scholarly journals Exploiting redox activity of MIL-100(Fe) carrier enables carvacrol prolonged antimicrobial activity

2021 ◽  
Author(s):  
Katia Caamaño ◽  
Jaquín Calbo ◽  
Raquel Heras-Mozos ◽  
Bruno J. C Vieira ◽  
Joao C. Waerenborgh ◽  
...  
Keyword(s):  
Chemical Interaction ◽  
Theoretical Calculations ◽  
Redox Activity ◽  
Impregnation Method ◽  
Charge Transfer Process ◽  
Smart Composite ◽  
Foodborne Illnesses ◽  
Contact Materials ◽  
E Coli ◽  
Physical Stimuli

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing foodborne illnesses. In this work, we develop a smart composite MOF-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural preserving food molecule, carvacrol, into the mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method and obtaining particularly high payloads. By exploiting the intrinsic redox nature of MIL-100(Fe) material it is possible to achieve a prolonged activity against E. coli bacteria due to a triggered two-step carvacrol release of films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction among MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge transfer process between the metallic MOF counterpart and the carvacrol upon certain physical stimuli. During this process, the preferred carvacrol binding site has been monitored by IR, Mössbauer and EPR spectroscopies and is supported by theoretical calculations.

scholarly journals Inhibition of stationary phase respiration impairs persister formation in E. coli

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Mehmet A. Orman ◽  
Mark P. Brynildsen
Keyword(s):  
Stationary Phase ◽  
Respiratory Activity ◽  
Redox Activity ◽  
Bacterial Respiration ◽  
Type I ◽  
E Coli ◽  
Improve Treatment ◽  
Endogenous Proteins ◽  
Prime Target

Abstract Bacterial persisters are rare phenotypic variants that temporarily tolerate high antibiotic concentrations. Persisters have been hypothesized to underlie the recalcitrance of biofilm infections, and strategies to eliminate these cells have the potential to improve treatment outcomes for many hospital-treated infections. Here we investigate the role of stationary phase metabolism in generation of type I persisters in Escherichia coli, which are those that are formed by passage through stationary phase. We find that persisters are unlikely to derive from bacteria with low redox activity, and that inhibition of respiration during stationary phase reduces persister levels by up to ∼1,000-fold. Loss of stationary phase respiratory activity prevents digestion of endogenous proteins and RNA, which yields bacteria that are more capable of translation, replication and concomitantly cell death when exposed to antibiotics. These findings establish bacterial respiration as a prime target for reducing the number of persisters formed in nutrient-depleted, non-growing populations.

Bacterial Contamination in Saeng-go-gi, a Ready-to-Eat Fresh Raw Beef Dish Sold in Restaurants in South Korea

2015 ◽  
Vol 78 (3) ◽  
pp. 619-623 ◽  
Author(s):  
MYOUNG SU PARK ◽  
JIN SAN MOON ◽  
EWEN C. D. TODD ◽  
GYUNG JIN BAHK
Keyword(s):  
Bacterial Contamination ◽  
Latex Agglutination ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Foodborne Illnesses ◽  
E Coli ◽  
Plate Counts ◽  
Handling Practices ◽  
Contamination Levels ◽  
Food Handling Practices

This study investigated the bacterial contamination levels in ready-to-eat fresh raw beef, Saeng-go-gi in Korean, sold in restaurants. A total of 462 samples were analyzed by performing an aerobic bacterial plate count, a coliform count, and an Escherichia coli O157:H7 count. Aerobic bacterial plate counts of fresh raw beef obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju retail store restaurants were 6.46, 6.89, 6.39, 6.58, and 6.67 log CFU/g, respectively, and coliforms were 4.05, 4.97, 4.76, 3.62, and 3.32 log CFU/g, respectively. Among the 462 assessed samples, suspected E. coli O157:H7 colonies were found in 32, 24, 20, 22, and 16 samples obtained from Seoul, Cheonan, Daegu, Gunsan, and Gwangju, respectively. The identity of these isolated colonies was further assessed by using a latex agglutination kit. The agglutination assay data showed that the isolates were not E. coli O157:H7. The data from this study could be used to design better food handling practices for reducing foodborne illnesses linked to fresh raw beef consumption.

