Impact of sodium chloride on Escherichia coli O157:H7 and Staphylococcus aureus analysed using transmission electron microscopy

2006 ◽  
Vol 23 (5) ◽  
pp. 446-452 ◽  
Author(s):  
Maha Hajmeer ◽  
Erdogan Ceylan ◽  
James L. Marsden ◽  
Daniel Y.C. Fung
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Sodium Chloride ◽  
Escherichia Coli O157 ◽  
Transmission Electron ◽  
And Staphylococcus Aureus

Effect of Slightly Acidic Electrolyzed Water for Inactivating Escherichia coli O157:H7 and Staphylococcus aureus Analyzed by Transmission Electron Microscopy

2010 ◽  
Vol 73 (12) ◽  
pp. 2211-2216 ◽  
Author(s):  
SONGJIAN NAN ◽  
YONGYU LI ◽  
BAOMING LI ◽  
CHAOYUAN WANG ◽  
XIAODONG CUI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Treatment Time ◽  
Escherichia Coli O157 ◽  
Electrolyzed Water ◽  
E Coli ◽  
Transmission Electron ◽  
And Staphylococcus Aureus

The use of different available chlorine concentrations (ACCs) of slightly acidic electrolyzed water (SAEW; 0.5 to 30 mg/liter), different treatment times, and different temperatures for inactivating Escherichia coli O157:H7 and Staphylococcus aureus was evaluated. The morphology of both pathogens also was analyzed with transmission electron microscopy. A 3-min treatment with SAEW (pH 6.0 to 6.5) at ACCs of 2 mg/liter for E. coli O157:H7 and 8 mg/liter for S. aureus resulted in 100% inactivation of two cultures (7.92- to 8.75-log reduction) at 25°C. The bactericidal activity of SAEW was independent of the treatment time and temperature at a higher ACC (P > 0.05). E. coli O157:H7 was much more sensitive than S. aureus to SAEW. The morphological damage to E. coli O157:H7 cells by SAEW was significantly greater than that to S. aureus cells. At an ACC as high as 30 mg/liter, E. coli O157:H7 cells were damaged, but S. aureus cells retained their structure and no cell wall damage or shrinkage was observed. SAEW with a near neutral pH may be a promising disinfectant for inactivation of foodborne pathogens.

Screening of Condensed Tannins from Canadian Prairie Forages for Anti–Escherichia coli O157:H7 with an Emphasis on Purple Prairie Clover (Dalea purpurea Vent)†

2013 ◽  
Vol 76 (4) ◽  
pp. 560-567 ◽  
Author(s):  
Y. WANG ◽  
L. JIN ◽  
K. H. OMINSKI ◽  
M. HE ◽  
Z. XU ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Condensed Tannins ◽  
Brown Seaweed ◽  
Coli Strain ◽  
Escherichia Coli O157 ◽  
Canadian Prairie ◽  
E Coli ◽  
Transmission Electron

Tannins from forages grown (n = 10) on the Canadian prairie, as well as from Quebracho, Rhus semialata, and brown seaweed (Ascophyllum nodosum), were screened for anti–Escherichia coli O157:H7 activity against E. coli O157:H7 strain 3081 at a concentration of 400 μg/ml for each tannin type, except for brown seaweed, which was at 50 μg/ml. Growth of the bacteria was assessed by measuring the optical density at 600 nm over 24 h. Tannin from seaweed at a concentration of 50 μg/ml inhibited growth of strain 3081. Among the terrestrial forages, only condensed tannins (CT) from purple prairie clover (Dalea purpurea Vent; PPC) increased (P < 0.05) the lag time and reduced (P < 0.05) the growth rate of E. coli O157:H7. The anti–E. coli O157:H7 activity of PPC CT was further assessed by culturing E. coli strain ATCC 25922 and eight strains of E. coli O157:H7 with PPC CT at 0, 25, 50, 100, or 200 μg/ml. Selected strains were enumerated after 0, 6, and 24 h of incubation, and fatty acid composition was determined after 24 h of incubation. E. coli strain 25922 was cultured with 0, 50, or 200 μg of CT per ml and harvested during the exponential growth phase for examination by transmission electron microscopy. Increasing CT concentration linearly increased (P < 0.001) the lag times of seven strains and linearly reduced (P < 0.001) the growth rates of eight E. coli O157:H7 strains. Proportions of unsaturated fatty acids in the total fatty acids were decreased (P < 0.01) by CT at 50 μg/ml. Transmission electron microscopy showed that CT disrupted the outer membrane structure. Anti–E. coli O157:H7 activity of PPC CT at levels of up to 200 μg/ml was bacteriostatic rather than bactericidal, and the mechanism of anti–E. coli activity may involve alteration in the fatty acid composition and disruption of the outer membrane of the cell.

Hemolysis, Platelet Aggregation and Antibacterial Activities of Human Antiphospholipid Antibody

2020 ◽  
Vol 18 (3) ◽  
pp. 268-274
Author(s):  
Farzaneh Ahmadi Shapoorabadi ◽  
Maryam Sadat Mirbagheri Firoozabad ◽  
Neda Habibi ◽  
Giti Emtiazi
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Antiphospholipid Antibodies ◽  
Diffusion Method ◽  
Klebsiella Pneumonia ◽  
Antiphospholipid Antibody ◽  
Bacterial Membranes ◽  
Transmission Electron ◽  
And Staphylococcus Aureus

