Assessment of Photodynamic Destruction of Escherichia coli O157:H7 and Listeria monocytogenes by Using ATP Bioluminescence

ABSTRACT Antimicrobial photodynamic therapy was shown to be effective against a wide range of bacterial cells, as well as for fungi, yeasts, and viruses. It was shown previously that photodestruction of yeast cells treated with photosensitizers resulted in cell destruction and leakage of ATP. Three photosensitizers were used in this study: tetra(N-methyl-4-pyridyl)porphine tetratosylate salt (TMPyP), toluidine blue O (TBO), and methylene blue trihydrate (MB). A microdilution method was used to determine MICs of the photosensitizers against both Escherichia coli O157:H7 and Listeria monocytogenes. To evaluate the effects of photodestruction on E. coli and L. monocytogenes cells, a bioluminescence method for detection of ATP leakage and a colony-forming assay were used. All tested photosensitizers were effective for photodynamic destruction of both bacteria. The effectiveness of photosensitizers (in microgram-per-milliliter equivalents) decreased in the order TBO > MB > TMPyP for both organisms. The MICs were two- to fourfold higher for E. coli O157:H7 than for L. monocytogenes. The primary effects of all of the photosensitizers tested on live bacterial cells were a decrease in intracellular ATP and an increase in extracellular ATP, accompanied by elimination of viable cells from the sample. The time courses of photodestruction and intracellular ATP leakage were different for E. coli and L. monocytogenes. These results show that bioluminescent ATP-metry can be used for investigation of the first stages of bacterial photodestruction.

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Optical Tweezers Cause Physiological Damage to Escherichia coli and Listeria Bacteria

Applied and Environmental Microbiology ◽

10.1128/aem.02265-07 ◽

2008 ◽

Vol 74 (8) ◽

pp. 2441-2446 ◽

Cited By ~ 112

Author(s):

M. B. Rasmussen ◽

L. B. Oddershede ◽

H. Siegumfeldt

Keyword(s):

Escherichia Coli ◽

Cell Wall ◽

Listeria Monocytogenes ◽

Optical Tweezers ◽

Laser Power ◽

Fluorescent Protein ◽

Growth Conditions ◽

Ph Gradient ◽

Bacterial Cells ◽

E Coli

ABSTRACT We investigated the degree of physiological damage to bacterial cells caused by optical trapping using a 1,064-nm laser. The physiological condition of the cells was determined by their ability to maintain a pH gradient across the cell wall; healthy cells are able to maintain a pH gradient over the cell wall, whereas compromised cells are less efficient, thus giving rise to a diminished pH gradient. The pH gradient was measured by fluorescence ratio imaging microscopy by incorporating a pH-sensitive fluorescent probe, green fluorescent protein or 5(6)-carboxyfluorescein diacetate succinimidyl ester, inside the bacterial cells. We used the gram-negative species Escherichia coli and three gram-positive species, Listeria monocytogenes, Listeria innocua, and Bacillus subtilis. All cells exhibited some degree of physiological damage, but optically trapped E. coli and L. innocua cells and a subpopulation of L. monocytogenes cells, all grown with shaking, showed only a small decrease in pH gradient across the cell wall when trapped by 6 mW of laser power for 60 min. However, another subpopulation of Listeria monocytogenes cells exhibited signs of physiological damage even while trapped at 6 mW, as did B. subtilis cells. Increasing the laser power to 18 mW caused the pH gradient of both Listeria and E. coli cells to decrease within minutes. Moreover, both species of Listeria exhibited more-pronounced physiological damage when grown without shaking than was seen in cells grown with shaking, and the degree of damage is therefore also dependent on the growth conditions.

