scholarly journals Magnesium Hydroxide Nanoparticles Kill Exponentially Growing and Persister Escherichia coli Cells by Causing Physical Damage

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1584
Author(s):  
Yohei Nakamura ◽  
Kaede Okita ◽  
Daisuke Kudo ◽  
Dao Nguyen Duy Phuong ◽  
Yoshihito Iwamoto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Magnesium Hydroxide ◽  
Cell Damage ◽  
Low Cost ◽  
Bactericidal Effect ◽  
Physical Damage ◽  
E Coli ◽  
In The Wild ◽  
Low Toxicity ◽  
Magnesium Hydroxide Nanoparticles

Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D50 = 75.2 nm) showed a higher bactericidal effect against Escherichia coli than larger nanoparticles (D50 = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that E. coli cells treated with NM80 were directly injured.

scholarly journals Bactericidal effect of nanostructures via lytic transglycosylases of Escherichia coli

RSC Advances ◽  
2022 ◽  
Vol 12 (3) ◽  
pp. 1645-1652
Author(s):  
Soma Mimura ◽  
Tomohiro Shimizu ◽  
Shoso Shingubara ◽  
Hiroaki Iwaki ◽  
Takeshi Ito
Keyword(s):  
Escherichia Coli ◽  
Growth Phase ◽  
Cell Damage ◽  
Bactericidal Effect ◽  
Active Cell ◽  
Lytic Transglycosylases ◽  
E Coli ◽  
Time Profiles

The time profiles of active cell ratios depended on the growth phase and the absence of some lytic transglycosylases of E. coli. Significant cell damage was not found on the autolysis inhibition condition.

Potentiation by L-cysteine of the bactericidal effect of hydrogen peroxide in Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 81-88
Author(s):  
E H Berglin ◽  
M B Edlund ◽  
G K Nyberg ◽  
J Carlsson
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Metal Ion ◽  
Chelating Agent ◽  
Fold Increase ◽  
Bactericidal Effect ◽  
Anaerobic Conditions ◽  
Dna Breakage ◽  
E Coli ◽  
K 12

Under anaerobic conditions an exponentially growing culture of Escherichia coli K-12 was exposed to hydrogen peroxide in the presence of various compounds. Hydrogen peroxide (0.1 mM) together with 0.1 mM L-cysteine or L-cystine killed the organisms more rapidly than 10 mM hydrogen peroxide alone. The exposure of E. coli to hydrogen peroxide in the presence of L-cysteine inhibited some of the catalase. This inhibition, however, could not fully explain the 100-fold increase in hydrogen peroxide sensitivity of the organism in the presence of L-cysteine. Of other compounds tested only some thiols potentiated the bactericidal effect of hydrogen peroxide. These thiols were effective, however, only at concentrations significantly higher than 0.1 mM. The effect of L-cysteine and L-cystine could be annihilated by the metal ion chelating agent 2,2'-bipyridyl. DNA breakage in E. coli K-12 was demonstrated under conditions where the organisms were killed by hydrogen peroxide.

O6-methylguanine-DNA methyltransferase in wild-type and ada mutants of Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 534-537
Author(s):  
S Mitra ◽  
B C Pal ◽  
R S Foote
Keyword(s):  
Escherichia Coli ◽  
Dna Methyltransferase ◽  
Wild Type ◽  
E Coli ◽  
Methylguanine Dna Methyltransferase ◽  
Synthetic Dna ◽  
In The Wild ◽  
Low Levels ◽  
Enzyme Molecules ◽  
Dna Substrate

O(6)-Methylguanine-DNA methyltransferase is induced in Escherichia coli during growth in low levels of N-methyl-N'-nitro-N-nitrosoguanidine. We have developed a sensitive assay for quantitating low levels of this activity with a synthetic DNA substrate containing 3H-labeled O(6)-methylguanine as the only modified base. Although both wild-type and adaptation-deficient (ada) mutants of E. coli contained low but comparable numbers (from 13 to 60) of the enzyme molecules per cell, adaptation treatment caused a significant increase of the enzyme in the wild type but not in the ada mutants, suggesting that the ada mutation is in a regulatory locus and not in the structural gene for the methyltransferase.

