scholarly journals Identification of Substances Produced by Cercospora brachiata in Absence of Light and Evaluation of Antibacterial Activity

2021 ◽  
Vol 7 (9) ◽  
pp. 680
Author(s):  
John K. R. P. Felisbino ◽  
Bruno S. Vieira ◽  
Alberto de Oliveira ◽  
Neiliane A. da Silva ◽  
Carlos H. G. Martins ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Antibacterial Activity ◽  
Ethyl Acetate Extract ◽  
Phytopathogenic Fungus ◽  
Broth Microdilution ◽  
Actinomyces Naeslundii ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Almost All

Cercospora brachiata is a phytopathogenic fungus. To know more about the metabolites produced by this fungus, the objective of this work was to identify, isolate and characterize substances present in extracts of the growth broth and mycelium, using gas chromatography with mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was also objective to evaluate the antibacterial activity of the extracts. Among the compounds identified, fatty acids, esters, and steroids can be highlighted. The main compounds identified are 9-hexadecenoic, hexadecenoic, oleic, octadecanoic, lauric, myristic, palmitic, doceno-13-enoic, stearic, linoleic, and nonadecanoic acids present in almost all extracts. For the antibacterial activity, the broth microdilution method was used. The ethyl acetate extract of the mycelium presented inhibitory concentrations (MICs) against the bacterium Actinomyces naeslundii (100 μg mL−1) and Streptococcus sanguinis (200 μg mL−1). Finally, two steroids were isolated and identified in the hexane extract of mycelium: ergosta-6,22-dien-3β,5α,8α-triol and brassicasterol.

scholarly journals Antibacterial Triterpenoids from the Bark of Sonneratia alba (Lythraceae)

2015 ◽  
Vol 10 (2) ◽  
pp. 1934578X1501000
Author(s):  
Harizon ◽  
Betry Pujiastuti ◽  
Dikdik Kurnia ◽  
Dadan Sumiarsa ◽  
Yoshihito Shiono ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Mass Spectrometric ◽  
Broth Microdilution ◽  
Mass Spectrometric Data ◽  
Spectrometric Data ◽  
Gram Positive Bacteria ◽  
Microdilution Method ◽  
Sonneratia Alba ◽  
Broth Microdilution Method

The new lupane-type triterpenoid, 3β-hydroxy-lup-9(11), 12-diene, 28-oic acid (1), along with two known lupane-type triterpenoids, lupeol (2) and lupan-3p-ol (3), were isolated from the bark of Sonnetaria alba. The structure of the new compound was elucidated on the basis of spectroscopic and mass spectrometric data analysis. Using the broth microdilution method, all compounds exhibited antibacterial activity against the Gram-positive bacteria Staphylococcus aureus ATCC 6538 and Streptococcus mutans ATCC 25175, with minimum inhibitory concentrations ranging from 15-33 to 35-55 ng/mL, respectively.

scholarly journals Antibacterial Activity of Antibiotic-Impregnated Bone Cement Based Coatings Against Microorganisms with Different Antibiotic Resistance Levels

2018 ◽  
Vol 24 (4) ◽  
pp. 105-110
Author(s):  
D. V. Tapalski ◽  
P. A. Volotovski ◽  
A. I. Kozlova ◽  
A. Sitnik
Keyword(s):  
Antibacterial Activity ◽  
Bone Cement ◽  
Antibiotic Activity ◽  
Broth Microdilution ◽  
Antibiotic Resistant ◽  
Microdilution Method ◽  
Bactericidal Properties ◽  
Broth Microdilution Method ◽  
Marked Activity ◽  
Agar Method

Purpose — to evaluate the presence and duration of antibiotic activity of antibiotic-impregnated bone cement based coatings samples against antibiotic-sensitive and antibiotic-resistant microorganisms.Material and Methods. Bone cement based coatings impregnated with antibiotics (gentamycin, vancomycin, colistin, meropenem, fosfomycin) are formed on titanium (Ti) plates. A plate rinse was carried out; antibiotic concentrations in the rinsed solutions were estimated by a serial broth microdilution method. Antibacterial activity of the control and rinsed samples against the antibiotic-sensitive and multiple-antibiotic-resistant Staphylococcus aureus and Pseudomonas aeruginosa strains was estimated by a bilayer agar method.Results. The meropenem and fosfomycin concentrations in the rinsed solutions obtained at a one-fold (16 μg/ml for both antibiotics) and two-fold treatment (2 μg/ml for meropenem and 8 μg/ml for fosfomycin) were sufficient to suppress the growth of the control strains. One-fold rinse of samples with colistin eliminated their antibacterial activity completely. The marked activity of the samples with meropenem and fosfomycin persisted against the antibiotic-sensitive P. aeruginosa ATCC 27853 strain after 2 rinse cycles; single-rinsed samples with fosfomycin also maintained the activity against the extensively antibioticresistant P. aeruginosa BP-150 strain. Vancomycin-containing samples possessed the sufficient antibacterial activity against both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) S. aureus strains; two-fold rinse of the samples eliminated their bactericidal properties.Conclusion. Bone cement based coatings impregnated with fosfomycin and meropenem possess the most marked and long-lasting antibacterial activity, manifested mainly against the antibiotic-sensitive strains. 

