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Results for “Total Microbial Load”

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PubMed1983

Degradation of chlorophenols by a defined mixed microbial community.

Synthetic sewage containing phenol, acetone, and alkanols plus 4-chlorophenol or a mixture of isomeric chlorophenols is completely degraded by a defined mixed culture with Pseudomonas sp. strain B13 as a chlorocatechol-dissimilating member of the community. Total degradation of the organic carbon was indicated by release of stoichiometric amounts of chloride and low content of dissolved organic carbon in the cell-free effluents. During adaptation to high loads of chlorophenols the initial meta-cleavage activity was completely replaced by ortho-cleavage activity of type I and II. In the fully acclimated culture, hybrid strains such as Alcaligenes sp. strain A7-2 were detected, which are more competitive than Pseudomonas sp. strain B13 with respect to chlorophenol degradation.

Alcaligenes↗

PubMed1998

Immunomagnetic separation with mediated flow injection analysis amperometric detection of viable Escherichia coli O157.

The coupling of an immunological separation (using immunomagnetic beads) with amperometric flow injection analysis detection of viable bacteria is presented. Using a solution containing Escherichia coli O157, the electrochemical response with two different mediators [potassium hexacyanoferrate(III) and 2,6-dichlorophenolindophenol] was evaluated in the FIA system. Antibody-derivatized Dynabeads were used to selectively separate E. coli O157 from a matrix. The kinetics and the capacity parameters regarding the attachment of bacteria to the immunobeads were studied. The immunomagnetic separation was then used in conjunction with electrochemical detection to measure the concentration of viable bacteria. A calibration curve of colony-forming units (cfu) against electrochemical response was obtained. The detection limit for this rapid microbiological method was 10(5) cfu mL-1, and the complete assay was performed in 2 h. Some advantages over ELISA methods are the direct detection of viable cells (and not total bacterial load) and the need for only one antibody (not enzyme-labeled), thus making the assay faster (only one washing step is necessary) and less expensive.

2,6-Dichloroindophenol↗

PubMed2005

Integrated natural treatment systems for developing communities: low-tech N-removal through the fluctuating microbial pathways.

Integration of natural treatment systems (NTS) (WSP, wetlands etc.) with each other as well as with advanced unit processes (biofiltration) offers a second lease of life to NTS. Long-term full and pilot cale experience in South Africa and Thailand have shown that contrary to a common view, a low tech N-removal from municipal and light industrial wastewater is a reality for a developing community The high treatment efficiency is ascribed to interplay of N-related processes complementing each other. The present FISH-based (Fluorescence In Situ Hybridization) approach to microbial community structure is a pioneering effort in the field of NTS. It establishes interrelationships between major N-removing groups (aerobic and anaerobic ammonia oxidizers (ANAMMOX), denitrifiers) within integrated systems and links them to the high treatment performance. Seasonally fluctuating presence of the ANAMMOX bacteria (0-2.5% of total bacterial numbers) in the NTS (free surface flow wetland) is reported for the first time. Their numbers correlate with metabolically dependent ammonia-oxidizers (2.0-3.0%) but not with stable overall Planctomycetes population (4.5-5.1%). As a result of the flexible microbial structure the robust low cost removal down to TN < 10 mg/L is routinely feasible at the loading rates ranging from 0.005 to 0.08 TN kg/m3/day.

Ammonia↗

PubMed2001

[Quality of water of dental units. A survey in the region of Berne, Switzerland].

The aim of this study was to assess the microbial contamination of the water from 175 dental units, which had not been in use for at least 12 hours, and to determine the usefulness of rinsing the water lines for 3 minutes. Only 10% of all units fulfilled all criteria for drinking water. Frequently the total bacterial counts markedly exceeded 100 CFU/ml. In all cases the rinsing decreased bacterial loads significantly. Bacterial contamination of water lines increased with the time the dental units remained unused. It is recommended to rinse dental unit water lines daily for at least 3 minutes before working on patients.

Data Collection↗

PubMed1998

Mathematical analysis of antiretroviral therapy aimed at HIV-1 eradication or maintenance of low viral loads.

