scholarly journals Antibacterial Activity of Chitosan Nanoparticles: A Review

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1173 ◽  
Author(s):  
Murugesan Chandrasekaran ◽  
Ki Deok Kim ◽  
Se Chul Chun
Keyword(s):  
Molecular Weight ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Negative Charge ◽  
Bacterial Species ◽  
Chitosan Nanoparticles ◽  
Gram Negative ◽  
Factors Affecting ◽  
Bacterial Surface ◽  
Degree Of Acetylation

In recent years, nanotechnology has attracted attention in many fields because it has several up-and-coming novel uses. Many researchers have suggested that chitosan nanoparticles (CS-NPs) and their derivatives are one of the best nanomaterials for delivering antibacterial activity. CS-NPs have a broad spectrum of antibacterial activity, but they manifest different inhibitory efficacy against gram-negative (G−) and gram-positive (G+) bacterial species. The mechanism of antibacterial action is an intricate process that varies between G− and G+ bacteria as a result of the differences in cell wall and cell membrane chemistry. In previous studies, greater antibacterial activity was more evident against G− bacteria than G+ bacteria, whereas in some studies G+ bacteria were more sensitive. Researchers predicted that the varied responses of bacteria are caused by the mixed hydrophilicity and negative charge distribution on the bacterial surface. Moreover, its activity depends on a number of variables including bacterial target (i.e., G− or G+ bacteria) and bacterial growth, as well as its concentration, pH, zeta-potential, molecular weight, and degree of acetylation. Therefore, this review examines current research on the mechanisms and factors affecting antibacterial activity, and application of CS-NPs specifically against animal and plant pathogenic bacteria.

scholarly journals Targeted-Antibacterial-Plasmids (TAPs) combining conjugation and CRISPR/Cas systems achieve strain-specific antibacterial activity

2020 ◽  
Author(s):  
Audrey Reuter ◽  
Cécile Hilpert ◽  
Annick Dedieu-Berne ◽  
Sophie Lematre ◽  
Erwan Gueguen ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Carbapenem Resistance ◽  
Double Strand Breaks ◽  
Resistant Bacteria ◽  
Innovative Strategy ◽  
Strand Breaks ◽  
Drug Resistant Bacteria

AbstractThe global emergence of drug-resistant bacteria leads to the loss of efficacy of our antibiotics arsenal and severely limits the success of currently available treatments. Here, we developed an innovative strategy based on Targeted-Antibacterial-Plasmids (TAPs) that use bacterial conjugation to deliver CRISPR/Cas systems exerting a strain-specific antibacterial activity. TAPs are highly versatile as they can be directed against any specific genomic or plasmid DNA using the custom algorithm (CSTB) that identifies appropriate targeting spacer sequences. We demonstrate the ability of TAPs to induce strain-selective killing by introducing lethal double strand breaks (DSBs) into the targeted genomes. TAPs directed against a plasmid-born carbapenem resistance gene efficiently resensitise the strain to the drug. This work represents an essential step towards the development of an alternative to antibiotic treatments, which could be used for in situ microbiota modification to eradicate targeted resistant and/or pathogenic bacteria without affecting other non-targeted bacterial species.

scholarly journals Evaluation of Antibacterial Activity of Some Traditionally Used Medicinal Plants against Human Pathogenic Bacteria

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Bishnu P. Marasini ◽  
Pankaj Baral ◽  
Pratibha Aryal ◽  
Kashi R. Ghimire ◽  
Sanjiv Neupane ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Medicinal Plants ◽  
Inhibitory Action ◽  
Pathogenic Bacteria ◽  
Cynodon Dactylon ◽  
Bacterial Species ◽  
Dilution Method ◽  
Chloroform Fraction ◽  
Ethanolic Extracts

