In Vitro Synergy Between Some Cationic Amphipathic Cyclooctapeptides and Antibiotics

2015 ◽  
Vol 68 (2) ◽  
pp. 218 ◽  
Author(s):  
Maria Ngu-Schwemlein ◽  
Jenna Dumond ◽  
Lisa Rudd ◽  
Jean-Herbert Rigaud
Keyword(s):  
Synergistic Effects ◽  
Antimicrobial Activities ◽  
The Other ◽  
Helical Peptides ◽  
Inhibition Concentration ◽  
Titration Assay ◽  
Fast Acting ◽  
Checkerboard Titration ◽  
And Staphylococcus Aureus

The antimicrobial activities of some cationic amphipathic cyclooctapeptides in combination with select antibiotics are investigated. Accordingly, cyclooctapeptides (CPs 1–11) derived from the sequence cyclo[Leu-d-Leu-Leu-d-Leu-Lys-d-Lys-Lys-d-Lys] were tested against Escherichia coli and Staphylococcus aureus. Synergistic effects were evaluated in combination with tetracycline, chloramphenicol, oflaxacin, rifampicin, colistin, clindamycin, and vancomycin by the checkerboard titration assay. The results show that these cyclooctapeptides are fast acting bactericidals and are comparable to the related α-helical peptides in their activities. Significantly, some of these cyclooctapeptides exert selective synergistic effects in combination with the bacteriostatic tetracycline against S. aureus; a greater than 4-fold decrease in the minimum inhibition concentration was observed. Their synergism with the other evaluated antibiotics was generally partial or additive. Cationic amphipathic cyclooctapeptides in combination with some antibiotics could offer a possible solution to the increasing antimicrobial resistance predicament.

scholarly journals The Synergistic Effect of Nicotine and Staphylococcus aureus on Peri-Implant Infections

2021 ◽  
Vol 9 ◽  
Author(s):  
Yao Hu ◽  
Wen Zhou ◽  
Chengguang Zhu ◽  
Yujie Zhou ◽  
Qiang Guo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Synergistic Effects ◽  
Protein A ◽  
Treated Group ◽  
Combination Group ◽  
Staphylococcal Protein A ◽  
Receptor Activator ◽  
And Staphylococcus Aureus

Smoking is considered a key risk factor for implant survival; however, how it interacts with the pathogens in peri-implant infections is not clear. Here, we identified that nicotine, the key component of cigarette smoking, can interact with Staphylococcus aureus and synergistically induce peri-implant infections in a rat osteolysis model. The nicotine–S. aureus combination group increased the gross bone pathology, osteolysis, periosteal reactions, and bone resorption compared to the nicotine or S. aureus single treated group (p < 0.05). Nicotine did not promote the proliferation of S. aureus both in vitro and in vivo, but it can significantly upregulate the expression of staphylococcal protein A (SpA), a key virulence factor of S. aureus. The nicotine–S. aureus combination also synergistically activated the expression of RANKL (receptor activator of nuclear factor-kappa B ligand, p < 0.05) to promote the development of peri-implant infections. The synergistic effects between nicotine and S. aureus infection can be a new target to reduce the peri-implant infections.

scholarly journals Antimicrobial Activity of Artemisinin and Precursor Derived fromIn VitroPlantlets ofArtemisia annuaL.

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Suganthi Appalasamy ◽  
Kiah Yann Lo ◽  
Song Jin Ch'ng ◽  
Ku Nornadia ◽  
Ahmad Sofiman Othman ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Artemisia Annua ◽  
Antimicrobial Property ◽  
Bioactive Compound ◽  
Antimicrobial Activities ◽  
Hot Climate ◽  
Inhibition Concentration ◽  
Brine Shrimps ◽  
Layer Chromatography

Artemisia annuaL., a medicinal herb, produces secondary metabolites with antimicrobial property. In Malaysia due to the tropical hot climate,A. annuacould not be planted for production of artemisinin, the main bioactive compound. In this study, the leaves of threein vitro A. annuaL. clones were, extracted and two bioactive compounds, artemisinin and a precursor, were isolated by thin layer chromatography. These compounds were found to be effective in inhibiting the growth of Gram-positive and Gram-negative bacteria but notCandida albicans. Their antimicrobial activity was similar to that of antibactericidal antibiotic streptomycin. They were found to inhibit the growth of the tested microbes at the minimum inhibition concentration of 0.09 mg/mL, and toxicity test using brine shrimp showed that even the low concentration of 0.09 mg/mL was very lethal towards the brine shrimps with 100% mortality rate. This study hence indicated thatin vitrocultured plantlets ofA. annuacan be used as the alternative method for production of artemisinin and its precursor with antimicrobial activities.