Motivated by the ability of combinations of antiretroviral agents to sustain viral suppression in HIV-1-infected individuals, we analyse the transient and steady-state behavior of a mathematical model of HIV-1 dynamics in vivo in order to predict whether these drug regimens can eradicate HIV-1 or maintain viral loads at low levels. The model incorporates two cell types (CD4+ T cells and a long-lived pool of cells), two strains of virus (drug-sensitive wild type and drug-resistant mutant) and two types of antiretroviral agents (reverse transcriptase and protease inhibitors). The transient behavior of the cells and virus and the eventual eradication of the virus are determined primarily by the strength of the combination therapy against the mutant strain and the maximum achievable increase in the uninfected CD4+ T cell concentration. We also predict, if the parameters of the model remain constant during therapy, that less intensive maintenance regimens will be unable to maintain low viral loads for extensive periods of time. However, if the reduction in viral load produced by therapy reduces the state of activation of the immune system, the number of cells susceptible for HIV-1 infection may decrease even though total CD4+ T cells increase. Our model predicts that if this occurs strong inductive therapy that reduces viral load followed by weaker maintenance regimes may succeed.

Antiviral Agents↗

PubMed1991

Bacteriological safety of cook-chill food at the Royal Free Hospital, with particular reference to Listeria.

Cook-chill food prepared by the Catering Department of the Royal Free Hospital was examined over an 8-month period commencing October 1989. Total aerobic viable counts (TAVCs) were performed on 200 food specimens which were also examined for Listeria using selective enrichment culture. Ten of 200 food samples tested had TAVCs greater than 10(5) colony forming units (cfu) g-1, and nine of these were from non-vegetarian (meat) dishes. Although most of the food prepared by cook-chill had microbial loads within the limits recommended by current Department of Health guidelines (i.e. less than 10(5) cfu g-1), our findings for the non-vegetarian dishes suggest that extra caution is required when preparing such food. Listeria were not isolated from any food sample. In a survey of listeria faecal carriage, Listeria monocytogenes was isolated from only two of 100 faeces specimens obtained from patients.

Colony Count, Microbial↗

PubMed2000

Bacteriological quality of raw oysters in Trinidad and the attitudes, knowledge and perceptions of the public about its consumption.

In Trinidad and Tobago, raw oyster cocktails are a delicacy, but they are generally believed to be responsible for illness in the consumer. The microbial loads of raw oysters, condiments/spices and ready-to-consume oyster cocktails were determined in four sampling areas. Questionnaires were also administered to 72 oyster vendors to determine practices that affect the bacteriological quality of the products. Three hundred members of the public were interviewed to determine the attitudes, knowledge and perceptions of the public about raw oyster consumption. The mean total aerobic plate count (TAPC) per g of 50 samples each, of raw oysters, condiments/spices and ready-to-consume raw oyster cocktails averaged from 1.0 x 10(7)+/-4.3 x 10(7) to 1.4 x 10(8)+/-6.4 x 10(8), 2.0 x 10(5)+/-1.0 x 10(6) to 2.0 x 10(7)+/-1.4 x 10(8), and 4.3 x 10(5)+/-1.0 x 10(6) to 2.2 x 10(6)+/-1.0 x 10(7), respectively. The difference for each product among the four areas was statistically significant (P < or = 0.05; chi2). Using a recommended maximum standard of TAPC per g of 5.0 x 10(5), 115 (57.5%), 27 (13.5%) and 51 (25.5%) of 200 samples each, of raw oysters, condiments/spices and oyster cocktails, respectively, were considered unfit for human consumption. Amongst vendor practices, source of oyster harvest and length of time between separation of oyster meat from shell and sale, significantly affected the mean TAPC per g and the prevalence of unfit oyster cocktail samples. Consumption of raw oyster cocktails was more prevalent amongst males (73.6%) than females (26.4%) (P < 0.002), East Indians (63.2%) as compared with other respondents (36.8%) (P < 0.001), individuals < or = 40 years old (82.1%) than in individuals > 40 years of age (17.9%) (P < 0.01), and in individuals who were aware that raw oysters are considered to be a sexual enhancer (86.8%) as compared to those who did not have this perception (11.3%) (P < 0.03). Fear of falling ill prevented 44 (37.9%) of 116 non-consumers from eating oyster cocktails, while 13 of 106 consumers (12.3%) reported having experienced an oyster-borne illness. The rather high prevalence of raw oyster cocktails found to be unfit for human consumption, coupled with the perceptions and attitudes of the consumers about the product, pose a significant health risk to the public.

Animals↗

PubMed2005

High rate anaerobic thermophilic technologies for distillery wastewater treatment.