The worldwide increase of multidrug resistance in both community- and health-care associated bacterial infections has impaired the current antimicrobial therapy, warranting the search for other alternatives. We aimed to find thein vitroantibacterial activity of ethanolic extracts of 16 different traditionally used medicinal plants of Nepal against 13 clinical and 2 reference bacterial species using microbroth dilution method. The evaluated plants species were found to exert a range ofin vitrogrowth inhibitory action against the tested bacterial species, andCynodon dactylonwas found to exhibit moderate inhibitory action against 13 bacterial species including methicillin-resistantStaphylococcus aureus, imipenem-resistantPseudomonas aeruginosa, multidrug-resistantSalmonella typhi, andS. typhimurium. The minimum inhibitory concentration (MIC) values of tested ethanolic extracts were found from 31 to >25,000 μg/mL. Notably, ethanolic extracts ofCinnamomum camphora, Curculigo orchioides, andCurcuma longaexhibited the highest antibacterial activity againstS. pyogeneswith a MIC of 49, 49, and 195 μg/mL, respectively; whereas chloroform fraction ofCynodon dactylonexhibited best antibacterial activity againstS. aureuswith a MIC of 31 μg/mL. Among all,C. dactylon, C. camphora, C. orchioides, andC. longaplant extracts displayed a potential antibacterial activity of MIC < 100 μg/mL.

scholarly journals COMPARATIVE ANALYSIS OF METAL NANOPARTICLES SYNTHESIZED FROM HIBISCUS ROSA SINESIS AND THEIR ANTIBACTERIAL ACTIVITY ESTIMATION AGAINST NINE PATHOGENIC BACTERIA

2017 ◽  
Vol 10 (5) ◽  
pp. 323
Author(s):  
Shruti Tyagi
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Au Nanoparticles ◽  
Size Range ◽  
Micrococcus Luteus ◽  
Bacterial Species ◽  
Cost Effective ◽  
Antibacterial Activities ◽  
Agar Disc ◽  
Vis Spectroscopy

Objective: This study demonstates  a simple, cost effective protocol  for biosynthesis of stable silver (Ag) and gold (Au) nanoparticles from Hibiscus Rosa sinesis and their comparison by applying antibacterial activities against nine pathogenic bacterial species.Methods: Silver (Ag) and gold (Au) nanoparticles were biosynthesized from Hibiscus Rosa sinesis were characterized by UV–VIS spectroscopy, FTIR and TEM. The antibacterial activities  of AgNPs  and AuNPs were evaluated against  9 pathogenic bacterial species  Pseudomonas aeroginosa, Bacillus subtilis Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Enterobacter aerogens, Escherichia coli, Streptococcus pneumoniae, Aeromonas hydrophila by the agar disc diffusion method.Results: Synthesized AgNPs  were obtained in 13.01 to 28.14 nm size range, while AuNPs were in  6.32 to 18.19 nm size range. The results of Fourier transform infrared spectroscopy (FTIR) spectra indicates  that the AuNPs are bound to amine groups and the AgNPs to carboxylate ion groups. The antibacterial activities  of AgNPs,  the zone of inhibition significantly increased with the  increases of concentrations of AgNPs in all pathogenic bacterial species  except  in the case of S. epidermidis at 50%, S. aerogenes and A. hydrophila at 70%, while in case of AuNPs antibacterial activity  was displayed  only against B. subtilis at 20% and 100% concentration.Conclusion: This study suggests that AgNPs exhibits outstanding antibacterial activity against pathogenic bacteria as compared to AuNPs synthesized from Hibiscus Rosa sinensis leaf extract and insights to their potential applicability as an alternative antibacterial  agent in microbial and human health system to reduce the resistance ability of pathogenic bacteria. Keywords: silver nanoparticles; gold  nanoparticles; UV–VIS spectroscopy; FTIR; TEM; antibacterial activities.  

Antibacterial activity of β-thujaplicin

1973 ◽  
Vol 19 (11) ◽  
pp. 1341-1346 ◽  
Author(s):  
T. J. Trust ◽  
R. W. Coombs
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
Tetracycline Hydrochloride ◽  
Penicillin G ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Agar Diffusion ◽  
Tube Dilution

The cedar extractive β-thujaplicin was shown to inhibit the growth of a wide variety of bacterial species, and to be bactericidal for several species. The compound caused the lysis of cells of several species of Gram-negative bacteria. The antibacterial activity of β-thujaplicin was quantitated by agar diffusion and tube-dilution assays, and shown to be less potent than sodium penicillin G and tetracycline hydrochloride.

