scholarly journals Graphene Matrices as Carriers for Metal Ions against Antibiotic Susceptible and Resistant Bacterial Pathogens

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 352
Author(s):  
Anthony J. Slate ◽  
Nathalie Karaky ◽  
Grace S. Crowther ◽  
Jonathan A. Butler ◽  
Craig E. Banks ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Metal Ions ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Therapeutic Option ◽  
Bacterial Strains ◽  
Graphene Foam ◽  
Coating Method ◽  
Resistant Strains ◽  
Specific Metal

Due to the ever-increasing burden of antimicrobial-resistant (AMR) bacteria, the development of novel antimicrobial agents and biomaterials to act as carriers and/or potentiate antimicrobial activity is essential. This study assessed the antimicrobial efficacy of the following ionic metals, silver, gold, palladium, platinum, zinc, and gallium alone and in combination with graphene matrices (which were coated via a drop casting coating method). The graphene foam was utilized as a carrier for the ionic metals against both, antibiotic susceptible and resistant bacterial strains of Acinetobacter baumannii,Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Ionic gold, palladium and platinum demonstrated the greatest antimicrobial activity against the susceptible and resistant strains. Scanning electron microscopy (SEM) visualized cellular ultrastructure damage, when the bacteria were incubated upon the graphene foam alone. This study suggests that specific metal ions applied in combination with graphene foam could present a potential therapeutic option to treat AMR bacterial infections. The application of the graphene foam as a potential carrier could promote antimicrobial activity, provide a sustained release approach and reduce possible resistance acquisition. In light of this study, the graphene foam and ionic metal combinations could potentially be further developed as part of a wound dressing.

scholarly journals Ultraviolet Radiation and Salinity-Induced Physiological Changes and Scytonemin Induction in Cyanobacteria Isolated from Diverse Habitats

2021 ◽  
Vol 12 (3) ◽  
pp. 3590-3606
Keyword(s):  
Antimicrobial Activity ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Antimicrobial Agents ◽  
Free Ligand ◽  
The Novel ◽  
Bacterial Strains ◽  
Resistant Strains ◽  
Antimicrobial And Antifungal Activity

A novel series of transition metal (II) complexes (5a-h) were conveniently synthesized via reaction of important transition metals (Co, Cu, Zn, Ni) with (E)-N-(4-methylbenzylidene)-2-((Z)-(4-methylbenzylidene)amino)benzamide Schiff base (3) which was previously synthesized by reacting 2- aminobenzohydrazide (1) with 4-methylbenzaldehyde (2). The synthesized metal complexes' structure was elucidated by IR, NMR, mass, and elemental analysis. Additionally, we also evaluated the antioxidant, antimicrobial and antifungal activity of the synthesized metal complexes. The bioassay of the novel transition metal complexes envisioned that compounds5eand5c showed better antimicrobial activity than the free ligand, and compounds5g and 5a showed good activity against most bacterial strains. On the other hand, hydrated metal complexes 5b, 5d, 5f, and 5h showed moderate to good antimicrobial activity. In comparison with ascorbic acid, most of the metal complexes showed moderate to good antioxidant activity. The current bioassay was investigated and proved that the compounds 5e and 5c as antimicrobial agents act on highly resistant strains of microbes.

scholarly journals Antibiotic Resistance of Heterotrophic Bacteria Isolated from Various Habitats of the Litoral Area of Lake Baikal

2019 ◽  
Vol 29 (4) ◽  
pp. 513-522
Author(s):  
Ekaterina Zimens ◽  
Elena Sukhanova ◽  
Olga Belykh
Keyword(s):  
Antimicrobial Activity ◽  
Antibiotic Resistance ◽  
Microbial Community ◽  
Lake Baikal ◽  
Antimicrobial Agents ◽  
Heterotrophic Bacteria ◽  
Bacterial Strains ◽  
Gram Positive Bacteria ◽  
Resistant Strains ◽  
First Time

This is the first time the data on the antibiotic resistance of heterotrophic bacteria were obtained. These bacteria were isolated from fouling of stone substrates and also from «healthy» and «diseased» sponges of Lake Baikal. We have analysed 377 strains for the resistance to 11 antimicrobial agents. 133 of them were isolated from the water column, 277 from stone fouling, 17 from «healthy» sponges, and 20 from «diseased» sponges of Lake Baikal. We have revealed 9 sensitive strains and 36 strains resistant to all antibiotics. A high percentage of bacterial strains from both plankton (34–82 %) and periphyton (23–94 %) are resistant to a number of broad-spectrum antibiotics. At the same time, they have different sensitivity to azithromycin, vancomycin, tetracycline, and meropenem. The strains isolated from periphyton showed the most effective antimicrobial activity to azithromycin, tetracycline and meroperem; those isolated from water showed the most effective antimicrobial activity to meroperem. The strains sensitive to antibiotics (18–71 %) prevail in the microbial community of «healthy» sponges. At the same time, the microbial community of «diseased» sponges has a larger share of sensitive strains, which accounts for 30–75 %. The proportion of resistant strains with gram-negative cell wall is higher for most antibiotics compared to the gram-positive bacteria.

