A model for assessing mammal contribution of Escherichia coli to a Texas floodplain

2015 ◽  
Vol 42 (3) ◽  
pp. 217
Author(s):  
Israel D. Parker ◽  
Roel R. Lopez ◽  
Raghupathy Karthikeyan ◽  
Nova J. Silvy ◽  
Donald S. Davis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Didelphis Virginiana ◽  
Data Uncertainty ◽  
Sensitivity Analyses ◽  
Model Parameters ◽  
Mammal Species ◽  
Important Species ◽  
Faecal Material ◽  
E Coli ◽  
Free Ranging

Context Free-ranging mammals contribute to faecal pollution in United States water bodies. However, research into wildlife impact on water quality is dependent upon unreliable data (e.g. data uncertainty, unknown importance of parameters). Aims Our goal was to determine the potential impacts of common free-ranging mammal species and their management on Escherichia coli in the study floodplain. Our objectives for this research were to construct a model from study area- and literature-derived data, determine important species for E. coli deposition, and conduct sensitivity analyses on model parameters to focus future research efforts. Methods We constructed a model that incorporated parameters for four wildlife species known to contribute E. coli in central Texas: raccoons (Procyon lotor), white-tailed deer (Odocoileus virginianus), Virginia opossums (Didelphis virginiana), and wild pigs (Sus scrofa). These parameters were (1) population density estimates, (2) defaecation rates, (3) defaecation areas, (4) E. coli concentration in faecal material estimates, and (5) E. coli survival. We conducted sensitivity analyses on the model parameters to determine relative importance of each parameter and areas for additional study. Key results We found that adjustment of raccoon and Virginia opossum population densities had higher impacts on E. coli in the floodplain than similar changes in other species across all spatial and seasonal variations. We also found that the changes in E. coli survival, E. coli concentration in raccoon faecal material, and defaecation rates had the highest impacts on E. coli in the floodplain. Conclusions Our sensitivity analyses indicated that the largest impacts to projected E. coli loads were from changes in defaecation rates followed by E. coli concentration in faecal material and E. coli survival. Watershed planners, ranchers, and regulators must be cautioned that faecal deposition patterns are location specific and could significantly impact which species are considered the most important contributors. Implications Although all parameters require more research, we recommend that researchers determine defaecation rates for contributing species due to their relatively large impacts on E. coli in comparison to the other parameters. We also suggest additional research in free-ranging wildlife faecal morphology (form and structure) and area of deposition. Finally, species-specific E. coli survival studies for free-ranging wildlife should be conducted.

scholarly journals Role of free-ranging mammals in the deposition of Escherichia coli into a Texas floodplain

2013 ◽  
Vol 40 (7) ◽  
pp. 570 ◽  
Author(s):  
Israel D. Parker ◽  
Roel R. Lopez ◽  
Reema Padia ◽  
Meghan Gallagher ◽  
Raghupathy Karthikeyan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Population Density ◽  
Didelphis Virginiana ◽  
Large Mammals ◽  
Density Estimates ◽  
Cedar Creek ◽  
E Coli ◽  
Free Ranging

Context The role of wildlife in faecal pollution of water bodies (deposition of Escherichia coli (E. coli)) is not well understood. Current water-quality and land-use planning research largely relies on unreliable wildlife data (e.g. poor sourcing of abundance estimates, population density estimates applied to multiple fundamentally different areas, suspect or insufficiently described data collection techniques) Aims Our goal for the present research was to investigate deposition of E. coli into a floodplain by free-ranging mammals. Objectives of the research were to determine the density of important free-ranging meso- and large mammals in the study area, determine faecal E. coli loads for each species, and evaluate spatial data on species-specific faecal deposition. Methods We conducted our research in south-eastern Texas, USA, on two cattle ranches bisected by Cedar Creek (44-km long). Cedar Creek has elevated E. coli concentrations. We conducted mark–recapture and mark–resight population density estimates (2008/09) for meso- and large mammals in the study areas. We collected faecal samples from all captured wildlife. We also conducted transects through the study area to determine faecal-deposition patterns. Key results We found that raccoons (Procyon lotor), wild pigs (Sus scrofa), Virginia opossums (Didelphis virginiana) and white-tailed deer (Odocoileus virginianus) all had substantial faecal E. coli loads and population densities, thus implying an important role in E. coli deposition into the study floodplain. All species were widely distributed through the floodplain. Conclusions Free-ranging mammals contribute E. coli to floodplains and potentially affect water quality. We determined that four species commonly found in floodplains throughout North America all contributed E. coli to the study floodplain, thus implying mammal E. coli contributions in many locations and this is potentially important for E. coli management. Implications Improved locally specific mammal population estimates and estimates of locally derived E. coli concentration will improve floodplain and water-quality models that often depend on data of various quality. Additionally, our analyses demonstrated the need for continued research into the role of wildlife in E. coli deposition.