scholarly journals Green propolis as an adjuvant against nontuberculous mycobacteria

Rodriguésia ◽  
2021 ◽  
Vol 72 ◽  
Author(s):  
Suzane Olachea Allend ◽  
Lisiane Volcão ◽  
Carolina da Silva Canielles ◽  
Israel Barbosa ◽  
Dara Biatobock ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Nontuberculous Mycobacteria ◽  
Ethanol Extract ◽  
Antimycobacterial Activity ◽  
Antimicrobial Activities ◽  
Resistance Mechanisms ◽  
The Other ◽  
New Drugs ◽  
Mycobacterium Chelonae

Abstract Natural products have been touted as important tools because of their vast potential for the development of compounds with antimicrobial activity and the possible inhibitory activity and/or adjuvant resistance mechanisms. Propolis has been empirically used for many years for the treatment of diseases, mainly due to its antioxidant, anti inflammatory and antimicrobial activities. This study aimed to evaluate the in vitro antimycobacterial activity of the ethanol extract of propolis alone and in combination with rifampicin (RIF), amikacin (AMI) and ciprofloxacin (CIP). The ethanol extract of propolis showed antibacterial activity against Mycobacterium chelonae and M. kansasii and was capable of increasing AMI, RIF and CIP activity in combination. On the other hand, compared to M. absecessus, M. fortuitum and M. avium, the extract was not active at 200 µg/mL and did not show pronounced adjuvant capacity when evaluated in association with the drugs. Based on these results, it can be concluded that the ethanol extract of propolis could be an alternative in the development of new drugs and can be used complementary with the current mycobacteriosis treatment.

scholarly journals Chitosan-Stabilized Ag Nanoparticles with Superior Biocompatibility and Their Synergistic Antibacterial Effect in Mixtures with Essential Oils

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 826 ◽  
Author(s):  
Ludmila Cinteza ◽  
Cristina Scomoroscenco ◽  
Sorina Voicu ◽  
Cristina Nistor ◽  
Sabina Nitu ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Essential Oils ◽  
Metallic Nanoparticles ◽  
Synergistic Effects ◽  
Medical Application ◽  
Colloidal Dispersion ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Promising Alternative

Silver nanoparticles (AgNPs) are considered a promising alternative to the use of antibiotics in fighting multidrug-resistant pathogens. However, their use in medical application is hindered by the public concern regarding the toxicity of metallic nanoparticles. In this study, rationally designed AgNP were produced, in order to balance the antibacterial activity and toxicity. A facile, environmentally friendly synthesis was used for the electrochemical fabrication of AgNPs. Chitosan was employed as the capping agent, both for the stabilization and to improve the biocompatibility. Size, morphology, composition, capping layer, and stability of the synthesized nanoparticles were characterized. The in vitro biocompatibility and antimicrobial activities of AgNPs against common Gram-negative and Gram-positive bacteria were evaluated. The results revealed that chitosan-stabilized AgNPs were nontoxic to normal fibroblasts, even at high concentrations, compared to bare nanoparticles, while significant antibacterial activity was recorded. The silver colloidal dispersion was further mixed with essential oils (EO) to increase the biological activity. Synergistic effects at some AgNP–EO ratios were observed, as demonstrated by the fractionary inhibitory concentration values. Our results reveal that the synergistic action of both polymer-stabilized AgNPs and essential oils could provide a significant efficiency against a large variety of microorganisms, with minimal side effects.

scholarly journals Antimicrobial activity of essential oils extracted from leaves of native Moroccan plants against clinical bacterial isolates

10.3823/819 ◽  
2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Fatima El Malki ◽  
Kamal Eddaraji ◽  
Rajae Alloudane ◽  
Hassane Greche ◽  
Haiat Essalmani ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Essential Oils ◽  
Bactericidal Effect ◽  
Antimicrobial Activities ◽  
Acinetobacter Baumanii ◽  
And Staphylococcus Aureus

