scholarly journals Synthesis and Evaluation of 3-Halobenzo[b]thiophenes as Potential Antibacterial and Antifungal Agents

2021 ◽  
Vol 15 (1) ◽  
pp. 39
Author(s):  
Prerna J. Masih ◽  
Tanay Kesharwani ◽  
Elivet Rodriguez ◽  
Mia A. Vertudez ◽  
Mina L. Motakhaveri ◽  
...  
Keyword(s):  
Antimicrobial Activities ◽  
Environmentally Benign ◽  
Health Concern ◽  
Gram Positive Bacteria ◽  
Sodium Halides ◽  
Thiophene Derivatives ◽  
Kill Curve ◽  
High Yields ◽  
Antibacterial And Antifungal ◽  
Time Kill

The global health concern of antimicrobial resistance has harnessed research interest to find new classes of antibiotics to combat disease-causing pathogens. In our studies, 3-halobenzo[b]thiophene derivatives were synthesized and tested for their antimicrobial activities using the broth microdilution susceptibility method. The 3-halo substituted benzo[b]thiophenes were synthesized starting from 2-alkynyl thioanisoles using a convenient electrophilic cyclization methodology that utilizes sodium halides as the source of electrophilic halogens when reacted along with copper(II) sulfate. This environmentally benign methodology is facile, uses ethanol as the solvent, and results in 3-halo substituted benzo[b]thiophene structures in very high yields. The cyclohexanol-substituted 3-chloro and 3-bromobenzo[b]thiophenes resulted in a low MIC of 16 µg/mL against Gram-positive bacteria and yeast. Additionally, in silico absorption, distribution, metabolism, and excretion (ADME) properties of the compounds were determined. The compounds with the lowest MIC values showed excellent drug-like properties with no violations to Lipinski, Veber, and Muegge filters. The time-kill curve was obtained for cyclohexanol-substituted 3-chlorobenzo[b]thiophenes against Staphylococcus aureus, which showed fast bactericidal activity at MIC.

scholarly journals In Vitro Antimicrobial Activities of Novel Anilinouracils Which Selectively Inhibit DNA Polymerase III of Gram-Positive Bacteria

2000 ◽  
Vol 44 (8) ◽  
pp. 2217-2221 ◽  
Author(s):  
Jennifer S. Daly ◽  
Theodore J. Giehl ◽  
Neal C. Brown ◽  
Chengxin Zhi ◽  
George E. Wright ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Antimicrobial Activities ◽  
Dna Polymerase Iii ◽  
Coagulase Negative Staphylococci ◽  
Gram Positive ◽  
New Agents ◽  
Gram Positive Bacteria ◽  
Polymerase Iii ◽  
Time Kill

ABSTRACT The 6-anilinouracils are novel dGTP analogs that selectively inhibit the replication-specific DNA polymerase III of gram-positive eubacteria. Two specific derivatives, IMAU (6-[3′-iodo-4′-methylanilino]uracil) and EMAU (6-[3′-ethyl-4′-methylanilino]uracil), were substituted with either a hydroxybutyl (HB) or a methoxybutyl (MB) group at their N3 positions to produce four agents: HB-EMAU, MB-EMAU, HB-IMAU, and MB-IMAU. These four new agents inhibited Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus faecalis, and Enterococcus faecium. Time-kill assays and broth dilution testing confirmed bactericidal activity. These anilinouracil derivatives represent a novel class of antimicrobials with promising activities against gram-positive bacteria that are resistant to currently available agents, validating replication-specific DNA polymerase III as a new target for antimicrobial development.

scholarly journals Antimicrobial activities of widely consumed herbal tea’s alone or in combination with antibiotics: An in vitro study

2016 ◽  
Author(s):  
Mayram Tuysuz ◽  
Sibel Dosler ◽  
Ayse Seher Birteksoz Tan ◽  
Gulten Otuk
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
In Vitro Study ◽  
Antimicrobial Activities ◽  
Combination Studies ◽  
Kill Curve ◽  
Time Kill ◽  
Microbroth Dilution ◽  
Antagonistic Interactions

