scholarly journals Gentamicin-Montmorillonite Intercalation Compounds as an Active Component of Hydroxypropylmethylcellulose Bionanocomposite Films with Antimicrobial Properties

2022 ◽  
Author(s):  
Margarita Darder ◽  
Jing He ◽  
Laurent Charlet ◽  
Eduardo Ruiz-Hitzky ◽  
Pilar Aranda
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Wound Dressing ◽  
Intercalation Compounds ◽  
Klebsiella Pneumonia ◽  
Bacterial Reduction ◽  
Buffer Solution ◽  
X Ray ◽  
Bionanocomposite Films

AbstractThe present study introduces an overview of gentamicin-clay mineral systems for applications in biomedicine and then focuses on the development of a series of gentamicin/clay hybrid materials to be used as the bioactive phase of hydroxypropylmethylcellulose (HPMC) to produce bionanocomposite membranes possessing antimicrobial activity of interest in wound-dressing applications. Gentamicin (Gt) was adsorbed from aqueous solutions into a montmorillonite (Cloisite®-Na+) to produce intercalation compounds with tunable content of the antibiotic. The hybrids were characterized by CHN chemical analysis, energy-dispersive X-ray analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis, confirming the intercalation of Gt by an ion-exchange mechanism. The release of Gt from the hybrids was tested in water and in buffer solution to check their stability. Hybrids with various amounts of Gt were incorporated into a HPMC matrix at various loadings and processed as films by the casting method. The resulting Gt-clay/HPMC bionanocomposites were characterized by means of field-emission scanning electron microscopy, and were also evaluated for their water-adsorption and mechanical properties to confirm their suitability for wound-dressing applications. The antimicrobial activity of the bionanocomposite films was tested in vitro toward various microorganisms (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium, Acinetobacter baumannii, and Klebsiella pneumonia), showing a complete bacterial reduction even in films with small Gt contents.

Antimicrobial Activity of PET-Silver Nanocomposite Filaments

2018 ◽  
Vol 930 ◽  
pp. 212-217
Author(s):  
Marcos Antônio Guerra ◽  
Jeferson Prado Swerts ◽  
Mei Abe Funcia ◽  
Maria Gabriela Nogueira Campos
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Dermal Fibroblasts ◽  
Klebsiella Pneumonia ◽  
Dyeing Process ◽  
Colony Forming Units ◽  
Silver Nanocomposite

This study evaluated the antimicrobial activity of PET-Silver nanocomposite filaments at different concentrations (0, 0.180%, 0.135%, 0.090%, 0.045% and 0.022% w/w) of silver nanoparticles in order to determine the minimum inhibitory concentration and minimum bactericidal concentration of silver incorporated in the PET matrix. The in vitro antibacterial activity was evaluated by the AATCC standard 100: 2012 method, against Staphylococcus aureus ATCC 6538, and Klebsiella pneumonia ATCC 4532. The filaments were tested after one and twenty-one months of preparation to evaluate the effect of time on the antimicrobial activity of the nanocomposites. Moreover, the antimicrobial activity was also evaluated after dyeing the filaments. The silver-free PET filaments have not demonstrated antimicrobial activity and cytotoxicity against human dermal fibroblasts. Nevertheless, excepted for the filament with 0.022% of silver nanoparticles, all PET-Silver nanocomposites reduced more than 99% the colony-forming units (CFU) of Staphylococcus aureus and Klebsiella pneumonia after one and twenty-one months of preparation. This suggests that the MIC of silver nanoparticles incorporated in the PET matrix is lower than 220 ppm (w/w) and the MBC is between 0.022 and 0.045% (w/w). However, after the dyeing process, no antimicrobial activity was observed for any PET-Silver nanocomposite filaments. This may be attributed to the release of silver from the PET matrix during the dyeing process or to the reaction/inactivation of the silver ions by the salts used in this chemical treatment.

scholarly journals In-vitro antimicrobial activity of methanolic and aqueous leaf extracts of Chrysophyllum albidum (African star apple) and Garcinia kola (Bitter kola)

2021 ◽  
Vol 14 (03) ◽  
pp. 249-253
Author(s):  
Nicholas Chinedu Ewelike ◽  
Joy Chinyere Okammadu ◽  
Vincent Ezechukwu Ogwudire ◽  
Raymond Ikechukwu Nnadozie
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Klebsiella Pneumonia ◽  
Leaf Extracts ◽  
Garcinia Kola ◽  
Test Organisms ◽  
African Star Apple

