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Indicator Organisms (indicator + organism)
Selected AbstractsApplication of microbial source tracking methods in a Gulf of Mexico field settingJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2009A. Korajkic Abstract Aims:, Microbial water quality and possible human sources of faecal pollution were assessed in a Florida estuary that serves shellfishing and recreational activities. Methods and Results:, Indicator organisms (IO), including faecal coliforms, Escherichia coli and enterococci, were quantified from marine and river waters, sediments and oysters. Florida recreational water standards were infrequently exceeded (6,10% of samples); however, shellfishing standards were more frequently exceeded (28%). IO concentrations in oysters and overlaying waters were significantly correlated, but oyster and sediment IO concentrations were uncorrelated. The human-associated esp gene of Enterococcus faecium was detected in marine and fresh waters at sites with suspected human sewage contamination. Lagrangian drifters, used to determine the pathways of bacterial transport and deposition, suggested that sediment deposition from the Ochlockonee River contributes to frequent detection of esp at a Gulf of Mexico beach. Conclusions:, These data indicate that human faecal pollution affects water quality in Wakulla County and that local topography and hydrology play a role in bacterial transport and deposition. Significance and Impact of the Study:, A combination of IO enumeration, microbial source tracking methods and regional hydrological study can reliably inform regulatory agencies of IO sources, improving risk assessment and pollution mitigation in impaired waters. [source] Phenotypic and genotypic characterization of encapsulated Escherichia coli isolated from blooms in two Australian lakesENVIRONMENTAL MICROBIOLOGY, Issue 5 2005Michelle L. Power Summary Escherichia coli has long been used as an indicator organism for water quality assessment. Recently there has been an accumulation of evidence that suggests some strains of this organism are able to proliferate in the environment, a characteristic that would detract from its utility as an indicator of faecal pollution. Phenotypic and genotypic characterization of E. coli isolated from blooms in two Australian lakes, separated by a distance of approximately 200 km, identified that the blooms were dominated by three E. coli strains. A major phenotypic similarity among the three bloom strains was the presence of a group 1 capsule. Genetic characterization of a conserved region of the cps gene cluster, which encodes group 1 capsules, identified a high degree of genetic variation within the bloom isolates. This differs from previously described encapsulated E. coli strains which are highly conserved at the cps locus. The phenotypic or genotypic profiles of the bloom strains were not identified in 435 E. coli strains isolated from vertebrates. The occurrence of these encapsulated strains suggests that some E. coli have evolved a free-living lifestyle and do not require a host in order to proliferate. The presence of the same three strains in bloom events in different geographical regions of a temperate climate, and at different times, indicates that free-living E. coli strains are able to persist in these water reservoirs. This study provides further evidence of circumstances where caution is required in using E. coli as an indicator organism for water quality. [source] Evaluation of novel fluorogenic substrates for the detection of glycosidases in Escherichia coli and enterococciJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2006J.D. Perry Abstract Aims:, Enzyme substrates based on 4-methylumbelliferone are widely used for the detection of Escherichia coli and enterococci in water, by detection of , -glucuronidase and , -glucosidase activity respectively. This study aimed to synthesize and evaluate novel umbelliferone-based substrates with improved sensitivity for these two enzymes. Methods and Results:, A novel , -glucuronide derivative based on 6-chloro-4-methylumbelliferone (CMUG) was synthesized and compared with 4-methylumbelliferyl- , - d -glucuronide (MUG) using 42 strains of E. coli in a modified membrane lauryl sulfate broth. Over 7 h of incubation, the fluorescence generated from the hydrolysis of CMUG by E. coli was over twice that from MUG, and all of the 38 glucuronidase-positive strains generated a higher fluorescence with CMUG compared with MUG. Neither substrate caused inhibition of bacterial growth in any of the tested strains. Four , -glucosidase substrates were also synthesized and evaluated in comparison with 4-methylumbelliferyl- , - d -glucoside (MU-GLU) using 42 strains of enterococci in glucose azide broth. The four substrates comprised , -glucoside derivatives of umbelliferone-3-carboxylic acid and its methyl, ethyl and benzyl esters. Glucosides of the methyl, ethyl and benzyl esters of umbelliferone-3-carboxylic acid, were found to be superior to MU-GLU for the detection of enterococci, especially after 18 h of incubation, while umbelliferone-3-carboxylic acid- , - d -glucoside was inferior. However, the variability in detectable , -glucosidase activity among the different strains of enterococci in short-term assays using the three carboxylate esters (7 h