scholarly journals Size Attenuated Copper Doped Zirconia Nanoparticles Enhances in Vitro Antimicrobial Properties

2021 ◽  
Author(s):  
Nishakavya S ◽  
Agnishwar Girigoswami ◽  
Deepa R ◽  
Divya A ◽  
Ajith S ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Biomedical Applications ◽  
Antimicrobial Properties ◽  
Gram Positive ◽  
Antimicrobial Drugs ◽  
Xtt Assay ◽  
Gram Positive Bacteria ◽  
Positively Charged ◽  
Zirconia Nanoparticles

Abstract Biofilm formation hinders the activity of antimicrobial drugs at the site of infections and any agent that can act on both Gram- positive and Gram- bacteria by inhibiting the bacterial growth and rupture the biofilm is needed for the management of infection. In the present study, we have synthesized ZrO2 NPs and copper doped zirconia nanoparticles (Cu-ZrO2 NPs) and characterized them using dynamic light scattering, X-ray diffractometry and scanning electron microscopy (SEM). The size of the Cu-ZrO2 NPs drastically reduced compared to ZrO2 NPs and the antimicrobial activity was studied against Gram- positive bacteria (Lactobacillus sp.) and Gram- negative bacteria (Pseudomonas aeruginosa), respectively. The synthesized Cu-ZrO2 NPs showed superior inhibitory action against Lactobacillus sp. compared to ZrO2 NPs, due to the negatively charged cell wall of Lactobacillus sp. which could attract readily the positively charged Cu-ZrO2 NPs, thereby inhibiting its activity. The biocompatibility was tested using XTT assay in FL cells and the results demonstrated that Cu-ZrO2 NPs were non- toxic to mammalian cells. Hence, it could be proposed that the synthesized Cu-ZrO2 NPs possess possible biomedical applications and can be used as antibacterial agents without causing toxicity in mammalian cells.

scholarly journals A3, a Scorpion Venom Derived Peptide Analogue with Potent Antimicrobial and Antibiofilm Activity against Clinical Isolates of Multi-Drug Resistant Gram Positive Bacteria

2018 ◽  
Author(s):  
Ammar Almaaytah ◽  
Ahmad Farajallah ◽  
Ahmad Abualhaijaa ◽  
Qosay Al-balas
Keyword(s):  
Host Defense ◽  
Mammalian Cells ◽  
Scorpion Venom ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Gram Positive ◽  
Peptide Analogue ◽  
Gram Positive Bacteria ◽  
Conventional Antibiotics

Current research in the field of antimicrobials is focused on the development of novel antibiotics and antimicrobial agents to counteract the huge dilemma that the human population is mainly facing in regards to the rise of bacterial resistance and biofilm infections. Host Defense peptides (HDPs) are a promising group of molecules for antimicrobial development as they share unique characteristics suitable for antimicrobial activity including their broad spectrum of activity and potency against bacteria. AamAP1 is a novel HDP that was identified through molecular cloning from the venom of the North African scorpion Androctonus amoeruxi. In vitro antimicrobial assays revealed that the peptide displays moderate activity against different strains of Gram-positive and Gram-negative bacteria. Additionally, the peptide proved to be highly hemolytic and displaying significantly high toxicity against mammalian cells. In our study, a novel synthetic peptide analogue named A3 was designed from the naturally occurring scorpion venom host defense peptide. The design strategy depended on modifying the amino acid sequence of the parent peptide in order to increase its net positive charge, percentage helicity and optimize other physico-chemical parameters involved theoretically in HDPs activity. Accordingly, A3 was evaluated for its in vitro antimicrobial and anti-biofilm activity individually and in combination with four different types of conventional antibiotics against clinical isolates of multi-drug resistant (MDR) Gram-positive bacteria. A3 was also evaluated for its cytotoxicity against mammalian cells. A3 displayed potent and selective in vitro antimicrobial activities against a wide range of MDR Gram-positive bacteria. Our results also showed that combining A3 with conventional antibiotics displayed a synergistic mode of action which resulted in decreasing the MIC value for A3 peptide as low as 0.125 µM. These effective concentrations were associated with negligible toxicities on mammalian cells. In conclusion, A3 exhibits enhanced activity and selectivity when compared with the parent natural scorpion venom peptide. The combination of A3 with conventional antibiotics may be pursued as a potential novel treatment strategy against MDR and biofilm forming bacteria.

