Evidence for Escherichia coli O157:H7 Attachment to Water Distribution Pipe Materials by Scanning Electron Microscopy

2002 ◽  
Vol 65 (12) ◽  
pp. 1970-1975 ◽  
Author(s):  
MAFU AKIER ASSANTA ◽  
DENIS ROY ◽  
MARIE-JOSÉE LEMAY ◽  
DIANE MONTPETIT
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Scanning Electron Microscopy ◽  
Water Distribution ◽  
Escherichia Coli O157 ◽  
Exposure Condition ◽  
Copper Surfaces ◽  
E Coli ◽  
Plastic Surfaces ◽  
Scanning Electron

Scanning electron microscopy observation was used to investigate the adhesion of Escherichia coli O157:H7 on water distribution pipe surfaces such as copper and polyethylene plastic at different contact times and storage temperatures. Our results indicated that E. coli cells could easily attach to both surface types after exposures as short as 1 or 4 h at ambient (20°C) and refrigeration temperatures (4°C). Also, we found that copper surfaces have a higher number of attached E. coli cells than plastic surfaces. The number of cells attached to each type of material depended on the nature of the water distribution pipe surfaces and the length of contact time. In addition, the surface energy value of each surface estimated by contact angle measurements using water, ∝-bromonaphthalene, and dimethyl sulfoxide as wetting agents showed that both copper (41.2 megajoules [MJ]·m−2) and plastic (45.8 MJ·m−2) have a low energy surface. In no cases could evidence of extracellular material be observed on surfaces with either exposure condition.

scholarly journals Enterohemorrhagic Escherichia coli O157:H7 Present in Radish Sprouts

1998 ◽  
Vol 64 (4) ◽  
pp. 1532-1535 ◽  
Author(s):  
Yoshinori Itoh ◽  
Yoshiko Sugita-Konishi ◽  
Fumiko Kasuga ◽  
Masaaki Iwaki ◽  
Yukiko Hara-Kudo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Scanning Electron Microscopy ◽  
Outer Surface ◽  
Immunofluorescence Microscopy ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Radish Sprouts ◽  
Scanning Electron

ABSTRACT Using cultivation, immunofluorescence microscopy, and scanning electron microscopy, we demonstrated the presence of viable enterohemorrhagic Escherichia coli O157:H7 not only on the outer surfaces but also in the inner tissues and stomata of cotyledons of radish sprouts grown from seeds experimentally contaminated with the bacterium. HgCl2 treatment of the outer surface of the hypocotyl did not kill the contaminating bacteria, which emphasized the importance of either using seeds free from E. coli O157:H7 in the production of radish sprouts or heating the sprouts before they are eaten.

scholarly journals N-halamine antibacterial nanofibrous mats based on polyacrylonitrile and N-halamine for protective face masks

2019 ◽  
Vol 14 ◽  
pp. 155892501984322 ◽  
Author(s):  
Chengbo Huang ◽  
Ying Liu ◽  
Zhiguang Li ◽  
Rong Li ◽  
Xuehong Ren ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Scanning Electron Microscopy ◽  
Air Permeability ◽  
Escherichia Coli O157 ◽  
Electrospinning Technique ◽  
Antibacterial Materials ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Biocidal Properties ◽  
Scanning Electron

The main objective of this study was to develop antibacterial materials based on polyacrylonitrile for potential application in protective face masks to combat airborne pathogens. To achieve biocidal properties, 1-chloro-2, 2, 5, 5-tetramethyl-4-imidazolidinone as a kind of N-halamine was introduced into the polyacrylonitrile nanofibers by an electrospinning technique to form nanofibers by an electrospinning technique to form polyacrylonitrile/1-chloro-2, 2, 5, 5-tetramethyl-4-imidazolidinone-5% nanofibers. Scanning electron microscopy and Fourier transformed infrared spectroscopy were employed to characterize the structure of nanofibers. The antimicrobial efficacies of electrospinning nanofibers with 1-chloro-2, 2, 5, 5-tetramethyl-4-imidazolidinone against both Staphylococcus aureus and Escherichia coli O157:H7 were evaluated at different contact times. The antimicrobial efficacies against bioaerosol of S. aureus were also performed. The polyacrylonitrile/1-chloro-2, 2, 5, 5-tetramethyl-4-imidazolidinone-5% nanofibers possess excellent antimicrobial efficacies against bacteria bioaersol, and it has good air permeability.

