scholarly journals The Antimicrobial Efficacy Of Plasma Activated Water Is Modulated By Reactor Design And Water Composition

2021 ◽  
Author(s):  
Joanna G Rothwell ◽  
David Alam ◽  
Dee A Carter ◽  
Behdad Soltani ◽  
Robyn McConchie ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Tap Water ◽  
Fresh Produce ◽  
Critical Role ◽  
Reactive Species ◽  
Antimicrobial Efficacy ◽  
Model Organisms ◽  
Atmospheric Conditions ◽  
E Coli ◽  
Plasma Activated Water

Plasma activated water (PAW) contains a cocktail of reactive oxidative species and free radicals and has demonstrated efficacy as a sanitizer for fresh produce, however there is a need for further optimization. The antimicrobial efficacy of PAW produced by a bubble spark discharge (BSD) reactor and a dielectric barrier discharge-diffuser (DBDD) reactor operating at atmospheric conditions with air, discharge frequencies of 500, 1000 and 1500 Hz, and MilliQ and tap water, was investigated with model organisms Listeria innocua and Escherichia coli.  Optimal conditions were subsequently employed for pathogenic bacteria Listeria monocytogenes, E. coli and Salmonella enterica. PAW generated with the DBDD reactor decontaminated more than 6-log CFU of bacteria within 1 minute of treatment. The BSD-PAW, while attaining high CFU reduction was less effective, particularly for L. innocua. Analysis of physicochemical properties revealed BSD-PAW had a greater variety of reactive species than DBDD-PAW. Scavenger assays were employed to specifically sequester reactive species, including the short-lived superoxide (?O2-) radical that could not be directly measured in the PAW. This demonstrated a critical role of superoxide for the inactivation of both E. coli and L. innocua by DBDD-PAW, while in BSD-PAW it had a role in L. innocua inactivation only. Overall, this study demonstrates the potential of DBDD-PAW in fresh produce, where there is a need for sterilization while minimizing chemical inputs and residues and maintaining food quality. Highly effective PAW was generated using air as a processing gas and tap water, making this a feasible and cost-effective option.

scholarly journals Antimicrobial efficacy of a new tri-antibiotic combination against resistant endodontic pathogens: An in-vitro study

2020 ◽  
Vol 23 (4) ◽  
pp. 8p ◽  
Author(s):  
Prasanna T. Dahake ◽  
Sudhindra M Baliga
Keyword(s):  
Root Canal ◽  
Pathogenic Bacteria ◽  
Culture Media ◽  
In Vitro Study ◽  
Vitro Study ◽  
New Combination ◽  
Antimicrobial Efficacy ◽  
E Coli ◽  
Background Removal

Background: Removal of all the pathogenic bacteria from the root canal system is of prime importance for the success of endodontic therapy. Objective: The study aimed to determine the antimicrobial efficacy of three antibiotics and their new combination against selected endodontic pathogens. Methods: In this in-vitro study, we used bacterial strains associated with the refractory endodontic condition and determined MIC and MBC of Clindamycin (C), Metronidazole (M), Doxycycline (D) as well as their combination CMD. We cultured Candida Albicans, Pseudomonas Aeruginosa, Escherichia Coli, Enterococcus Faecalis, Streptococcus Mutans, Bacillus Subtilis subsp. spizizenii, Actinomyces Actinomycetemcomitans on selective culture media. We analyzed the data using paired 't' test, one-way ANOVA, and Tuckey's HSD post hoc test. Results: Clindamycin inhibited the growth of C. Albicans (90%) and S. Mutans (90%) significantly and P. Aeruginosa, E. Coli, E. Faecalis, B. Subtilis, and A. Actinomycetemcomitans were resistant to it. Metronidazole did not inhibit any of the bacteria. Doxycycline inhibited C. Albicans (90%), P. Aeruginosa (90%), and S. Mutans (90%) significantly while E. Coli, E. Faecalis, B. Subtilis, and A. Actinomycetemcomitans were resistant to it. The combination of CMD inhibited all the microbes significantly. However, at bactericidal concentrations of CMD, E. Faecalis (p = 0.024), B. Subtilis (p = 0.021) and A. Actinomycetemcomitans (p = 0.041) were eliminated significantly, while C. Albicans (p = 0.164), P. Aeruginosa (p = 0.489), E. Coli (p = 0.106) and S. Mutans (p = 0.121) showed resistance. Conclusion: Combination CMD can be used against resistant endodontic pathogens to achieve predictable endodontic results.KEYWORDSAntimicrobial agents; Clindamycin; Doxycycline; Metronidazole; Root canal therapy.    