In this paper, performance of two high rate technologies, upflow anaerobic fixed-film reactor and fluidized bed laboratory-scale, treating distillery wastewater (wine vinasses) at anaerobic thermophilic conditions have been compared. The results obtained show that the stationary packed bed, with a corrugated plastic support, operated under stable conditions at organic loading rates (OLR0) around 20 kgCOD/m3/d, gives maximal total CODr of 76% at OLR0 of 6.29 kgCOD/m3/d; the fluidized bed reactor, operated on open pore sintered-glass media, gives total CODr of 96% at OLR0 of 5.88 kgCOD/m3/d. The anaerobic fluidized bed technology is more effective than the upflow anaerobic fixed-film technology due, fundamentally, to this technology favouring the transport of microbial cells from the bulk to the surface and enhancing the contact between the microorganism-substrate phases, In this sense, the stationary packed bed technology is adequate for the treatment of easily biodegradable wastewater, or for the cases where elevated percentages of CODr removal are not required, while the fluidized bed technology is especially suitable for treatment of hazardous wastes with recalcitrant compositions.

Bacteria, Anaerobic↗

PubMed1998

A silicone ventricular catheter coated with a combination of rifampin and trimethoprim for the prevention of catheter-related infections.

So-called antiinfective catheters which are generated by incorporation of antimicrobial substances into polymers appear to be effectful devices in the prevention of catheter related infections. Such devices mainly act by prevention of bacterial colonization of the catheter surface rather than by inhibition of adherence. In a preceding study, we developed a rifampin-containing silicone catheter for the prevention of ventricular shunt infection. In the present study, this work was continued with a combination of antimicrobials incorporated in silicone ventricular catheters to reduce the risk of rifampin resistance and to expand the antimicrobial spectrum. We found that the drug release kinetics could be greatly influenced by the incorporation conditions. It was possible to incorporate an optimal antibiotic combination of rifampin and trimethoprim into the polymer resulting in defined release rates and a defined total release. A catheter loaded with this combination showed an excellent reduction of the colonization with Staphylococcus aureus (99.97% reduction within 3 hours) under in-vitro conditions.

Anti-Bacterial Agents↗

PubMed2005

Wind, rain and bacteria: The effect of weather on the microbial composition of roof-harvested rainwater.

The microbiological and chemical quality of tank-stored rainwater is impacted directly by roof catchment and subsequent run-off contamination, via direct depositions by birds and small mammals, decay of accumulated organic debris, and atmospheric deposition of airborne micro-organisms and chemical pollutants. Previous literature reports on roof water quality have given little consideration to the relative significance of airborne micro-organisms. This study involved analyses of direct roof run-off at an urban housing development in Newcastle, on the east coast of Australia. A total of 77 samples were collected during 11 separate rainfall events, and microbial counts and mean concentrations of several ionic contaminants were matched to climatic data corresponding to each of the monitored events. Conditions both antecedent to, and those prevailing during each event, were examined to investigate the influence of certain meteorological parameters on the bacterial composition of the roof water and indirectly assess the relative contribution of airborne micro-organisms to the total bacterial load. Results indicated that airborne micro-organisms represented a significant contribution to the bacterial load of roof water at this site, and that the overall contaminant load was influenced by wind velocities, while the profile (composition) of the load varied with wind direction. The implications of these findings to the issues of tank water quality and health risk analysis, appropriate usage and system design are discussed.

Aerosols↗

PubMed1994

Production and storage stability of non alcoholic banana beverage powder.

Powder for an instant, non-alcoholic beverage formulation was manufactured by sundrying and ovendrying of a popular dessert ('silk') banana variety. The reconstituted beverage was organoleptically acceptable. The effect of traditional sundrying on mats and ovendrying methods on product quality was investigated. Sundrying resulted in losses of Vitamin A, C and total sugar contents by 74, 91 and 63%, while ovendrying losses were 73, 90 and 62%, respectively. Nutrient losses during storage for three months in transparent polythene bags reached 93, 93 and 70% in sundried samples and 84, 99 and 55% in ovendried samples, respectively. The moisture content of sundried and ovendried samples increased by 12 and 17%, respectively, during storage. The increase in microbial load in this period was higher in sundried samples.

Beverages↗

PubMed2003

Gut failure and abdominal visceral transplantation.

Despite the reported high survival with total parenteral nutrition (TPN) therapy for patients with intestinal failure, a considerable number of patients do not escape the potential risks of TPN-associated complications, including hepatic failure, vanishing of central venous access and line sepsis. Thus, intestinal, liver-intestinal and multivisceral transplantation have recently emerged to rescue those who can no longer be maintained on TPN. Before this development, and for nearly three decades, small-bowel transplantation was plagued with uncontrolled rejection, graft v. host disease and fatal infection. These barriers stemmed from the large gut lymphoid mass and heavy microbial load contained in the intestinal lumen. The recent improvement in survival after the clinical introduction of tacrolimus with achievement of full enteric nutritional autonomy qualified the procedure by the US Health Care Financing Administration as the standard of care for patients with intestinal and TPN failure. The decision was supported by a decade of clinical experience with cumulative improvement in patient and graft survival. In addition, the introduction of new effective immunoprophylactic agents and novel therapeutic approaches has contributed to a further increase in the therapeutic advantages of the procedure. The present review article outlines the current clinical practice of intestinal transplantation and defines new management strategies with the aim of raising the level of the procedure to be a better alternative therapy for TPN-dependent patients.