scholarly journals SINTESIS DAN KARAKTERISASI NANOPARTIKEL CuFe2O4 SERTA APLIKASINYA SEBAGAI ANTIBAKTERI

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Almendo G. Lasera ◽  
Henry Aritonang ◽  
Harry Koleangan
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
E Coli ◽  
Activity Test ◽  
Sem Imaging ◽  
Scanning Electron

ABSTRAKNanopartikel CuFe2O4 disintesis menggunakan metode kopresipitasi. Material yang telah disintesis, kemudian dikarakterisasi dengan menggunakan Scanning Electron Microscopy (SEM) dan Xray-Diffraction (XRD) serta di uji aktifitasnya sebagai antibakteri dengan menggunakan bakteri Staphylococcus aureus (Gram positif) dan Escherichia coli (Gram negatif). Hasil citra SEM memperlihatkan morfologi nanopartikel CuFe2O4 berbentuk persegi yang tidak beraturan. Difraktogram XRD menunjukkan bahwa ukuran sampel CuFe2O4 yang diperoleh adalah sebesar 20,136 nm. Uji aktifitas antibakteri yang telah dilakukan menunjukkan bahwa, nanopartikel CuFe2O4  jauh lebih baik dalam menghambat pertumbuhan bakteri E. coli dibandingkan dengan bakteri S.aureus, masing-masing 24 mm dan 6,5 mm. ABSTRACTCuFe2O4 nanoparticles were synthesized using the coprecipitation method. The synthesized material was then characterized using Scanning Electron Microscopy (SEM) and Xray-Difraction (XRD) and tested as antibacterial activity using Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) bacteria. SEM imaging showed morphology of CuFe2O4 nanoparticles shaped like a rod. XRD diffractogram showed that the size of CuFe2O4 nanoparticles that obtained at 20.13 nm. The antibacterial activity test that has been done shows, CuFe2O4 nanoparticles are much better in inhibiting the growth of E. coli bacteria compared with S. aureus bacteria, 24 mm and 6,5 respertivelly. 

scholarly journals Impact of the contamination time by Escherichia coli on biofilm formation in surgical instruments

2021 ◽  
Vol 74 (3) ◽  
Author(s):  
Síntia de Souza Evangelista ◽  
Simone Gonçalves dos Santos ◽  
Adriana Cristina de Oliveira
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Scanning Electron Microscopy ◽  
Biofilm Formation ◽  
Surgical Instruments ◽  
Microbial Load ◽  
Surgical Instrument ◽  
E Coli ◽  
Over Time ◽  
Scanning Electron

ABSTRACT Objectives: to evaluate the microbial load and adherence of Escherichia coli in different areas of the surgical instrument surface exposed to experimental contamination over time. Methods: experimental study in which fragments of crile forceps (serrated, rod and rack) were contaminated by immersion in Tryptic Soy Broth, containing 106 CFU/mL of E. coli, for 1, 2, 4, 6, 8, 12 and 24 hours. Microbial load and bacterial adherence were evaluated using microbiological culture and scanning electron microscopy, respectively. Results: there was an increase in the microbial load on the surgical instrument, proportional to the contamination interval, ranging from 102 after 1 hour to 105 CFU/cm2 in 24 hours. The presence of exopolysaccharide was detected after two hours of contamination. Conclusions: microbial load and adhesion of E. coli increased over time, reaching 105 CFU/cm2 after 24 hours of contamination, starting biofilm formation after two hours.

Relative Efficacy of Sodium Hypochlorite Wash Versus Irradiation To Inactivate Escherichia coli O157:H7 Internalized in Leaves of Romaine Lettuce and Baby Spinach†

2007 ◽  
Vol 70 (11) ◽  
pp. 2526-2532 ◽  
Author(s):  
BRENDAN A. NIEMIRA
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ionizing Radiation ◽  
Sodium Hypochlorite ◽  
Escherichia Coli O157 ◽  
Romaine Lettuce ◽  
E Coli ◽  
Perfusion Process ◽  
Scanning Electron ◽  
Spinach Leaves