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.

STUDIES ON SOME BACTERIAL DISEASES IN OREOCHROMIS NILOTICUS WITH SPECIAL REFERENCES TO TREATMENT

2018 ◽  
pp. 39-47
Author(s):  
Viola Zaki ◽  
Ahmed EL-gamal ◽  
Yasmin Reyad
Keyword(s):  
Oreochromis Niloticus ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Histopathological Examination ◽  
Klebsiella Oxytoca ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Tissue Samples ◽  
Hydropic Degeneration ◽  
Total Prevalence

he present research carried out to study the common bacterial infections in Oreochromis niloticus (Nile tilapia) in Manzala area at Dakahlia governorate and possible antimicrobial agents used for treatment. A total number of 400 fish were randomly collected from Manzala private farms at Dakahlia governorate and subjected to the clinical, bacteriological and histopathological examination. The highest prevalence of bacterial isolates during the whole period of examination of naturally infected O.niloticus was recorded for A.hydrophila (22.66%), followed by V.alginolyticus (19.01%), V.parahemolyticus (13.80%), Streptococcus spp. (12.24%), A.caviae (11.72%), V.cholera (10.16%), A.salmonicida (7.55%), while the lowest prevalence was recorded for Klebsiella oxytoca (2.86%). The seasonal highest total prevalence of bacterial isolates from examined naturally infected O. niloticus was recorded in spring (30.21%), followed by autumn (28.39%), then summer (22.40%) and the lowest prevalence was recorded in winter (19.01%). Histopathological findings of the tissue samples which collected from different organs of naturally infected O.niloticus revealed that spleen show marked hemosiderosis and sever hemorrhage, gills showsever congestion of lamellar capillaries with marked aneurysm, necrosis and hemorrhage of lamellar epithelium and liver show sever hydropic degeneration and necrosis of hepatocytes, Ciprofloxacin was the most effective antibiotic against all isolated bacterial strains

scholarly journals Silver (I) N-Heterocyclic Carbene Complexes: A Winning and Broad Spectrum of Antimicrobial Properties

2021 ◽  
Vol 22 (5) ◽  
pp. 2497
Author(s):  
Filippo Prencipe ◽  
Anna Zanfardino ◽  
Michela Di Napoli ◽  
Filomena Rossi ◽  
Stefano D’Errico ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Resistance Mechanisms ◽  
Heterocyclic Carbenes ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Development Of Resistance ◽  
Starting Point ◽  
Catalytic Chemistry

The evolution of antibacterial resistance has arisen as the main downside in fighting bacterial infections pushing researchers to develop novel, more potent and multimodal alternative drugs.Silver and its complexes have long been used as antimicrobial agents in medicine due to the lack of silver resistance and the effectiveness at low concentration as well as to their low toxicities compared to the most commonly used antibiotics. N-Heterocyclic Carbenes (NHCs) have been extensively employed to coordinate transition metals mainly for catalytic chemistry. However, more recently, NHC ligands have been applied as carrier molecules for metals in anticancer applications. In the present study we selected from literature two NHC-carbene based on acridinescaffoldand detailed nonclassicalpyrazole derived mono NHC-Ag neutral and bis NHC-Ag cationic complexes. Their inhibitor effect on bacterial strains Gram-negative and positivewas evaluated. Imidazolium NHC silver complex containing the acridine chromophore showed effectiveness at extremely low MIC values. Although pyrazole NHC silver complexes are less active than the acridine NHC-silver, they represent the first example of this class of compounds with antimicrobial properties. Moreover all complexesare not toxic and they show not significant activity againstmammalian cells (Hek lines) after 4 and 24 h. Based on our experimental evidence, we are confident that this promising class of complexes could represent a valuable starting point for developing candidates for the treatment of bacterial infections, delivering great effectiveness and avoiding the development of resistance mechanisms.