scholarly journals Antimicrobial Properties of MX-2401, an Expanded-Spectrum Lipopeptide Active in the Presence of Lung Surfactant

2011 ◽  
Vol 55 (8) ◽  
pp. 3720-3728 ◽  
Author(s):  
Dominique Dugourd ◽  
Haiyan Yang ◽  
Melissa Elliott ◽  
Raymond Siu ◽  
Jacob J. Clement ◽  
...  
Keyword(s):  
Lung Surfactant ◽  
Antimicrobial Properties ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Lipopeptide Antibiotic ◽  
Hospital Acquired

ABSTRACTMX-2401 is an expanded-spectrum lipopeptide antibiotic selective for Gram-positive bacteria that is a semisynthetic analog of the naturally occurring lipopeptide amphomycin. It was active againstEnterococcusspp., including vancomycin-sensitiveEnterococcus(VSE),vanA-,vanB-, andvanC-positive vancomycin-resistantEnterococcus(VRE), linezolid- and quinupristin-dalfopristin-resistant isolates (MIC90of 4 μg/ml), methicillin-resistantStaphylococcus aureus(MRSA) and methicillin-sensitiveS. aureus(MSSA) (MIC90of 2 μg/ml), coagulase-negative staphylococci, including methicillin-sensitiveStaphylococcus epidermidis(MSSE) and methicillin-resistantS. epidermidis(MRSE) (MIC90of 2 μg/ml), andStreptococcusspp. including viridans group streptococci, and penicillin-resistant, penicillin-sensitive, penicillin-intermediate and macrolide-resistant isolates ofStreptococcus pneumoniae(MIC90of 2 μg/ml). MX-2401 demonstrated a dose-dependent postantibiotic effect varying from 1.5 to 2.4 h. Furthermore, MX-2401 was rapidly bactericidal at 4 times the MIC againstS. aureusandEnterococcus faecalis, with more than 99.9% reduction in viable bacterial attained at 4 and 24 h, respectively. The MICs of MX-2401 against MRSA, MSSA, VSE, and VRE strains serially exposed for 15 passages to sub- to supra-MICs of MX-2401 remained within three dilutions of the original MIC. In contrast to that of the lipopeptide daptomycin, the antibacterial activity of MX-2401 was not affectedin vitroby the presence of lung surfactant, and MX-2401 was activein vivoin the bronchial-alveolar pneumonia mouse model, in which daptomycin failed to show any activity. Moreover, the activity of MX-2401 was not as strongly dependent on the Ca2+concentration as is the activity of daptomycin. In conclusion, MX-2401 is a promising new-generation lipopeptide for the treatment of serious infections with Gram-positive bacteria, including hospital-acquired pneumonia.

scholarly journals Comparative Antimicrobial Activity of Areca catechu Nut Extracts using Different Extracting Solvents

2016 ◽  
pp. 19-23 ◽  
Author(s):  
M Arifur Rahman ◽  
Papeya Sultana ◽  
M Sahidul Islam ◽  
M Toslim Mahmud ◽  
M Mamun Or Rashid ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Water Extract ◽  
Ethanol Extract ◽  
Antimicrobial Effect ◽  
Inhibitory Effects ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Potential Source ◽  
Areca Catechu

Scientists from different sectors are investigating plants for their antimicrobial usefulness. Studies have found thousands of plants which have inhibitory effects on a range of microorganisms in vitro. Surprisingly, only around 10% of all the plants have been investigated in this purpose. The antimicrobial properties of Areca catechu nut extract has been reported earlier. In our study, we have observed and compared the antibacterial activity among n-hexane, ethanol and water extract of A. catechu nut. We found antimicrobial effect only from ethanol and water extract. On the contrary, there was no antibacterial effect observed from n-hexane extract. Furthermore, the extracts are effective only against gram positive bacteria. The ethanol extract concentration from 0.188-0.377 mg/ml was the minimum inhibitory concentration (MIC) for gram positive bacteria used in our study. While, minimum bactericidal concentrations (MBC) were 0.377-0.753 mg/ml for this group of microorganisms. On the other hand, in case of water extract the MIC and MBC were 0.047-1.56 and 0.094-3.125 mg/ml respectively for Gram-positive organisms. This study suggest that A. catechu nut extract can be a potential source for developing antibacterial agents against Gram-positive bacteria which are commonly found on human oral cavity and responsible for dental caries.Bangladesh J Microbiol, Volume 31, Number 1-2,June-Dec 2014, pp 19-23

