scholarly journals Antibacterial Activity Against Multidrug-Resistant Staphylococcus aureus and in Silico Evaluation of MepA Efflux Pump by Cinnamaldehyde Chalcone

2021 ◽  
Vol 12 (6) ◽  
pp. 7523-7531
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Natural Products ◽  
Efflux Pump ◽  
Competitive Inhibitor ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Efflux Pump Inhibition ◽  
Phytochemical Studies

Phytochemical studies on Croton species have identified the presence of secondary metabolites responsible for a wide variety of pharmacological activities, among them antimicrobial activity. Research for new substances with antimicrobial activity derived from natural products can give a major contribution to human health worldwide by finding more efficient and fewer toxic formulas in the race against pathogenic microorganisms' resistance. Among bacterial pathogens, Staphylococcus aureus species, despite being present in the skin and nasal mucosa, can cause many infections and diseases. These opportunists reach debilitated people in hospitals and are challenging to treat. Here, we performed the structural characterization, determination of antibiotic activity, and MepA efflux pump inhibition potential against S. aureus of the chalcone (2E, 4E) -1- (2-hydroxy-3,4,6-trimethoxyphenyl)-5-phenylpenta-2,4-dien-1-one, derived from natural products 2-hydroxy-3,4,6-trimethoxyacetophenone isolated from Croton anisodontus and cinnamaldehyde. The chalcone was synthesized by the Claisen-Schmidt condensation. In addition, microbiological tests were performed to investigate the antibacterial activity, modulator potential, and efflux pump inhibition against the S. aureus multi-resistant strains. MIC values obtained to chalcone were not clinically relevant (MIC ≥ 1024 µg/mL). However, chalcone hampers the binding of the antibiotic to the binding site of the MepA efflux pump. It acts as a competitive inhibitor, being expelled from the bacteria in place of the antibiotic and potentiating ciprofloxacin's action against multidrug-resistant bacterial strains of K2068. Therefore, chalcone can be used as a base for substance design with antibiotic modifying activity.

scholarly journals Chemical Composition, Antioxidant and Antibacterial Activity of Bunium persicum, Eucalyptus globulus, and Rose Water on Multidrug-Resistant Listeria Species

2018 ◽  
Vol 23 ◽  
pp. 2515690X1775131 ◽  
Author(s):  
Farhad Sharafati Chaleshtori ◽  
Mohamad Saholi ◽  
Reza Sharafati Chaleshtori
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Eucalyptus Globulus ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Antioxidant Power ◽  
Listeria Species ◽  
Bunium Persicum

This research was aimed at investigating the antioxidant and antibacterial activity of Bunium persicum, Eucalyptus globulus, and rose water on multidrug-resistant Listeria species. The antibiotic resistance of Listeria spp obtained from seafood samples were determined by the Kirby-Bauer method. The antioxidant and antibacterial activity of the essential oils and extracts were evaluated using ferric reducing antioxidant power and microdilution methods, respectively. A total 2 samples (1.88%) were positive for Listeria spp. L monocytogenes was found to be resistant to ampicillin, amoxicillin/clavulanic acid, penicillin, vancomycin, and kanamycin. B persicum essential oil showed the greatest antioxidant activity (248.56 ± 1.09 µM Fe2+/g). The E globulus essential oil showed consistently strong antimicrobial activity against L monocytogenes and L grayi, while rose water showed no antimicrobial activity against any of the tested bacterial strains. The results showed that after adding the B persicum and E globulus essential oils to bacteria, the cell components’ release increased significantly.

scholarly journals In Vitro Bactericidal Activity of Human β-Defensin 3 against Multidrug-Resistant Nosocomial Strains

2006 ◽  
Vol 50 (2) ◽  
pp. 806-809 ◽  
Author(s):  
Giuseppantonio Maisetta ◽  
Giovanna Batoni ◽  
Semih Esin ◽  
Walter Florio ◽  
Daria Bottai ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Bactericidal Activity ◽  
Stenotrophomonas Maltophilia ◽  
Bactericidal Effect ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Gram Negative

