scholarly journals Targeting Bacterial Sortases in Search of Anti-Virulence Therapies with Low Risk of Resistance Development

2021 ◽  
Vol 14 (5) ◽  
pp. 415
Author(s):  
Georgiana Nitulescu ◽  
Denisa Margina ◽  
Anca Zanfirescu ◽  
Octavian Tudorel Olaru ◽  
George Mihai Nitulescu
Keyword(s):  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Structural Variations ◽  
Resistance Development ◽  
Structure Activity ◽  
Rapid Spread ◽  
Alkanoic Acids ◽  
Acrylic Acids ◽  
Isoquinoline Derivatives ◽  
Compound Effect

Increasingly ineffective antibiotics and rapid spread of multi- and pan-resistant bacteria represent a global health threat; hence, the need of developing new antimicrobial medicines. A first step in this direction is identifying new molecular targets, such as virulence factors. Sortase A represents a virulence factor essential for the pathogenesis of Gram-positive pathogens, some of which have a high risk for human health. We present here an exhaustive collection of sortases inhibitors grouped by relevant chemical features: vinyl sulfones, 3-aryl acrylic acids and derivatives, flavonoids, naphtoquinones, anthraquinones, indoles, pyrrolomycins, isoquinoline derivatives, aryl β-aminoethyl ketones, pyrazolethiones, pyridazinones, benzisothiazolinones, 2-phenyl-benzoxazole and 2-phenyl-benzofuran derivatives, thiadiazoles, triazolothiadiazoles, 2-(2-phenylhydrazinylidene)alkanoic acids, and 1,2,4-thiadiazolidine-3,5-dione. This review focuses on highlighting their structure–activity relationships, using the half maximal inhibitory concentration (IC50), when available, as an indicator of each compound effect on a specific sortase. The information herein is useful for acquiring knowledge on diverse natural and synthetic sortases inhibitors scaffolds and for understanding the way their structural variations impact IC50. It will hopefully be the inspiration for designing novel effective and safe sortase inhibitors in order to create new anti-infective compounds and to help overcoming the current worldwide antibiotic shortage.

scholarly journals Tackling Virulence of Pseudomonas aeruginosa by the Natural Furanone Sotolon

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 871
Author(s):  
Mohammed F. Aldawsari ◽  
El-Sayed Khafagy ◽  
Ahmed Al Saqr ◽  
Ahmed Alalaiwe ◽  
Hisham A. Abbas ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Therapeutic Agent ◽  
Bacterial Resistance ◽  
Inhibitory Concentration ◽  
Bacterial Biofilm ◽  
Resistant Bacteria ◽  
Resistance Development

The bacterial resistance development due to the incessant administration of antibiotics has led to difficulty in their treatment. Natural adjuvant compounds can be co-administered to hinder the pathogenesis of resistant bacteria. Sotolon is the prevailing aromatic compound that gives fenugreek its typical smell. In the current work, the anti-virulence activities of sotolon on Pseudomonas aeruginosa have been evaluated. P. aeruginosa has been treated with sotolon at sub-minimum inhibitory concentration (MIC), and production of biofilm and other virulence factors were assessed. Moreover, the anti-quorum sensing (QS) activity of sotolon was in-silico evaluated by evaluating the affinity of sotolon to bind to QS receptors, and the expression of QS genes was measured in the presence of sotolon sub-MIC. Furthermore, the sotolon in-vivo capability to protect mice against P. aeruginosa was assessed. Significantly, sotolon decreased the production of bacterial biofilm and virulence factors, the expression of QS genes, and protected mice from P. aeruginosa. Conclusively, the plant natural substance sotolon attenuated the pathogenicity of P. aeruginosa, locating it as a plausible potential therapeutic agent for the treatment of its infections. Sotolon can be used in the treatment of bacterial infections as an alternative or adjuvant to antibiotics to combat their high resistance to antibiotics.