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Persister Cells Resuscitate via Ribosome Modification by 23S rRNA Pseudouridine Synthase RluD

10.1101/678425 ◽

2019 ◽

Cited By ~ 1

Author(s):

Sooyeon Song ◽

Thomas K. Wood

Keyword(s):

Escherichia Coli ◽

Small Rna ◽

23S Rrna ◽

Bacterial Cells ◽

Persister Cells ◽

E Coli ◽

Pseudouridine Synthase ◽

Dormant Cells ◽

Wide Range ◽

Persister Cell

ABSTRACTUpon a wide range of stress conditions (e.g., nutrient, antibiotic, oxidative), a subpopulation of bacterial cells known as persisters survive by halting metabolism. These cells resuscitate rapidly to reconstitute infections once the stress is removed and nutrients are provided. However, how these dormant cells resuscitate is not understood well but involves reactivating ribosomes. By screening 10,000 compounds directly for stimulating Escherichia coli persister cell resuscitation, we identified that 2-{[2-(4-bromophenyl)-2-oxoethyl]thio}-3-ethyl-5,6,7,8-tetrahydro[1]benzothieno[2,3-d]pyrimidin-4(3H)-one (BPOET) stimulates resuscitation. Critically, by screening 4,267 E. coli proteins, we determined that BPOET activates hibernating ribosomes via 23S rRNA pseudouridine synthase RluD, which increases ribosome activity. Corroborating the increased waking with RluD, production of RluD increased the number of active ribosomes in persister cells. Also, inactivating the small RNA RybB which represses rluD led to faster persister resuscitation. Hence, persister cells resuscitate via activation of RluD.

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An Improved Membrane Filtration Method for Enumeration of Faecal Coliforms and E. Coli by a Fluorogenic β-Glucuronidase Assay

Water Science & Technology ◽

10.2166/wst.1993.0357 ◽

1993 ◽

Vol 27 (3-4) ◽

pp. 267-270 ◽

Cited By ~ 4

Author(s):

M. T. Augoustinos ◽

N. A. Grabow ◽

B. Genthe ◽

R. Kfir

Keyword(s):

Escherichia Coli ◽

Water Samples ◽

Membrane Filtration ◽

Faecal Coliforms ◽

Environmental Waters ◽

Filtration Method ◽

E Coli ◽

Wide Range ◽

Pure Cultures ◽

Glucuronidase Assay

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.

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Vibrio cholerae Triggers SOS and Mutagenesis in Response to a Wide Range of Antibiotics: a Route towards Multiresistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01549-10 ◽

2011 ◽

Vol 55 (5) ◽

pp. 2438-2441 ◽

Cited By ~ 107

Author(s):

Zeynep Baharoglu ◽

Didier Mazel

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Vibrio Cholerae ◽

Fluorescent Protein ◽

Resistance Development ◽

Content Type ◽

E Coli ◽

Wide Range ◽

Green Fluorescent ◽

Regulated Promoters

ABSTRACTAntibiotic resistance development has been linked to the bacterial SOS stress response. InEscherichia coli, fluoroquinolones are known to induce SOS, whereas other antibiotics, such as aminoglycosides, tetracycline, and chloramphenicol, do not. Here we address whether various antibiotics induce SOS inVibrio cholerae. Reporter green fluorescent protein (GFP) fusions were used to measure the response of SOS-regulated promoters to subinhibitory concentrations of antibiotics. We show that unlike the situation withE. coli, all these antibiotics induce SOS inV. cholerae.

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ATIVIDADE ANTIMICROBIANA DE MICRORGANISMOS ISOLADOS DE GRÃOS DE KEFIR

Ciência Animal Brasileira ◽

10.1590/1809-6891v19e-40548 ◽

2018 ◽

Vol 19 (0) ◽

Author(s):