Modeling Preharvest and Harvest Interventions for Escherichia coli O157 Contamination of Beef Cattle Carcasses

2011 ◽  
Vol 74 (9) ◽  
pp. 1422-1433 ◽  
Author(s):  
CHARLES C. DODD ◽  
MICHAEL W. SANDERSON ◽  
MEGAN E. JACOB ◽  
DAVID G. RENTER
Keyword(s):  
Escherichia Coli ◽  
Assessment Model ◽  
Sensitivity Analyses ◽  
Feed Additive ◽  
Future Research ◽  
Escherichia Coli O157 ◽  
Concentration Effects ◽  
Modeling Framework ◽  
E Coli ◽  
Carcass Contamination

Field studies evaluating the effects of multiple concurrent preharvest interventions for Escherichia coli O157 are logistically and economically challenging; however, modeling techniques may provide useful information on these effects while also identifying crucial information gaps that can guide future research. We constructed a risk assessment model with data obtained from a systematic search of scientific literature. Parameter distributions were incorporated into a stochastic Monte Carlo modeling framework to examine the impacts of different combinations of preharvest and harvest interventions for E. coli O157 on the risk of beef carcass contamination. We estimated the risk of E. coli O157 carcass contamination conditional on preharvest fecal prevalence estimates, inclusion of feed additive(s) in the diet, vaccination for E. coli O157, transport and lairage effects, hide intervention(s), and carcass intervention(s). Prevalence parameters for E. coli O157 were assumed to encompass potential effects of concentration; therefore, concentration effects were not specifically evaluated in this study. Sensitivity analyses revealed that fecal prevalence, fecal-to-hide transfer, hide-to-carcass transfer, and carcass intervention efficacy significantly affected the risk of carcass contamination (correlation coefficients of 0.37, 0.56, 0.58, and −0.29, respectively). The results indicated that combinations of preharvest interventions may be particularly important for supplementing harvest interventions during periods of higher variability in fecal shedding prevalence (i.e., summer). Further assessments of the relationships among fecal prevalence and concentration, hide contamination, and subsequent carcass contamination are needed to further define risks and intervention impacts for E. coli O157 contamination of beef.

Quantitative Microbial Risk Assessment for Escherichia coli O157:H7 in Fresh-Cut Lettuce

2017 ◽  
Vol 80 (2) ◽  
pp. 302-311 ◽  
Author(s):  
Hao Pang ◽  
Elisabetta Lambertini ◽  
Robert L. Buchanan ◽  
Donald W. Schaffner ◽  
Abani K. Pradhan
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
The United States ◽  
Intervention Strategies ◽  
Sensitivity Analyses ◽  
Escherichia Coli O157 ◽  
Baseline Model ◽  
Microbial Risk ◽  
E Coli ◽  
Fresh Cut

ABSTRACT Leafy green vegetables, including lettuce, are recognized as potential vehicles for foodborne pathogens such as Escherichia coli O157:H7. Fresh-cut lettuce is potentially at high risk of causing foodborne illnesses, as it is generally consumed without cooking. Quantitative microbial risk assessments (QMRAs) are gaining more attention as an effective tool to assess and control potential risks associated with foodborne pathogens. This study developed a QMRA model for E. coli O157:H7 in fresh-cut lettuce and evaluated the effects of different potential intervention strategies on the reduction of public health risks. The fresh-cut lettuce production and supply chain was modeled from field production, with both irrigation water and soil as initial contamination sources, to consumption at home. The baseline model (with no interventions) predicted a mean probability of 1 illness per 10 million servings and a mean of 2,160 illness cases per year in the United States. All intervention strategies evaluated (chlorine, ultrasound and organic acid, irradiation, bacteriophage, and consumer washing) significantly reduced the estimated mean number of illness cases when compared with the baseline model prediction (from 11.4- to 17.9-fold reduction). Sensitivity analyses indicated that retail and home storage temperature were the most important factors affecting the predicted number of illness cases. The developed QMRA model provided a framework for estimating risk associated with consumption of E. coli O157:H7–contaminated fresh-cut lettuce and can guide the evaluation and development of intervention strategies aimed at reducing such risk.

scholarly journals Prevalence and antimicrobial resistance profiles of Escherichia coli isolated from free-range pigs

2017 ◽  
Vol 11 (08) ◽  
pp. 652-655
Author(s):  
Hongna Zhang ◽  
Xiaonan Zhao ◽  
Xuepeng Wang ◽  
Weishan Chang
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Eastern China ◽  
Resistance Rate ◽  
E Coli ◽  
Free Range ◽  
Resistant Genes ◽  
Potential Reservoir ◽  
Free Ranging ◽  
M 14