incubation) may compromise their use for rapid detection and enumeration of these faecal indicator bacteria. Conclusions:, The , -glucuronidase substrate CMUG appears to be a more promising detection system than the various , -glucosidase substrates tested. Significance and Impact of the Study:, The novel substrate CMUG showed enhanced sensitivity for the detection of , -glucuronidase-producing bacteria such as E. coli, with a clear potential for application in rapid assays for the detection of this indicator organism in natural water and other environmental samples. [source] Die Geschichte der Kolibakterien.BIOLOGIE IN UNSERER ZEIT (BIUZ), Issue 3 2010Vom Darmbewohner zum Bioreaktor Abstract Das von Theodor Escherich vor 125 Jahren entdeckte E. coli -Bakterium hat wie kein anderes die Entwicklung der molekularbiologischen Forschung und der medizinischen und industriellen Biotechnologie beeinflusst. Vor allem die Eigenschaften des K12-Stammes im Hinblick auf Apathogenität, Kultivierbarkeit und Transformierbarkeit haben E. coli zum "Haustier" der Genetiker und Molekularbiologen gemacht. Die Leichtigkeit, mit der gentechnisch veränderte E. coli hergestellt werden können, ließen dieses Bakterium zum beliebten Produktionsorganismus in der modernen Biotechnologie zur Erzeugung von Medikamenten und Feinchemikalien werden. Als physiologischer Darmbewohner von Menschen und Tieren wird E. coli als Indikatororganismus für fäkale Verunreinigungen von Grund- und Trinkwasser verwendet. Neben seiner mikroökologischen Rolle im Magen-Darm-Trakt kommt ihm in Form von pathogenen Stämmen auch eine Bedeutung als Erreger von Durchfallerkrankungen zu. The history of colibacteria The E. coli bacterium discovered by Theodor Escherich 125 years ago has influenced the development of molecular-biological research and medicinal and industrial biotechnology like no other bacterium. In particular, the characteristics of the K12-strain with respect to apathogenicity, culturability and transformability made E. coli the "workhorse" of geneticists and molecular biologists. The easiness with which genetically modified E. coli can be made let this bacterium become a popular production organism of modern biotechnology for the making of drugs and fine chemicals. As a physiological inhabitant of the intestine of humans and animals, E. coli is used as an indicator organism of faecal pollution of ground and drinking water. Alongside its micro-ecological role in the gastrointestinal tract, the E. coli bacterium, in terms of pathogenic strains, also has significance as a causative agent of diarrhoeal diseases. [source] Growth potential of faecal bacteria in simulated psychrophilic/mesophilic zones during composting of organic wasteJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2010J. Elving Abstract Aim:, This study investigated the growth potential of Salmonella serotype Typhimurium and faecal indicator organisms in compost materials and the correlation between bacterial growth potential and the physico-chemical composition of the compost substrate and temperature. Methods and Results:, Survival of Salm. Typhimurium, Enterococcus spp. and total coliforms at 14, 24 and 37°C was determined in material of different degrees of maturity collected from composting plants for household waste and manure. All three micro-organisms showed the potential for growth in the material from active composts (Solvita index 4) but inactivation generally occurred over time in mature compost material (Solvita index 7,8). Conclusions:,Salm. Typhimurium had the potential for growth in psychrophilic/mesophilic (P/M) zones of immature compost material and its growth potential correlated negatively with the maturity of the compost and the temperature within the simulated P/M zone. Significance and Impact of the Study:, The risk of pathogen regrowth in P/M zones during organic waste composting further emphasizes the importance of good management practices and of avoiding P/M zones in combination with low compost maturity. [source] Microbiological status of piggery effluent from 13 piggeries in the south east Queensland region of AustraliaJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2004H.N. Chinivasagam Abstract Aims:, To assist in the development of safe piggery effluent re-use guidelines by determining the level of selected pathogens and indicator organisms in the effluent ponds of 13 south-east Queensland piggeries. Methods and Results:, The numbers of thermotolerant coliforms, Campylobacter jejuni/coli, Erysipelothrix rhusiopathiae, Escherichia coli, Salmonella and rotavirus were determined in 29 samples derived from the 13 piggeries. The study demonstrated that the 13 final effluent ponds contained an average of 1·2 × 105 colony-forming units (CFU) 100 ml,1 of thermotolerant coliforms and 1·03 × 105 CFU 100 ml,1 of E. coli. The Campylobacter level varied from none detectable (two of 13 piggeries) to a maximum of 930 most probable number (MPN) 100 ml,1 (two of 13 piggeries). Salmonella was detected in the final ponds of only four of the 13 piggeries and then only at a low level (highest level being 51 MPN 100 ml,1). No rotavirus and no Erysip. rhusiopathiae were detected. The average log10 reductions across the ponding systems to the final irrigation pond were 1·77 for thermotolerant coliforms, 1·71 for E. coli and 1·04 for