scholarly journals Functionalized Magnetic Nanoparticles and Their Effect onEscherichia coliandStaphylococcus aureus

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mohamed S. A. Darwish ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Ivan Stibor
Keyword(s):  
Electron Microscopy ◽  
Magnetite Nanoparticles ◽  
Biological Effect ◽  
Bacterial Strains ◽  
Gram Negative ◽  
E Coli ◽  
Functionalized Magnetic Nanoparticles ◽  
Nanoparticle Morphology ◽  
Average Size ◽  
Scanning Electron

Magnetite (Fe3O4) nanoparticles were prepared using coprecipitation and subsequently surface-functionalized with 3-aminopropyltriethoxysilane (APTS), polyethylene glycol (PEG), and tetraethoxysilane (TEOS). Nanoparticle morphology was characterized using scanning electron microscopy, while structure and stability were assessed through infrared spectroscopy and zeta potential, respectively. Average size of the nanoparticles analysed by dynamic light scattering was 89 nm, 123 nm, 109 nm, and 130 nm for unmodified magnetite and APTS-, PEG-, and TEOS-modified magnetite nanoparticles, respectively. Biological effect was studied on two bacterial strains: Gram-negativeEscherichia coliCCM 3954 and Gram-positiveStaphylococcus aureusCCM 3953. Most of modified magnetite nanoparticles had a significant effect onS. aureusand not onE. coli, whereas PEG-magnetite nanoparticles displayed no significant effect on the growth rate of either bacteria.

Organic additives as antimicrobial agents in thermoplastics compounds

2016 ◽  
Vol 1817 ◽  
Author(s):  
Daiane Tomacheski ◽  
Michele Pittol ◽  
Vanda F. Ribeiro ◽  
Ruth M. C. Santana
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Organic Additives ◽  
Bacterial Strains ◽  
Melt Mixing ◽  
Polymeric Matrices ◽  
E Coli ◽  
Scanning Electron

ABSTRACTDevelopment of polymers with antimicrobial characteristics can avoid deterioration and assist in containing spread of pathogens harmful to human health. This study aimed to compare the antimicrobial and mechanical properties of polymeric matrices containing organic antimicrobial additives. Silver organomodified bentonite (Ag_bentonite) and organochlorine molecule in a masterbatch based polyethylene (Cl_PE) were tested in proportion of 2% in a thermoplastic elastomeric formulation. The polymeric matrices were prepared by melt mixing and evaluated in tensile and antimicrobial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains. The additives were characterized by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The nanoscale of Ag_bentonite was verified by SEM. TGA assay showed that Cl_PE is more sensitive to heat than Ag_bentonite. As a result of this lower thermal stability, the addition of Cl_PE reduced the tensile properties of the compound. The sample with Cl_PE was effective against both bacterial strains, reducing the populations of S. aureus and E. coli in 99 and 96%, respectively. The addition of Ag_bentonite did not affect the tensile strength and decreased in 97 and 40% S. aureus and E. coli populations, respectively. The results indicate that the use of organic additives is promissory, but further modifications in processing must be necessary.

Bioceramic Materials Show Reduced Pathological Biofilm Formation

2014 ◽  
Vol 631 ◽  
pp. 448-453 ◽  
Author(s):  
Corrado Piconi ◽  
Andrei Cristian Ionescu ◽  
Andrea Cochis ◽  
Erica Iasi ◽  
Eugenio Brambilla ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Morphological Data ◽  
Alumina Matrix ◽  
Bacterial Strains ◽  
E Coli ◽  
Viable Biomass ◽  
Alumina Matrix Composite ◽  
Scanning Electron

The aim of the present work was to assess the surface ability of three bioceramic materials (A: alumina BIOLOX®forte; B: Si3N4; C: alumina matrix composite BIOLOX®delta) to inhibit bacterial biofilm formation. For this purpose, ceramic disks at standardized roughness (Ra = 0,25 μm) were used as test materials while commercial polystyrene was considered as control. Two biofilm-producing bacterial strains (S. epidermidis ATCC14990, Escherichia coli ATCC25922) were used for experiments. The viable biomass was assessed by the metabolic MTT assay after 24h incubation. Morphological data regarding biofilms structure were obtained by scanning electron microscopy. In general, results revealed that all bioceramics materials were significantly less colonized compared to polystyrene. The degree of biofilm formation onto bioceramics ranged between about 30 to 60% less than the polystyrene control. Moreover, some differences were noticed by comparing the three bioceramics inhibition ratio: bioceramic A showed significanlty less S. epidermidis biofilm formation (p<0.005) compared to B and C that showed similar performance. Conversely, no difference were noted for E. coli biofilm amount for A, B and C. In conclusion, the tested materials showed capability to reduce biofilm formation to a different extent depending on the tested bacterial strains.