Background: Because of increasing antibiotic resistance, herbal teas are the most popular natural alternatives, which are gaining even more importance. We examined the antimicrobial activities of 31 herbal teas both alone and in combination with antibiotics or antifungals against the standard and clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, methicillin susceptible/resistant Staphylococcus aureus and Candida albicans. Methods: The antimicrobial activities of the teas were determined by using the disk diffusion and microbroth dilution methods, and the combination studies were examined by using the microbroth checkerboard and time killing curve methods. Results: Rosehip, rosehip bag, pomegranate blossom, thyme, wormwood, mint, echinacea bag, cinnamon, black, and green teas were active against most of the studied microorganisms. In the combination studies, we characterized all the expected effects (synergistic, additive, and antagonistic) between the teas and the antimicrobials. While synergy was observed more frequently between ampicillin, ampicillin-sulbactam, or nystatine, and the various tea combinations, most of the effects between the ciprofloxacin, erythromycin, cefuroxime, or amikacin and various tea combinations, particularly rosehip, rosehip bag, and pomegranate blossom teas, were antagonistic. The results of the time kill curve analyses showed that none of the herbal teas were bactericidal in their usage concentrations; however, in combination they were. Discussion: Some herbal teas, particularly rosehip and pomegranate blossom should be avoided because of antagonistic interactions during the course of antibiotic treatment or should be consumed alone.

scholarly journals Synthesis and Antimicrobial Activities of N-(Heteroaryl-substituted)-p-toluenesulphonamides

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Ozoh Chinwe Francisca ◽  
Okoro Uchechukwu Chris ◽  
Ugwu David Izuchukwu
Keyword(s):  
Biological Activities ◽  
Condensation Reaction ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Gram Positive Bacteria ◽  
New Class ◽  
Bacteria And Fungi ◽  
Antibacterial And Antifungal ◽  
C Nmr

A new class of N-(heteroaryl-substituted)-p-toluenesulphonamides has been synthesized exhibiting antibacterial and antifungal properties. The condensation reaction of p-toluenesulphonyl chloride 1 with appropriate substituted amino pyridines 2a–g in acetone furnished N-(heteroaryl-substituted)-p-toluenesulphonamides 3a–g. These derivatives were characterized by IR, 1H-, and 13C-NMR spectroscopy and were screened in vitro against gram-positive bacteria, gram-negative bacteria, and fungi organisms using agar-diffusion method. Results indicated improved biological activities over reference drugs such as Tetracycline (TCN) and Fluconazole (FLU).

scholarly journals Antimicrobial activity of DU-6681a, a parent compound of novel oral carbapenem DZ-2640.

1997 ◽  
Vol 41 (6) ◽  
pp. 1260-1268 ◽  
Author(s):  
M Tanaka ◽  
M Hohmura ◽  
T Nishi ◽  
K Sato ◽  
I Hayakawa
Keyword(s):  
Parent Compound ◽  
Inoculum Size ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Alkaline Conditions ◽  
In Vitro Antibacterial Activity ◽  
Acidic Conditions ◽  
Kill Curve ◽  
Time Kill

The in vitro antibacterial activity of DU-6681a, a parent compound of DZ-2640, against gram-positive and -negative bacteria was compared with those of penems and cephalosporins currently available. MICs at which 90% of the isolates are inhibited (MIC90s) of the compound for clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus and Staphylococcus epidermidis, including methicillin-susceptible and -resistant strains, were 0.10, 25, and 12.5 microg/ml, respectively. DU-6681a inhibited the growth of all strains of Streptococcus pyogenes and of penicillin-susceptible and -insusceptible Streptococcus pneumoniae at 0.006, 0.025, and 0.20 microg/ml, respectively, and MIC90s of the compound were 6.25 and >100 microg/ml for Enterococcus faecalis and Enterococcus faecium, respectively. MIC90s of DU-6681a were 0.20, 0.10, and 0.025 microg/ml for Haemophilus influenzae, Moraxella catarrhalis, and Neisseria gonorrhoeae, respectively. For Pseudomonas aeruginosa, the MIC50 and MIC90 of DU-6681a were 25 and 50 microg/ml, respectively. DU-6681a activity was not affected by different media, varied inoculum size (10(4) to 10(7) CFU), or the addition of human serum but was decreased under acidic conditions against gram-negative bacteria, under alkaline conditions against gram-positive bacteria, and in human urine, as was the activity of the other antibiotics tested. The frequency of spontaneous resistance to DU-6681a was less than or equal to those of the reference compounds. Time-kill curve studies demonstrated the bactericidal action of DU-6681a against S. aureus, S. pneumoniae, Escherichia coli, and H. influenzae.