Campylobacter. Conclusions:, This study has provided a baseline knowledge on the levels of indicator organisms and selected pathogens in piggery effluent. Significance and Impact of the Study:, The knowledge gained in this study will assist in the development of guidelines to ensure the safe and sustainable re-use of piggery effluent. [source] Purification and characterization of a bacteriocin-like compound (Lichenin) produced anaerobically by Bacillus licheniformis isolated from water buffaloJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2001P. Pattnaik Aims:,To characterize a bacteriocin-like factor from Bacillus licheniformis 26 L-10/3RA isolated from buffalo rumen. Methods and Results:,The culture supernatant exhibited the antibacterial activity against a number of indicator organisms in a cut-well agar assay under anaerobic conditions. The inhibitory component was purified by following ammonium sulphate precipitation, gel filtration and ion exchange chromatography and confirmed to be a single peptide. A single band on tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis confirmed that the peptide was purified to homogeneity and having an estimated molecular mass of approximately 1400 dalton. Complete amino acid sequence of the peptide yielded 12 amino acids from the N-terminal end (ISLEICXIFHDN). No homology with previously reported bacteriocins was observed and has been designated as Lichenin. Lichenin was found to be hydrophobic, sensitive to atmospheric oxygen, retained biological activity even after boiling for 10 min and was active over a pH range of 4·0,9·0. Conclusions:,The Lichenin represents the first anaerobiosis specific expression of bacteriocin-like compound isolated from Bacillus licheniformis 26 L-10/3RA of buffalo rumen origin. Significance and Impact of the Study:,Lichenin could be a potential condidate for manipulating the rumen function at molecular level intended for improving the productivity of the ruminant. [source] Runoff transport of faecal coliforms and phosphorus released from manure in grass buffer conditionsLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2005W.L. Stout Abstract Aims:, To test the hypothesis that faecal coliform (FC) and phosphorus (P) are transported similarly in surface runoff through the vegetative filter strip after being released from land-applied manure. Methods and Results:, The Hagerstown soil was packed into boxes that were 10 cm deep, 30 cm wide and 100, 200 or 300 cm long. Grass was grown in boxes prior experiments. Same-length boxes were placed under rainfall simulator and tilted to have with either 2% or 4% slopes. Dairy manure was broadcast on the upper 30-cm section. Rainfall was simulated and runoff samples were collected and analysed for Cl, FC and total phosphorus (TP). Mass recovery, the concentration decrease rate k, and the ratio FC : TP showed that there was a consistent relationship between FC and TP in runoff. Conclusion:, The FC and TP transport through simulated vegetated buffer strips were highly correlated. Significance and Impact of the Study:, As a knowledge base on the effect of the environmental parameters on P transport in vegetated buffer strips is substantially larger than for manure-borne bacteria, the observed similarity may enhance ability to assess the efficiency of the vegetated buffer strips in retention of FC currently used as indicator organisms for manure-borne pathogens. [source] High Pressure Processing , a Database of Kinetic InformationCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 8 2008R. Buckow Abstract Hydrostatic high pressure technology is relatively new to food industry and is more and more considered as an alternative to traditional preservation methods like heat processing. The inactivation of bacteria, spores, viruses and enzymes has been demonstrated in numerous papers, and various schemes for modelling the experimental inactivation data have been suggested. Although there are similarities to heat inactivation kinetics it is generally agreed that the heat process safety assessment with its typical indicator organisms cannot simply be transferred to high pressure treatment. In this paper a database is introduced which aims at the comparison of published kinetic high pressure inactivation data by using suitable mathematical modelling tools. For the sake of clarity, the functional associations of pressure, temperature and exposure time is presented by means of pressure-temperature diagrams (pT -diagrams), which show pressure-temperature combinations yielding to a desired reaction (e.g. inactivation) rate constant. Thus, the database software was particularly designed to enable the user to call up pressure-temperature dependent function equations for a number of micro-organisms, enzymes and food constituents and to visualize them in pT -diagrams for predetermined treatment times or as kinetics under predetermined p - T conditions. In addition, the database also features a simple calculator tool which allows the user to make an entry in three of the four process conditions (pressure level, temperature level, inactivation level, dwell time) and calculate the remaining forth process condition. The database is accessible through the internet and is continuously updated on the basis of the most recent publications and own experimental data. [source] | ||||||||||