Incidence and Toxin Production Ability of Escherichia coli O157:H7 Isolated from Cattle Trucks†

2007 ◽  
Vol 70 (10) ◽  
pp. 2383-2385 ◽  
Author(s):  
E. P. CUESTA ALONSO ◽  
S. E. GILLILAND ◽  
C. R. KREHBIEL
Keyword(s):  
Escherichia Coli ◽  
Potential Risk ◽  
Foodborne Pathogen ◽  
Toxin Production ◽  
Escherichia Coli O157 ◽  
Foodborne Illnesses ◽  
E Coli

Twelve cattle trucks were analyzed for the presence of Escherichia coli O157:H7. Three of them had been washed prior to arrival, and the others had not. Seventy-five percent of the trailers were positive for the presence of this foodborne pathogen. A total of 54 cultures were isolated and identified as E. coli O157:H7, all from the trucks that had not been cleaned. Most of the cultures (96.4%) produced Shiga-like toxin (verotoxin). No E. coli O157:H7 was detected in cattle trucks that were cleaned before arrival at the cattle pens. The incidence of E. coli O157:H7 in transport trailers increases the potential risk of contamination of cattle and transmission from farms to feedlots and to packing plants. This contamination increases the potential of contamination of meat during harvest and the risk of foodborne illnesses.

scholarly journals Photodynamic Inactivation of Bacteria with Porphyrin Derivatives: Effect of Charge, Lipophilicity, ROS Generation, and Cellular Uptake on Their Biological Activity In Vitro

2020 ◽  
Vol 21 (22) ◽  
pp. 8716
Author(s):  
Adam Sułek ◽  
Barbara Pucelik ◽  
Marcin Kobielusz ◽  
Agata Barzowska ◽  
Janusz M. Dąbrowski
Keyword(s):  
Cellular Uptake ◽  
Efflux Pump ◽  
Theoretical Calculations ◽  
Resistant Bacteria ◽  
Ros Generation ◽  
Photodynamic Inactivation ◽  
Efflux Pump Inhibitor ◽  
E Coli ◽  
Charge Interaction

Resistance of microorganisms to antibiotics has led to research on various therapeutic strategies with different mechanisms of action, including photodynamic inactivation (PDI). In this work, we evaluated a cationic, neutral, and anionic meso-tetraphenylporphyrin derivative’s ability to inactivate the Gram-negative and Gram-positive bacteria in a planktonic suspension under blue light irradiation. The spectroscopic, physicochemical, redox properties, as well as reactive oxygen species (ROS) generation capacity by a set of photosensitizers varying in lipophilicity were investigated. The theoretical calculations were performed to explain the distribution of the molecular charges in the evaluated compounds. Moreover, logP partition coefficients, cellular uptake, and phototoxicity of the photosensitizers towards bacteria were determined. The role of a specific microbial efflux pump inhibitor, verapamil hydrochloride, in PDI was also studied. The results showed that E. coli exhibited higher resistance to PDI than S. aureus (3–5 logs) with low light doses (1–10 J/cm2). In turn, the prolongation of irradiation (up to 100 J/cm2) remarkably improved the inactivation of pathogens (up to 7 logs) and revealed the importance of photosensitizer photostability. The PDI potentiation occurs after the addition of KI (more than 3 logs extra killing). Verapamil increased the uptake of photosensitizers (especially in E. coli) due to efflux pump inhibition. This effect suggests that PDI is mediated by ROS, the electrostatic charge interaction, and the efflux of photosensitizers (PSs) regulated by multidrug-resistance (MDR) systems. Thus, MDR inhibition combined with PDI gives opportunities to treat more resistant bacteria.

