scholarly journals Preparation of Antimicrobial Coatings from Cross-Linked Copolymers Containing Quaternary Dodecyl-Ammonium Compounds

2021 ◽  
Vol 22 (24) ◽  
pp. 13236
Author(s):  
Denisa Druvari ◽  
Aggeliki Antonopoulou ◽  
Georgia C. Lainioti ◽  
Alexios Vlamis-Gardikas ◽  
Georgios Bokias ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Glycidyl Methacrylate ◽  
Alkyl Chain ◽  
Pure Water ◽  
Polymeric Membranes ◽  
Antimicrobial Coatings ◽  
E Coli ◽  
Antimicrobial Materials ◽  
The Cross ◽  
Ammonium Compounds

One of the concerns today’s societies face is the development of resistant pathogenic microorganisms. The need to tackle this problem has driven the development of innovative antimicrobial materials capable of killing or inhibiting the growth of microorganisms. The present study investigates the dependence of the antimicrobial activity and solubility properties on the hydrophilicity/hydrophobicity ratio of antimicrobial coatings based on quaternary ammonium compounds. In this line, suitable hydrophilic and hydrophobic structural units were selected for synthesizing the antimicrobial copolymers poly(4-vinylbenzyl dimethyldodecylammonium chloride-co-acrylic acid), P(VBCDDA-co-AA20) and poly(dodecyltrimethylammonium 4-styrene sulfonate-co-glycidyl methacrylate), P(SSAmC12-co-GMA20), bearing an alkyl chain of 12 carbons either through covalent bonding or through electrostatic interaction. The cross-linking reaction of the carboxylic group of acrylic acid (AA) with the epoxide group of glycidyl methacrylate (GMA) of these two series of reactive antimicrobial copolymers was explored in blends, obtained through solution casting after curing at various temperatures. The release of the final products in pure water and NaCl 1 M solutions (as analyzed by gravimetry and total organic carbon, TOC/total nitrogen, TN analyses), could be controlled by the coating composition. The cross-linked polymeric membranes of composition 60/40 w/w % ratios led to 97.8 and 99.7% mortality for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively, whereas the coating 20/80 w/w % resulted in 96.6 and 99.8% cell reduction. Despite the decrease in hydrophobicity (from a 16- to a 12-carbon alkyl chain), the new materials maintained the killing efficacy, while at the same time resulting in increased release to the aqueous solution.

scholarly journals Phenotypic and Genotypic Properties of Fluoroquinolone-Resistant, qnr-Carrying Escherichia coli Isolated from the German Food Chain in 2017

2021 ◽  
Vol 9 (6) ◽  
pp. 1308
Author(s):  
Katharina Juraschek ◽  
Carlus Deneke ◽  
Silvia Schmoger ◽  
Mirjam Grobbel ◽  
Burkhard Malorny ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Point Mutations ◽  
Beta Lactamase ◽  
Resistance Development ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
German Food ◽  
Sequence Types ◽  
Ammonium Compounds ◽  
Additional Point

Fluoroquinolones are the highest priority, critically important antimicrobial agents. Resistance development can occur via different mechanisms, with plasmid-mediated quinolone resistance (PMQR) being prevalent in the livestock and food area. Especially, qnr genes, commonly located on mobile genetic elements, are major drivers for the spread of resistance determinants against fluoroquinolones. We investigated the prevalence and characteristics of qnr-positive Escherichia (E.) coli obtained from different monitoring programs in Germany in 2017. Furthermore, we aimed to evaluate commonalities of qnr-carrying plasmids in E. coli. We found qnr to be broadly spread over different livestock and food matrices, and to be present in various sequence types. The qnr-positive isolates were predominantly detected within selectively isolated ESBL (extended spectrum beta-lactamase)-producing E. coli, leading to a frequent association with other resistance genes, especially cephalosporin determinants. Furthermore, we found that qnr correlates with the presence of genes involved in resistance development against quaternary ammonium compounds (qac). The detection of additional point mutations in many isolates within the chromosomal QRDR region led to even higher MIC values against fluoroquinolones for the investigated E. coli. All of these attributes should be carefully taken into account in the risk assessment of qnr-carrying E. coli from livestock and food.

Preparation and Characterization of Hydrophilic PVDF Hollow Fiber Ultrafiltration Membrane

2011 ◽  
Vol 480-481 ◽  
pp. 201-206
Author(s):  
Li Guo Wang ◽  
Xiu Ju Wang ◽  
Ai Min Wang ◽  
Wen Juan Liu ◽  
Shi Qi Guo ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Breaking Strength ◽  
Pure Water ◽  
Water Flux ◽  
Technical Parameters ◽  
Rupture Pressure ◽  
Pure Water Flux

Hydrophilic Polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of acrylic acid grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated via orthogonal test, the technical parameters of preparation of hydrophilic PVDF membranes were determined, and hydrophilic PVDF membranes were prepared. Then hydrophilic PVDF membranes were characterized in terms of breaking strength, breaking elongation, rupture pressure, pure water flux and rejection. The fouling properties and the conditions of acrylic acid grafted onto PVDF were also examined. The results showed that acrylic acid had been grafted onto PVDF, the breaking strength and rupture pressure improved greatly, and the fouling properties were better than PS hollow fiber UF membrane.