Synthesizing selenium- and silver-substituted hydroxyapatite-based bone grafts and their effects on antibacterial efficiency and cell viability

2018 ◽  
Vol 63 (3) ◽  
pp. 291-300
Author(s):  
Bunyamin Aksakal ◽  
Mehtap Demirel ◽  
Zeynep A. Sinirlioglu
Keyword(s):  
Electron Microscopy ◽  
Cell Viability ◽  
Sol Gel ◽  
Control Group ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray ◽  
E Coli ◽  
Scanning Electron

Abstract Hydroxyapatite (HA)-based biografts with selenium (Se) and silver (Ag) substitutions were synthesized using the sol-gel method. The synthesized HA-based biografts at various Se and Ag quantity ratios (wt%) were characterized via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDX). Escherichia coli (JM103) and Gram-positive Staphylococcus aureus (ATCC29293) bacteria were used for the cell viability tests by performing the MTT assay. During antibacterial tests, it was determined that the synthesized biografts showed significant antimicrobial activity on E. coli and S. aureus; however, some materials were effective on Gram-negative E. coli, but had no effect on Gram-positive S. aureus. In vitro cell viability tests revealed that some of the synthesized biografts such as H30Ag10Se15 and H40Ag20Se10 provided the highest cell viability rates compared to those in the control group.

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Analysis ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Biological Evaluation ◽  
Fungal Strain ◽  
Bacterial Strains ◽  
Standard Drug ◽  
Gram Negative ◽  
E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

scholarly journals Epidemiological and phylogenetic analysis reveals Flavobacteriaceae as potential ancestral source of tigecycline resistance gene tet(X)

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Rong Zhang ◽  
Ning Dong ◽  
Zhangqi Shen ◽  
Yu Zeng ◽  
Jiauyue Lu ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Resistance Gene ◽  
Gc Content ◽  
Zhejiang Province ◽  
Bacterial Strains ◽  
Gram Negative ◽  
E Coli ◽  
Transmission Mechanisms ◽  
Low Prevalence ◽  
Potential Origin

Abstract Emergence of tigecycline-resistance tet(X) gene orthologues rendered tigecycline ineffective as last-resort antibiotic. To understand the potential origin and transmission mechanisms of these genes, we survey the prevalence of tet(X) and its orthologues in 2997 clinical E. coli and K. pneumoniae isolates collected nationwide in China with results showing very low prevalence on these two types of strains, 0.32% and 0%, respectively. Further surveillance of tet(X) orthologues in 3692 different clinical Gram-negative bacterial strains collected during 1994–2019 in hospitals in Zhejiang province, China reveals 106 (2.7%) tet(X)-bearing strains with Flavobacteriaceae being the dominant (97/376, 25.8%) bacteria. In addition, tet(X)s are found to be predominantly located on the chromosomes of Flavobacteriaceae and share similar GC-content as Flavobacteriaceae. It also further evolves into different orthologues and transmits among different species. Data from this work suggest that Flavobacteriaceae could be the potential ancestral source of the tigecycline resistance gene tet(X).

scholarly journals Morphology of the eggs of the genus Belminus (Hemiptera: Reduviidae: Triatominae) by optical and scanning electron microscopy

Zootaxa ◽  
2011 ◽  
Vol 2970 (1) ◽  
pp. 33 ◽  
Author(s):  
CLAUDIA M. SANDOVAL ◽  
ELSA NIEVES ◽  
VÍCTOR M. ANGULO ◽  
JOÃO ARISTEU DA ROSA ◽  
ELIS ALDANA
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Discriminant Analysis ◽  
Generic Character ◽  
Polygonal Pattern ◽  
Average Size ◽  
First Time ◽  
Simple Convex ◽  
Caudal Area ◽  
Scanning Electron

The external morphology of eggs of the species Belminus corredori Galvão & Angulo, 2006, Belminus herreri Lent & Wygodzinsky, 1979 and Belminus ferroae Sandoval, Pabón, Jurberg & Galvão, 2007 is described for the first time using scanning electron microscopy (SEM). Females lay one egg at a time; the shape of the egg is oval with lateral flattening, a rounded caudal area and a true and simple convex operculum. The average size of the egg among these species is 0.51– 0.58 mm in length and 0.36–0.4 mm in width. As a generic character we highlight the discovery of a chorion rim with one to four grooves always joined to the micropyles. All species present a clear polygonal pattern only in the operculum and in the egg’s cephalic region, while the median and caudal regions show a smooth appearance, features that are shared only with the eggs of the genus Alberprosenia. A discriminant analysis of the polygonal design of the operculum proved to be useful for the identification of the species.