Methanolic and aqueous leaf extracts of Chrysophyllum albidum (African star apple) and Garcinia kola (bitter kola) were studied for in-vitro microbial activity using the disc diffusion technique. The aqueous and methanolic leaf extracts of Chrysophyllum albidum showed antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans but showed no antibacterial activity against Klebsiella pneumonia. The methanolic leaf extract of Garcinia kola inhibited the growth of Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia while the aqueous extract of the leaf inhibited the growth of Staphylococcus aureus and Escherichia coli. Both methanolic and aqueous leaf extracts of the plant showed no antifungal activity against Candida albicans. The minimum inhibitory concentrations of the leaf extracts of Chrysophyllum albidum ranged from 12.5 mgL-1 to 25 mgL-1 while those of Garcinia kola ranged from 25 mgL-1 to 50 mgL-1. The results obtained suggest that the leaves of these plants can be used in treating diseases caused by the test organisms. The further investigation on the crude extracts would characterize bioactive components of the leaves of Chrysophyllum albidum and Garcinia kola.

scholarly journals Antibacterial Efficacy Testing of a Bioelectric Wound Dressing Against Clinical Wound Pathogens

2014 ◽  
Vol 8 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Hosan Kim ◽  
Inder Makin ◽  
Jeff Skiba ◽  
Amy Ho ◽  
Greggory Housler ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Wound Dressing ◽  
Reduction Rate ◽  
Multidrug Resistant ◽  
Wound Dressings ◽  
Antibacterial Efficacy ◽  
Bacterial Reduction ◽  
Resistant Species ◽  
Vancomycin Resistant

Silver-based wound dressings have been developed for the control of bioburden in wounds. However, the popularity and extensive use of silver-based dressings has been associated with emerging microbial resistances to silver. In this study we examined in vitro antibacterial efficacy of a bioelectric dressing containing silver and zinc against various wound pathogens. Antibiotic-sensitive clinical wound isolates showed a 100% reduction in bacterial growth, except that Enterococcus faecalis isolate was shown to survive with a bacterial log10 reduction rate of less than 102 CFU. We also investigated antibacterial efficacy against the extended spectrum β-lactamase (ESBL) bacteria, multidrug-resistant (MDR) bacteria, and methicillin-resistant Staphylococcus aureus (MRSA). The bioelectric dressing was effective in killing wound pathogens including ESBL, MDR, and MRSA in vitro. Furthermore, based on the primary results against E. faecalis, we carried out extensive studies against several nosocomial Enterococcus species including vancomycin-resistant species. Overall, the vancomycin-sensitive or -resistant Enterococcus species were resistant to this dressing at up to 48 h, except for the vancomycin-resistant Enterococcus raffinosus isolate only showing a 100% bacterial reduction at 48 h, but not at 24 h. The results demonstrated the effective bactericidal activity of a bioelectric dressing against antibiotic-sensitive and MDR strains, but Enterococcus species are bacteriostatic.

scholarly journals Efficiency of Antimicrobial Photodynamic Therapy with Photodithazine® on MSSA and MRSA Strains

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 869
Author(s):  
Beatriz Müller Nunes Souza ◽  
Juliana Guerra Pinto ◽  
André Henrique Correia Pereira ◽  
Alejandro Guillermo Miñán ◽  
Juliana Ferreira-Strixino
Keyword(s):  
Staphylococcus Aureus ◽  
Photodynamic Therapy ◽  
Antimicrobial Photodynamic Therapy ◽  
Bacterial Inactivation ◽  
Bacterial Reduction ◽  
Complete Inactivation ◽  
Opportunistic Bacteria ◽  
Significant Difference ◽  
Mrsa Strains

Staphylococccus aureus is a ubiquitous and opportunistic bacteria associated with high mortality rates. Antimicrobial photodynamic therapy (aPDT) is based on the application of a light source and a photosensitizer that can interact with molecular oxygen, forming Reactive Oxygen Species (ROS) that result in bacterial inactivation. This study aimed to analyze, in vitro, the action of aPDT with Photodithazine® (PDZ) in methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains. The strains were incubated with PDZ at 25, 50, 75, and 100 mg/L for 15 min and irradiated with fluences of 25, 50, and 100 J/cm2. The internalization of PDZ was evaluated by confocal microscopy, the bacterial growth by counting the number of colony-forming units, as well as the bacterial metabolic activity post-aPDT and the production of ROS. In both strains, the photosensitizer was internalized; the production of ROS increased when the aPDT was applied; there was a bacterial reduction compared to the control at all the evaluated fluences and concentrations; and, in most parameters, it was obtained complete inactivation with significant difference (p < 0.05). The implementation of aPDT with PDZ in clinical strains of S. aureus has resulted in its complete inactivation, including the MRSA strains.