scholarly journals A New Azafluorenone from the Roots of Polyalthia cerasoides and its Biological Activity

2010 ◽  
Vol 5 (12) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Kanchana Pumsalid ◽  
Haruthai Thaisuchat ◽  
Chatchanok Loetchutinat ◽  
Narong Nuntasaen ◽  
Puttinan Meepowpan ◽  
...  
Keyword(s):  
Ethyl Acetate Extract ◽  
Positive Control ◽  
Cytotoxic Activities ◽  
Strong Inhibition ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Antibiotic Drugs ◽  
Broth Microdilution Method ◽  
Mrp1 Protein ◽  
Mic Value

Chromatographic separation of the ethyl acetate extract of roots of Polyalthia cerasoides has led to the isolation of the new compound, 6,8-dihydroxy-7-methoxy-1-methyl-azafluorenone. This compound exhibited potent cytotoxic activities with IC50 values in the range of 2.64-3.58 μg.mL−1 for A549, GLC4 and GLC4/Adr cells, but was not recognized by ABCC1/MRP1 protein. The compound also showed very strong inhibition of M. tuberculosis using a broth microdilution method, with an MIC value of 0.78 μg.mL−1, which was equal to that of ofloxacin, one of the four antibiotic drugs used as a positive control.

scholarly journals In Vitro Activity of Auranofin in Combination With Aztreonam-Avibactam Against Metallo-β-lactamase (MBL)-Producing Enterobacterales

2021 ◽  
Vol 11 ◽  
Author(s):  
Wen Wang ◽  
Shifeng Huang ◽  
Chunhong Zou ◽  
Yanhui Ding ◽  
Huijuan Wang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Genetic Background ◽  
Sanger Sequencing ◽  
Resistant Mutant ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Mutant Strains

ObjectivesTo assess the efficacy of aztreonam-avibactam-auranofin (ATM-AVI-AUR) against a collection of 88 carbapenemase-producing Enterobacterales (CPE) clinical isolates and 6 in vitro selected ATM-AVI-resistant CPE with CMY-16 Tyr150Ser and Asn346His mutants or transformants.MethodsMICs of imipenem, ceftazidime-avibact8am (CAZ-AVI), ATM-AVI, CAZ-AVI-AUR and ATM-AVI-AUR were determined via the broth microdilution method. Genetic background and carbapenemase genes were determined by PCR and Sanger sequencing.ResultsAUR alone showed little antibacterial activity with AUR MICs were greater than 64 μg/mL for all the 88 clinical CPE isolates. The addition of AUR (16 μg/mL) resulted in an 3-folding dilutions MIC reduction of ATM-AVI MIC50 (0.5 to 0.0625 μg/mL) and a 2-folding dilutions MIC reduction of MIC90 (1 to 0.25 μg/mL) against all 88 clinical CPE isolates, respectively. Notably, the reduced ATM-AVI MIC values were mainly found in MBL-producers, and the MIC50 and MIC90 reduced by 2-folding dilutions (0.25 to 0.0625 μg/mL) and 3-folding dilutions (2 to 0.25 μg/mL) respectively by AUR among the 51 MBL-producers. By contrast, the addition of AUR did not showed significant effects on ATM-AVI MIC50 (0.0625 μg/mL) and MIC90 (0.125 μg/mL) among single KPC-producers. Interestingly, the addition of AUR restored the ATM-AVI susceptibility against the 6 in vitro selected ATM-AVI-resistant CMY-16 Tyr150Ser and Asn346His mutants or transfromants, with the MICs reduced from ≥32 μg/mL (32->256 μg/mL) to ≤8 μg/mL (0.0625-8 μg/mL).ConclusionsOur results demonstrated that AUR potentiated the activities of CAZ-AVI and ATM-AVI against MBL-producing isolates in vitro. Importantly, AUR restored the ATM-AVI activity against ATM-AVI resistant mutant strains. As a clinically approved drug, AUR might be repurposed in combination with ATM-AVI to treat infections caused by highly resistant MBL-producing Enterobacterales.

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.