Phenolic Imidazole Derivatives with Dual Antioxidant/Antifungal Activity: Synthesis and Structure-Activity Relationship

2019 ◽  
Vol 15 (4) ◽  
pp. 341-351 ◽  
Author(s):  
Ana P. Bettencourt ◽  
Marián Castro ◽  
João P. Silva ◽  
Francisco Fernandes ◽  
Olga P. Coutinho ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antifungal Activity ◽  
Organic Molecules ◽  
Inhibitory Concentration ◽  
Yeast Species ◽  
Dpph Radical ◽  
Dpph Assay ◽  
Gram Negative ◽  
Structure Activity ◽  
Deoxyribose Degradation

Background: Previous publications show that the addition of a phenolic antioxidant to an antifungal agent, considerably enhances the antifungal activity. Objective: Synthesis of novel compounds combining phenolic units with linear or cyclic nitrogencontaining organic molecules with antioxidant/antifungal activity using methodologies previously developed in the group. Methods: Several N- [1,2-dicyano-2- (arylidenamino) vinyl]-O-alkylformamidoximes 3 were synthesized and cyclized to 4,5-dicyano-N- (N´-alcoxyformimidoyl)-2-arylimidazoles 4 upon reflux in DMF, in the presence of manganese dioxide or to 6-cyano-8-arylpurines 5 when the reagent was refluxed in acetonitrile with an excess of triethylamine. These compounds were tested for their antioxidant activity by cyclic voltammetry, DPPH radical (DPPH•) assay and deoxyribose degradation assay. The minimum inhibitory concentration (MIC) of all compounds was evaluated against two yeast species, Saccharomyces cerevisiae and Candida albicans, and against bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram negative). Their cytotoxicity was evaluated in fibroblasts. Results: Among the synthetised compounds, five presented higher antioxidant activity than reference antioxidant Trolox and from these compounds, four presented antifungal activity without toxic effects in fibroblasts and bacteria. Conclusion: Four novel compounds presented dual antioxidant/antifungal activity at concentrations that are not toxic to bacteria and fibroblasts. The active molecules can be used as an inspiration for further studies in this area.

New Groups of Potential Antituberculotics: Bis(1-aryltetrazol-5-yl) Disulfides. Structure Activity Relationship

1994 ◽  
Vol 59 (1) ◽  
pp. 234-238 ◽  
Author(s):  
Karel Waisser ◽  
Jiří Kuneš ◽  
Alexandr Hrabálek ◽  
Želmíra Odlerová
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Antimycobacterial Activity ◽  
Activity Relationship ◽  
Active Derivative ◽  
Structure Activity ◽  
Medium Activity ◽  
Substituent Constants ◽  
Atypical Strains

Oxidation of 1-aryltetrazole-5-thiols afforded bis(1-aryltetrazol-5-yl) disulfides. The compounds were tested for antimycobacterial activity against Mycobacterium tuberculosis, M. kansasii, M. avium and M. fortuitum. In the case of M. tuberculosis, the logarithm of minimum inhibitory concentration showed a parabolic dependence on hydrophobic substituent constants. Although the compounds exhibited low to medium activity, the most active derivative, bis(4-chlorophenyltetrazol-5-yl) disulfide (III) was more effective against atypical strains than are the commercial tuberculostatics used as standards.

scholarly journals Antibacterial Activity of Fluorobenzoylthiosemicarbazides and Their Cyclic Analogues with 1,2,4-Triazole Scaffold

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 170
Author(s):  
Urszula Kosikowska ◽  
Monika Wujec ◽  
Nazar Trotsko ◽  
Wojciech Płonka ◽  
Piotr Paneth ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Resistant Bacteria ◽  
Binding Affinities ◽  
Substitution Pattern ◽  
Minimal Inhibitory Concentrations ◽  
Gram Positive Bacteria ◽  
Structure Activity ◽  
Drug Resistant Bacteria ◽  
Reference Strains