Influence of Titanium Alloying Element Substrata on Bacterial Adhesion

2012 ◽  
Vol 535-537 ◽  
pp. 992-995
Author(s):  
Kun Mediaswanti ◽  
Vi Khanh Truong ◽  
Jafar Hasan ◽  
Elena P. Ivanova ◽  
Francois Malherbe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Bacterial Adhesion ◽  
Infection Risk ◽  
Bacterial Attachment ◽  
Bacterial Strains ◽  
Alloying Element ◽  
Bacteria Adhesion ◽  
Scanning Electron

Titanium and titanium alloys have been widely employed in many load-bearing orthopaedic applications due to their excellent strength and corrosion resistance. However, postimplantation infections might occur even though considerable studies have been made. Choosing a bio-friendly alloying element is one way to reduce infection risk. The aim of this study is to evaluate the extent of bacterial attachment on titanium, tantalum, niobium and tin surfaces. Two pathogenic bacterial strains, namely Staphylococcus aureus CIP 65.8T and Pseudomonas aeruginosa ATCC 9027, were used in this study. Quantification of bacterial attachment was performed using scanning electron microscopy. Results indicated that the surface chemistry and topography of the investigated materials significantly influence the degree of P. aeruginosa and S. aureus adhesion; however, surface wettability did not show a significant impact upon bacterial retention. In this study, tin was shown to be the most attractive material for bacteria adhesion but tantalum limits the bacterial adhesion. Therefore, it is suggested to limit the amount of tin as an titanium alloying element due to its nature to attract P. aeruginosa and S. aureus adhesion.

Effect of KBF4 Addition on the Microstructure of Mg-6Zn-1Si Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 996-999 ◽  
Author(s):  
Bao Feng Zhang ◽  
Qi Chen ◽  
Xiao Wei Chen ◽  
Hong Liang Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Energy Dispersive Spectrometer ◽  
Energy Dispersive ◽  
Chinese Script ◽  
Mg2si Phase ◽  
Small Block ◽  
Average Size ◽  
Scanning Electron

In this study, the effect of KBF4 addition on the microstructure of the Mg-6Zn-1Si alloy has been investigated by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) with Energy Dispersive Spectrometer(EDS). At 1.5wt% KBF4 addition, the morphology of Mg2Si phase completely changed from Chinese script type into uniformly, dispersedly distributed graininess or small block, with the average size of the Mg-6Zn-1Si alloy decreasing from 135μm to 82μm.

scholarly journals Biofunctionalization of Textile Materials. 2. Antimicrobial Modification of Poly(lactide) (PLA) Nonwoven Fabricsby Fosfomycin

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 768 ◽  
Author(s):  
Marcin H. Kudzin ◽  
Zdzisława Mrozińska
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Antimicrobial Properties ◽  
Air Permeability ◽  
Gram Negative ◽  
Textile Materials ◽  
Nonwoven Fabrics ◽  
Ftir Spectrometry ◽  
Escherichia Coli Bacteria ◽  
Scanning Electron

This research is focused on obtaining antimicrobial hybrid materials consisting of poly(lactide) nonwoven fabrics and using phosphoro-organic compound—fosfomycin—as a coating and modifying agent. Polylactide (PLA) presents biodegradable polymer with multifunctional application, widely engaged in medical related areas. Fosfomycin as functionalized phosphonates presents antibiotic properties expressed by broad spectrum of antimicrobial properties. The analysis of these biofunctionalized nonwoven fabrics processed by the melt-blown technique, included: scanning electron microscopy (SEM), UV/VIS transmittance, FTIR spectrometry, air permeability. The functionalized nonwovens were tested on microbial activity tests against colonies of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria.

Evolution of Our Experience in Diagnosis and Therapy for Urinary Infections

2009 ◽  
Vol 76 (2) ◽  
pp. 140-143
Author(s):  
R. Pizzorno ◽  
A. Simonato ◽  
M. Esposito ◽  
T. Montanaro ◽  
M. Mussap ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Empirical Therapy ◽  
Enterococcus Species ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Diagnosis And Therapy ◽  
Urinary Infections ◽  
Spectrum Activity

The therapy for urinary infections is advised according to the antibiogram; the symptoms request an empirical therapy based on urinary infections knowledge and drugs spectrum activity. We considered the urinoculture performed on 3834 patients, 3012 male and 822 female, hospitalized in our Institute in the period between 01/01/2005 and 31/10/2006; 444 of these were positive (12.7 % - 451 bacterial strains). Table 1: bacterial strains isolaed. We reported some evaluations obtained by antibiogram. E. coli strains Ciprofloxacin sensitive resulted in 60% of cases. Enterococcus species and Enterococcus faecalis strains Ampicillin sensitive resulted in 96.4% and 100% of cases, respectively. In this study there is a Gram negative prevalence, whereas we had previously observed an equivalence between Gram negative and Gram positive (p 0.001). These data are useful for empirical therapy.

Sign in / Sign up

Export Citation Format

Share Document