Utilization of Gaseous Ozone for the Decontamination of Escherichia coli O157:H7 and Salmonella on Raspberries and Strawberries

2007 ◽  
Vol 70 (5) ◽  
pp. 1093-1098 ◽  
Author(s):  
KATHERINE L. BIALKA ◽  
ALI DEMIRCI
Keyword(s):  
Escherichia Coli ◽  
The United States ◽  
Ozone Treatment ◽  
Escherichia Coli O157 ◽  
Foodborne Illnesses ◽  
Treatment Scenario ◽  
Novel Technologies ◽  
E Coli ◽  
Gaseous Ozone ◽  
Ozone Maximum

Each year in the United States, there are approximately 76 million foodborne illnesses, and fresh produce is the second most common vehicle for such illnesses. Before going to market, small fruits are not washed or treated in any manner to extend their shelf life. Washing alone is not a viable option, and the use of novel technologies should be investigated. One such technology is ozone treatment, which has been used with drinking water since the late 19th century. The efficacy of gaseous ozone for killing pathogens on strawberries and raspberries, which were used as a model for small fruits, was investigated in this study. Strawberries and raspberries were artificially contaminated with five strains of Escherichia coli O157:H7 and Salmonella enterica. Fruits were treated with four ozone treatments: (i) continuous ozone flow (5%, wt/wt) for 2, 4, 8, 16, 32, and 64 min; (ii) pressurized ozone (83 kPa) for 2, 4, 8, 16, 32, and 64 min; (iii) continuous ozone (64 min) followed by pressurized ozone (64 min); and (iv) vacuum followed by 64 min of pressurized ozone. Maximum reductions for both strawberries and raspberries were achieved with the third treatment scenario. On strawberries, 2.60- and 2.96-log reductions were achieved for Salmonella and E. coli O157:H7, respectively. For raspberries, 3.55- and 3.75-log reductions were achieved for Salmonella and E. coli O157:H7, respectively. These results indicate that gaseous ozone should be a useful treatment for decontamination of small fruits.

scholarly journals Synthesis and Characterization of Potent and Safe Ciprofloxacin-LoadedAg/TiO2/CS Nanohybrid against Mastitis Causing E. coli

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 319
Author(s):  
Naheed Zafar ◽  
Bushra Uzair ◽  
Muhammad Bilal Khan Niazi ◽  
Ghufrana Samin ◽  
Asma Bano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Clinical Laboratory ◽  
Anatase Phase ◽  
Reference Value ◽  
Multidrug Resistant ◽  
Release Kinetic ◽  
Impregnation Method ◽  
Drug Release Profile ◽  
E Coli ◽  
Antibacterial Potential