The development of drug-resistant bacteria is currently one of the major challenges in medicine. Therefore, the discovery of novel lead structures for the design of antibacterial drugs is urgently needed. In this structure–activity relationship study, a library of ortho-, meta-, and para-fluorobenzoylthiosemicarbazides, and their cyclic analogues with 1,2,4-triazole scaffold, was created and tested for antibacterial activity against Gram-positive bacteria strains. While all tested 1,2,4-triazoles were devoid of potent activity, the antibacterial response of the thiosemicarbazides was highly dependent on substitution pattern at the N4 aryl position. The optimum activity for these compounds was found for trifluoromethyl derivatives such as 15a, 15b, and 16b, which were active against both the reference strains panel, and pathogenic methicillin-sensitive and methicillin-resistant Staphylococcus aureus clinical isolates at minimal inhibitory concentrations (MICs) ranging from 7.82 to 31.25 μg/mL. Based on the binding affinities obtained from docking, the conclusion can be reached that fluorobenzoylthiosemicarbazides can be considered as potential allosteric d-alanyl-d-alanine ligase inhibitors.

scholarly journals Pseudomonas aeruginosa PAO 1 In Vitro Time–Kill Kinetics Using Single Phages and Phage Formulations—Modulating Death, Adaptation, and Resistance

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 877
Author(s):  
Ana Mafalda Pinto ◽  
Alberta Faustino ◽  
Lorenzo M. Pastrana ◽  
Manuel Bañobre-López ◽  
Sanna Sillankorva
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phage Therapy ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Chronic Infections ◽  
Swarming Motility ◽  
Resistance Development ◽  
Healthcare Settings ◽  
Time Kill

Pseudomonas aeruginosa is responsible for nosocomial and chronic infections in healthcare settings. The major challenge in treating P. aeruginosa-related diseases is its remarkable capacity for antibiotic resistance development. Bacteriophage (phage) therapy is regarded as a possible alternative that has, for years, attracted attention for fighting multidrug-resistant infections. In this work, we characterized five phages showing different lytic spectrums towards clinical isolates. Two of these phages were isolated from the Russian Microgen Sextaphage formulation and belong to the Phikmvviruses, while three Pbunaviruses were isolated from sewage. Different phage formulations for the treatment of P. aeruginosa PAO1 resulted in diversified time–kill outcomes. The best result was obtained with a formulation with all phages, prompting a lower frequency of resistant variants and considerable alterations in cell motility, resulting in a loss of 73.7% in swimming motility and a 79% change in swarming motility. These alterations diminished the virulence of the phage-resisting phenotypes but promoted their growth since most became insensitive to a single or even all phages. However, not all combinations drove to enhanced cell killings due to the competition and loss of receptors. This study highlights that more caution is needed when developing cocktail formulations to maximize phage therapy efficacy. Selecting phages for formulations should consider the emergence of phage-resistant bacteria and whether the formulations are intended for short-term or extended antibacterial application.

scholarly journals Novel Seleno- and Thio-Urea Containing Dihydropyrrol-2-One Analogues as Antibacterial Agents

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 321
Author(s):  
Shekh Sabir ◽  
Tsz Tin Yu ◽  
Rajesh Kuppusamy ◽  
Basmah Almohaywi ◽  
George Iskander ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Positive Bacterium ◽  
Quorum Sensing Inhibition ◽  
Drug Resistant Bacteria

The quorum sensing (QS) system in multi-drug-resistant bacteria such as P. aeruginosa is primarily responsible for the development of antibiotic resistance and is considered an attractive target for antimicrobial drug discovery. In this study, we synthesised a series of novel selenourea and thiourea-containing dihydropyrrol-2-one (DHP) analogues as LasR antagonists. The selenium DHP derivatives displayed significantly better quorum-sensing inhibition (QSI) activities than the corresponding sulphur analogues. The most potent analogue 3e efficiently inhibited the las QS system by 81% at 125 µM and 53% at 31 µM. Additionally, all the compounds were screened for their minimum inhibitory concentration (MIC) against the Gram-positive bacterium S. aureus, and interestingly, only the selenium analogues showed antibacterial activity, with 3c and 3e being the most potent with a MIC of 15.6 µM.