Characterization and Immunobiologic Activities of Lipopolysaccharides From Periodontal Bacteria

1988 ◽  
Vol 2 (2) ◽  
pp. 284-291 ◽  
Author(s):  
S. Hamada ◽  
T. Koga ◽  
T. Nishihara ◽  
T. Fujiwara ◽  
N. Okahashi
Keyword(s):  
B Cell ◽  
Pathogenic Bacteria ◽  
Biological Activities ◽  
Periodontal Diseases ◽  
Critical Role ◽  
Spleen Cells ◽  
E Coli ◽  
Periodontopathic Bacteria ◽  
Bacteroides Gingivalis ◽  
Fusobacterium Species

Bacterial surface structures play a critical role in the initiation of infectious diseases. Various surface components of pathogenic bacteria have been reported to be involved in host injury. There is a great deal of evidence incriminating certain Gram-negative, anaerobic bacteria present in the gingival crevice as etiologic agents of human periodontal diseases. We have isolated endotoxic cellular components from suspected periodontopathic bacteria and examined their immunobiological activities. Lipopolysaccharides (LPS) and lipid-associated proteoglycans (LPG) were prepared from whole cells by the phenol-water and butanol-water procedures, respectively. LPS from Bacteroides gingivalis, B. intermedius, B. oralis, and B. loescheii, Fusobacterium nucleatum and F. necrophorum, and Actinobacillus (Haemophilus) actinomycetemcomitans were found to possess biological activities comparable with those of LPS from E. coli K235 in terms of activation of Limulus lysate, B-cell mitogenicity, polyclonal B-cell activation, induction of bone resorption, and IL-1 production by macrophages. These LPS contained mainly sugars, amino sugars, and fatty acids. No heptose or 2-keto-3-deoxyoctonate (KDO) was detected in the Bacteroides LPS, while LPS from Actinobacillus and Fusobacterium species contained significant amounts of heptose as well as small quantities of KDO. Bacteroides LPS were clearly mitogenic for spleen cells of C3H/HeJ mice, which are non-responsive to LPS from E. coli, A. actinomycetemcomitans, and Fusobacterium species. Furthermore, polymyxin B was found to abrogate the mitogenic activity of LPS from E. coli, Actinobacillus, and Fusobacterium species, but not those from Bacteroides species. Spleen cells from both C3H/HeN and C3H/HeJ mice responded to all butanol-water-extracted LPG preparations, including those from E. coli, A. actinomycetemcomitans, and Fusobacterium species. It may be concluded that LPS and LPG isolated from suspected periodontopathic bacteria possess marked immunobiological potencies on lymphoreticular and bone cells.

Effect of Surface Roughness on Inactivation of Escherichia coli O157:H7 87-23 by New Organic Acid–Surfactant Combinations on Alfalfa, Broccoli, and Radish Seeds

2012 ◽  
Vol 75 (2) ◽  
pp. 261-269 ◽  
Author(s):  
LILIA FRANSISCA ◽  
HAO FENG
Keyword(s):  
Surface Roughness ◽  
Malic Acid ◽  
Pathogenic Bacteria ◽  
Tap Water ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Seed Type ◽  
E Coli ◽  
Microbial Removal ◽  
Alfalfa Seeds

Surface roughness has been reported as one of the factors affecting microbial attachment and removal. Seed surfaces are complex, and different seed varieties have different surface topographies. As a result, a sanitizer effective in eliminating pathogenic bacteria on one seed may not be as effective when applied to another seed. The objectives of this research were (i) to investigate the efficacy of malic acid and thiamine dilaurylsulfate (TDS) combined treatments for inactivation of E. coli O157:H7 strain 87-23 on alfalfa, broccoli, and radish seeds, (ii) to quantify surface roughness of the seeds, and (iii) to determine the correlation between microbial removal and surface roughness. The surface roughness of each seed type was measured by confocal laser scanning microscopy (CLSM) and surface profilometry. Surface roughness (Ra) values of the seeds were then calculated from CLSM data. Seeds inoculated with E. coli O157:H7 87-23 were washed for 20 min in malic acid and TDS solutions and rinsed for 10 min in tap water. Radish seeds had the highest Ra values, followed by broccoli and alfalfa seeds. A combination of 10% malic acid and 1% TDS was more effective than 20,000 ppm of Ca(OCl)2 for inactivation of E. coli O157:H7 87-23 on broccoli seeds, while the inactivation on radish and alfalfa seeds was not significantly different compared with the 20,000-ppm Ca(OCl)2 wash. Overall, a negative correlation existed between the seeds' Ra values and microbial removal. Different seeds had different surface roughness, contributing to discrepancies in the ability of the sanitizers to eliminate E. coli O157:H7 87-23 on the seeds. Therefore, the effectiveness of one sanitizer on one seed type should not be translated to all seed varieties.