scholarly journals Antibacterial Activity of Ethanolic Extract ofSyzygium polyanthumL.(Salam)Leaves against Foodborne Pathogens and Application as Food Sanitizer

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Suzita Ramli ◽  
Son Radu ◽  
Khozirah Shaari ◽  
Yaya Rukayadi
Keyword(s):  
Antibacterial Activity ◽  
Foodborne Pathogens ◽  
Ethanolic Extract ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Disk Diffusion Test ◽  
E Coli ◽  
Natural Microflora ◽  
Kill Curve ◽  
Time Kill

The aim of this study was to determine antibacterial activity ofS. polyanthumL.(salam)leaves extract foodborne pathogens. All the foodborne pathogens were inhibited after treating with extract in disk diffusion test with range6.67±0.58–9.67±0.58 mm of inhibition zone. The range of MIC values was between 0.63 and 1.25 mg/mL whereas MBC values were in the range 0.63 mg/mL to 2.50 mg/mL. In time-kill curve,L. monocytogenesandP. aeruginosawere found completely killed after exposing to extract in 1 h incubation at 4x MIC. Four hours had been taken to completely killE. coli,S. aureus,V. cholerae,andV. parahaemolyticusat 4x MIC. However, the population ofK. pneumoniae,P. mirabilis,andS. typhimuriumonly reduced to 3 log CFU/mL. The treated cell showed cell rupture and leakage of the cell cytoplasm in SEM observation. The significant reduction of natural microflora in grapes fruit was started at 0.50% of extract at 5 min and this concentration also was parallel to sensory attributes acceptability where application of extract was accepted by the panellists until 5%. In conclusion,S. polyanthumextract exhibits antimicrobial activities and thus might be developed as natural sanitizer for washing raw food materials.

scholarly journals Antimicrobial Evaluation of Leaf and Stem Extract of Cordia macleodii

2014 ◽  
Vol 1 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Deepkumar Joshi ◽  
Rinku Patel ◽  
Nupur Patel ◽  
Devendra Patel ◽  
Chintan Pandya
Keyword(s):  
Antimicrobial Activities ◽  
Maximum Amount ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Antifungal Potential ◽  
Stem Extract ◽  
Antimicrobial Evaluation ◽  
Antibacterial And Antifungal

The leaf and stem of cordia macleodii plant were investigated for evaluating antibacterial and antifungal properties.Different extracts of leaf and stem viz. double distilled water, methanol, ethyl acetate ane n-hexane were collectedand content was optimized for the maximum amount of extraction with varying time of 6 and 12 h. The extracts weretested for their antimicrobial activities against gram-positive bacteria (B. sutilis), gram-negative bacteria (E. coli) andfungi (A. niger). The extracts were found to be more active against bacteria as compared to fungi. It was also observedthat the antibacterial and antifungal potential of the water extracts were found to be excellent as 1A (38 mm) and 1B (22mm) compared to the other extracts. Graphical Abstract:

scholarly journals Antimicrobial activities of widely consumed herbal tea’s alone or in combination with antibiotics: An in vitro study

2016 ◽  
Author(s):  
Mayram Tuysuz ◽  
Sibel Dosler ◽  
Ayse Seher Birteksoz Tan ◽  
Gulten Otuk
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
In Vitro Study ◽  
Antimicrobial Activities ◽  
Combination Studies ◽  
Kill Curve ◽  
Time Kill ◽  
Microbroth Dilution ◽  
Antagonistic Interactions

Background: Because of increasing antibiotic resistance, herbal teas are the most popular natural alternatives, which are gaining even more importance. We examined the antimicrobial activities of 31 herbal teas both alone and in combination with antibiotics or antifungals against the standard and clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, methicillin susceptible/resistant Staphylococcus aureus and Candida albicans. Methods: The antimicrobial activities of the teas were determined by using the disk diffusion and microbroth dilution methods, and the combination studies were examined by using the microbroth checkerboard and time killing curve methods. Results: Rosehip, rosehip bag, pomegranate blossom, thyme, wormwood, mint, echinacea bag, cinnamon, black, and green teas were active against most of the studied microorganisms. In the combination studies, we characterized all the expected effects (synergistic, additive, and antagonistic) between the teas and the antimicrobials. While synergy was observed more frequently between ampicillin, ampicillin-sulbactam, or nystatine, and the various tea combinations, most of the effects between the ciprofloxacin, erythromycin, cefuroxime, or amikacin and various tea combinations, particularly rosehip, rosehip bag, and pomegranate blossom teas, were antagonistic. The results of the time kill curve analyses showed that none of the herbal teas were bactericidal in their usage concentrations; however, in combination they were. Discussion: Some herbal teas, particularly rosehip and pomegranate blossom should be avoided because of antagonistic interactions during the course of antibiotic treatment or should be consumed alone.