ABSTRACT The antimicrobial activity of human β-defensin 3 (hBD-3) against multidrug-resistant clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter baumannii was evaluated. A fast bactericidal effect (within 20 min) against all bacterial strains tested was observed. The presence of 20% human serum abolished the bactericidal activity of hBD-3 against gram-negative strains and reduced the activity of the peptide against gram-positive strains.

scholarly journals Synthesis and biological evaluation of some new 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines as antimicrobial agents

2022 ◽  
Vol 11 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Iryna Myrko ◽  
Taras Chaban ◽  
Vasyl Matiychuk
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antimicrobial Agents ◽  
Biological Evaluation ◽  
Bacterial Strains ◽  
Synthesis And Biological Evaluation

A series of some new pyrazole-substituted 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines was synthesized in this study. The structures of target substances were confirmed by using 1H and 13С NMR spectroscopy, mass spectrometry and elemental analysis. The synthesized compounds have been evaluated for antimicrobial activity against five bacterial strains (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus) and two fungal strains (Candida albicans and Cryptococcus neoformans). The antimicrobial screening studies of synthesized substances established that 2 of 12 compounds show pronounced antibacterial activity against the strain Staphylococcus aureus.

scholarly journals Nigritanine as a New Potential Antimicrobial Alkaloid for the Treatment of Staphylococcus aureus-Induced Infections

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 511 ◽  
Author(s):  
Bruno Casciaro ◽  
Andrea Calcaterra ◽  
Floriana Cappiello ◽  
Mattia Mori ◽  
Maria Loffredo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Biological Activities ◽  
Human Keratinocytes ◽  
Chemical Diversity ◽  
Bioactive Molecules ◽  
Bacterial Strains ◽  
Wide Range

Staphylococcus aureus is a major human pathogen causing a wide range of nosocomial infections including pulmonary, urinary, and skin infections. Notably, the emergence of bacterial strains resistant to conventional antibiotics has prompted researchers to find new compounds capable of killing these pathogens. Nature is undoubtedly an invaluable source of bioactive molecules characterized by an ample chemical diversity. They can act as unique platform providing new scaffolds for further chemical modifications in order to obtain compounds with optimized biological activity. A class of natural compounds with a variety of biological activities is represented by alkaloids, important secondary metabolites produced by a large number of organisms including bacteria, fungi, plants, and animals. In this work, starting from the screening of 39 alkaloids retrieved from a unique in-house library, we identified a heterodimer β-carboline alkaloid, nigritanine, with a potent anti-Staphylococcus action. Nigritanine, isolated from Strychnos nigritana, was characterized for its antimicrobial activity against a reference and three clinical isolates of S. aureus. Its potential cytotoxicity was also evaluated at short and long term against mammalian red blood cells and human keratinocytes, respectively. Nigritanine showed a remarkable antimicrobial activity (minimum inhibitory concentration of 128 µM) without being toxic in vitro to both tested cells. The analysis of the antibacterial activity related to the nigritanine scaffold furnished new insights in the structure–activity relationships (SARs) of β-carboline, confirming that dimerization improves its antibacterial activity. Taking into account these interesting results, nigritanine can be considered as a promising candidate for the development of new antimicrobial molecules for the treatment of S. aureus-induced infections.

scholarly journals Synergy between Essential Oils of Calamintha Species (Lamiaceae) and Antibiotics

2018 ◽  
Vol 13 (3) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Marina Milenković ◽  
Jelena Stošović ◽  
Violeta Slavkovska
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Broth Microdilution ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
The Subject

The subject of the study was the investigation of the chemical composition and antimicrobial activity of the essential oils (EOs) isolated from Calamintha sylvatica, C. vardarensis, C. nepeta and C. glandulosa, as well as their antibacterial activity in combination with antibiotics. The quantitative and qualitative analysis of EOs was performed using the GC/FID and GC/MS methods. The antimicrobial activity of EOs against six standard bacterial strains and one strain of yeast was tested using the broth microdilution method, while the antimicrobial activity of a combination of essential oils and gentamicin/ciprofloxacin was tested by the checkerboard method. The dominant components (> 10%) of the essential oils were: cis-piperitone epoxide and menthone ( C. sylvatica), pulegone and menthone ( C. vardarensis), pulegone and piperitenone ( C. nepeta), pulegone, piperitenone, menthone and piperitone ( C. glandulosa). EOs did not exhibit significant antimicrobial activity except the essential oil of C. vardarensis which was selectively active against Staphylococcus aureus (MIC - 21.25 μg/mL). The overall effect of essential oil-antibiotic combinations varied from synergistic (FICI ≤ 0.5) to antagonistic (FICI ≥ 2) depending on the bacterial strain tested.

