scholarly journals Antimicrobial Activity of Methanolic Extracts of Sambucus ebulus and Urtica dioica Against Clinical Isolates of Methicillin Resistant Staphylococcus aureus

2014 ◽  
Vol 11 (5) ◽  
pp. 38 ◽  
Author(s):  
Ali Salehzadeh ◽  
L Asadpour ◽  
AS Naeemi ◽  
E Houshmand
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Urtica Dioica ◽  
Clinical Isolates ◽  
Methicillin Resistant ◽  
Methanolic Extracts ◽  
Sambucus Ebulus

scholarly journals Fluoroquinolone Metalloantibiotics: A Promising Approach against Methicillin-Resistant Staphylococcus aureus

2020 ◽  
Vol 17 (9) ◽  
pp. 3127 ◽  
Author(s):  
Mariana Ferreira ◽  
Lucinda J. Bessa ◽  
Carla F. Sousa ◽  
Peter Eaton ◽  
Dafne Bongiorno ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Mechanism Of Action ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Synergistic Activity ◽  
Divalent Metal Ions ◽  
Methicillin Resistant ◽  
Force Microscopy

Fluoroquinolones (FQs) are antibiotics commonly used in clinical practice, although nowadays they are becoming ineffective due to the emergence of several mechanisms of resistance in most bacteria. The complexation of FQs with divalent metal ions and phenanthroline (phen) is a possible approach to circumvent antimicrobial resistance, since it forms very stable complexes known as metalloantibiotics. This work is aimed at determining the antimicrobial activity of metalloantibiotics of Cu(II)FQphen against a panel of multidrug-resistant (MDR) clinical isolates and to clarify their mechanism of action. Minimum inhibitory concentrations (MICs) were determined against MDR isolates of Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA). Metalloantibiotics showed improved antimicrobial activity against several clinical isolates, especially MRSA. Synergistic activity was evaluated in combination with ciprofloxacin and ampicillin by the disk diffusion and checkerboard methods. Synergistic and additive effects were shown against MRSA isolates. The mechanism of action was studied though enzymatic assays and atomic force microscopy (AFM) experiments. The results indicate a similar mechanism of action for FQs and metalloantibiotics. In summary, metalloantibiotics seem to be an effective alternative to pure FQs against MRSA. The results obtained in this work open the way to the screening of metalloantibiotics against other Gram-positive bacteria.

Antimicrobial Activity of Different Antimicrobial Peptides (AMPs) Against Clinical Methicillin-resistant Staphylococcus aureus (MRSA)

2019 ◽  
Vol 18 (24) ◽  
pp. 2116-2126 ◽  
Author(s):  
Eleonora Ciandrini ◽  
Gianluca Morroni ◽  
Daniela Arzeni ◽  
Wojciech Kamysz ◽  
Damian Neubauer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Growth Inhibition ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clinical Isolates ◽  
Methicillin Resistant ◽  
Time Kill ◽  
Citropin 1.1 ◽  
Temporin A

Background: Antimicrobial research is being focused to look for more effective therapeutics against antibiotic-resistant infections caused by methicillin-resistant Staphylococcus aureus (MRSA). In this direction, antimicrobial peptides (AMP) appear as promising tool. Objectives: This study evaluated the antimicrobial activity of different AMPs (Citropin 1.1, Temporin A, Pexiganan, CA(1–7)M(2–9)NH2, Pal-KGK-NH2, Pal-KKKK-NH2, LL-37) against human MRSA clinical isolates. Methods: The Minimum Inhibitory Concentration (MIC) was assessed for each AMP; then, the most active ones (Citropin 1.1, Temporin A, CA(1–7)M(2–9)NH2 and Pal-KGK-NH2) were tested against selected MRSA strains by time-kill studies. Results: The lowest MIC value was observed for Pal-KGK-NH2 (1 µg/ml), followed by Temporin A (4- 16 µg/ml), CA(1–7)M(2–9)NH2 (8-16 µg/ml) and Citropin 1.1 (16-64 µg/ml), while higher MICs were evidenced for LL-37, Pexiganan and Pal-KKKK-NH2 (> 128 µg/ml). In time-kill experiments, Citropin 1.1 and CA(1-7)M(2-9)NH2 showed a relatively high percentage of growth inhibition (>30 %) for all the tested MRSA clinical isolates, with a dose-dependent activity resulting in the highest percentage of bacterial growth inhibition (89.39%) at 2MIC concentration. Conclusion: Overall, our data demonstrated the potential of some AMPs against MRSA isolates, such as Citropin 1.1 and CA(1-7)M(2-9)NH2, that represents a promising area of development for different clinical applications.

scholarly journals Bioactivities of Chuquiraga Straminea Sandwith

2011 ◽  
Vol 6 (7) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
María Elena Mendiondo ◽  
Berta E. Juárez ◽  
Catiana Zampini ◽  
María Inés Isla ◽  
Roxana Ordoñez
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antioxidant Activity ◽  
Nosocomial Infection ◽  
Total Phenolics ◽  
Methicillin Resistant ◽  
Positive Correlation ◽  
Methanolic Extracts ◽  
Antioxidant And Antimicrobial Activity

Methanolic extracts of Chuquiraga straminea Sandwith, subfamily Barnadesioideae (Asteraceae) showed the presence of quercetin-3- O-glucoside, quercetin-3- O-rutinoside, kaempferol, kaempferol-3- O-glucoside and kaempferol-3- O-rutinoside. Antioxidant and antimicrobial activity was determined. The total extracts showed antioxidant activity by DPPH and ABTS method (SC50 14.5 to 34.9 μg/mL). A significantly positive correlation was observed between the antioxidant activity and the total phenolics (R2>0.93). The extracts were active against ten methicillin resistant and sensitive Staphylococcus aureus strains isolated from nosocomial infection (MIC values between 200 to 800 μg/mL). These preliminary studies are highly interesting as they open new ways for further applications in the treatment of infections by methicillin resistant S. aureus.

scholarly journals Antimicrobial Metabolites against Methicillin-Resistant Staphylococcus aureus from the Endophytic Fungus Neofusicoccum australe

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1094
Author(s):  
Melissa M. Cadelis ◽  
Soeren Geese ◽  
Benedict B. Uy ◽  
Daniel R. Mulholland ◽  
Shara J. van de Pas ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Natural Products ◽  
Structure Elucidation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Spectroscopic Methods ◽  
Methicillin Resistant ◽  
Bioassay Guided Fractionation ◽  
Antimicrobial Metabolites

Antimicrobial bioassay-guided fractionation of the endophytic fungi Neofusicoccum australe led to the isolation of a new unsymmetrical naphthoquinone dimer, neofusnaphthoquinone B (1), along with four known natural products (2–5). Structure elucidation was conducted by nuclear magnetic resonance (NMR) spectroscopic methods, and the antimicrobial activity of all the natural products was investigated, revealing 1 to be moderately active towards methicillin-resistant Staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 16 µg/mL.

Sign in / Sign up

Export Citation Format

Share Document