Pathogenic bacteria that become internalized in leaf tissues are protected from the antimicrobial effects of surface treatments. Ionizing radiation is known to penetrate food tissues, but the efficacy of the process against internalized bacteria is unknown. Leaves of Romaine lettuce and baby spinach were cut into pieces, submerged in a cocktail mixture of three isolates of Escherichia coli O157:H7, and subjected to a vacuum perfusion process to force the bacterial cells into the intercellular spaces in the leaves. Scanning electron microscopy was used to evaluate the efficacy of the perfusion process. The inoculated leaves were then treated with a 3-min water wash, a 3-min wash with a sodium hypochlorite sanitizing solution (300 or 600 ppm), or various doses of ionizing radiation (0.25 to 1.5 kGy). Leaves were stomached to recover the internalized pathogen cells, which were enumerated. The vacuum perfusion effectively forced bacteria into the leaf vasculature and apoplast, as confirmed by scanning electron microscopy. For spinach leaf pieces, neither the water nor the sodium hypochlorite washes resulted in significant reductions of E. coli O157:H7 cells relative to the untreated control. For Romaine lettuce leaf pieces, 300 and 600 ppm sodium hypochlorite each resulted in less than 1-log reduction; water wash was ineffective. Ionizing radiation, in contrast, significantly reduced the pathogen population, with 4-log (Romaine lettuce) or 3-log (spinach) reductions at the highest dose tested. In Romaine leaves, the reduction was dose dependent across the range of doses tested, with a D10-value (the amount of irradiation necessary to reduce the population by 1 log unit) of 0.39 kGy. In spinach leaves, the pathogen had a biphasic response, with a D10-value of 0.27 kGy in the range of 0 to 0.75 kGy but only slight additional reductions from 0.75 to 1.5 kGy. In this study, ionizing radiation but not chemical sanitizers effectively reduced viable E. coli O157:H7 cells internalized in leafy green vegetables, but the response of the pathogen to irradiation was more complex in spinach leaves than in Romaine lettuce leaves.

scholarly journals SINTESIS NANOKOMPOSIT Nata de coco/TiO2/Ag DAN EFEKTIVITASNYA SEBAGAI ANTIBAKTERI TERHADAP BAKTERI Escherichia coli dan Staphylococcus aureus

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Heriyanto Tinentang ◽  
Henry F Aritonang ◽  
Harry S. J. Koleangan
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Chemical Reduction ◽  
Bacterial Activity ◽  
Energy Dispersive ◽  
X Ray ◽  
Escherichia Coli Bacteria ◽  
Scanning Electron

Telah dilakukan penelitian tentang kemampuan aktivitas anti bakteri untuk bakteri Staphylococcus aureus (gram positif) dan Escherichia coli (gram negatif) dengan menggunakan nanokomposit nata de coco/TiO2, nata de coco/Ag, dan nata de coco/TiO2/Ag dengan variasi konsentrasi Ag 0,5 M; 0,6 M; 0,7 M; 0,8 M dan 0,9 M  menggunakan metode reduksi kimia. Nanopartikel tersebut dikarakterisasi menggunakan X-Ray Diffractometry (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy  (SEM-EDS) dan anti bakteri. Untuk uji aktivitas antibakteri menggunakan metode kertas cakram dan dilakukan sebanyak dua kali ulangan untuk tiap-tiap sampel dan bakteri yang diuji. Hasil penelitian menunjukan, aktivitas anti bakteri nanokomposit yang paling baik dalam menghambat pertumbuhan bakteri adalah nanokomposit Nata de coco/TiO2/Ag mampu menghambat pertumbuhan bakteri Escherichiacoli dan Staphylococcusaureus, namun nanokomposit tersebut lebih efektif menghambat pertumbuhan bakteri Escherichiacoli.ABSRACT Research on the ability of anti-bacterial activity for Staphylococcus aureus (gram positive) and Escherichia coli (gram negative) bacteria using nata de coco / nanocomposites TiO2, nata de coco / Ag, and nata de coco / TiO2 / Ag with variations of Ag 0,5 M; 0.6 M; 0.7 M; 0.8 M and 0.9 M using the chemical reduction method. Nanoparticles were characterized using X-Ray Diffractometry (XRD), scanning electron microscopy-energy dispersive X-ray spctroscopy  (SEM-EDS) and anti-bacterial actvity. Test the antibacterial activity using the paper disc method and repeated two times for each sample and bacteria tested. The results showed that the good anti-bacterial activity of nanocomposites in inhibiting bacterial growth was nanocomposite nata de coco /TiO2/Ag  able to inhibit the growth of Escherichia coli and S. aureus, but the nanocomposite is more effective in inhibiting the growth of Escherichia  coli bacteria.