Contraindications↗

PubMed2004

Transformation of effluent organic matter during subsurface wetland treatment in the Sonoran Desert.

The fate of dissolved organic matter (DOM) during subsurface wetland treatment of wastewater effluent in a hot, semi-arid environment was examined. The study objectives were to (1) discern changes in the character of dissolved organics as consequence of wetland treatment (2) establish the nature of wetland-derived organic matter, and (3) investigate the impact of wetland treatment on the formation potential of trihalomethanes (THMs). Subsurface wetland treatment produced little change in DOM polarity (hydrophobic-hydrophilic) distribution. Biodegradation of labile effluent organic matter (EfOM) and internal loading of wetland-derived natural organic matter (NOM) together produced only minor changes in the distribution of carbon moieties in hydrophobic acid (HPO-A) and transphilic acid (TPI-A) isolates of wetland effluent. Aliphatic carbon decreased as a percentage of total carbon during wetland treatment. The ratio of atomic C:N in wetland-derived NOM suggests that its character is determined by microbial activity. Formation of THMs upon chlorination of HPO-A and TPI-A isolates increased as a consequence of wetland treatment. Wetland-derived NOM was more reactive in forming THMs and less biodegradable than EfOM. For both HPO-A and TPI-A fractions, relationships between biodegradability and THM formation potential were similar among EfOM and NOM isolates; the less biodegradable isolates exhibited greater THM formation potential.

Arizona↗

PubMed1969

Control Mechanisms Operative in a Natural Microbial Population Selected for Its Ability to Degrade L-Lysine. III. Effects of Carbohydrates in Continuous-Flow Systems Under Shock Load Conditions.

Two naturally selected microbial populations were maintained under continuousflow conditions with glucose or magnesium growth-limiting. The reactors were subjected to shock loads by changing the influent substrate from L-lysine to a mixture of L-lysine and glucose, L-lysine and fructose, or L-lysine and ribose. During the subsequent transient state, the following parameters were examined: lysine chemical oxygen demand (COD), carbohydrate COD, total COD, biological solids concentration, cell protein, enzymatic capability (lysine-degrading enzymes), and the rate of lysine removal. The carbohydrate was then removed from the influent and the same parameters were examined until a new steady state was established. In all cases, glucose and fructose caused a significant repression of the synthesis of lysine-degrading enzymes, resulting in a decrease in the enzymatic capability of the cells. In the carbon-limited reactor, the faster the flow rate, the greater was the repression, whereas, in the magnesium-limited reactor, the slower the flow rate, the greater was the repression. The introduction of ribose into the reactors caused an initial increase in lysine enzymatic capability followed by a slight repression when ribose degradation started.

Journal Article↗

PubMed2001

Evaluating microbial indicators of environmental condition in Oregon rivers.

Traditional bacterial indicators used in public health to assess water quality and the Biolog system were evaluated to compare their response to biological, chemical, and physical habitat indicators of stream condition both within the state of Oregon and among ecoregion aggregates (Coast Range, Willamette Valley, Cascades, and eastern Oregon). Forty-three randomly selected Oregon river sites were sampled during the summer in 1997 and 1998. The public health indicators included heterotrophic plate counts (HPC), total coliforms (TC), fecal coliforms (FC) and Escherichia coli (EC). Statewide, HPC correlated strongly with physical habitat (elevation, riparian complexity, % canopy presence, and indices of agriculture, pavement, road, pasture, and total disturbance) and chemistry (pH, dissolved O2, specific conductance, acid-neutralizing capacity, dissolved organic carbon, total N, total P, SiO2, and SO4). FC and EC were significantly correlated generally with the river chemistry indicators. TC bacteria significantly correlated with riparian complexity, road disturbance, dissolved O2, and SiO2 and FC. Analyzing the sites by ecoregion, eastern Oregon was characterized by high HPC, FC, EC, nutrient loads, and indices of human disturbance, whereas the Cascades ecoregion had correspondingly low counts of these indicators. The Coast Range and Willamette Valley presented inconsistent indicator patterns that are more difficult to characterize. Attempts to distinguish between ecoregions with the Biolog system were not successful, nor did a statistical pattern emerge between the first five principle components and the other environmental indicators. Our research suggests that some traditional public health microbial indicators may be useful in measuring the environmental condition of lotic systems.