scholarly journals Antibacterial Activity of Colloidal Silver against Gram-Negative and Gram-Positive Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 36 ◽  
Author(s):  
Andrea Vila Domínguez ◽  
Rafael Ayerbe Algaba ◽  
Andrea Miró Canturri ◽  
Ángel Rodríguez Villodres ◽  
Younes Smani
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Colloidal Silver ◽  
Ros Production ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Kill Curve

Due to the emergence of antimicrobial resistance, new alternative therapies are needed. Silver was used to treat bacterial infections since antiquity due to its known antimicrobial properties. Here, we aimed to evaluate the in vitro activity of colloidal silver (CS) against multidrug-resistant (MDR) Gram-negative and Gram-positive bacteria. A total of 270 strains (Acinetobacter baumannii (n = 45), Pseudomonas aeruginosa (n = 25), Escherichia coli (n = 79), Klebsiella pneumoniae (n = 58)], Staphylococcus aureus (n = 34), Staphylococcus epidermidis (n = 14), and Enterococcus species (n = 15)) were used. The minimal inhibitory concentration (MIC) of CS was determined for all strains by using microdilution assay, and time–kill curve assays of representative reference and MDR strains of these bacteria were performed. Membrane permeation and bacterial reactive oxygen species (ROS) production were determined in presence of CS. CS MIC90 was 4–8 mg/L for all strains. CS was bactericidal, during 24 h, at 1× and 2× MIC against Gram-negative bacteria, and at 2× MIC against Gram-positive bacteria, and it did not affect their membrane permeabilization. Furthermore, we found that CS significantly increased the ROS production in Gram-negative with respect to Gram-positive bacteria at 24 h of incubation. Altogether, these results suggest that CS could be an effective treatment for infections caused by MDR Gram-negative and Gram-positive bacteria.

scholarly journals Synthesis, Characterization, and Antimicrobial Properties of Peptides Mimicking Copolymers of Maleic Anhydride and 4-Methyl-1-pentene

2018 ◽  
Vol 19 (9) ◽  
pp. 2617 ◽  
Author(s):  
Marian Szkudlarek ◽  
Elisabeth Heine ◽  
Helmut Keul ◽  
Uwe Beginn ◽  
Martin Möller
Keyword(s):  
Maleic Anhydride ◽  
Mammalian Cells ◽  
Antimicrobial Properties ◽  
Amphiphilic Copolymers ◽  
Gram Positive ◽  
One Pot ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Alternating Copolymer ◽  
The Difference

Synthetic amphiphilic copolymers with strong antimicrobial properties mimicking natural antimicrobial peptides were obtained via synthesis of an alternating copolymer of maleic anhydride and 4-methyl-1-pentene. The obtained copolymer was modified by grafting with 3-(dimethylamino)-1-propylamine (DMAPA) and imidized in a one-pot synthesis. The obtained copolymer was modified further to yield polycationic copolymers by means of quaternization with methyl iodide and dodecyl iodide, as well as by being sequentially quaternized with both of them. The antimicrobial properties of obtained copolymers were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. Both tested quaternized copolymers were more active against the Gram-negative E. coli than against the Gram-positive S. aureus. The copolymer modified with both iodides was best when tested against E. coli and, comparing all three copolymers, also exhibited the best effect against S. aureus. Moreover, it shows (limited) selectivity to differentiate between mammalian cells and bacterial cell walls. Comparing the minimum inhibitory concentration (MIC) of Nisin against the Gram-positive bacteria on the molar basis instead on the weight basis, the difference between the effect of Nisin and the copolymer is significantly lower.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

scholarly journals In Vitro Characterization of the Bacillus subtilis Protein Tyrosine Phosphatase YwqE