scholarly journals Thymol and its Derivatives as Antimicrobial Agents

2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Ajai Kumar ◽  
Suriya P. Singh ◽  
Sudarshan S. Chhokar
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Single Step ◽  
Acid Chlorides ◽  
Disc Diffusion ◽  
Bacterial Strains ◽  
Fungal Strains ◽  
Broth Dilution

From the seeds of C arum copticum thymol (1) was isolated as the major component and ten derivatives (2–11) were prepared by reacting it with different acid chlorides in a single step. They were evaluated for antimicrobial activity against twelve bacterial strains and nine fungal strains using disc diffusion and broth dilution assays. Derivative 9 was found to be most active against both bacterial and fungal strains.

scholarly journals A Novel Hybrid Peptide Composed of LfcinB6 and KR-12-a4 With Enhanced Antimicrobial, Anti-Inflammatory and Anti-Biofilm Activities

2021 ◽  
Author(s):  
Chelladurai Ajish ◽  
Sungtae Yang ◽  
S. Dinesh Kumar ◽  
Eun Young Kim ◽  
Hye Jung Min ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Laser Scanning ◽  
Antimicrobial Agents ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Hybrid Peptide ◽  
Cell Selectivity ◽  
Anti Inflammatory

Abstract Hybridizing two known antimicrobial peptides (AMPs) is a simple and effective strategy for designing antimicrobial agents with enhanced cell selectivity against bacterial cells. Here, we generated a hybrid peptide Lf-KR in which LfcinB6 and KR-12-a4 were linked with a Pro hinge to obtain a novel AMP with potent antimicrobial, anti-inflammatory, and anti-biofilm activities. Lf-KR exerted superior cell selectivity for bacterial cells over sheep red blood cells. Lf-KR showed broad-spectrum antimicrobial activities (MIC: 4–8 mM) against tested 12 bacterial strains and retained its antimicrobial activity in the presence of salts at physiological concentrations. Membrane depolarization and dye leakage assays showed that the enhanced antimicrobial activity of Lf-KR was due to increased permeabilization and depolarization of microbial membranes. Lf-KR significantly inhibited the expression and production of pro-inflammatory cytokines (NO and TNF-a) in LPS-stimulated mouse macrophage RAW264.7 cells. In addition, Lf-KR showed a powerful eradication effect on preformed multidrug-resistant Pseudomonas aeruginosa (MDRPA) biofilms. We confirmed using confocal laser scanning microscopy that a large portion of the preformed MDRPA biofilm structure was perturbed by the addition of Lf-KR. Collectively, our results suggest that Lf-KR can be an antimicrobial, anti-inflammatory, and anti-biofilm candidate as a pharmaceutical agent.

scholarly journals ANTIMICROBIAL ACTIVITY OF METHANOLIC EXTRACT OF LUDWIGIA PARVIFLORA L. AGAINST STANDARD BACTERIAL STRAINS AND COMPARISON OF ITS ACTIVITY WITH THAT OF STANDARD ANTIBIOTICS

2019 ◽  
pp. 430-432
Author(s):  
SHIBU GEORGE ◽  
MEVLIN JOY
Keyword(s):  
Antimicrobial Activity ◽  
Bacterial Infections ◽  
Methanolic Extract ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Whole Plant ◽  
The Common ◽  
Susceptibility Tests

Objective: The objective of this study was to evaluate the antimicrobial activity of methanolic extract of Ludwigia parviflora L. using standard bacterial strains and compare its activity with that of standard antibiotics. Methods: The antibacterial activity and antibiotic susceptibility tests were done by disk diffusion method using MTCC bacterial strains. Results: The study revealed that the methanolic extract of the whole plant of L. parviflora L. was effective to inhibit the growth of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Among the tested strains, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli were more susceptible to the methanolic extract of L. parviflora than the commonly using antibiotic tetracycline 30 mcg. The activity of methanolic extract was also higher than the activity of gentamicin 10 mcg against the P. aeruginosa. Conclusion: The study concluded that the crude methanolic extract of the whole plant of L. parviflora L. is a good source for antibacterial agent against S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. Hence, this plant can be used as a natural alternative to the common antibiotics such as gentamicin and tetracycline against common bacterial infections after validating its pharmacological and toxicological activities.

scholarly journals Phytochemical Study and Biological Activities of Two Medicinal Plants used in Burkina Faso: Lannea velutina A. Rich (Anacardiaceae) and Ximenia americana L. (Olacaceae)