scholarly journals The Human CXC Chemokine Granulocyte Chemotactic Protein 2 (GCP-2)/CXCL6 Possesses Membrane-Disrupting Properties and Is Antibacterial

2008 ◽  
Vol 52 (7) ◽  
pp. 2599-2607 ◽  
Author(s):  
Helena M. Linge ◽  
Mattias Collin ◽  
Pontus Nordenfelt ◽  
Matthias Mörgelin ◽  
Martin Malmsten ◽  
...  
Keyword(s):  
Amino Acids ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Membrane Disruption ◽  
Minimal Bactericidal Concentration ◽  
Bacterial Surface ◽  
Bacterial Membranes ◽  
Chemotactic Protein ◽  
Cxc Chemokine ◽  
Α Helix

ABSTRACT Granulocyte chemotactic protein 2 (GCP-2)/CXCL6 is a CXC chemokine expressed by macrophages and epithelial and mesenchymal cells during inflammation. Through binding and activation of its receptors (CXCR1 and CXCR2), it exerts neutrophil-activating and angiogenic activities. Here we show that GCP-2/CXCL6 itself is antibacterial. Antibacterial activity against gram-positive and gram-negative pathogenic bacteria of relevance to mucosal infections was seen at submicromolar concentrations (minimal bactericidal concentration at which 50% of strains tested were killed, 0.063 ± 0.01 to 0.37 ± 0.03 μM). In killed bacteria, GCP-2/CXCL6 associated with bacterial surfaces, which showed membrane disruption and leakage. A structural prediction indicated the presence of three antiparallel NH2-terminal β-sheets and a short amphipathic COOH-terminal α-helix; the latter feature is typical of antimicrobial peptides. However, when the synthetic derivatives corresponding to the NH2-terminal (50 amino acids) and COOH-terminal (19 amino acids, corresponding to the putative α-helix) regions were compared, higher antibacterial activity was observed for the NH2-terminus-derived peptide, indicating that the holopeptide is necessary for full antibacterial activity. An artificial model of bacterial membranes confirmed these findings. The helical content of GCP-2/CXCL6 in the presence or absence of lipopolysaccharide or negatively charged membranes was studied by circular dichroism. As with many antibacterial peptides, membrane disruption by GCP-2/CXCL6 was dose-dependently reduced in the presence of NaCl, which, we here demonstrate, inhibited the binding of the peptide to the bacterial surface. Compared with CXC chemokines ENA-78/CXCL5 and NAP-2/CXCL7, GCP-2/CXCL6 showed a 90-fold-higher antibacterial activity. Taken together, GCP/CXCL6, in addition to its chemotactic and angiogenic properties, is likely to contribute to direct antibacterial activity during localized infection.

scholarly journals A polyalanine peptide derived from polar fish with anti-infectious activities

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Marlon H. Cardoso ◽  
Suzana M. Ribeiro ◽  
Diego O. Nolasco ◽  
César de la Fuente-Núñez ◽  
Mário R. Felício ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Bacterial Infections ◽  
Rational Design ◽  
Pathogenic Bacteria ◽  
Cd Spectroscopy ◽  
Design Strategies ◽  
Promising Alternative ◽  
Gram Negative ◽  
Bacterial Surface ◽  
Polar Fish

Abstract Due to the growing concern about antibiotic-resistant microbial infections, increasing support has been given to new drug discovery programs. A promising alternative to counter bacterial infections includes the antimicrobial peptides (AMPs), which have emerged as model molecules for rational design strategies. Here we focused on the study of Pa-MAP 1.9, a rationally designed AMP derived from the polar fish Pleuronectes americanus. Pa-MAP 1.9 was active against Gram-negative planktonic bacteria and biofilms, without being cytotoxic to mammalian cells. By using AFM, leakage assays, CD spectroscopy and in silico tools, we found that Pa-MAP 1.9 may be acting both on intracellular targets and on the bacterial surface, also being more efficient at interacting with anionic LUVs mimicking Gram-negative bacterial surface, where this peptide adopts α-helical conformations, than cholesterol-enriched LUVs mimicking mammalian cells. Thus, as bacteria present varied physiological features that favor antibiotic-resistance, Pa-MAP 1.9 could be a promising candidate in the development of tools against infections caused by pathogenic bacteria.

scholarly journals Antibacterial Activities of Xanthium Strumarium L.