Introduction: Medicinal plants are plentiful of bioactive molecules effective against multi-resistance bacteria. The aims of this study were to assess the in vitro antimicrobial activities of essential oils extracted from three Moroccan aromatic plants. Methodology: Analysis of essential oils of Origanum compactum, Rosmarinus officinalis and Pelargonium asperum, collected from different localities in Morocco, were performed using a GC-MS spectrophotometry. Antibacterial activity was evaluated in vitro for five clinical multi-resistant isolates. Results: Origanum showed strong antibacterial activity against tested strains except Pseudomonas aeruginosa while Rosmarinum showed a bactericidal effect against Acinetobacter baumanii, Escherichia coli and Staphylococcus aureus. Pelargonium presented only slight growth inhibition of Staphylococcus aureus on solid medium, but provided bactericidal effect against Acinetobacter baumanii and Staphylococcus aureus. Interestingly, fractions F7 and F8 of Pelargonium which represented only 0.3% and 0.1% of the total mass were found bactericidal respectively against Klebsiella pneumoniae and Pseudomonas aeruginosa. Conclusions: Ours results showed that the antimicrobial activities were variables depending on the chemical composition of essential oils, the fraction used and the microorganism tested.Essential oils fractionation allows detection of bioactive substances, especially those owning antimicrobial activity, present in small quantities.

scholarly journals Comparative In Vitro Activities of First and Second-Generation Ceragenins Alone and in Combination with Antibiotics Against Multidrug-Resistant Klebsiella pneumoniae Strains

Antibiotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 130 ◽  
Author(s):  
Berna Ozbek-Celik ◽  
Damla Damar-Celik ◽  
Emel Mataraci-Kara ◽  
Cagla Bozkurt-Guzel ◽  
Paul B. Savage
Keyword(s):  
Klebsiella Pneumoniae ◽  
Second Generation ◽  
Synergistic Effects ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Resistant Bacteria ◽  
Microdilution Method ◽  
Kill Curve ◽  
Time Kill

Objectives: The ceragenins, or CSAs, were designed to mimic the activities of antimicrobial peptides and represent a new class of antimicrobial agent. The aim of this study was to comparatively investigate the antimicrobial activities of first/second generation ceragenins and various antibiotics against multidrug-resistant (MDR) Klebsiella pneumoniae, including colistin-resistant bacteria. Also, the synergistic effects of two ceragenins with colistin or meropenem were investigated with six K. pneumoniae strains presenting different resistant patterns. Methods: Minimal inhibition concentrations (MICs) were determined by the microdilution method according to the CLSI. Antibiotic combination studies were evaluated by the time–kill curve method. Results: MIC50 and MIC90 values of tested ceragenins ranged from 8 to 32 mg/L and 16 to 128 mg/L. Overall, among the ceragenins tested, CSA-131 showed the lowest MIC50 and MIC90 values against all microorganisms. The MICs of the ceragenins were similar or better than tested antibiotics, except for colistin. Synergistic activities of CSA-131 in combination with colistin was found for strains both at 1× MIC and 4× MIC. No antagonism was observed with any combination. Conclusions: First-generation ceragenins CSA-13 and CSA-44 and second-generation ceragenins CSA-131, CSA-138 and CSA-142 have significant antimicrobial effects on MDR K. pneumoniae. Mechanisms allowing resistance to clinical comparator antibiotics like colistin did not impact the activity of ceragenins. These results suggest that ceragenins may play a role in treating infections that are resistant to known antibiotics.

scholarly journals Bifidobacterium Bifidum Isolated From Chicken Intestine Along With Polyvinylpyrrolidone Showed Synergistic Effects on Reduction of AFB1 Contamination- in Vitro Study

2021 ◽  
Author(s):  
sorour Aalipanah ◽  
Mohhammad Reza Fazeli ◽  
Abbas Akhavan Sepahi ◽  
Farid Shariatmadari
Keyword(s):  
Synergistic Effects ◽  
Food Contamination ◽  
In Vitro Study ◽  
Antimicrobial Activities ◽  
Bifidobacterium Bifidum ◽  
E Coli ◽  
Chicken Intestine ◽  
Antibiotic Susceptibility Test ◽  
Probiotic Activity