scholarly journals Interplay of phosphate and carbonate ions with flavin photosensitizers in photodynamic inactivation of bacteria

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253212
Author(s):  
Daniel Bernhard Eckl ◽  
Stefanie Susanne Eben ◽  
Laura Schottenhaml ◽  
Anja Eichner ◽  
Rudolf Vasold ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Light Exposure ◽  
Tap Water ◽  
Model Organisms ◽  
Photodynamic Inactivation ◽  
Bacterial Cells ◽  
Ion Concentrations ◽  
Phosphate Ions ◽  
Cell Counts ◽  
The Impact

Photodynamic inactivation (PDI) of pathogenic bacteria is a promising technology in different applications. Thereby, a photosensitizer (PS) absorbs visible light and transfers the energy to oxygen yielding reactive oxygen species (ROS). The produced ROS are then capable of killing microorganisms via oxidative damage of cellular constituents. Among other PS, some flavins are capable of producing ROS and cationic flavins are already successfully applied in PDI. When PDI is used for example on tap water, PS like flavins will encounter various ions and other small organic molecules which might hamper the efficacy of PDI. Thus, the impact of carbonate and phosphate ions on PDI using two different cationic flavins (FLASH-02a, FLASH-06a) was investigated using Staphylococcus aureus and Pseudomonas aeruginosa as model organisms. Both were inactivated in vitro at a low light exposure of 0.72 J cm-2. Upon irradiation, FLASH-02a reacts to single substances in the presence of carbonate or phosphate, whereas the photochemical reaction for FLASH-06a was more unspecific. DPBF-assays indicated that carbonate and phosphate ions decreased the generation of singlet oxygen of both flavins. Both microorganisms could be easily inactivated by at least one PS with up to 6 log10 steps of cell counts in low ion concentrations. Using the constant radiation exposure of 0.72 J cm-2, the inactivation efficacy decreased somewhat at medium ion concentrations but reached almost zero for high ion concentrations. Depending on the application of PDI, the presence of carbonate and phosphate ions is unavoidable. Only upon light irradiation such ions may attack the PS molecule and reduce the efficacy of PDI. Our results indicate concentrations for carbonate and phosphate, in which PDI can still lead to efficient reduction of bacterial cells when using flavin based PS.

scholarly journals Preharvest Transmission Routes of Fresh Produce Associated Bacterial Pathogens with Outbreak Potentials: A Review

2019 ◽  
Vol 16 (22) ◽  
pp. 4407 ◽  
Author(s):  
Chidozie Declan Iwu ◽  
Anthony Ifeanyi Okoh
Keyword(s):  
Food Safety ◽  
Pathogenic Bacteria ◽  
Fresh Produce ◽  
Treatment Options ◽  
Disease Outbreaks ◽  
Salmonella Spp ◽  
E Coli ◽  
Shigella Spp ◽  
Clinically Significant ◽  
Vegetables And Fruits

Disease outbreaks caused by the ingestion of contaminated vegetables and fruits pose a significant problem to human health. The sources of contamination of these food products at the preharvest level of agricultural production, most importantly, agricultural soil and irrigation water, serve as potential reservoirs of some clinically significant foodborne pathogenic bacteria. These clinically important bacteria include: Klebsiella spp., Salmonella spp., Citrobacter spp., Shigella spp., Enterobacter spp., Listeria monocytogenes and pathogenic E. coli (and E. coli O157:H7) all of which have the potential to cause disease outbreaks. Most of these pathogens acquire antimicrobial resistance (AR) determinants due to AR selective pressure within the agroecosystem and become resistant against most available treatment options, further aggravating risks to human and environmental health, and food safety. This review critically outlines the following issues with regards to fresh produce; the global burden of fresh produce-related foodborne diseases, contamination between the continuum of farm to table, preharvest transmission routes, AR profiles, and possible interventions to minimize the preharvest contamination of fresh produce. This review reveals that the primary production niches of the agro-ecosystem play a significant role in the transmission of fresh produce associated pathogens as well as their resistant variants, thus detrimental to food safety and public health.