scholarly journals Antimicrobial Activities and Time-Kill Kinetics of Extracts of Selected Ghanaian Mushrooms

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Theresa Appiah ◽  
Yaw Duah Boakye ◽  
Christian Agyare
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Schizophyllum Commune ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Methanol Extracts ◽  
Test Organisms ◽  
Antibacterial And Antifungal ◽  
Time Kill ◽  
Kinetics Of

The rapid rise of antimicrobial resistance is a worldwide problem. This has necessitated the need to search for new antimicrobial agents. Mushrooms are rich sources of potential antimicrobial agents. This study investigated the antimicrobial properties of methanol extracts of Trametes gibbosa, Trametes elegans, Schizophyllum commune, and Volvariella volvacea. Agar well diffusion, broth microdilution, and time-kill kinetic assays were used to determine the antimicrobial activity of the extracts against selected test organisms. Preliminary mycochemical screening revealed the presence of tannins, flavonoids, triterpenoids, anthraquinones, and alkaloids in the extracts. Methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea showed mean zone of growth inhibition of 10.00±0.0 to 21.50±0.84, 10.00±0.0 to 22.00±1.10, 9.00±0.63 to 21.83±1.17, and 12.00±0.0 to 21.17±1.00 mm, respectively. The minimum inhibitory concentration of methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea ranged from 4.0 to 20, 6.0 to 30.0, 8.0 to 10.0, and 6.0 to 20.0 mg/mL, respectively. Time-kill kinetics studies showed that the extracts possess bacteriostatic action. Methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea exhibited antimicrobial activity and may contain bioactive compounds which may serve as potential antibacterial and antifungal agents.

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 Comparison of the In Vitro Efficacies of Moxifloxacin and Amoxicillin against Listeria monocytogenes

2008 ◽  
Vol 52 (5) ◽  
pp. 1697-1702 ◽  
Author(s):  
S. Grayo ◽  
O. Join-Lambert ◽  
M. C. Desroches ◽  
A. Le Monnier
Keyword(s):  
Listeria Monocytogenes ◽  
Bactericidal Effect ◽  
Cross Resistance ◽  
Resistant Bacteria ◽  
Gram Positive Bacteria ◽  
Severe Infections ◽  
Potential Alternative ◽  
Kill Curve ◽  
Time Kill

ABSTRACT Listeria monocytogenes is a facultative intracellular bacterium that causes severe infections associated with a high mortality rate. Moxifloxacin presents extended activity against gram-positive bacteria and has recently been suggested to be a potential alternative in the treatment of listeriosis. We evaluated the in vitro efficacy of moxifloxacin against L. monocytogenes using a combination of epidemiological and experimental approaches. The median MIC of moxifloxacin for a large collection of L. monocytogenes strains of various origins (human, food, and environment) was 0.5 μg/ml (MIC range, 0.064 to 1 μg/ml). No differences were observed, irrespective of the origin of the strains. Moreover, no cross-resistance with fluoroquinolones was detected in strains that have been reported to be resistant to ciprofloxacin. The in vitro activities of moxifloxacin and amoxicillin were compared by time-kill curve and inhibition of intracellular growth experiments by using a model of bone marrow-derived mouse macrophages infected by L. monocytogenes EGDe. Both moxifloxacin and amoxicillin were bactericidal in broth against extracellular forms of L. monocytogenes. However, moxifloxacin acted much more rapidly, beginning to exert its effects in the first 3 h and achieving complete broth sterilization within 24 h of incubation. Moxifloxacin has a rapid bactericidal effect against intracellular reservoirs of bacteria, whereas amoxicillin is only bacteriostatic and appears to prevent cellular lysis and the subsequent bacterial spreading to adjacent cells. No resistant bacteria were selected during the in vitro experiments. Taken together, our results suggest that moxifloxacin is an interesting alternative to the reference treatment, combining rapid and bactericidal activity, even against intracellular bacteria.

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