Introduction: Numerous studies about antimicrobial resistant Escherichia coli (E. coli) of animal origins have been conducted around the world, most of them focus on bacteria from animals raised in intensive breeding farms, but systematic studies on antimicrobial resistance in E. coli of free range animals are still lacking. Methodology: This study aimed to investigate the prevalence and antimicrobial resistance profiles of E. coli from free-range pigs in Laiwu mountainous areas, eastern China. Results: Among 123 fecal samples, 123 non-duplicate E. coli were obtained with an isolation rate of 100.0％ (123/123). These E. coli showed the highest resistance rate to tetracycline (77/123, 62.6％), but all were sensitive to amoxicillin/clavulanic acid. Thirty-eight E. coli (38/123, 30.9％) showed multidrug resistance (MDR). Among 123 E. coli isolates, only 39 carried antimicrobial resistant genes detected in this study. Of these 39 isolates, blaTEM-1, blaCTX-M-14, blaCTX-M-15, qnrB, qnrD, qnrS1, floR and cfr genes were detected in 13, 9, 4, 7, 10, 7, 20, and 7 isolates, respectively. blaTEM-1 and blaCTX-M-14 genes were concomitantly detected in 6 isolates, and blaTEM, qnrB, qnrS and qnrD genes were concomitantly detected in 7 isolates. Conclusions: Free-ranging pigs may be regarded as a potential reservoir for antibiotic resistant genes.

scholarly journals Determining Thermal Inactivation of Escherichia coli O157:H7 in Fresh Compost by Simulating Early Phases of the Composting Process

2011 ◽  
Vol 77 (12) ◽  
pp. 4126-4135 ◽  
Author(s):  
Randhir Singh ◽  
Jinkyung Kim ◽  
Marion W. Shepherd ◽  
Feng Luo ◽  
Xiuping Jiang
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Weibull Model ◽  
Model Parameters ◽  
Pathogen Inactivation ◽  
Content Type ◽  
Factors Affecting ◽  
E Coli ◽  
Pathogen Survival ◽  
Heating Up

ABSTRACTA three-strain mixture ofEscherichia coliO157:H7 was inoculated into fresh dairy compost (ca. 107CFU/g) with 40 or 50% moisture and was placed in an environmental chamber (ca. 70% humidity) that was programmed to ramp from room temperature to selected composting temperatures in 2 and 5 days to simulate the early composting phase. The survivingE. coliO157:H7 population was analyzed by direct plating and enrichment. Optimal and suboptimal compost mixes, with carbon/nitrogen (C/N) ratios of 25:1 and 16:1, respectively, were compared in this study. In the optimal compost mix,E. coliO157:H7 survived for 72, 48, and 24 h in compost with 40% moisture and for 72, 24, and 24 h with 50% moisture at 50, 55, and 60°C, respectively, following 2 days of come-up time (rate of heating up). However, in the suboptimal compost mix, the pathogen survived for 288, 72, and 48 h in compost with 40% moisture and for 240, 72, 24 h in compost with 50% moisture at the same temperatures, respectively. Pathogen survival was longer, with 5 days of come-up time compared with 2 days of come-up. Overall,E. coliO157:H7 was inactivated faster in the compost with 50% moisture than in the compost with 40% at 55 and 60°C. Both moisture and come-up time were significant factors affecting Weibull model parameters. Our results suggest that slow come-up time at the beginning of composting can extend pathogen survival during composting. Additionally, both the C/N ratio and the initial moisture level in the compost mix affect the rate of pathogen inactivation as well.

scholarly journals Prevalence, Characteristics and Antibiogram Profiles of Escherichia coli Isolated from Apparently Healthy Chickens in Mymensingh, Bangladesh

2013 ◽  
Vol 1 (1) ◽  
pp. 27-29 ◽  
Author(s):  
ATM Jakaria ◽  
Md Ariful Islam ◽  
Mst Minara Khatun
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Sensitivity ◽  
Blood Agar ◽  
Sensitivity Analyses ◽  
E Coli ◽  
Indigenous Chickens ◽  
Bright Pink ◽  
Sensitivity Pattern ◽  
Metallic Sheen ◽  
Apparently Healthy

