scholarly journals Acquisition of virulence-associated factors by the enteric pathogens Escherichia coli and Salmonella enterica

2001 ◽  
Vol 356 (1411) ◽  
pp. 1027-1034 ◽  
Author(s):  
John Wain ◽  
Deborah House ◽  
Derek Pickard ◽  
Gordon Dougan ◽  
Gad Frankel
Keyword(s):  
Escherichia Coli ◽  
Genetic Variation ◽  
Salmonella Enterica ◽  
Associated Factors ◽  
Enteric Pathogens ◽  
Genomic Studies ◽  
Shed Light

In this review we summarize recent genomic studies that shed light on the mechanism through which pathogenic Escherichia coli and Salmonella enterica have evolved. We show how acquisition of DNA at specific sites on the chromosome has contributed to increased genetic variation and virulence of these two genera of the Enterobacteriaceae.

Fate of Salmonella and Enterohemorrhagic Escherichia coli on Wheat Grain

2021 ◽  
Author(s):  
Jessica R Lauer ◽  
Senay Simsek ◽  
Teresa Bergholz
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Room Temperature ◽  
Enterohemorrhagic Escherichia Coli ◽  
Enteric Pathogens ◽  
Wheat Grain ◽  
Term Survival ◽  
Wide Range ◽  
D Values

Wheat flour has been connected to outbreaks of foodborne illnesses with increased frequency in recent years, specifically, outbreaks involving Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC). However, there is little information regarding the survival of these pathogens on wheat grain during long-term storage in a low-moisture environment. This study aims to evaluate the long-term survival of these enteric pathogens on wheat grain over the course of a year. Hard red spring wheat was inoculated with strains of four serovars of Salmonella enterica (Enteritidis , Agona, Tennessee, and Montevideo) and six serotypes of EHEC (O157:H7, O26:H11, O121:H19, O45:NM, O111:H8, and O103:H2) in triplicate, sealed in Mylar bags to maintain the water activity, and stored at room temperature (22 ± 1°C). The survival of each pathogen was evaluated by plating onto differential media . Viable counts of strains from all four serovars of Salmonella (Enteritidis , Agona, Tennessee, and Montevideo) were detected on wheat grain stored at room temperature (22 ± 1°C) for the duration of the study (52 weeks). Viable counts of strains from EHEC serotypes O45:NM, O111:H8, and O26:H11 were only detected for 44 weeks and strains from serotypes O157:H7, O121:H19, and O103:H2 were only detected for 40 weeks until they passed below the limit of detection (2.0 log CFU/g). D -values were found to be significantly different between Salmonella and EHEC (adj. p ≤ 0.05) with Salmonella D -values ranging from 22.9 ± 2.2 to 25.2 ± 1.0 weeks and EHEC D -values ranging from 11.4 ± 0.6 to 13.1 ± 1.8 weeks. There were no significant differences amongst the four Salmonella strains or amongst the six EHEC strains (adj. p > 0.05). These observations highlight the wide range of survival capabilities of enteric pathogens in a low-moisture environment and confirm these pathogens are a food safety concern when considering the long shelf life of wheat grain and its products.

scholarly journals Comparison between Whatman FTA Elute Cards and Conventional Swab for the Detection of Pathogenic Enteric Bacteria Using an RT-qPCR Assay

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Na Yue ◽  
Zichao Jia
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Enteric Bacteria ◽  
Enteric Pathogens ◽  
Escherichia Coli O157 ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Fta Cards ◽  
And Staphylococcus Aureus

The emergence of outbreaks of foodborne illness is closely associated with food contamination caused by various enteric pathogens, such as Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus. The control of enteric pathogens poses a challenge due to the fact that these pathogens can persist for a long period of time in the environment. The rapid detection of pathogenic organisms plays a crucial role in the prevention and identification of crises related to health, safety, and well-being. Improper sample handling and processing may influence the diagnostic efficacy and accuracy. The aim of the present study was to compare the preservation capacity for enteric bacteria between Whatman Flinders Technology Associates (FTA) cards and swabs for reverse transcription-quantitative PCR (RT-qPCR) detection. It was found that Whatman FTA cards exhibited an improved preservation capacity for five types (both laboratory and environmental strains) of enteric bacteria, including Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus for RT-qPCR detection. Hence, Whatman FTA cards may be a suitable tool for the routine isolation of foodborne bacteria for molecular diagnosis. Therefore, the use of Whatman FTA cards for sample collection and preservation may increase sensitivity and accuracy for bacteria isolation and diagnosis.