scholarly journals Synergistic activities of methanol leave extracts of Acalypha wilkesiana, Senna alata, Psidium guajava against selected resistant bacteria isolates

2021 ◽  
Vol 16 (2) ◽  
pp. 049-061
Author(s):  
Joy Ogugua Igwe ◽  
Ugochukwu Moses Okezie ◽  
Moses Nkechukwu Ikegbunam ◽  
Charles Okechukwu Esimone
Keyword(s):  
Antibacterial Activity ◽  
Inhibitory Concentration ◽  
Synergistic Effects ◽  
Severe Infection ◽  
Psidium Guajava ◽  
Prolonged Treatment ◽  
Resistant Bacteria ◽  
Methanol Extracts ◽  
Acalypha Wilkesiana ◽  
Senna Alata

Resistant strains of bacteria has over the years rendered conventional antibiotics ineffective. Consequently, this has resulted to severe infection, prolonged treatment, high cost of treatment and often times death. This study aimed to identify reliable alternative sources of bioactive agents with activity against resistant Staphylococcus aureus, Escherichia coli and Salmonella typhi. Methanol extracts of Acalypha wilkesiana (MEAW), Senna alata (MESA) and Psidium guajava (MEPG) were tested alone and in combination against three clinical isolates. Ciprofloxacin was used as the positive control drug. A combination of Microscopic, macroscopic and molecular protocols was used to identify the test isolates. The antibiotic profiles of the isolates E. coli (E1), S. aureus (S4) and S. typhi (St2) indicated MultiDrug-Resisitant status (MDR). All the extracts demonstrated antibacterial activity against the resistant isolates with zones of inhibition that ranged between 3.1 – 25 mm and minimum inhibitory concentration of 12.5 – 200 mg/ml. Amongst the extracts tested, MESA was found to be the most active extract while MEPG was the least active extract. The combination of the different methanol extracts demonstrated synergistic effects against the test organisms with a fractional inhibitory concentration that ranged between 0.06 – 0.8 mg/ml. The observed antibacterial activity may be linked to the presence of some bioactive components such as phenolic compounds and flavonoids present in the extracts. The results of this study suggest A. wilkesiana, S. alata and P. guajava may represent reliable sources of important bioactive compounds for new drug development.

Synthesis and antimicrobial activity of aryldiazenyl/arylhydrazono pyrazoles

2021 ◽  
Vol 45 (11-12) ◽  
pp. 1093-1099
Author(s):  
Abdulrhman Alsayari ◽  
Yahya I Asiri ◽  
Abdullatif Bin Muhsinah ◽  
Mohd. Zaheen Hassan
Keyword(s):  
Active Site ◽  
Phenyl Ring ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Docking Studies ◽  
Considerable Effect ◽  
Design Synthesis ◽  
Structure Activity ◽  
Antimicrobial Evaluation

We report the design, synthesis, and in vitro antimicrobial evaluation of functionalized pyrazoles containing a hydrazono/diazenyl moiety. Among these newly synthesized derivatives, 4-[2-(4-chlorophenyl)hydrazono]-5-methyl-2-[2-(naphthalen-2-yloxy)acetyl]-2,4-dihydro-3 H-pyrazol-3-one is a promising antimicrobial agent against Staphylococcus aureus (minimum inhibitory concentration 0.19 μg mL−1). Structure–activity relationship studies reveal that the electronic environment on the distal phenyl ring has a considerable effect on the antimicrobial potential of the hybrid analogues. Molecular docking studies into the active site of S. aureus dihydrofolate reductase also prove the usefulness of hybridizing a pyrazole moiety with azo and hydrazo groups in the design of new antimicrobial agents.

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