Escherichia coli known to cause food-borne illnesses worldwide that are closely associated with the consumption of conta-minated poultry and egg products. This study was undertaken for cultural, biochemical and antibiotic sensitivity analyses of E. coli recovered from apparently healthy chickens. Cloacal samples (n=350) were aseptically collected from layers (n=150), broilers (n=150) and indigenous chickens (n=50). The samples were enriched in nutrient broth and streaked onto eosin methylene blue (EMB) agar, MacConkey (MC) agar, blood agar, salmonella-shigella (SS) agar and brilliant green agar (BGA) for cultural characterization of the E. coli isolates. Culture-positive samples yielded characteristic colonies of E. coli with metallic sheen on EMB agar, bright pink or red colonies on MC agar, hemolysis on blood agar, slight pink smooth colonies on SS agar and green color colonies on BGA media. The E. coli isolates produced acid and gas by ferm-enting sugars (dextrose, sucrose, lactose, maltose and mannitol) and gave positive reaction to indole, methyl red (MR) and catalase tests, but were negative to Voges-Proskauer (VP) test. The prevalence of E. coli in layers, broilers and indigenous chickens were 78.67, 82 and 70%, respectively. The antibiotic sensitivity pattern demonstrated that E. coli isolates were mostly sensitive to ciprofloxacin, gentamicin and cephalexin, and resistant to streptomycin, tetracycline, amoxicillin and nalidixic acid. Data of this study suggested that intestine of chicken could be a major reservoir of antibiotic resistant E. coli.DOI: http://dx.doi.org/10.3329/mh.v1i1.13710 Microbes and Health Vol.1(1) June 2012 pp.27-29

scholarly journals Evolutionary history of the global emergence of the Escherichia coli epidemic clone ST131

2015 ◽  
Author(s):  
Nicole Stoesser ◽  
Anna Sheppard ◽  
Louise Pankhurst ◽  
Nicola de Maio ◽  
Catrin E Moore ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Evolutionary History ◽  
Clinical Medicine ◽  
The United States ◽  
M Gene ◽  
Important Species ◽  
E Coli ◽  
Extended Spectrum ◽  
History Of

ABSTRACT Background Escherichia coli sequence type 131 (ST131) has emerged globally as the most predominant lineage within this clinically important species, and its association with fluoroquinolone and extended-spectrum cephalosporin resistance impacts significantly on treatment. The evolutionary histories of this lineage, and of important antimicrobial resistance elements within it, remain unclearly defined. Results This study of the largest worldwide collection (n = 215) of sequenced ST131 E. coli isolates to date demonstrates that clonal expansion of two previously recognized antimicrobial-resistant clades, C1/H30R and C2/H30Rx, started around 25 years ago, consistent with the widespread introduction of fluoroquinolones and extended-spectrum cephalosporins in clinical medicine. These two clades appear to have emerged in the United States, with the expansion of the C2/H30Rx clade driven by the acquisition of a blaCTX-M-15-containing IncFII-like plasmid that has subsequently undergone extensive rearrangement. Several other evolutionary processes influencing the trajectory of this drug-resistant lineage are described, including sporadic acquisitions of CTX-M resistance plasmids, and chromosomal integration of blaCTX-M within sub-clusters followed by vertical evolution. These processes are also occurring for another family of CTX-M gene variants more recently observed amongst ST131, the blaCTX-M-14/14-like group. Conclusions The complexity of the evolutionary history of ST131 has important implications for antimicrobial resistance surveillance, epidemiological analysis, and control of emerging clinical lineages of E. coli. These data also highlight the global imperative to reduce specific antibiotic selection pressures, and demonstrate the important and varied roles played by plasmids and other mobile genetic elements in the perpetuation of antimicrobial resistance within lineages.

scholarly journals A Survey for Escherichia coli Virulence Factors in Asymptomatic Free-Ranging Parrots

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
André Becker Saidenberg ◽  
Neiva Maria Robaldo Guedes ◽  
Gláucia Helena Fernandes Seixas ◽  
Mariangela da Costa Allgayer ◽  
Erica Pacífico de Assis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Carrier State ◽  
Free Living ◽  
E Coli ◽  
In Captivity ◽  
Parasite Relationship ◽  
Polymerase Chain ◽  
Host Parasite ◽  
Free Ranging

Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear’s macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 samples were cultured and E. coli isolates were yielded, from which DNA was extracted and processed by PCR. Genes commonly found in APEC isolates from Blue-fronted Amazon parrots and Hyacinth macaws were expressed in 14 of these 44 samples. One atypical EPEC isolate was obtained from a sample from Lear’s macaw. The most commonly found gene was the increased serum survival (iss) gene. This is the first report, that describes such pathotypes in asymptomatic free-living parrots. The findings of this study suggest the presence of a stable host/parasite relationship at the time of the sampling brings a new understanding to the role that E. coli plays in captive and wild parrots. Such information can be used to improve husbandry protocols as well as help conservation efforts of free-living populations.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

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