EFECTO INHIBITORIO DE EXTRACTOS DE Vitex mollis Kunth CONTRA BACTERIAS Y ESPECIES DE Fusarium DE IMPORTANCIA HUMANA Y AGRÍCOLA

2018 ◽  
Vol 41 (4) ◽  
pp. 353-363
Author(s):  
Alberto J. Valencia-Botin ◽  
Melesio Gutiérrez-Lomelí ◽  
Juan A. Morales-Del-Río ◽  
Pedro J. Guerrero-Medina ◽  
Miguel A. Robles-García ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Salmonella Enterica ◽  
Micrococcus Luteus ◽  
E Coli

Actualmente existe la necesidad de hacer frente al problema de la resistencia a los antibióticos y al uso indiscriminado de fungicidas químicos en la agricultura. El objetivo de este trabajo fue evaluar el efecto inhibitorio de extractos acuosos, metanólicos, acetónicos y hexánicos de hoja y tallo de Vitex mollis Kunth (Lamiaceae) contra diferentes bacterias (Escherichia coli, Micrococcus luteus, Salmonella enterica y Staphylococcus aureus) y especies del hongo Fusarium (F. verticillioides, F. oxysporum, F. tapsinum y F. oxysporum f.sp. lycopersici) de importancia en la salud y en la agricultura, así como determinar su composición química general. Se determinaron las concentraciones inhibitorias mínimas (CIM) de todos los extractos por la técnica de microdilución, excepto del hexánico, que no presentó inhibición en las bacterias estudiadas. S. enterica fue la bacteria que mostró mayor sensibilidad al extracto metanólico de tallo (CIM = 28 μg mL-1), le siguieron M. luteus (CIM = 32 μg mL-1), S. aureus (CIM = 75 μg mL-1) y E. coli (CIM = 80 μg mL- 1). Los extractos metanólicos y acuosos de tallo presentaron mayor porcentaje de inhibición contra los diferentes tipos de Fusarium evaluados por el método de dilución en agar. Los extractos de V. mollis inhibieron a F. verticillioides entre 62 y 91 % con 120 μg mL-1 de extracto. El orden de las especies de hongos inhibidas por los extractos fue: F. verticillioides > F. oxysporum > F. tapsinum > F. oxysporum f.sp. lycopersici. La composición química de las especies se determinó mediante pruebas para fenoles, taninos, flavonoides, triterpenos, alcaloides, cumarinas y saponinas. Ninguno de los extractos presentó alcaloides y saponinas. Los fenoles (37.1 mg EAG/g muestra seca) y flavonoides (26.8 mg EQ/g muestra seca) fueron los compuestos mayoritarios en los extractos metanólicos y acuosos. En conclusión, se requieren cantidades muy pequeñas de extracto para la inhibición de bacterias y de Fusarium; por lo tanto, V. mollis puede ser considerada una fuente de metabolitos para este fin y en la agricultura como control alternativo dentro de un manejo integrado de enfermedades.

scholarly journals Long-Term Experimental Evolution in Escherichia coli. VI. Environmental Constraints on Adaptation and Divergence

Genetics ◽  
1997 ◽  
Vol 146 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Michael Travisano
Keyword(s):  
Escherichia Coli ◽  
Genetic Variation ◽  
Experimental Evolution ◽  
Population Genetic ◽  
Environmental Constraints ◽  
Asymmetric Pattern ◽  
Nutrient Environment ◽  
Mean Fitness ◽  
Population Genetic Variation

The effect of environment on adaptation and divergence was examined in two sets of populations of Escherichia coli selected for 1000 generations in either maltose- or glucose-limited media. Twelve replicate populations selected in maltose-limited medium improved in fitness in the selected environment, by an average of 22.5%. Statistically significant among-population genetic variation for fitness was observed during the course of the propagation, but this variation was small relative to the fitness improvement. Mean fitness in a novel nutrient environment, glucose-limited medium, improved to the same extent as in the selected environment, with no statistically significant among-population genetic variation. In contrast, 12 replicate populations previously selected for 1000 generations in glucose-limited medium showed no improvement, as a group, in fitness in maltose-limited medium and substantial genetic variation. This asymmetric pattern of correlated responses suggests that small changes in the environment can have profound effects on adaptation and divergence.

scholarly journals Genetic variation in the Middle East—an opportunity to advance the human genetics field