scholarly journals Use of bacteriophages as biological control agents in horticulture

2019 ◽  
Vol 40 (1) ◽  
pp. 47
Author(s):  
Rhianna O'Regan ◽  
Annaleise Wilson ◽  
İpek Kurtböke
Keyword(s):  
Ecosystem Health ◽  
Pathogenic Bacteria ◽  
Control Strategies ◽  
Fresh Produce ◽  
Bacterial Diseases ◽  
E Coli ◽  
Development Of Resistance ◽  
Preventative Measures ◽  
Laboratory Report ◽  
Colony Forming Units

Bacterial diseases in horticultural settings or infestation of fresh produce with human pathogenic bacteria can constitute a serious public health risk. To control horticultural bacterial diseases, chemical control strategies have traditionally been used, such as the application of bactericides and copper-based products, which resulted in development of resistance in bacteria against these agents. Moreover, the use of such chemical preventative measures on fresh produce can detrimentally affect human, animal and ecosystem health. Bacteriophages have been used to control pathogenic bacteria since the 1920s due to their specificity against host bacteria, as well as their ability to survive and infect their host without detrimental effects to the surrounding environments. As a result, their targeted host specific applications in horticultural settings can be of interest to growers as well as to the consumers. In this laboratory report, the efficacy of a bacteriophage cocktail when applied to fresh herbs inoculated with Escherichia coli was determined. Significant (P ≤ 0.001) reductions in E. coli colony forming units were observed in phage treated herb samples compared to counts in the control. These findings suggest that bacteriophage present as an alternative biocontrol for E. coli in horticulture.

Prevalence of Multidrug-Resistant Bacteria from U.S.-Grown and Imported Fresh Produce Retailed in Chain Supermarkets and Ethnic Stores of Davidson County, Tennessee

2017 ◽  
Vol 80 (3) ◽  
pp. 506-514 ◽  
Author(s):  
Siqin Liu ◽  
Agnes Kilonzo-Nthenge
Keyword(s):  
Pathogenic Bacteria ◽  
Fresh Produce ◽  
Agricultural Practices ◽  
Multidrug Resistant ◽  
Leafy Vegetables ◽  
Resistant Bacteria ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Public Health Hazards

ABSTRACTThe aim of this study was to determine whether U.S.-grown and imported fresh produce retailed in ethnic stores and chain supermarkets was a reservoir of antibiotic-resistant bacteria. A total of 360 (129 imported and 231 U.S.-grown) samples of fresh produce were purchased from retail stores and analyzed for Enterobacteriaceae, including three pathogenic bacteria (Escherichia coli O157:H7, Shigella, and Salmonella), using standard methods. Presumptive pathogenic isolates were confirmed using PCR. The mean Enterobacteriaceae counts for imported produce were 6.87 ± 0.15 log CFU/g and 7.16 ± 0.11 log CFU/g in ethnic stores and chain supermarkets, respectively. For U.S.-grown produce, the contamination levels were at 8.35 ± 0.17 log CFU/g and 7.52 ± 0.13 log CFU/g in ethnic stores and chain supermarkets, respectively. Salmonella (0 and 0.3%), Shigella (1.7 and 0.6%), E. coli (3.1 and 1.4%), Enterobacter (9.4 and 8.6%), Klebsiella (6.7 and 0.6%), and Serratia (5.8 and 1.4%) were detected in produce from ethnic stores and chain supermarkets, respectively. None of the samples were positive for E. coli O157:H7. Regarding distribution by produce type, leafy vegetables had a significantly (P < 0.05) higher prevalence of Enterobacteriaceae (19.2%) than the other types, followed by root vegetables (6.4%), tomatoes (5.6%), and fruits (3.9%). Antibiotic-resistant Salmonella, Shigella, E. coli, Enterobacter, Klebsiella, and Erwinia bacteria were also isolated from fresh produce. The frequencies of vancomycin resistance (98.1 and 100%) were significantly higher (P < 0.05) than the frequencies of ampicillin resistance (42.3 and 72.9%) for imported and U.S.-grown produce, respectively. Despite the increased attention to the role of imported produce as a source of antimicrobial resistance, this study indicates that U.S.-grown produce is also contaminated with antibiotic-resistant bacteria. Good agricultural practices on the farms and washing of fresh produce before consumption are greatly recommended to avoid possible public health hazards.

