concentrations exceeding 293 microg/L. Emergence at 927 microg/L also declined relative to the control. Adverse responses for mayflies and chironomids were indicated using univariate statistical techniques. Multivariate techniques indicated these taxa plus mollusks, aquatic worms, caddisflies, and stoneflies were impaired at some concentrations. Bioavailability of C(12)LAS was investigated in streams as a function of the total suspended solid load in the water column driven by local weather and watershed patterns. A continuous bioavailability model indicated exposure was reduced by an average of 8.5+/-8.9%. A model ecosystem no-observed-effect concentration (NOEC) was concluded to be 293 microg/L based on measured water column exposure and adjusted to 268 microg/L by the bioavailability model. A literature review of 13 available model ecosystem studies was conducted and NOEC conclusions were adjusted by a structure-activity relationship to a dodecyl chain length (sulfophenyl position and distribution being ignored due to lack of information in the reviewed studies). Lentic studies (n=7) were found to have higher NOECs than lotic studies (n=6) and were more variable. Mean NOECs+/-SD for all studies, lentic studies only, and lotic studies only were 3320+/-6040, 5720+/-7640, and 530+/-430 microg/L, respectively. Interpretation of results for anomalies from specific studies suggests the importance of experimental design, use of laboratory versus natural surface water, biological complexity of the test system, and physical test system design as relevant factors for consideration. The specific results of the new model ecosystem study presented in this article can be well defended on the basis of a robust experimental and physical design and because the system contained a diverse and sensitive aquatic community. A low or no uncertainty factor could be applied to the result.

Adsorption↗
PubMed1999

Effect of dehairing operations on microbiological quality of swine carcasses.

To develop a hazard analysis and critical control point plan for food processing operations, critical control points must be determined. Swine slaughtering and dressing operations were investigated to establish their critical control points. We monitored the microbiology of swine carcasses by surface swabbing carcass bellies at various steps during the process and by quantitating total aerobic plate count (APC) and coliforms. Starting with a dehaired carcass, the sequential steps monitored included presingeing, postsingeing, polishing, and chilling. Initial results indicate that singeing and chilling substantially reduced the levels of APC and coliforms, whereas polishing increased their levels. The hygienic characteristics of individual operations involved in dressing swine carcasses were then evaluated in the second experiment. A set of 40 randomly selected carcasses leaving singeer, polisher, shaver, and washer were sampled. Carcasses were heavily contaminated during the final polishing procedure, and the APC increased threefold compared with prepolishing levels. Washing reduced the bacterial numbers by 69%. To reduce the microbial load on swine carcasses, final polishing and manual shaving steps were not used during the dressing operation on a set of 90 carcasses. APCs on singed carcasses were reduced from 1.34 to -0.15 log10 CFU/cm2 when the final polisher and manual shavers were not used. However, carcasses were subsequently recontaminated with bacteria after evisceration, and the APCs were similar (P > 0.05) regardless of whether the final polishing and manual shaving steps were used, averaging 1.30 and 1.46 log10 CFU/cm2. These results indicated that individual operations can be identified as critical control points, appropriate limits can be set and monitored in a hazard analysis and critical control point system, and steps where further changes to reduce bacterial levels may be needed for swine slaughtering plants.

Abattoirs↗
PubMed2006

The effect of organic loading on process performance and membrane fouling in a submerged membrane bioreactor treating municipal wastewater.

The results of experiments on municipal wastewater primary effluent are presented for a pilot-scale submerged membrane bioreactor (SMBR). The SMBR pilot plant employed an ultrafiltration membrane with a nominal pore size of 0.035 microm and was operated at a constant membrane flux of 30 L/m(2)h. The mixed liquor suspended solids (MLSS) concentration was maintained at 8+/-2 g/L and steady-state fouling rates were determined for 10, 5, 4, 3, and 2-d MCRTs, corresponding to food-to-microorganism (F/M) ratios of 0.34, 0.55, 0.73, 0.84, and 1.41 gCOD/gVSS d, respectively. Membrane fouling rates increased as the F/M was increased. Steady-state membrane fouling rates were correlated with total soluble microbial products (SMP) concentrations. The membrane fouling rates did not correlate well with soluble COD measured on a 0.45 microm membrane filtrate of mixed liquor or with soluble COD rejection (effluent COD/soluble COD).

Ammonia↗
PubMed1999

Varying cecal bacterial loads influences colitis and gastritis in HLA-B27 transgenic rats.

BACKGROUND & AIMS: Recent data support an important role of resident luminal bacteria in experimental colitis. We determined how altered cecal bacterial loads influence colitis and gastritis. METHODS: A cecal self-filling blind loop (SFBL) was created or the cecum was excluded from the fecal stream in specific pathogen-free HLA-B27 transgenic (TG) rats with early colitis and in nontransgenic (nonTG) littermates; controls underwent sham operation (SHAM). Luminal bacterial concentrations were determined by culture and counting chamber. RESULTS: TG rats with SFBL had more severe cecal inflammation and leukocytosis than TG SHAM controls. TG excluded rats with low cecal bacterial loads had no cecal inflammation and less colitis and gastritis than SHAM controls, despite having normal distal colonic and gastric bacterial concentrations. Metronidazole attenuated cecal inflammation and eliminated Bacteroides in SFBL TG rats. NonTG SFBL rats had mild cecal inflammation and no gastritis and colitis. The ratio of total anaerobic to aerobic bacteria was 1000-fold greater in SFBL than in SHAM rats, with a 10,000-fold increased ratio of Bacteroides spp. to aerobes. CONCLUSIONS: The luminal bacterial load and composition determines the activity of cecal inflammation in genetically susceptible hosts. Lowering cecal bacterial concentrations can diminish inflammation in remote organs.

Animals↗