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Ahmad N. Abou Tayoun ◽  
Heidi L. Rehm
Keyword(s):  
Genetic Variation ◽  
Middle East ◽  
Human Genetics ◽  
High Impact ◽  
Limiting Factors ◽  
Sequencing Data ◽  
Clinical Sequencing ◽  
The World ◽  
Genomic Studies

AbstractWe highlight the current lack of representation of the Middle East from large genomic studies and emphasize the expected high impact of cataloging its variation. We discuss the limiting factors and possible solutions to generating and accessing research and clinical sequencing data from this part of the world.

scholarly journals Inhibition of Escherichia coli O157:H7 and Salmonella enterica Isolates on Spinach Leaf Surfaces Using Eugenol-Loaded Surfactant Micelles

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 575
Author(s):  
Songsirin Ruengvisesh ◽  
Chris R. Kerth ◽  
T. Matthew Taylor
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Microbial Pathogens ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Surfactant Micelles ◽  
Leaf Surfaces ◽  
Spinach Leaf

Spinach and other leafy green vegetables have been linked to foodborne disease outbreaks of Escherichia coli O157:H7 and Salmonella enterica around the globe. In this study, the antimicrobial activities of surfactant micelles formed from the anionic surfactant sodium dodecyl sulfate (SDS), SDS micelle-loaded eugenol (1.0% eugenol), 1.0% free eugenol, 200 ppm free chlorine, and sterile water were tested against the human pathogens E. coli O157:H7 and Salmonella Saintpaul, and naturally occurring microorganisms, on spinach leaf surfaces during storage at 5 °C over 10 days. Spinach samples were immersed in antimicrobial treatment solution for 2.0 min at 25 °C, after which treatment solutions were drained off and samples were either subjected to analysis or prepared for refrigerated storage. Whereas empty SDS micelles produced moderate reductions in counts of both pathogens (2.1–3.2 log10 CFU/cm2), free and micelle-entrapped eugenol treatments reduced pathogens by >5.0 log10 CFU/cm2 to below the limit of detection (<0.5 log10 CFU/cm2). Micelle-loaded eugenol produced the greatest numerical reductions in naturally contaminating aerobic bacteria, Enterobacteriaceae, and fungi, though these reductions did not differ statistically from reductions achieved by un-encapsulated eugenol and 200 ppm chlorine. Micelles-loaded eugenol could be used as a novel antimicrobial technology to decontaminate fresh spinach from microbial pathogens.

scholarly journals Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 285
Author(s):  
Da Liu ◽  
Ronald Walcott ◽  
Kevin Mis Solval ◽  
Jinru Chen
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Salmonella Enterica ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Enterohemorrhagic Escherichia Coli ◽  
Biocontrol Agents ◽  
Human Pathogens ◽  
Bacterial Strains ◽  
Pathogen Populations

Interests in using biological agents for control of human pathogens on vegetable seeds are rising. This study evaluated whether probiotic bacterium Lactobacillus rhamnosus GG, bacterial strains previously used as biocontrol agents in plant science, as well as a selected plant pathogen could compete with foodborne human pathogens, such as Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC), for growth in microbiological media and attachment to vegetable seeds; and to determine whether the metabolites in cell-free supernatants of competitive bacterial spent cultures could inhibit the growth of the two pathogens. The results suggest that the co-presence of competitive bacteria, especially L. rhamnosus GG, significantly (p < 0.05) inhibited the growth of Salmonella and EHEC. Cell-free supernatants of L. rhamnosus GG cultures significantly reduced the pathogen populations in microbiological media. Although not as effective as L. rhamnosus GG in inhibiting the growth of Salmonella and EHEC, the biocontrol agents were more effective in competing for attachment to vegetable seeds. The study observed the inhibition of human bacterial pathogens by competitive bacteria or their metabolites and the competitive attachment to sprout seeds among all bacteria involved. The results will help strategize interventions to produce vegetable seeds and seed sprouts free of foodborne pathogens.

scholarly journals Factors associated with Salmonella enterica and Escherichia coli during downtime in commercial broiler chicken barns in Ontario

2021 ◽  
Vol 100 (5) ◽  
pp. 101065
Author(s):  
Chelsea E. Course ◽  
Patrick Boerlin ◽  
Durda Slavic ◽  
Jean-Pierre Vaillancourt ◽  
Michele T. Guerin
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Broiler Chicken ◽  
Factors Associated ◽  
Commercial Broiler
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