2019 ◽  
pp. 1-9 ◽  
Author(s):  
Dramane Pare ◽  
Jotham Yhi-pênê N’do ◽  
Samson Guenne ◽  
Mahamadi Nikiema ◽  
Adama Hilou
Keyword(s):  
Antimicrobial Activity ◽  
Medicinal Plants ◽  
Burkina Faso ◽  
Bacterial Infections ◽  
Biological Activities ◽  
Public Health Problem ◽  
Bacterial Strains ◽  
Phytochemical Study ◽  
Ximenia Americana ◽  
Study Laboratory

Background: Bacterial infections are at the origin of a number of serious pathologies, including meningitis, bronchopneumopathies, typhoid fever and especially diarrhea, which are still a real public health problem for the child population in developing countries. In most of these countries, people use medicinal plants for primary health care. The objective of this study was to determine the content of phenolic compounds, the antioxidant and antimicrobial activity of extracts from two plants used in traditional medicine in Burkina Faso, Lannea velutina and Ximenia americana. Place and Duration of Study: Laboratory of Biochemistry and Applied Chemistry (LABIOCA). Methods: The total phenolics and flavonoid content of the ethanolic extract extracts were determined by spectrometric assay. The DPPH and FRAP method were used to measure the antioxidant capacity of the extracts. The antibacterial potential was determined on five bacterial strains. Results: The ethanolic extracts of Lannea velutina showed the best polyphenol content with 969.67±8.23 ​​mgGAE/g extract against 753.145917±66.31 mgGAE/g extract for Ximenia americana. On the DPPH radical Ximenia americana gave the best activity with a percentage inhibition of 62.32±0.17% compared to Lannea velutina. This species also gave the best reducing activity with a reducing capacity of 3.45±0.97 mmol EAA/10 g of extract. Shigella dysenteria and Staphylococcus aureus were susceptible to Lannea velutina and Ximenia americana with inhibition diameters greater than 8 mm. Conclusion: These results showed that the extract has good antioxidant potential as well as antimicrobial activity. These extracts could be used to prevent damage from oxidative stress and infections.

scholarly journals Investigation of the Biochemical and Ultrastructural Mechanisms Underlying the Antimicrobial Activity of Mimusops spp. Extracts

2020 ◽  
Vol 17 (2) ◽  
pp. 0452
Author(s):  
Mahmoud S.M. Mohamed ◽  
Gehad Abdelmohsen ◽  
Gouda T. M. Dawoud
Keyword(s):  
Bacterial Infections ◽  
High Performance ◽  
Antimicrobial Agents ◽  
Antimicrobial Effect ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Ultrastructural Changes ◽  
Bacterial Strains ◽  
Leaf Extracts ◽  
Traditional Medicines

Antibiotic resistance is the major growing threat facing the pharmacological treatment of bacterial infections. Therefore, bioprospecting the medicinal plants could provide potential sources for antimicrobial agents. Mimusops, the biggest and widely distributed plant genus of family Sapotaceae, is used in traditional medicines due to its promising pharmacological activities. This study was conducted to elucidate the antimicrobial effect of three unexplored Mimusops spp. (M. kummel, M. laurifolia and M. zeyheri). Furthermore, the mechanisms underlying such antibacterial activity were studied. The Mimusops leaf extracts revealed significant antibacterial activities against the five tested bacterial strains with a maximum inhibition zone diameter of 22.0 mm against B. subtilis compared with standard antibiotic ciprofloxacin. The minimal inhibitory and bactericidal concentration values against tested Gram-positive and Gram-negative bacterial strains ranged from 3.15-12.5 µg/ml. However, weak antifungal effect was recorded against Candida albicans with MIC value ˃25 µg/ml. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay showed that M. caffra was the best antioxidant (IC50=14.75±0.028 µg/ml), while M. laurifolia was the least one (IC50=34.22±0.014 µg/ml). The phenolics in plant leaves extracts were identified and quantified by high performance liquid chromatography (HPLC) which revealed the presence of seven phenolic acids and four flavonoids. The abundant phenolic compounds were rutin (5.216±0.067 mg/g dried wt.) and gallic acid (0.296±0.068 mg/g) followed by myricetin (0.317±0.091 mg/g) then kaempferol (0.113±0.049 mg/g) as flavonoids. The antibacterial mechanism of M. laurifolia extract, as a representative species, induces ultrastructural changes in the model bacterium Staphylococcus aureus with cell wall and plasma membrane lysis as revealed by transmission electron microscopy. Overall, Mimusops species (M. laurifolia, M. kummel and M. zeyheri) are promising natural alternative sources for antimicrobial agents.

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