Priscila Alves Dias ◽

Daiani Teixeira Silva ◽

Cláudio Dias Timm

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Listeria Monocytogenes ◽

Salmonella Typhimurium ◽

Salmonella Enterica ◽

Escherichia Coli O157 ◽

E Coli

Resumo Kefir é o produto da fermentação do leite pelos grãos de kefir. Esses grãos contêm uma mistura simbiótica de bactérias e leveduras imersas em uma matriz composta de polissacarídeos e proteínas. Muitos benefícios à saúde humana têm sido atribuídos ao kefir, incluindo atividade antimicrobiana contra bactérias Gram positivas e Gram negativas. A atividade antimicrobiana de 60 microrganismos isolados de grãos de kefir, frente à Escherichia coli O157:H7, Salmonella enterica subsp. enterica sorotipos Typhimurium e Enteritidis, Staphylococcus aureus e Listeria monocytogenes, foi estudada através do teste do antagonismo. A ação antimicrobiana dos sobrenadantes das bactérias ácido-lácticas que apresentaram atividade no teste do antagonismo foi testada. O experimento foi repetido usando sobrenadantes com pH neutralizado. Salmonella Typhimurium e Enteritidis sobreviveram por 24 horas no kefir em fermentação. E. coli O157:H7, S. aureus e L. monocytogenes foram recuperados até 72 horas após o início da fermentação. Todos os isolados apresentaram atividade antimicrobiana contra pelo menos um dos patógenos usados no teste do antagonismo. Sobrenadantes de 25 isolados apresentaram atividade inibitória e três mantiveram essa atividade com pH neutralizado. As bactérias patogênicas estudadas sobreviveram por tempo superior àquele normalmente utilizado para a fermentação do kefir artesanal, o que caracteriza perigo em potencial para o consumidor quando a matéria-prima não apresentar segurança sanitária. Lactobacillus isolados de grãos de kefir apresentam atividade antimicrobiana contra cepas de E. coli O157:H7, Salmonella sorotipos Typhimurium e Enteritidis, S. aureus e L. monocytogenes além daquela exercida pela diminuição do pH.

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One-Step Preparation of Competent E. coli: Transformation and Storage of Bacterial Cells in the Same Solution

Cold Spring Harbor Protocols ◽

10.1101/pdb.prot101212 ◽

2021 ◽

Vol 2021 (11) ◽

pp. pdb.prot101212 ◽

Cited By ~ 1

Author(s):

Michael R. Green ◽

Joseph Sambrook

Keyword(s):

Escherichia Coli ◽

Convenient Method ◽

Plasmid Dna ◽

Transformation Efficiency ◽

Bacterial Cells ◽

E Coli ◽

One Step ◽

And Storage

This protocol describes a convenient method for the preparation, use, and storage of competent Escherichia coli. The reported transformation efficiency of this method is ∼5 × 107 transformants/µg of plasmid DNA.

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PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽

10.1099/mic.0.001031 ◽

2021 ◽

Vol 167 (3) ◽

Author(s):

Sathi Mallick ◽

Shanti Kiran ◽

Tapas Kumar Maiti ◽

Anindya S. Ghosh

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Type Species ◽

Pentose Phosphate ◽

Bacterial Cells ◽

Surface Adhesion ◽

Content Type ◽

Penicillin Binding Proteins ◽

E Coli ◽

Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

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Changes in Aerobic Plate and Escherichia coli–Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage

Journal of Food Protection ◽

10.4315/0362-028x.jfp-15-553 ◽

2016 ◽

Vol 79 (7) ◽

pp. 1143-1153 ◽

Cited By ~ 8

Author(s):

JOHN C. FRELKA ◽

GORDON R. DAVIDSON ◽

LINDA J. HARRIS

Keyword(s):

Escherichia Coli ◽

Listeria Monocytogenes ◽

Relative Humidity ◽

Low Temperature ◽

Foodborne Pathogens ◽

Limit Of Detection ◽

Sampling Time ◽

E Coli ◽

Plate Counts ◽

Forced Air

ABSTRACT After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli–coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (~8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of −0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by −0.17 log CFU per nut per month and −0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent sampling time by either plating or by enrichment.

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Growth Inhibition of Escherichia coli O157:H7 and Listeria monocytogenes by Carvacrol and Eugenol Encapsulated in Surfactant Micelles

Journal of Food Protection ◽

10.4315/0362-028x-68.12.2559 ◽

2005 ◽

Vol 68 (12) ◽

pp. 2559-2566 ◽

Cited By ~ 92

Author(s):

SYLVIA GAYSINSKY ◽

P. MICHAEL DAVIDSON ◽

BARRY D. BRUCE ◽

JOCHEN WEISS

Keyword(s):