scholarly journals Diagnostic of Water Purity by Using Solar Distiller

2018 ◽  
Vol 29 (2) ◽  
pp. 10 ◽  
Author(s):  
Hazim Hussain
Keyword(s):  
Stream Water ◽  
Pure Water ◽  
Total Content ◽  
Total Water ◽  
Water Distillation ◽  
E Coli ◽  
Total Percentage ◽  
Environmental Laboratory ◽  
Water Purity ◽  
Research Show

In Present research ,the validity of a solar distiller which is made of two parts ( a solar tank and a solar distiller ) has been tested and distillered the water of one water- trench in Baghdad was treated using this equipment which produced pure water with an average of ( 1106 ml/m2 .h) during the day and (222 ml/m2 .h ) at night .The total water produced is thus ( 1324 ml/m2 . h ) . The laboratorial tests of the samples water before distillation showed that the stream water contained T.P.C/ 1ml =2900 ( Total Content Of Bacteria ) , T.C/100ml >1600 T.C (Total coli form) , F.C /100 ml>1600 (Fecal Coli Formand ) and E. coli /100ml>1600 . The total percentage of salt in water trench before distillation was T.D.S mg/l 1886 \ After water treatment and distillation , the Total Content of Bacteria ( T.P.C) was decreased to T.P.C / 1ml = 210 , (Total coli form) T.C /100 ml = Zero , ( Fecal Coli Formand) F.C/100ml= Zero and E.coli /100ml = Zero . In and, the total percentage of salt after distillation T.D.S was decreased to 105 mg/l . The results of this research show that water distillation using solar distiller is a successful and efficient process led to decreasing T.C.P 93.8% and killing all types of harmful T.C , F.C. and E. coli bacteria. )By analyzing the samples of sterile water using the solar distiller in the laboratories of the Ministry of Health and Environment- Central Environmental Laboratory as shown in Table (6)).

scholarly journals The Emergence of Quaternary Ammonium Compounds Resistance in Escherichia coli Isolated from Hospitals of Qazvin, Iran

2020 ◽  
Vol 20 (4) ◽  
pp. 455-460
Author(s):  
Narges Habibollah-Pourzereshki ◽  
Amir Peymani ◽  
Fatemeh Keshavarz-Saleh
Keyword(s):  
Escherichia Coli ◽  
Infection Control ◽  
Critical Issue ◽  
Cross Sectional Study ◽  
Resistance Rate ◽  
Healthcare Associated Infection ◽  
Cross Sectional ◽  
E Coli ◽  
Healthcare Associated ◽  
Ammonium Compounds

Introduction: Escherichia coli is one of the most important agents involved in healthcare-associated infection, and resistance to quantum ammonium compounds (QACs) has become a major challenge for infection control practitioners. The aim of the current study was to determine the frequency of qacE and qacEΔ1 genes in E. coli isolated from hospitalized patients in Qazvin, Iran. Material and Methods: In the current cross-sectional study, 102 E. coli were collected from hospitals of Qazvin. All bacterial isolates were identified using standard laboratory methods and the antimicrobial susceptibility was evaluated by Kirby-Baer test. The presence of qacE and qacEΔ1 genes was investigated using polymerase chain reaction (PCR) technique. Results: In this study, 65 (63.7%) isolates showed a multidrug resistance (MDR) pattern which was resistant to at least three classes of antimicrobials including ß-lactams, aminoglycosides, and fluoroquinolones. The highest rates of resistance were observed against cefotaxime (75.5%) and nalidixic acid (66.7%). The PCR showed that 5 (4.9%) isolates harbored qacE gene, 62 (60.8%) isolates qacEΔ1, and 10 (9.8%) isolates carried both genes, simultaneously. There was a significant relationship between the QACs resistance and MDR pattern (P=0.03). Conclusion: This study indicated a significant resistance rate against disinfectant compounds in the studied hospitals. However, more attention should be paid to this critical issue in the infection control committees of the hospitals.

VARIATIONS IN THE CHARACTERISTICS OF E. COLI INDUCED BY QUATERNARY AMMONIUM COMPOUNDS

1951 ◽  
Vol 14 (4) ◽  
pp. 138-141 ◽  
Author(s):  
C. Kenneth Crocker
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Induced Resistance ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Compounds ◽  
Liquid Media ◽  
E Coli ◽  
Metallic Sheen ◽  
Small Colony ◽  
Ammonium Compounds

Escherichia coli lost the ability to produce gas in liquid media and formed atypical small colony variants on desoxycholate agar, concurrent with induced resistance to quaternary ammonium compounds. Paralleling high resistance, the metallic sheen of colonies on confirmatory medium did not appear. The variant strains showed a decrease in growth rate, failed to reduce methylene blue, and were unable to ferment normal sugars. Thus, with induced resistance, variations occurred in Escherechia coli such as to reduce the value of coliform tests used to identify its presence.