Etomidate inhibits the growth of MRSA and exhibits synergism with oxacillin

2020 ◽  
Vol 15 (17) ◽  
pp. 1611-1619
Author(s):  
Lívia G do AV Sá ◽  
Cecília R da Silva ◽  
João B de A Neto ◽  
Thiago M Cândido ◽  
Leilson C de Oliveira ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Antimicrobial Activity ◽  
Cell Death ◽  
Antibacterial Activity ◽  
Antibacterial Effect ◽  
Broth Microdilution ◽  
Action Mechanism ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Mrsa Strains

Aim: The purpose of this study was to evaluate the antimicrobial activity of the anesthetic etomidate against strains of MRSA and biofilms. Materials & methods: The antibacterial effect of etomidate was assessed by the broth microdilution method. To investigate the probable action mechanism of the compound flow cytometry techniques were used. Results: MRSA strains showed MIC equal to 500 and 1000 μg/ml of etomidate. Four-fifths (80%) of the tested MRSA strains demonstrated synergistic effect with oxacillin. Etomidate also showed activity against MRSA biofilm at concentration of 250 μg/ml. Cytometric analysis revealed that the cells treated with etomidate leading to cell death, probably by apoptosis. Conclusion: Etomidate showed antibacterial activity against MRSA.

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 Cannabidiol (CBD) repurposing as antibacterial: promising therapy of CBD plus polymyxin B against superbugs

2021 ◽  
Author(s):  
Nathalia Abichabki ◽  
Luisa Vieira Zacharias ◽  
Natalia Columbaro Moreira ◽  
Fernando Bellissimo-Rodrigues ◽  
Fernanda de Lima Moreira ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
Public Health Problem ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Rescue Treatment ◽  
Broth Microdilution Method

Multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria are a major worldwide public health problem. In the last decades, resistance to last-resort antibiotics such as polymyxin B (PB) have been increasingly observed among these superbugs, compromising the effectiveness of antimicrobial therapy. The present study aimed (i) to assess the ultrapure Cannabidiol (CBD) antibacterial activity against a broad diversity of Gram-negative (GN) and Gram-positive (GP) bacteria (44 different species, 95 strains), comprising standard strains and clinical isolates, and (ii) to investigate the antibacterial activity of the combination CBD + PB against GN bacteria, including chromosomal- and plasmid-acquired PB-resistant and intrinsically PB-resistant GNB. We evaluated CBD in vitro antibacterial activity using the standard broth microdilution method, and the antibacterial activity of the combination CBD + PB was screened using the standard broth microdilution and confirmed by checkerboard assay. CBD exhibited antibacterial activity against different GP bacterial species, lipooligosaccharide (LOS)-expressing GN diplococcus (GND) (Neisseria gonorrhoeae, Neisseria meningitidis, and Moraxella catarrhalis), and Mycobacterium tuberculosis. The combination CBD + PB exhibited antibacterial activity against PB-resistant GNB (e.g., Klebsiella pneumoniae) as well as additive and/or synergistic effect against LOS-expressing GND. The antibacterial activity of the combination CBD + PB against Pseudomonas aeruginosa and plasmid-mediated colistin-resistant (MCR-1) E. coli strains could be only demonstrated in the presence of phenylalanine-arginine-beta-naphthylamide (PA-beta-N). In conclusion, our results show promising translational potential of the combination CBD + PB against MDR and XDR GNB, including PB-resistant K. pneumoniae, highlighting its potential as a rescue treatment for life-threatening infections caused by these superbugs.

scholarly journals Evaluation of the Antibacterial Activity and Efflux Pump Reversal of Thymol and Carvacrol against Staphylococcus aureus and Their Toxicity in Drosophila melanogaster

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2103 ◽  
Author(s):  
Zildene de Sousa Silveira ◽  
Nair Silva Macêdo ◽  
Joycy Francely Sampaio dos Santos ◽  
Thiago Sampaio de Freitas ◽  
Cristina Rodrigues dos Santos Barbosa ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Drosophila Melanogaster ◽  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Antibacterial Activities ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Efflux Pump Inhibition ◽  
Broth Microdilution Method

The antibacterial activity and efflux pump reversal of thymol and carvacrol were investigated against the Staphylococcus aureus IS-58 strain in this study, as well as their toxicity against Drosophila melanogaster. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method, while efflux pump inhibition was assessed by reduction of the antibiotic and ethidium bromide (EtBr) MICs. D. melanogaster toxicity was tested using the fumigation method. Both thymol and carvacrol presented antibacterial activities with MICs of 72 and 256 µg/mL, respectively. The association between thymol and tetracycline demonstrated synergism, while the association between carvacrol and tetracycline presented antagonism. The compound and EtBr combinations did not differ from controls. Thymol and carvacrol toxicity against D. melanogaster were evidenced with EC50 values of 17.96 and 16.97 µg/mL, respectively, with 48 h of exposure. In conclusion, the compounds presented promising antibacterial activity against the tested strain, although no efficacy was observed in terms of efflux pump inhibition.

Sign in / Sign up

Export Citation Format

Share Document