To improve the efficacy of existing classes of antibiotics (ciprofloxacin), allow dose reduction, and minimize related toxicity, this study was executed becausenew target-oriented livestock antimicrobials are greatly needed to battle infections caused by multidrug-resistant (MDR) strains. The present study aims to green synthesize a biocompatible nanohybrid of ciprofloxacin (CIP)-Ag/TiO2/chitosan (CS). Silver and titanium nanoparticles were green synthesized using Moringa concanensis leaves extract. The incorporation of silver (Ag) nanoparticles onto the surface of titanium oxidenanoparticles (TiO2NPs) was done by the wet chemical impregnation method, while the encapsulation of chitosan (CS) around Ag/TiO2 conjugated with ciprofloxacin (CIP) was done by the ionic gelation method. The synthesized nanohybrid (CIP-Ag/TiO2/CS) was characterized using standard techniques. The antibacterial potential, killing kinetics, cytotoxicity, drug release profile, andminimum inhibitory concentration (MIC) were determined. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed spherical agglomerated nanoparticles (NPs) of Ag/TiO2 with particle sizes of 47–75 nm, and those of the CIP-Ag/TiO2/CS nanohybrid were in range of 20–80 nm. X-ray diffractometer(XRD)patterns of the hetero system transmitted diffraction peaks of anatase phase of TiO2 and centered cubic metallic Ag crystals. Fourier Transform Infrared spectroscopy (FTIR) confirmed the Ti-O-Ag linkage in the nanohybrid. The zeta potential of CIP-Ag/TiO2/CS nanohybrid was found (67.45 ± 1.8 mV), suggesting stable nanodispersion. The MIC of CIP-Ag/TiO2/CS was 0.0512 μg/mL, which is much lower than the reference value recorded by the global CLSI system (Clinical Laboratory Standards Institute). The CIP-Ag/TiO2/CS nanohybrid was found to be effective against mastitis causing MDR E. coli; killing kinetics showed an excellent reduction of E. coli cells at 6 h of treatment. Flow cytometry further confirmed antibacterial potential by computing 67.87% late apoptosis feature at 6 h of treatment; antibiotic release kinetic revealed a sustained release of CIP. FESEM and TEM confirmed the structural damages in MDR E. coli (multidrug-resistant Escherichia coli). The CIP-Ag/TiO2/CS nanohybrid was found to be biocompatible, as more than 93.08% of bovine mammary gland epithelial cells remained viable. The results provide the biological backing for the development of nanohybrid antibiotics at a lower MIC value to treat infectious diseases of cattle and improve the efficacy of existing classes of antibiotics by conjugation with nanoparticles.

Antibacterial Capability of Triclosan Treated on Filter Fiber Materials

2021 ◽  
Author(s):  
yanju li ◽  
Qinging MIAO ◽  
Xinyu WANG ◽  
Jinlu HE
Keyword(s):  
Fiber Material ◽  
Woven Fabric ◽  
Control Technique ◽  
Chemical Fiber ◽  
Impregnation Method ◽  
Percent Reduction ◽  
E Coli ◽  
Filter Materials ◽  
Filtration Material ◽  
Fiber Materials

Abstract Antibacterial filtration material is an effectively control technique of airborne biological pollutant to purify indoor air. This study aims to assess the antibacterial capability of triclosan treated on three filter fiber materials: the glass fiber (GF), the non-woven fabric (NF) and the chemical fiber (CF). Triclosan was loaded on filtration materials by the impregnation method. E. coli, S. albus and S. aureus were used as test strains. It’s found that the filter materials loaded with triclosan showed obvious antibacterial zone: the antibacterial zones against E. coli were 11.5 mm(GF), 13.2 mm(NF) and 11.0 mm(CF) respectively; zones against S. albus were 28.0 mm(GF), 21.0 mm(NF) and 25.0 mm(CF); zones against S. aureus were 21.5 mm(GF), 14.0 mm(NF) and 11.5 mm(CF). The percent reduction of bacteria of antibacterial fiber treated with triclosan against E. coli were 78.57% (CF) and 80.00% (GF), the percent reduction of bacteria of triclosan treated fiber against S. albus were 68.59% (NF) and 82.52% (CF), respectively. This research provided an effective antibacterial filter fiber material loaded with triclosan and it aids to reduce the transmission and harm of infectious diseases and to decontaminate the indoor environment.

Characterization of Enterohemorrhagic Escherichia coli on Veal Hides and Carcasses

2016 ◽  
Vol 80 (1) ◽  
pp. 136-145 ◽  
Author(s):  
JOSEPH M. BOSILEVAC ◽  
RONG WANG ◽  
BRANDON E. LUEDTKE ◽  
SUSANNE HINKLEY ◽  
TOMMY L. WHEELER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Sample Collection ◽  
Foodborne Illnesses ◽  
Screening Assay ◽  
Department Of Agriculture ◽  
E Coli ◽  
Inspection Service ◽  
Collection Date