scholarly journals Antibacterial activity of selected snake venoms on pathogenic bacterial strains

2019 ◽  
Vol 27 (3) ◽  
pp. 305-317 ◽  
Author(s):  
Francisc Andrei Boda ◽  
Anca Mare ◽  
Zoltán István Szabó ◽  
Lavinia Berta ◽  
Augustin Curticapean ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Multidrug Resistant ◽  
Bacterial Strains ◽  
Snake Venoms ◽  
Starting Point ◽  
Sds Page ◽  
Potential Use ◽  
Selection Of

Abstract Snake venoms are aqueous solutions containing peptides and proteins with various biochemical, physiological, and pathophysiological effects. Several snake venom components are used as lead molecules in the development of new active substances for the treatment of cardiovascular diseases, clotting disorders, cancer or pain. Antibacterial activity has also been attributed to snake venoms and proteins isolated from snake venoms. This study provides information regarding the antibacterial activity of venoms obtained from various snake species from the Elapidae and Viperidae families. Minimum inhibitory and bactericidal concentrations of snake venoms were determined for three Gram-positive (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213, and Methicillin-resistant Staphylococcus aureus ATCC 43300) and three Gram-negative (Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883, and Pseudomonas aeruginosa ATCC 27853) pathogenic bacteria. The observed effects were correlated with the protein content of each venom, determined using SDS-PAGE analysis and comparison with data available in the literature. Our findings represent a starting point for the selection of snake venoms containing components with potential use as lead molecules in the development of new antibacterial agents, targeting multidrug resistant bacterial strains.

Two Epimeric Flavalignans from Trichilia catigua (Meliaceae) with Antimicrobial Activity

2002 ◽  
Vol 57 (5-6) ◽  
pp. 483-488 ◽  
Author(s):  
Moacir G. Pizzolatti ◽  
Andreia F. Venson ◽  
Artur Smânia Júnior ◽  
Elza de F. A. Smânia ◽  
Raimundo Braz-Filho
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Natural Products ◽  
Bacillus Cereus ◽  
Spectroscopic Data ◽  
2D Nmr ◽  
And Staphylococcus Aureus

A mixture of flavalignan cinchonains Ia and Ib was isolated from the bark of Trichilia catigua. The structures were established on the basis of spectroscopic data of the natural products and their methylated derivatives including 2D NMR experiments, and compared with data in the literature. These flavalignans exhibited antibacterial activity against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.

scholarly journals Combination Therapy of Sophoraflavanone B against MRSA:In VitroSynergy Testing

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Su-Hyun Mun ◽  
Ok-Hwa Kang ◽  
Dae-Ki Joung ◽  
Sung-Bae Kim ◽  
Yun-Soo Seo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Multidrug Resistant ◽  
Antibacterial Drug ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Kill Curve ◽  
Time Kill

Sophoraflavanone B (SPF-B), a known prenylated flavonoid, was isolated from the roots ofDesmodium caudatum. The aim of this study was to determine the antimicrobial synergism of SPF-B combined with antibiotics against methicillin-resistantStaphylococcus aureus(MRSA). MRSA, a multidrug-resistant pathogen, causes both hospital- and community-acquired infections worldwide. The antimicrobial activity of SPF-B was assessed by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The MIC of SPF-B for 7 strains ofS. aureusranges from 15.6 to 31.25 μg/mL determined. In the checkerboard method, the combinations of SPF-B with antibiotics had a synergistic effect; SPF-B markedly reduced the MICs of theβ-lactam antibiotics: ampicillin (AMP) and oxacillin (OXI); aminoglycosides gentamicin (GET); quinolones ciprofloxacin (CIP) and norfloxacin (NOR) against MRSA. The time-kill curves assay showed that a combined SPF-B and selected antibiotics treatment reduced the bacterial counts below the lowest detectable limit after 24 h. These data suggest that the antibacterial activity of SPF-B against MRSA can be effectively increased through its combination with three groups of antibiotics (β-lactams, aminoglycosides, and quinolones). Our research can be a valuable and significant source for the development of a new antibacterial drug with low MRSA resistance.

scholarly journals Antimicrobial activity of Rhipsalis baccifera and Drymoglossum piloselloides against Methicillin Resistant Staphylococcus Aureus and Drug Resistant Acinetobacter baumanii.