scholarly journals Matricaria recutita extract associated with norfloxacin or cephalexin enhances the antimicrobial activity of these drugs against Staphylococcus aureus

Biotemas ◽  
2017 ◽  
Vol 30 (2) ◽  
pp. 25
Author(s):  
Rodrigo Rafael Maia ◽  
Andréia Vieira Pereira ◽  
Marcelo Biondaro Góis ◽  
Karine Delgado Souza ◽  
Vanessa De Melo Cavalcanti-Dantas ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Matricaria Recutita

http://dx.doi.org/10.5007/2175-7925.2017v30n2p25O surgimento de infecções bacterianas, incluindo aquelas associadas com Staphylococcus aureus, traz à tona uma necessidade de buscar novas estratégias mais eficazes para tratamento clínico. O uso de plantas medicinais associados com os antibióticos convencionais pode ser uma opção terapêutica. Atualmente, estudos evidenciam o efeito sinérgico alcançado através da combinação de extratos vegetais com antibióticos. Nosso objetivo foi avaliar a atividade antimicrobiana e cinética bacteriana in vitro do extrato de Matricaria recutita (camomila) e sua associação com cefalexina e norfloxacin sobre isolados clínicos de S. aureus de origem bovina, caracterizada como resistente. Os ensaios foram realizados pelo método da diluição em meio sólido para a determinação da Concentração Inibitória Mínima (CIM). Em ambas as associações do extrato de M. recutita com os antibióticos norfloxacina e cefalexina, foi observada CIM na diluição 1:64 o que correspondeu a 8μg/mL dos antibióticos e 13.43 μg/mL do extrato. A associação Cefalexina com extrato de camomila produziu um efeito sinérgico em 75% das amostras na sua CIM. A combinação com produtos naturais frequentemente utilizados pela população e os antibióticos aqui ensaiados, poderiam representar uma opção terapêutica para o tratamento de infecções causadas por S. aureus, como também para prevenção do desenvolvimento crescente de resistência.

scholarly journals EVALUATION OF IN VITRO ANTI-INFLAMMATORY AND ANTIMICROBIAL ACTIVITY OF AQUEOUS AND METHANOLIC SEED EXTRACTS OF CITRULLUS LANATUS

2017 ◽  
Vol 9 (5) ◽  
pp. 29
Author(s):  
Iswariya S. ◽  
Uma T. S.
Keyword(s):  
Antimicrobial Activity ◽  
Bacillus Subtilis ◽  
Aqueous Extract ◽  
Seed Extract ◽  
Inflammatory Activity ◽  
Diffusion Method ◽  
Klebsiella Pneumonia ◽  
Anti Inflammatory ◽  
Seed Extracts

Objective: The present study was designed to identify the bioactive phytochemicals and its antibacterial and in vitro anti-inflammatory potential of aqueous and methanolic seed extract of Citrullus lanatus.Methods: The phytochemical screening of both the aqueous and methanolic seed extract was carried out qualitatively to identify the major Phyto-constituents present in the extracts. The antimicrobial activity of the extracts was evaluated against six pathogenic bacterial strains by agar well diffusion method and the Minimum inhibitory concentration (MIC) was determined by broth dilution method. In vitro anti-inflammatory activity of C. lanatus seed extracts was evaluated by using human red blood cell (HRBC) membrane stabilization and inhibition of albumin denaturation method.Results: The results of the study indicated that both the extracts of the seed having antimicrobial activity, while the methanolic extract showed more significant activity against the tested organism than aqueous extract. Methanol extract had the lowest MIC of 1.562 mg/ml against Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa and Bacillus subtilis, whereas in aqueous extract was highly sensitive to Bacillus subtilis, E. coli and Klebsiella pneumonia with MIC of 3.125 and 6.25 mg/ml, respectively. Methanolic extracts exerted comparative higher anti-inflammatory activity than aqueous extract.Conclusion: Present study provides a firm evidence to support that the synergistic effect of C. lanatus seed extracts having potent anti-inflammatory and antimicrobial property, which might serve as an effective drug for various microbial infections and inflammatory disorders.

scholarly journals Nitrogen and Bromide Co-Doped Hydroxyapatite Thin Films with Antimicrobial Properties