Bacteria↗

PubMed1994

Production and storage stability of non-alcoholic pawpaw beverage powder.

Powder for instant non-alcoholic pawpaw beverage formulation was manufactured by traditional sundrying and controlled ovendrying. The reconstituted beverage was organoleptically acceptable. The effect of sundrying on mats and ovendrying on product quality was investigated. Sundrying resulted into losses of vitamins A and C, and total sugar by 97, 98 and 87 percent; while, oven drying losses were 92, 98 and 87 percent, respectively. Nutrient losses during storage in transparent polythene bags at ambient conditions reached 98, 98 and 82 percent in sundried samples and; 87, 99 and 67 percent in ovendried samples respectively. The moisture content of sundried and oven dried samples increased by 14 percent during storage. The increase in microbial load during storage was higher in sundried samples.

Ascorbic Acid↗

PubMed1998

The effect of a 1-stage full-mouth disinfection on oral malodor and microbial colonization of the tongue in periodontitis. A pilot study.

Oral malodor affects a large proportion of the population and may be the cause of a significant social and psychological handicap. This pilot study aimed to examine whether a 1-stage full-mouth disinfection in periodontitis patients (scaling and root planing of all pockets within 24 hours together with the application of chlorhexidine to all intra-oral niches followed by chlorhexidine mouth rinsing for 2 months) resulted in a significant improvement in malodor when compared to a fractionated periodontal therapy (consecutive root planings per quadrant, at a 1 to 2 week interval). The baseline and outcome data concerning oral malodor were linked to the presence of tongue coating and to its roughness (fissures). Twenty-four patients with severe periodontitis were randomly allocated to test and control groups. At baseline and after 1 and 2 months, the concentration of volatile sulfur compounds (VSC) in the mouth was measured and organoleptic ratings (expired air and total mouth air) were given. Plaque samples were collected from the dorsum of the tongue to calculate the number of colony forming units (CFU) per ml (anaerobic culturing) as well as the number of pigmented CFU/ml. Both the baseline organoleptic ratings and the VSC scores correlated well with the presence of tongue coating but not with the tongue roughness. Because a correlation between tongue coating and its microbial load could not be detected, it was hypothesized that the tongue coating per se, and not the bacteria, might be responsible for the malodor. The 1-stage full-mouth disinfection resulted in a faster and additional reduction in the organoleptic ratings of the oral malodor, even after 2 months. This might be explained by the improved periodontal outcome and/or the more significant reduction in the CFU/ml of pigmented species. In contrast to the organoleptic ratings, which were significantly reduced in both treatment groups (when compared to baseline), the VSC levels remained unchanged. This pilot study indicates that a 1-stage full-mouth disinfection has, in comparison to a standard periodontal therapy, additional beneficial effects in the treatment of oral malodor.

Adult↗

PubMed2002

Microbial profile and antibiotic susceptibility of Campylobacter spp. and Salmonella spp. in broilers processed in air-chilled and immersion-chilled environments.

Carcass chilling is considered a critical step for inhibiting bacterial growth during poultry processing. The objective of this study was to compare microbiological loads and the incidence of Salmonella spp. and Campylobacter spp. on broiler carcasses subjected to immersion chilling and air chilling. Additionally, the antibiotic resistance patterns of pathogen isolates were determined. The results of this study indicated that the incidence of Salmonella spp. and Campylobacter spp. tends to be significantly lower in air-chilled broilers, suggesting that cross-contamination may be more prevalent for immersion-chilled broilers. No significant differences were detected between chilling treatments for total aerobic populations or for generic E. coli or coliform counts. Psychrotrophic populations were significantly larger (P < 0.05) in immersion-chilled broilers than in their air-chilled counterparts. Campylobacter isolates from immersion-chilled broilers had a higher incidence of resistance to nalidixic acid (NAL) and related fluoroquinolones than isolates from air-chilled broilers did. Additionally, Campylobacter isolates from air-chilled broilers had a higher frequency of resistance to tetracycline than isolates from immersion-chilled broilers did. With regard to Salmonella, isolates from immersion-chilled broilers had a higher incidence of resistance to NAL than isolates from air-chilled samples did. No Salmonella isolates from immersion- or air-chilled broilers were resistant to the fluoroquinolones tested. The chilling method used during processing may influence the microbial profile of postchilled broilers.

Adaptation, Physiological↗