Antimicrobial Effects of Novel H2O2-Ag+ Complex on Membrane Damage to Staphylococcus aureus,Escherichia coli and Salmonella typhimurium

2021 ◽  
Author(s):  
Bing Han ◽  
Xiaoyu Han ◽  
Mengmeng Ren ◽  
Yilin You ◽  
Jicheng Zhan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Staphylococcus Aureus ◽  
Salmonella Typhimurium ◽  
Membrane Damage ◽  
Bactericidal Effect ◽  
E Coli ◽  
Bacterial Cell Membrane ◽  
Time Kill ◽  
Environmental Disinfection

Diseases caused by harmful microorganisms pose a serious threat to human health. Safe and environment-friendly disinfectants are, therefore, essential in preventing and controlling such pathogens. This study aimed to investigate the antimicrobial activity and mechanism of a novel hydrogen peroxide and silver (H 2 O 2 -Ag + ) complex (HSC) in combatting Staphylococcus aureus ATCC 29213, Escherichia coli O157:H7 NCTC 12900 and Salmonella typhimurium SL 1344. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against S. aureus were found to be 0.014 % H 2 O 2 -3.125 mg/L Ag + , while 0.028 % H 2 O 2 -6.25 mg/L Ag + for both E. coli and S. typhimurium . Results of the growth curve assay and time-kill trial suggest that the HSC could inhibit the growth of the tested bacteria, as 99.9 % of viable cells were killed following treatment at the 1 MIC for 3 h. Compared with Oxytech D10 disinfectant (0.25 % H 2 O 2 -5 mg/L Ag + ), the HSC exhibited better antibacterial efficacy at a lower concentration (0.045 % H 2 O 2 -10 mg/L Ag + ). The mechanism of antibacterial action of HSC was found including the disruption of the bacterial cell membrane, followed by entry into the bacteria cell to reduce intracellular adenosine triphosphate (ATP) concentration, and inhibit the activity of antioxidases, superoxide dismutase (SOD) and catalase (CAT). The enhanced bactericidal effect of hydrogen peroxide combined with silver indicates a potential for its application in environmental disinfection, particularly in the food industry.

CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli

2019 ◽  
Vol 65 (9) ◽  
pp. 691-702 ◽  
Author(s):  
Yi Gou ◽  
Weiqi Liu ◽  
Jing Jing Wang ◽  
Ling Tan ◽  
Bin Hong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Motility ◽  
Biofilm Formation ◽  
Response Regulator ◽  
Signal Transmission ◽  
Bacterial Motility ◽  
Type I ◽  
E Coli ◽  
Real Time Quantitative Pcr ◽  
In The Wild

Generally, cell motility and biofilm formation are tightly regulated. The QseBC two-component system (TCS) serves as a bridge for bacterial signal transmission, in which the protein QseB acts as a response regulator bacterial motility, biofilm formation, and virulence. The mechanisms that govern the interaction between QseBC and their functions have been studied in general, but the regulatory role of QseB on bacterial motility and biofilm formation is unknown. In this study, the CRISPR-Cas9 system was used to construct the Escherichia coli MG1655ΔqseB strain (strain ΔqseB), and the effects of the qseB gene on changes in motility and biofilm formation in the wild type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p < 0.05) motility than the WT strain. However, there was no difference in the formation of biofilm between the ΔqseB and WT strains. Real-time quantitative PCR illustrated that deletion of qseB in the WT strain downregulated expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the downregulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, providing new insight into the functional importance of QseB in regulating cell motility and biofilm formation.

Inactivation of Escherichia coli O157:H7, Listeria monocytogenes, and Lactobacillus leichmannii by Combinations of Ozone and Pulsed Electric Field

2001 ◽  
Vol 64 (6) ◽  
pp. 777-782 ◽  
Author(s):  
RAGIP UNAL ◽  
JIN-GAB KIM ◽  
AHMED E. YOUSEF
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Electric Field ◽  
Pulsed Electric Field ◽  
Bactericidal Effect ◽  
Treatment Level ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Nonthermal Processing ◽  
Lactobacillus Leichmannii