2018 ◽  
Vol 29 ◽  
pp. 70-77 ◽  
Author(s):  
Anjana Devkota ◽  
Ritu Kumari Das
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Xanthium Strumarium ◽  
Distilled Water ◽  
Leaf Extracts ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Antibacterial activities of Xanthium strumarium L. (Asteraceae) was carried out in laboratory. Distilled water and methanol extracts of the leaves of plant was prepared. The antibacterial activity was studied against six pathogenic bacteria, three gram negative: Klebsiella pneumoniae (ATCC 15380), Proteus mirabilis (ATCC 49132), Escherichia coli (ATCC 25922) and three gram positive: Bacillus subtilis (ATCC 6633), Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 25932) at different concentrations (50 mg/ml, 100 mg/ml, 150 mg/ml, 200 mg/ ml, 250 mg/ml) of leaf extracts of X. strumurium. The phytochemical screening depicted the presence of terpenoids, saponins, flavonoids, tannins and alkaloids. The antibacterial activity of extracts was determined by disc diffusion method and zone of inhibition (ZOI) was measured. Gram negative bacteria was found more resistant than gram positive bacteria. The most susceptible bacterium was S. aureus while the most resistant bacterium was E. coli. Methanolic extract was found more effective than distilled water. These findings suggest that extracts obtained from leaves of X. strumurium possess biobactericidal potential, which can suitably be exploited for making antibacterial drugs.J. Nat. Hist. Mus. Vol. 29, 2015, Page: 70-77

scholarly journals In VitroAntibacterial Activity of AZD0914, a New Spiropyrimidinetrione DNA Gyrase/Topoisomerase Inhibitor with Potent Activity against Gram-Positive, Fastidious Gram-Negative, and Atypical Bacteria

2014 ◽  
Vol 59 (1) ◽  
pp. 467-474 ◽  
Author(s):  
Michael D. Huband ◽  
Patricia A. Bradford ◽  
Linda G. Otterson ◽  
Gregory S. Basarab ◽  
Amy C. Kutschke ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Legionella Pneumophila ◽  
Bacterial Species ◽  
Dna Gyrase ◽  
Cross Resistance ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Topoisomerase Inhibitor

ABSTRACTAZD0914 is a new spiropyrimidinetrione bacterial DNA gyrase/topoisomerase inhibitor with potentin vitroantibacterial activity against key Gram-positive (Staphylococcus aureus,Staphylococcus epidermidis,Streptococcus pneumoniae,Streptococcus pyogenes, andStreptococcus agalactiae), fastidious Gram-negative (Haemophilus influenzaeandNeisseria gonorrhoeae), atypical (Legionella pneumophila), and anaerobic (Clostridium difficile) bacterial species, including isolates with known resistance to fluoroquinolones. AZD0914 works via inhibition of DNA biosynthesis and accumulation of double-strand cleavages; this mechanism of inhibition differs from those of other marketed antibacterial compounds. AZD0914 stabilizes and arrests the cleaved covalent complex of gyrase with double-strand broken DNA under permissive conditions and thus blocks religation of the double-strand cleaved DNA to form fused circular DNA. Whereas this mechanism is similar to that seen with fluoroquinolones, it is mechanistically distinct. AZD0914 exhibited low frequencies of spontaneous resistance inS. aureus, and if mutants were obtained, the mutations mapped togyrB. Additionally, no cross-resistance was observed for AZD0914 against recent bacterial clinical isolates demonstrating resistance to fluoroquinolones or other drug classes, including macrolides, β-lactams, glycopeptides, and oxazolidinones. AZD0914 was bactericidal in both minimum bactericidal concentration andin vitrotime-kill studies. Inin vitrocheckerboard/synergy testing with 17 comparator antibacterials, only additivity/indifference was observed. The potentin vitroantibacterial activity (including activity against fluoroquinolone-resistant isolates), low frequency of resistance, lack of cross-resistance, and bactericidal activity of AZD0914 support its continued development.

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