Factors Influencing Attachment of Escherichia coli O157:H7 to Beef Tissues and Removal Using Selected Sanitizing Rinses‡

1996 ◽  
Vol 59 (5) ◽  
pp. 453-459 ◽  
Author(s):  
PINA M. FRATAMICO ◽  
FRANKIE J. SCHULTZ ◽  
ROBERT C. BENEDICT ◽  
ROBERT L. BUCHANAN ◽  
PETER H. COOKE
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Surface Structures ◽  
Escherichia Coli O157 ◽  
Adipose Tissues ◽  
E Coli ◽  
Factors Influencing ◽  
Significant Difference ◽  
Phosphate Buffered Saline ◽  
Scanning Electron

Attachment of E. coli O157:H7 and E. coli K12 to beef tenderloin filet, chuck, and adipose tissues was studied. Most attachment occurred within 1 min of incubation; the number of attached organisms depended on the concentration of bacteria in the liquid inoculum. Similar levels of E. coli bound to the three types of beef tissues tested. E. coli O157:H7 was heavily piliated; however, there was no significant difference between levels of bound E. coli O157:H7 and E. coli K12, indicating that these surface structures apparently are not involved in attachment. Scanning electron photomicrographs of meat tissue and of purified collagen suggested that bacteria attached primarily to collagen fibers. Rinsing solutions consisting of 10% trisodium phosphate (TSP), 2% acetic acid (HAc), phosphate-buffered saline (PBS) and combinations of each were tested for effectiveness in reducing the number of attached E. coli. The level of bacteria removed from tenderloin tissue following TSP, HAc, or PBS rinses did not differ considerably. When beef tissues were stored at 4°C for 18 h after the various rinse combinations, TSP rinse treatments reduced the levels of E. coli K12 and O157:H7 attached to adipose tissue up to 3.4 and 2.7 log units, respectively, compared to PBS rinse treatments. Therefore, TSP may be effective for reducing populations of E. coli O157:H7 on beef carcass tissue.

scholarly journals Reprocessing N95 Respirators During the COVID-19 Pandemic: Moist Heat Inactivates SARS-CoV-2 and Maintains N95 Filtration

2020 ◽  
Author(s):  
Simeon C. Daeschler ◽  
Niclas Manson ◽  
Kariym Joachim ◽  
Alex W. H. Chin ◽  
Katelyn Chan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Cost ◽  
Filtration Efficiency ◽  
Term Care ◽  
Protective Function ◽  
E Coli ◽  
Breathing Resistance ◽  
N95 Respirators ◽  
Scanning Electron

AbstractBackgroundThe unprecedented demand and consequent global shortage of N95 respirators during the COVID-19 pandemic have left frontline workers vulnerable to infection. To potentially expand the supply, we validated a rapidly applicable low-cost decontamination protocol in compliance with regulatory standards to enable the safe reuse of personalized, disposable N95-respirators.MethodsFour common models of N95-respirators were disinfected for 60 minutes at 70°C either at 0% or 50% relative humidity (RH). Effective inactivation of SARS-CoV-2 and E. coli was evaluated in inoculated masks. The N95 filter integrity was examined with scanning electron microscopy. The protective function of disinfected N95 respirators was tested against US NIOSH standards for particle filtration efficiency, breathing resistance and respirator fit.ResultsA single heat treatment inactivated both SARS-CoV-2 (undetectable, detection limit: 100 TCID50/ml) and E. coli (0 colonies at 50%RH) in all four respirator models. Even N95-respirators that underwent ten decontamination cycles maintained their integrity and met US-governmental criteria for approval regarding fit, filtration efficiency and breathing resistance. Scanning electron microscopy demonstrated maintained N95 fiber diameter compared to baseline.InterpretationThermal disinfection enables large-scale, low cost decontamination of existing N95 respirators using commonly sourced equipment during the COVID-19 pandemic. This process could be used in hospitals and long term care facilities and also provides a feasible approach to expand the N95 supply in low- and middle-income regions.

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