Escherichia Coli ◽

Antimicrobial Activity ◽

Listeria Monocytogenes ◽

Essential Oil ◽

Growth Inhibition ◽

Surfactant Concentration ◽

Escherichia Coli O157 ◽

Surfactant Micelles ◽

E Coli ◽

Oil Components

Growth inhibition of four strains of Escherichia coli O157:H7 (H1730, F4546, 932, and E0019) and Listeria monocytogenes (Scott A, 101, 108, and 310) by essential oil components (carvacrol and eugenol) solubilized in nonionic surfactant micelles (Surfynol 465 and 485W) was investigated. Concentrations of encapsulated essential oil components ranged from 0.02 to 1.25% depending on compound, surfactant type, and surfactant concentration (0.5 to 5%). Eugenol encapsulated in Surfynol 485W micelles was most efficient in inhibiting growth of the pathogens; 1% Surfynol 485W and 0.15% eugenol was sufficient to inhibit growth of all strains of E. coli O157:H7 and three of four strains of L. monocytogenes (Scott A, 310, and 108). The fourth strain, L. monocytogenes 101, was inhibited by 2.5% Surfynol and 0.225% eugenol. One percent Surfynol 485W in combination with 0.025% carvacrol was effective in inhibiting three of four strains of E. coli O157:H7. Strain H1730 was the most resistant strain, requiring 0.3% carvacrol and 5% surfactant for complete inhibition. Growth inhibition of L. monocytogenes by combinations of carvacrol and Surfynol 465 ranged between 0.15 and 0.35% and 1 and 3.75%, respectively. Generally, the antimicrobial activity of Surfynol 465 in combination with eugenol was higher than that for the combination with carvacrol. The potent activity was attributed to increased solubility of essential oil components in the aqueous phase due to the presence of surfactants and improved interactions of antimicrobials with microorganisms.

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Bacterial Secretions of Nonpathogenic Escherichia coli Elicit Inflammatory Pathways: a Closer Investigation of Interkingdom Signaling

mBio ◽

10.1128/mbio.00025-15 ◽

2015 ◽

Vol 6 (2) ◽

Cited By ~ 33

Author(s):

Amin Zargar ◽

David N. Quan ◽

Karen K. Carter ◽

Min Guo ◽

Herman O. Sintim ◽

...

Keyword(s):

Escherichia Coli ◽

Epithelial Cells ◽

Negative Feedback ◽

Cell Contact ◽

Bacterial Cells ◽

Content Type ◽

Phenotypic Differences ◽

E Coli ◽

Autoinducer 2 ◽

Human Epithelial Cells

ABSTRACTThere have been many studies on the relationship between nonpathogenic bacteria and human epithelial cells; however, the bidirectional effects of the secretomes (secreted substances in which there is no direct bacterium-cell contact) have yet to be fully investigated. In this study, we use a transwell model to explore the transcriptomic effects of bacterial secretions from two different nonpathogenicEscherichia colistrains on the human colonic cell line HCT-8 using next-generation transcriptome sequencing (RNA-Seq).E. coliBL21 and W3110, while genetically very similar (99.1% homology), exhibit key phenotypic differences, including differences in their production of macromolecular structures (e.g., flagella and lipopolysaccharide) and in their secretion of metabolic byproducts (e.g., acetate) and signaling molecules (e.g., quorum-sensing autoinducer 2 [AI-2]). After analysis of differential epithelial responses to the respective secretomes, this study shows for the first time that a nonpathogenic bacterial secretome activates the NF-κB-mediated cytokine-cytokine receptor pathways while also upregulating negative-feedback components, including the NOD-like signaling pathway. Because of AI-2's relevance as a bacterium-bacterium signaling molecule and the differences in its secretion rates between these strains, we investigated its role in HCT-8 cells. We found that the expression of the inflammatory cytokine interleukin 8 (IL-8) responded to AI-2 with a pattern of rapid upregulation before subsequent downregulation after 24 h. Collectively, these data demonstrate that secreted products from nonpathogenic bacteria stimulate the transcription of immune-related biological pathways, followed by the upregulation of negative-feedback elements that may serve to temper the inflammatory response.IMPORTANCEThe symbiotic relationship between the microbiome and the host is important in the maintenance of human health. There is a growing need to further understand the nature of these relationships to aid in the development of homeostatic probiotics and also in the design of novel antimicrobial therapeutics. To our knowledge, this is the first global-transcriptome study of bacteria cocultured with human epithelial cells in a model to determine the transcriptional effects of epithelial cells in which epithelial and bacterial cells are allowed to “communicate” with each other only through diffusible small molecules and proteins. By beginning to demarcate the direct and indirect effects of bacteria on the gastrointestinal (GI) tract, two-way interkingdom communication can potentially be mediated between host and microbe.

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