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin–producing E. coli associated with the most severe forms of foodborne illnesses. The U.S. Department of Agriculture, Food Safety and Inspection Service has identified a higher percentage of non-O157 EHEC compared with E. coli O157:H7–positive samples collected from veal trimmings than from products produced from other cattle slaughter classes. Therefore samples were collected from hides and preevisceration carcasses at five veal processors to assess E. coli O157:H7 and non-O157 EHEC contamination during bob veal and formula-fed veal dressing procedures. E. coli O157:H7 prevalence was measured by culture isolation and found to be on 20.3% of hides and 6.7% of carcasses. In contrast, a non-O157 EHEC molecular screening assay identified 90.3% of hides and 68.2% of carcasses as positive. Only carcass samples were taken forward to culture confirmation and 38.7% yielded one or more non-O157 EHEC isolates. The recovery of an EHEC varied by plant and sample collection date; values ranged from 2.1 to 87.8% among plants and from 4.2 to 64.2% within the same plant. Three plants were resampled after changes were made to sanitary dressing procedures. Between the two collection times at the three plants, hide-to-carcass transfer of E. coli O157:H7 and non-O157 EHEC was significantly reduced. All adulterant EHEC serogroups (O26, O45, O103, O111, O121, and O145) were isolated from veal carcasses as well as four other potentially pathogenic serogroups (O5, O84, O118, and O177). Bob veal was found to have a greater culture prevalence of E. coli O157:H7 and greater positive molecular screens for non-O157 EHEC than formula-fed veal (P < 0.05), but the percentage of culture-confirmed non-O157 EHEC was not different (P > 0.05) between the two types of calves. EHEC-O26, -O111, and -O121 were found more often in bob veal (P < 0.05), whereas EHEC-O103 was found more often in formula-fed veal (P < 0.05).

Using theoretical calculations to predict the redox potential of mononuclear manganese complexes

2018 ◽  
Vol 42 (18) ◽  
pp. 14827-14831
Author(s):  
Juan L. Puzzolo ◽  
Salvador I. Drusin ◽  
Verónica A. Daier ◽  
Sandra Signorella ◽  
Diego M. Moreno
Keyword(s):  
Redox Potential ◽  
Metal Complexes ◽  
Theoretical Calculations ◽  
Redox Activity ◽  
Manganese Complexes

Prediction of redox potential allows chemists to rationally design metal complexes with a desired redox activity.

Antibacterial Behavior of Ag-Ce-TiO2 Composite Films in the Different Irradiations

2009 ◽  
Vol 610-613 ◽  
pp. 463-466 ◽  
Author(s):  
Tie Zhang ◽  
Dong Bin Zhu ◽  
Chun Guang Wang ◽  
Xin He
Keyword(s):  
Escherichia Coli ◽  
Composite Film ◽  
Bactericidal Activity ◽  
Composite Films ◽  
Pure Tio2 ◽  
Impregnation Method ◽  
X Ray ◽  
E Coli ◽  
Antibacterial Performance ◽  
Anatase Titania

An Ag-Ce-TiO2 composite film was prepared by incorporating Ag in the Ce-TiO2 films with an impregnation method through photoreduction. The bactericidal activity of the Ag-Ce-TiO2 composite film and the effect of deposition of silver and doping cerium in the different irradiations on the antibacterial performance were assessed against Escherichia coli (E. coli). TIhrough characterization of X-ray diffraction (XRD), X-ray photoelectronic spectra (XPS) and UV/VIS diffusive reflectance spectra (DRS), it was found that the Ag-Ce-TiO2 composite film was composed of predominant anatase titania, cerium oxides (in the form of Ce2O3/CeO2) and silver nanoparticles. Moreover, the bactericidal activity of the Ag-Ce-TiO2 composite film and the effect of deposition of silver and doping cerium in the different irradiations on the antibacterial performance were assessed against Escherichia coli (E. coli). The results show that the Ag-Ce-TiO2 composite film has much higher antibacterial efficiency than that of glass and pure TiO2 film either in the room light or in the dark. Therefore, this composite film is promising in applications of antimicrobial and self-clean technologies.

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