Background: Anti-phospholipid antibodies have the potential to become an alternative to conventional antibiotics for humans. The Antiphospholipid Syndrome (APS) is an autoimmune disease where the body’s defense system incorrectly reacts against its own phospholipids. APS is distinct through the existence of venous and arterial thromboses, frequently multiple and recurring fetal losses, commonly accompanied by moderate thrombocytopenia. Anti-phospholipid antibodies include lupus anti-coagulant, anti- cardiolipin, anti-beta 2 glycoprotein 1, and anti-prothrombin antibodies. Methods: In this study, the mechanism of action of Anti-phospholipid antibodies against Klebsiella pneumonia and Staphylococcus aureus was investigated in great detail using a unique combination of imaging and biophysical techniques. Antibacterial activity of antiphospholipid antibodies was detected by a diffusion method and the investigation of the complexity of antibody-antigen was done by spectroscopic examination, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) imaging. Results: There was a profound change in the bacteria treated with healthy and patient serum in the optical microscopic study. In all of the studied fields, bacterial treatment with patient serum immediately induced bacterial swelling and cumulative accumulation of the bacteria while no changes were observed in the healthy serum. Anti-bacterial activities of patient serum were detected on the plate. The result of this study showed that after platelet activation by thrombin and incubation with antiphospholipid antibodies, the platelet was aggregated. The transmission electron microscopy (TEM) image showed that the cell wall of Klebsiella pneumonia and Staphylococcus aureus incubated with antiphospholipid had a bizarre shape and antiphospholipid antibodies bound to bacterial membranes. Conclusion: The data indicated that antiphospholipid antibodies with hemolysis activities have an effect on Gram-positive and negative bacteria and these antibodies have the potential to become antibiotic for human.

scholarly journals Evaluation of Ultrasound-Induced Damage to Escherichia coli and Staphylococcus aureus by Flow Cytometry and Transmission Electron Microscopy

2016 ◽  
Vol 82 (6) ◽  
pp. 1828-1837 ◽  
Author(s):  
Jiao Li ◽  
Juhee Ahn ◽  
Donghong Liu ◽  
Shiguo Chen ◽  
Xingqian Ye ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Cytoplasmic Membrane ◽  
Ultrasound Treatment ◽  
Cellular Damage ◽  
Content Type ◽  
Transmission Electron

ABSTRACTAs a nonthermal sterilization technique, ultrasound has attracted great interest in the field of food preservation. In this study, flow cytometry and transmission electron microscopy were employed to investigate ultrasound-induced damage toEscherichia coliandStaphylococcus aureus. For flow cytometry studies, single staining with propidium iodide (PI) or carboxyfluorescein diacetate (cFDA) revealed that ultrasound treatment caused cell death by compromising membrane integrity, inactivating intracellular esterases, and inhibiting metabolic performance. The results showed that ultrasound damage was independent of initial bacterial concentrations, while the mechanism of cellular damage differed according to the bacterial species. For the Gram-negative bacteriumE. coli, ultrasound worked first on the outer membrane rather than the cytoplasmic membrane. Based on the double-staining results, we inferred that ultrasound treatment might be an all-or-nothing process: cells ruptured and disintegrated by ultrasound cannot be revived, which can be considered an advantage of ultrasound over other nonthermal techniques. Transmission electron microscopy studies revealed that the mechanism of ultrasound-induced damage was multitarget inactivation, involving the cell wall, cytoplasmic membrane, and inner structure. Understanding of the irreversible antibacterial action of ultrasound has great significance for its further utilization in the food industry.

Transmission Electron Microscopy Study of Enterohemorrhagic Escherichia coli O157:H7 in Apple Tissue

2005 ◽  
Vol 68 (2) ◽  
pp. 216-224 ◽  
Author(s):  
MARLENE E. JANES ◽  
K. S. KIM ◽  
M. G. JOHNSON
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Plasma Membranes ◽  
Single Cells ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Transmission Electron ◽  
Apple Tissue

We investigated the ability of enterohemorrhagic Escherichia coli O157:H7 to spread in wounded apple tissue by transmission electron microscopy. Red Delicious apples were wounded with an artist knife (7 mm depth) and either inoculated with 10 μl per wound of decimally diluted E. coli O157:H7 or submerged into E. coli O157:H7 suspended in sterile distilled water and then stored at 37°C for 24 h. Transmission electron microscopy showed E. coli O157:H7 formed bacterial aggregates near the apple cell walls, and single cells were in close proximity to the apple cell wall surfaces and to plasma membranes. E. coli O157:H7 presence caused degradation of plasma membranes and release of the cytoplasm contents of the apple cortical cells into the central vacuole. Apple tissue turgor pressure tests showed that the apple cells infected with E. coli O157:H7 isolates were more likely to rupture than the control noninoculated apple cells. E. coli O157:H7 cells grown in apple tissue showed the formation of granules and vesicles within the bacterial cytoplasma and separation of the plasma membranes. Our study shows that E. coli O157:H7 can grow and survive in the apple tissue environment by causing degradation of the apple cellular components.

Comparison of Four Commercial DNA Extraction Kits for PCR Detection of Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Staphylococcus aureus in Fresh, Minimally Processed Vegetables

2008 ◽  
Vol 71 (10) ◽  
pp. 2110-2114 ◽  
Author(s):  
P. ELIZAQUÍVEL ◽  
R. AZNAR
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Dna Extraction ◽  
Pcr Detection ◽  
Escherichia Coli O157 ◽  
Minimally Processed ◽  
Green Pepper ◽  
Minimally Processed Vegetables ◽  
And Staphylococcus Aureus

Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytogenes, and E. coli O157:H7 and in onion for S. aureus. Despite being the most expensive of the methods compared, the DNeasy Tissue Kit can be successfully applied for any of the four most commonly studied pathogens, thus saving time and overall reducing the cost of the analysis.

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