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1505
Author(s):  
Simona Liliana Iconaru ◽  
Carmen Steluta Ciobanu ◽  
Daniela Predoi ◽  
Mikael Motelica-Heino ◽  
Constantin Cătălin Negrilă ◽  
...  
Keyword(s):  
Thin Films ◽  
Antimicrobial Activity ◽  
Spin Coating ◽  
Thin Layers ◽  
Precipitation Method ◽  
X Ray ◽  
Co Precipitation ◽  
First Time ◽  
Co Doped

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp), due to its high biocompatibility, is widely used as biomaterial. Doping with various ions of hydroxyapatite is performed to acquire properties as close as possible to the biological apatite present in bones and teeth. In this research the results of a study performed on thin films of hydroxyapatite co-doped with nitrogen and bromine (NBrHAp) are presented for the first time. The NBrHAp suspension was obtained by performing the adapted co-precipitation method using cetyltrimethylammonium bromide (CTAB). The thin layers of NBrHAp were obtained by spin-coating. The stability of the NBrHAp suspension was examined by ultrasound measurements. The thin layers obtained by the spin-coating method were examined by scanning electron microscopy (SEM), optical microscopy (OM), and metallographic microscopy (MM). The presence of nitrogen and bromine were highlighted by energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) studies. Fourier transform infrared spectroscopy (FTIR) was used to highlight the chemical status of nitrogen and bromine. In addition, the powder obtained from the NBrHAp suspension was analyzed by XRD. Moreover, the in vitro antimicrobial activity of the NBrHAp suspensions and coatings was investigated using the reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231. The results highlighted the successful obtainment of N and Br co-doped hydroxyapatite suspension for the first time by an adapted co-precipitation method. The obtained suspension was used to produce pure NBrHAp composite thin films with superior morphological properties. The NBrHAp suspensions and coatings exhibited in vitro antimicrobial activity against bacterial and fungal strains and revealed their good antimicrobial activity.

scholarly journals ANTIMICROBIAL ACTIVITY STUDY OF NEW QUINAZOLIN-4(3H)-ONES AGAINST STAPHYLOCOCCUS AUREUS AND STREPTOCOCCUS PNEUMONIAE

2021 ◽  
Vol 9 (4) ◽  
pp. 318-329
Author(s):  
M. A. Samotrueva ◽  
A. A. Ozerov ◽  
A. A. Starikova ◽  
N. M. Gabitova ◽  
D. V. Merezhkina ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Streptococcus Pneumoniae ◽  
Active Sites ◽  
Wide Spectrum ◽  
Experimental Studies ◽  
Amide Group ◽  
Pharmacological Effect ◽  
Dilution Method

Quinazolin-4(3H)-one derivatives exhibiting a wide spectrum of a pharmacological activity, represent a promising class of substances used to obtain antibacterial agents, which is especially important in the context of the emergence of pathogenic microorganisms’ resistance to drugs used in medicine. It has been proved that compounds having a naphthyl radical in the molecule, as well as an amide group bound to the benzene ring as quinazolinone substituents, are characterized by a pronounced antimicrobial activity against Staphylococcus aureus and Streptococcus pneumoniae.The aim of the research is a primary microbiological screening of the in vitro antimicrobial activity of new quinazolin-4(3H)-one derivatives against Staphylococcus aureus and Streptococcus pneumoniae, as well as the assessment of the relationship between the pharmacological effect and the structural transformation of the substance molecule, lipophilicity and the possibility of forming resistance to them.Materials and methods. The experimental studies have been carried out using well-known nosocomial pathogens of infectious and inflammatory diseases Staphylococcus aureus and Streptococcus pneumoniae by a serial dilution method.Results. A compound containing a naphthyl radical in its structure, which contributes to an increase in the hydrophobicity of the substance and its solubility in the membrane of a bacterial cell, has a bacteriostatic effect against both Staphylococcus aureus and Streptococcus pneumoniae. A similar pharmacological effect is exhibited by a derivative with an amide group as a substituent of the quinazolinone nucleus linked to a phenyl radical, which probably contributes to an increase in the degree of binding to active sites of enzymes involved in the DNA replication, and protein synthesis. Obviously, the increased lipophilicity, which promotes better binding to the efflux protein, cannot serve as objective characteristics of the emergence possibility of the pathogen’s resistance to this substance.Conclusion. Among the synthesized compounds, the leading substances that exhibit an antimicrobial activity against Staphylococcus aureus and Streptococcus pneumonia, have been identified. The assessment of the chemical structure made it possible to substantiate their pharmacological action and draw conclusions about the possibility of developing resistance to it in microbial cells.

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