Surface Modification for Polystyrene Colloidal Particles with Controlled Charge Densities

2007 ◽  
Vol 7 (11) ◽  
pp. 3995-3999
Author(s):  
Jongman Lee ◽  
Oh-Sun Kwon ◽  
Kwanwoo Shin ◽  
Ju-Myung Song ◽  
Joon-Seop Kim ◽  
...  
Keyword(s):  
Surface Modification ◽  
Acrylic Acid ◽  
Surface Charge Density ◽  
Colloidal Particles ◽  
Mixed Solvent ◽  
Pure Water ◽  
Random Copolymer ◽  
Aqueous Dispersions ◽  
Charge Densities ◽  
Quenching Process

A significant amount of polystyrene sulfonated acid (PSSA) and poly(styrene-ran-acrylic acid) (PSAA) random copolymer can be adsorbed by dispersion of PS particles via a swelling-quenching process. A THF-water mixed solvent was used in the swelling process and a large amount of pure water was used, to give a low concentration of THF% in quenching process. Our results showed that functional PSSA groups were randomly and tightly adsorbed to the PS particles. When the mol.% of charged segments was increased, the progressive adsorption of PSSA chains to the PS particles leads to an increase in the electrophoretic mobility and zeta-potential of aqueous dispersions. Thus, we were able to obtain well-distributed surface charge density on the PS particles.

scholarly journals Synthesis and characterization of thermoresponsive hydrogels cross-linked with chitosan

2008 ◽  
Vol 6 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Yueqin Yu ◽  
Xianzhi Chang ◽  
Hansheng Ning ◽  
Shusheng Zhang
Keyword(s):  
Acrylic Acid ◽  
Pure Water ◽  
Solution Temperature ◽  
Feed Ratio ◽  
Cross Linking ◽  
Environmentally Responsive ◽  
Extracellular Materials ◽  
Degradation Properties ◽  
Phosphate Buffered Saline

AbstractHydrogels composed of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) were prepared by redox polymerization with degradable chitosan cross-linkers. Chitosan degradable cross-linkers were synthesized by the acrylation of the amine groups of glucosamine units within chitosan and characterized with 1H NMR. With the chitosan cross-linkers, loosely cross-linked poly(N-isopropylacryamideco-acrylic acid) [P(NIPAAm-co-AAc)] hydrogels were prepared, and their phase transition behavior, lower critical solution temperature (LCST), water content and degradation properties were investigated. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels were pliable and transparent at room temperature. The LCST could be adjusted at 32∼39°C by alternating the feed ratio. Swelling was influenced by NIPAAm/AAc monomer ratio, cross-linking density, swelling media, and temperature. All hydrogels with different feeding ratios contained more than 95% water at 25°C in the ultra pure water and phosphate-buffered saline (PBS, pH = 7.4 ± 0.1), and had a prospective swelling in the simulated gastric fluids (SGF, pH = 1.2) > 72.54%. In degradation studies, breakdown of the chitosan cross-linked P(NIPAAm-co-AAc) hydrogels was dependent on the cross-linking density. The chitosan cross-linked P(NIPAAm-co-AAc) hydrogels which can be tailored to create environmentally-responsive artificial extracellular materials have great potential for future use.

Absence of Direct Association between Coliforms and Escherichia coli in Irrigation Water and on Produce

2013 ◽  
Vol 76 (6) ◽  
pp. 959-966 ◽  
Author(s):  
GAYEON WON ◽  
PAMELA J. SCHLEGEL ◽  
JENNIFER M. SCHROCK ◽  
JEFFREY T. LeJEUNE
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Irrigation Water ◽  
Cross Sectional Study ◽  
Microbial Quality ◽  
Sectional Study ◽  
Cross Sectional ◽  
Data Set ◽  
E Coli ◽  
The Cross

Irrigation water is considered a potential source of preharvest pathogen contamination of vegetables. Hence, several organizations have recommended microbiological standards for water used to irrigate edible plants. The purpose of this study was to determine the strength of association between microbial quality indicators (coliforms and Escherichia coli) in irrigation water and on irrigated vegetables. Data analyzed included original results from a cross-sectional study conducted in the Midwestern United States during summer 2009 and information presented in two previously published studies performed in France and Portugal to investigate microbial quality of irrigation water and watered produce. In the cross-sectional study, repetitive PCR (rep-PCR) was used to characterize genetic relatedness of E. coli isolates from water and vegetables. No significant correlations were found between fecal indicators on leafy greens (lettuce and parsley, n = 91) or fruit (tomatoes and green peppers, n = 22) and those found in irrigation water used in the cross-sectional study (P > 0.40) or in the previously published data sets (data set 1: lettuce and waste irrigation water, n = 15, P > 0.40; data set 2: lettuce and irrigation water, n = 32, P = 0.06). Rep-PCR banding patterns of E. coli strains were all distinguishable among the pairs of E. coli isolates recovered from produce and irrigation water on the same farm. From the available data, the concentration of indicator organisms based on a single measure of irrigation water quality was not associated with the presence of these indicators on produce. In the absence of additional information, the use of a single microbial water quality parameter as an indicator of produce safety is of limited value for predicting the safety of the produce.

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