Pulsed electric field (PEF) and ozone technologies are nonthermal processing methods with potential applications in the food industry. This research was performed to explore the potential synergy between ozone and PEF treatments against selected foodborne bacteria. Cells of Lactobacillus leichmannii ATCC 4797, Escherichia coli O157:H7 ATCC 35150, and Listeria monocytogenes Scott A were suspended in 0.1% NaCl and treated with ozone, PEF, and ozone plus PEF. Cells were treated with 0.25 to 1.00 μg of ozone per ml of cell suspension, PEF at 10 to 30 kV/cm, and selected combinations of ozone and PEF. Synergy between ozone and PEF varied with the treatment level and the bacterium treated. L. leichmannii treated with PEF (20 kV/cm) after exposure to 0.75 and 1.00 μg/ml of ozone was inactivated by 7.1 and 7.2 log10 CFU/ml, respectively; however, ozone at 0.75 and 1.00 μg/ml and PEF at 20 kV/cm inactivated 2.2, 3.6, and 1.3 log10 CFU/ml, respectively. Similarly, ozone at 0.5 and 0.75 μg/ml inactivated 0.5 and 1.8 log10 CFU/ml of E. coli, PEF at 15 kV/cm inactivated 1.8 log10 CFU/ml, and ozone at 0.5 and 0.75 μg/ml followed by PEF (15 kV/cm) inactivated 2.9 and 3.6 log10 CFU/ml, respectively. Populations of L. monocytogenes decreased 0.1, 0.5, 3.0, 3.9, and 0.8 log10 CFU/ml when treated with 0.25, 0.5, 0.75, and 1.0 μg/ml of ozone and PEF (15 kV/cm), respectively; however, when the bacterium was treated with 15 kV/cm, after exposure to 0.25, 0.5, and 0.75 μg/ml of ozone, 1.7, 2.0, and 3.9 log10 CFU/ml were killed, respectively. In conclusion, exposure of L. leichmannii, E. coli, and L. monocytogenes to ozone followed by the PEF treatment showed a synergistic bactericidal effect. This synergy was most apparent with mild doses of ozone against L. leichmannii.

scholarly journals Comparative assessment of the bactericidal effect of nanoparticles of copper oxide, silver, and chitosan-silver against Escherichia coli infection in broilers

2021 ◽  
Vol 41 (4) ◽  
Author(s):  
Eman I. Hassanen ◽  
Eman A. Morsy ◽  
Ahmed M. Hussien ◽  
Khaled Y. Farroh ◽  
Merhan E. Ali
Keyword(s):  
Escherichia Coli ◽  
Copper Oxide ◽  
Treated Group ◽  
Bactericidal Effect ◽  
Growth Promoter ◽  
Ag Nps ◽  
E Coli ◽  
Cuo Nps ◽  
Escherichia Coli Infection

Abstract Escherichia coli infection is considered one of the most economically important multi-systemic diseases in poultry farms. Several nanoparticles such as silver, chitosan, and copper oxide are known to be highly toxic to several microbes. However, there are no data concerning their success against in vivo experimental E. coli infection in broilers. Therefore, the present study was designed to investigate the bactericidal effect of low doses of CuO-NPs (5 mg/kg bwt), Ag-NPs (0.5 mg/kg bwt), and Ch-Ag NPs (0.5 mg/kg bwt) against E. coli experimental infection in broilers. One hundred chicks were divided into five groups as follows: (1) control; (2) E. coli (4 × 108 CFU/ml) challenged; (3) E. coli +CuO-NPs; (4) E. coli +Ag-NPs; (5) E. coli +Ch-Ag NPs. The challenged untreated group, not NPs treated groups, recorded the lowest weight gain as well as the highest bacterial count and lesion score in all examined organs. The highest liver content of silver was observed in Ag-NPs treated group compared with the Ch-Ag NPs treated group. Our results concluded that Ch-Ag NPs not only had the best antibacterial effects but also acted as a growth promoter in broilers without leaving any residues in edible organs. We recommend using Ch-Ag NPs in broiler farms instead of antibiotics or probiotics.

scholarly journals Sanitizing action of triple-strength vinegar against Escherichia coli on lettuce

2018 ◽  
Vol 36 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Giovanna C Souza ◽  
Wilma A Spinosa ◽  
Tereza CRM Oliveira
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Low Cost ◽  
Titratable Acidity ◽  
Total Acidity ◽  
Total Coliforms ◽  
E Coli ◽  
Total Titratable Acidity ◽  
Carcinogenic Effects ◽  
Interesting Alternative