2005 ◽  
Vol 187 (10) ◽  
pp. 3384-3390 ◽  
Author(s):  
Ivan Mijakovic ◽  
Lucia Musumeci ◽  
Lutz Tautz ◽  
Dina Petranovic ◽  
Robert A. Edwards ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Class Ii ◽  
Gram Positive ◽  
Protein Tyrosine ◽  
Gram Positive Bacteria ◽  
New Family ◽  
In Vitro Characterization

ABSTRACT Both gram-negative and gram-positive bacteria possess protein tyrosine phosphatases (PTPs) with a catalytic Cys residue. In addition, many gram-positive bacteria have acquired a new family of PTPs, whose first characterized member was CpsB from Streptococcus pneumoniae. Bacillus subtilis contains one such CpsB-like PTP, YwqE, in addition to two class II Cys-based PTPs, YwlE and YfkJ. The substrates for both YwlE and YfkJ are presently unknown, while YwqE was shown to dephosphorylate two phosphotyrosine-containing proteins implicated in UDP-glucuronate biosynthesis, YwqD and YwqF. In this study, we characterize YwqE, compare the activities of the three B. subtilis PTPs (YwqE, YwlE, and YfkJ), and demonstrate that the two B. subtilis class II PTPs do not dephosphorylate the physiological substrates of YwqE.

scholarly journals In Vitro and In Vivo Activities of DA-7867, a New Oxazolidinone, against Aerobic Gram-Positive Bacteria

2005 ◽  
Vol 49 (6) ◽  
pp. 2498-2500 ◽  
Author(s):  
Eun Jeong Yoon ◽  
Yeong Woo Jo ◽  
Sung Hak Choi ◽  
Tae Ho Lee ◽  
Jae Keol Rhee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Infection Models ◽  
Vancomycin Resistant

ABSTRACT In vitro and in vivo activities of DA-7867 were assessed against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and penicillin-resistant Streptococcus pneumoniae. All isolates were inhibited by DA-7867 at ≤0.78 μg/ml, a four-times-lower concentration than that of inhibition by linezolid. For murine infection models, DA-7867 also exhibited greater efficacy than linezolid against all isolates tested.

scholarly journals Antimicrobial Properties of 8-Hydroxyserrulat-14-en-19-oic Acid for Treatment of Implant-Associated Infections

2012 ◽  
Vol 57 (1) ◽  
pp. 333-342 ◽  
Author(s):  
Justyna Nowakowska ◽  
Hans J. Griesser ◽  
Marcus Textor ◽  
Regine Landmann ◽  
Nina Khanna
Keyword(s):  
Structural Changes ◽  
Treatment Options ◽  
Antimicrobial Properties ◽  
Bactericidal Effect ◽  
Mouse Tissue ◽  
Logarithmic Phase ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Time Kill

ABSTRACTTreatment options are limited for implant-associated infections (IAI) that are mainly caused by biofilm-forming staphylococci. We report here on the activity of the serrulatane compound 8-hydroxyserrulat-14-en-19-oic acid (EN4), a diterpene isolated from the Australian plantEremophila neglecta. EN4 elicited antimicrobial activity toward various Gram-positive bacteria but not to Gram-negative bacteria. It showed a similar bactericidal effect against logarithmic-phase, stationary-phase, and adherentStaphylococcus epidermidis, as well as against methicillin-susceptible and methicillin-resistantS. aureuswith MICs of 25 to 50 μg/ml and MBCs of 50 to 100 μg/ml. The bactericidal activity of EN4 was similar againstS. epidermidisand its Δicamutant, which is unable to produce polysaccharide intercellular adhesin-mediated biofilm. In time-kill studies, EN4 exhibited a rapid and concentration-dependent killing of staphylococci, reducing bacterial counts by >3 log10CFU/ml within 5 min at concentrations of >50 μg/ml. Investigation of the mode of action of EN4 revealed membranolytic properties and a general inhibition of macromolecular biosynthesis, suggesting a multitarget activity.In vitro-tested cytotoxicity on eukaryotic cells was time and concentration dependent in the range of the MBCs. EN4 was then tested in a mouse tissue cage model, where it showed neither bactericidal nor cytotoxic effects, indicating an inhibition of its activity. Inhibition assays revealed that this was caused by interactions with albumin. Overall, these findings suggest that, upon structural changes, EN4 might be a promising pharmacophore for the development of new antimicrobials to treat IAI.

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