2021 ◽  
pp. 32-40
Author(s):  
S. D. Kugaperumal ◽  
R. D. De Silva ◽  
T. D. Karunarathne ◽  
C. P. Gunasekara ◽  
D. N. A. W. Samarakoon
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Chronic Wounds ◽  
Multidrug Resistant ◽  
Antibiotic Activity ◽  
Diffusion Method ◽  
Acinetobacter Baumanii ◽  
Methicillin Resistant

Methicillin Resistant Staphylococcus aureus (MRSA) and multidrug-resistant Acinetobacter baumanii are known to cause delayed healing of infections in both acute and chronic wounds. Plants are a natural source of novel antimicrobials and many new drugs are derived from plants, as plants contain phytochemicals that have antimicrobial activity. Sri Lanka is a tropical country with a wide variety of plant species, many of which were identified as possessing medicinal qualities and have been used by traditional medicinal practitioners in the treatment of various diseases and ailments. Dressings made of Rhipsalis baccifera and Drymoglossum piloselloides have been used to treat wounds by Sri Lankan traditional medicine practitioners. This study determined the antibacterial activity of aqueous and methanol extracts of R. baccifera and D. piloselloides against MRSA and Multidrug-resistant A. baumanii. Aqueous and methanolic extractions of both plants were done by maceration. Their antibacterial properties were checked against MRSA and A. baumanii by the well diffusion method. The effectiveness of the extract was further tested against factors like temperature and storage time. R. baccifera (aqueous extract) exhibited antimicrobial properties against MRSA but no activity against A. baumanii. The antibiotic activity against MRSA was increased after two months of storage at 4°C. D. piloselloides exhibited no antibiotic activity against both MRSA and A. baumanii. The methanolic extracts did not demonstrate any antibacterial activity.

scholarly journals Modulating antibacterial activity against multidrugresistant Escherichia coli and Staphylococcus aureus of the flavonoid pectolinarin isolated from Lantana camara leaves

2021 ◽  
Vol 10 (6) ◽  
pp. 217-220
Author(s):  
Maria Regivânia Xavier ◽  
Aluísio Marques da Fonseca ◽  
Beatriz Gonçalves Cruz ◽  
Antonia Mayara dos Santos Mendes ◽  
Larissa Santos Oliveira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Natural Compound ◽  
Multidrug Resistant ◽  
Antagonistic Effect ◽  
Antibacterial Drug ◽  
Bacterial Strains ◽  
Gram Positive ◽  
And Staphylococcus Aureus

The antibiotic potentiating activity against standard and multidrug-resistant Escherichia coli and Staphylococcus aureus bacterial strains of the natural compound 5”-O-α-L-raminopyranosyl-1’-β-D-glycopyranosyl-4’,6-dimethoxyflavone (pectolinarin) isolated from L. camara leaves was evaluated. Tests for antibacterial activity of the pure natural substance and analysis of the potentiation of antibacterial activity of pectolinarin associated with antibiotics were carried out against standard and multiresistant bacterial strains of Escherichia coli and Staphylococcus aureus by microdilution. Pectolinarin, when combined with the antibiotic gentamicin, showed synergism, potentiating growth inhibition against Gram-positive S. aureus strains. The pectolinarin flavonoid when combined with the gentamicin antibiotic potentiated its action Gram-positive S. aureus bacteria. Moreover, an antagonistic effect was observed when the pectolinarin was combined with the penicillin antibiotic against the multiresistant S. aureus 358 strain. This research suggests that pectolinarin is a compound with potential application as an antibacterial drug.

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