ABSTRACT Vegetable sanitization protocols recommend the use of chlorine, which has adverse effects on the environment and carcinogenic effects on humans. Acetic acid is an interesting alternative to chlorine because it possesses no risk to human health and is widely available in the form of vinegar. This study aimed to evaluate the sanitizing action of vinegar, 130 g L-1 total titratable acidity expressed as acetic acid, on lettuce. Vinegar was chosen because it is a low-cost product widely available in the Brazilian market. The minimum inhibitory concentration and minimum bactericidal concentration of vinegar against Escherichia coli were 2.5 and 15 g L-1 total acidity, respectively. Lettuce leaves artificially contaminated with E. coli or naturally contaminated with total coliforms were washed with water and immersed in vinegar solution (15 g L-1 total acidity) for 15 min. This period was sufficient to reduce E. coli counts in artificially contaminated samples and total coliforms in naturally contaminated samples. There were no visual changes in lettuce leaves, which indicates that vinegar at 15 g L-1 total acidity can be used to sanitize vegetables without affecting their appearance.

Preharvest Internalization of Escherichia coli O157:H7 into Lettuce Leaves, as Affected by Insect and Physical Damage

2010 ◽  
Vol 73 (10) ◽  
pp. 1809-1816 ◽  
Author(s):  
MARILYN C. ERICKSON ◽  
JEAN LIAO ◽  
ALISON S. PAYTON ◽  
DAVID G. RILEY ◽  
CATHY C. WEBB ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Insect Pests ◽  
Enteric Pathogen ◽  
Escherichia Coli O157 ◽  
Physical Damage ◽  
E Coli ◽  
Leafy Greens ◽  
Different Populations ◽  
Pathogen Exposure ◽  
Spinach Leaves

Environmental pests may serve as reservoirs and vectors of zoonotic pathogens to leafy greens; however, it is unknown whether insect pests feeding on plant tissues could redistribute these pathogens present on the surface of leaves to internal sites. This study sought to differentiate the degree of tissue internalization of Escherichia coli O157:H7 when applied at different populations on the surface of lettuce and spinach leaves, and to ascertain whether lettuce-infesting insects or physical injury could influence the fate of either surface or internalized populations of this enteric pathogen. No internalization of E. coli O157:H7 occurred when lettuce leaves were inoculated with 4.4 log CFU per leaf, but it did occur when inoculated with 6.4 log CFU per leaf. Internalization was statistically greater when spinach leaves were inoculated on the abaxial (underside) than when inoculated on the adaxial (topside) side, and when the enteric pathogen was spread after surface inoculation. Brief exposure (~18 h) of lettuce leaves to insects (5 cabbage loopers, 10 thrips, or 10 aphids) prior to inoculation with E. coli O157:H7 resulted in significantly reduced internalized populations of the pathogen within these leaves after approximately 2 weeks, as compared with leaves not exposed to insects. Surface-contaminated leaves physically injured through file abrasions also had significantly reduced populations of both total and internalized E. coli O157:H7 as compared with nonabraded leaves 2 weeks after pathogen exposure.

scholarly journals Hydrothermal Fabrication of Spindle-Shaped ZnO/Palygorskite Nanocomposites Using Nonionic Surfactant for Enhancement of Antibacterial Activity

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1453 ◽  
Author(s):  
Aiping Hui ◽  
Shuqing Dong ◽  
Yuru Kang ◽  
Yanmin Zhou ◽  
Aiqin Wang
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Low Cost ◽  
Ionic Surfactants ◽  
E Coli ◽  
Antibacterial Performance ◽  
Good Antibacterial Activity ◽  
Controllable Growth ◽  
And Staphylococcus Aureus

In order to improve the antibacterial performance of natural palygorskite, spindle-like ZnO/palygorskite (ZnO/PAL) nanocomposites with controllable growth of ZnO on the surface of PAL were prepared in the presence of non-ionic surfactants using an easy-to-operate hydrothermal method. The obtained ZnO/PAL nanocomposites have a novel and special spindle-shaped structure and good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and are also low cost. The minimum inhibitory concentrations of ZnO/PAL nanocomposites toward E. coli and S. aureus reached 1.5 and 5 mg/mL, respectively.

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