Abstract Background: Food contamination with aflatoxin is one of the most important concerns of health professionals. One of the best ways to reduce aflatoxin content in food is to use probiotics. Therefore, this study was performed to isolate Bifidobacterium from the chick intestine and its probiotic activities and also its application with Polyvinylpyrrolidone (PVP) to reduce aflatoxin B1 (AFB1) toxin in the medium were investigated.Results: Samples were isolated from the chicken intestine. Biochemical and molecular evaluations indicated isolation of Bifidobacterium bifidum strain from chicken intestine. To measure probiotic activities, pH, bile, and salt tolerance tests were used. The selected B. bifidum had good probiotic activity. Then, the antimicrobial activity of isolate against gastrointestinal pathogens and the antibiotic susceptibility test were done. The selected strain showed antimicrobial activities on S. enterica, E. coli, and P. vulgaricus and was found to be resistant against Amikacin, Ampicillin, Erythromycin, and Ceftazidine antibiotics. Then, the effect of selected isolate and PVP on reducing AFB1 in the medium was studied using ELISA and HPLC. The selected strain showed the ability to reduce the concentration of AFB1 in the medium (50% reduction) and when used in combination with PVP showed the synergistic effects in reducing the concentration of AFB1 from the medium (up to 90%).Conclusion: In conclusion, it was found that selected B. bifidum strain together with PVP could have synergistic effects in reducing AFB1 toxin in medium up to 90%.

scholarly journals Synthesis and Antimicrobial Activity Evaluation of Some Novel Heterocycles Derived from Chromonyl-2(3H)-furanone

2018 ◽  
Vol 42 (6) ◽  
pp. 332-336 ◽  
Author(s):  
Sayed K. Ramadan ◽  
Eman A. E. El-Helw
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Spectral Data ◽  
Aspergillus Flavus ◽  
Antimicrobial Activities ◽  
Nitrogen Nucleophiles ◽  
And Staphylococcus Aureus

6-Chloro-3-((2-oxo-5-phenylfuran-3(2 H)-ylidene)methyl)-4 H-chromen-4-one was utilised for the construction of N-heterocycles. The proclivity of this furanone towards some nitrogen nucleophiles, i.e. glycine, thiosemicarbazide, thiocarbohydrazide, phenylhydrazine and o-phenylenediamine, was studied. The structures of all products obtained were established on the basis of their analytical and spectral data. All synthesised compounds were screened for their in vitro antibacterial (two strains of bacteria; Escherichia coli and Staphylococcus aureus) and antifungal (two fungus strains; Aspergillus flavus and Candida albicans) activities. Some products exhibited promising antimicrobial activities.

scholarly journals Synergistic Antibacterial Activity of Cassia auriculata L. Flowers and Ofloxacin

2012 ◽  
Vol 28 (2) ◽  
pp. 92-94 ◽  
Author(s):  
Varadharajan Subhadra Devi ◽  
Dr Ushanandhini ◽  
Kuppusamy AsokKumar ◽  
Muthuswamy UmaMaheswari ◽  
Andichettiar Thirumalaisamy Sivashanmugham ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Synergistic Effects ◽  
Ethanolic Extract ◽  
Cost Effective ◽  
Synergistic Activity ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Cassia Auriculata ◽  
Inhibition Concentration

A cost effective antimicrobial agent for multi drug resistant organisms, based on the synergistic activity of ofloxacin with ethanolic extract of flowers of Cassia auriculata was determined. The Minimum Inhibition Concentration (MIC) of ethanolic extract using 3 different Gram-positive bacteria, such as Staphylococcus aureus NCIM 2127 and Bacillus subtilis NCIM 2010, and Gram-negative bacteria Escherichia coli NCIM 2118 was found to be around 1024 to 2048 mg/ml. The synergistic activity varied using checkerboard synergy technique. The results of the conducted experiments showed in vitro interactions between antimicrobial agents and plant extract were additive against the strains tested, it also showed synergistic effects between combination of antibiotics and plant extracts with significant reduction in the MICs of the test antibiotics against these strains. It showed maximum synergistic activity against Gram-negative species. The higher synergistic rate was attained against E. coli NCIM 2118, and lowest synergistic shows against S. aureus NCIM 2127. DOI: http://dx.doi.org/10.3329/bjm.v28i2.11824 Bangladesh J Microbiol, Volume 28, Number 2, December 2011, pp 92-94  

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