Photocatalytically Enhanced Inactivation of Internalized Pathogenic Bacteria in Fresh Produce using Ultraviolet Irradiation with Nano-titanium Dioxide

2020 ◽  
Author(s):  
Seungjun Lee ◽  
Chulkyoon Mok ◽  
Jiyoung Lee
Keyword(s):  
Public Health ◽  
Titanium Dioxide ◽  
Food Safety ◽  
Uv Irradiation ◽  
Foodborne Pathogens ◽  
Pathogenic Bacteria ◽  
Safety Issue ◽  
Fresh Produce ◽  
Future Research ◽  
E Coli

Once pathogens are internalized in fresh produce, they pose a challenging food safety issue since they are not effectively inactivated by conventional rinsing or sanitization. To protect food safety and public health, the objectives were to examine internalized levels of foodborne pathogens in different types of fresh produce and to investigate the effectiveness of photocatalytically enhanced inactivation of internalized pathogens in fresh produce using UV irradiation with titanium dioxide (TiO 2 ). For this, green fluorescent protein-labeled S. Typhimurium and E. coli O157:H7 were inoculated on the leaf surface of four types of fresh produce (~10 8 CFU (colony-forming unit)/leaf) and varying concentrations of TiO 2 suspension (0.50, 0.75, 1.00, 1.25, and 1.50 µg/ml)) were applied to the surface of contaminated leaves. Depending on the nature of each vegetable, the internalized bacterial level differed (log 2 – 5 CFU/g of leaf). When UV irradiation (6,000 J/m 2 ) was applied, the internalized S. Typhimurium and E. coli levels were reduced by 0.8 – 2.4 log CFU/leaf and was with TiO 2 , the reduction was 1.1 – 3.7 log CFU/leaf. The inactivation efficiency increased as the TiO 2 concentration (up to 1.50 μg/leaf). These results indicate that the TiO 2 application enhanced the photocatalytic inactivation of internalized foodborne pathogens. The application of TiO2 would be most practical before UV irradiation and before distributing the produce. This study established a platform for future research on the inactivation of various internalized pathogens for protecting public health and scaling up fresh produce treatments by the food industry.

Concentrations of Escherichia coli and Genetic Diversity and Antibiotic Resistance Profiling of Salmonella Isolated from Irrigation Water, Packing Shed Equipment, and Fresh Produce in Texas

2005 ◽  
Vol 68 (1) ◽  
pp. 70-79 ◽  
Author(s):  
E. A. DUFFY ◽  
L. M. LUCIA ◽  
J. M. KELLS ◽  
A. CASTILLO ◽  
S. D. PILLAI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Diversity ◽  
Irrigation Water ◽  
Pathogenic Bacteria ◽  
Susceptibility Testing ◽  
Fresh Produce ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Element Sequence

Fresh produce has been repeatedly implicated as a vehicle in the transmission of foodborne gastroenteritis. In an effort to assess the risk factors involved in the contamination of fresh produce with pathogenic bacteria, a total of 1,257 samples were collected from cantaloupe, oranges, and parsley (both in the field and after processing) and from the environment (i.e., irrigation water, soil, equipment, etc.). Samples were collected twice per season from two production farms per commodity and analyzed for the presence of Salmonella and Escherichia coli. E. coli was detected on all types of commodities (cantaloupe, oranges, and parsley), in irrigation water, and on equipment surfaces. A total of 25 Salmonella isolates were found: 16 from irrigation water, 6 from packing shed equipment, and 3 from washed cantaloupes. Salmonella was not detected on oranges or parsley. Serotyping, pulsed-field gel electrophoresis (PFGE), and repetitive element sequence-based PCR (rep-PCR) assays were applied to all Salmonella isolates to evaluate the genetic diversity of the isolates and to determine relationships between sources of contamination. Using PFGE, Salmonella isolates obtained from irrigation water and equipment were determined to be different from cantaloupe isolates; however, DNA fingerprinting did not conclusively define relationships between contamination sources. All Salmonella isolates were subjected to antimicrobial susceptibility testing using the disk diffusion method, and 20% (5 of 25) of the isolates had intermediate sensitivity to streptomycin. One Salmonella isolate from cantaloupe was resistant to streptomycin.

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