Progress Report: Antimicrobial Drug Discovery in the Resistance Era

Indole clubbed 2,4-thiazolidinedione linked 1,2,3-triazole as a potent antimalarial and antibacterial agent against drug-resistant strain and molecular modeling studies

In the face of escalating challenges of microbial resistance strains, this study describes the design and synthesis of 5-({1-[(1H-1,2,3-triazol-4-yl)methyl]-1H-indol-3-yl}methylene)thiazolidine-2,4-dione derivatives, which have demonstrated significant antimicrobial properties. Compared with the minimum inhibitory concentrations (MIC) values of ciprofloxacin on the respective strains, compounds 5a, 5d, 5g, 5l, and 5m exhibited potent antibacterial activity with MIC values ranging from 16 to 25 µM. Almost all the synthesized compounds showed lower MIC compared to standards against vancomycin-resistant enterococcus and methicillin-resistant Staphylococcus aureus strains. Additionally, the majority of the synthesized compounds demonstrated remarkable antifungal activity, against Candida albicans and Aspergillus niger, as compared to nystatin, griseofulvin, and fluconazole. Furthermore, the majority of compounds exhibited notable inhibitory effects against the Plasmodium falciparum strain, having IC50 values ranging from 1.31 to 2.79 μM as compared to standard quinine (2.71 μM). Cytotoxicity evaluation of compounds 5a-q on SHSY-5Y cells at up to 100 μg/mL showed no adverse effects. Comparison with control groups highlights their noncytotoxic characteristics. Molecular docking confirmed compound binding to target active sites, with stable protein-ligand complexes displaying drug-like molecules. Molecular dynamics simulations revealed dynamic stability and interactions. Rigorous tests and molecular modeling unveil the effectiveness of the compounds against drug-resistant microbes, providing hope for new antimicrobial compounds with potential safety.

Reimagining the Past: A Future for Antibiotic Drug Discovery in Ophthalmology

ABSTRACT

Antibiotic resistance has emerged as a critical threat for the treatment of bacterial ocular infections. To address the critical need for novel therapeutics, antibiotic drug repurposing holds significant promise. As such, examples of existing FDA-approved drugs currently under development for new applications, novel combinations, and improved delivery systems are discussed.

Knowledge, Attitudes, and Practices among Pharmacy and Non-Pharmacy Interns in Saudi Arabia Regarding Antibiotic Use and Antibiotic Resistance: A Cross-Sectional Descriptive Study

This cross-sectional descriptive study aims to explore the knowledge, attitudes, and practices among pharmacy, dentistry, medicine, and nursing interns in Saudi Arabia regarding antibiotic use and antibiotic resistance. Interns received a soft copy of a structured and validated self-administered questionnaire using an online survey platform. A total of 266 interns responded to the questionnaire. On average, the participants achieved good scores in the knowledge and practice domains, followed by the attitude domain. The average knowledge percentage was 76.1% (SD 17.1) compared to 84.6% (SD 20.5) for practices and 61.5% (SD 23.2) for attitudes. The results suggest that pharmacy interns had insignificantly better overall scores compared to non-pharmacy interns for knowledge, attitudes, and practices. This study shows that the scores for knowledge, attitudes, and practices of pharmacy, dentistry, medicine, and nursing interns regarding antibiotic use and resistance were high overall. However, interns' belief in their responsibility in preventing antibiotic resistance is lacking.

Chemical synthesis and mechanism of a natural product from endolichenic fungus with a broad-spectrum anti microorganism activity

Background

The antibiotic resistance in various bacteria is consistently increasing and is posing a serious threat to human health, prompting the need for the discovery of novel structurally featured natural products with promising biological activities in drug research and development. Endolichenic microbes have been proven to be a fertile source to produce various chemical components, and therefore these microbes have been on a prime focus for exploring natural products. In this study, to explore potential biological resources and antibacterial natural products, the secondary metabolites of an endolichenic fungus have been investigated.

Methods

The antimicrobial products were isolated from the endolichenic fungus using various chromatographic methods, and the antibacterial and antifungal activities of the compounds were evaluated by the broth microdilution method under in vitro conditions. The antimicrobial mechanism has been discussed with measuring the dissolution of nucleic acid and protein, as well as the activity of alkaline phosphatase (AKP) in preliminary manner. Chemical synthesis of the active product compound 5 was also performed, starting from commercially available 2,6-dihydroxybenzaldehyde through a sequence of transformations that included methylation, the addition of propylmagnesium bromide on formyl group, the oxidation of secondary alcohol, and the deprotection of methyl ether motif.

Results

Among the 19 secondary metabolites of the endolichenic fungus, Daldinia childiae (compound 5) showed attractive antimicrobial activities on 10 of the 15 tested pathogenic strains, including Gram-positive bacteria, Gram-negative bacteria, and fungus. The Minimum Inhibitory Concentration (MIC) of compound 5 for Candida albicans 10213, Micrococcus luteus 261, Proteus vulgaris Z12, Shigella sonnet, and Staphylococcus aureus 6538 was identified as 16 μg/ml, whereas the Minimum Bactericidal Concentration (MBC) of other strains was identified as 64 μg/ml. Compound 5 could dramatically inhibit the growth of S. aureus 6538, P. vulgaris Z12, and C. albicans 10213 at the MBC, likely affecting the permeability of the cell wall and cell membrane. These results enriched the library of active strains and metabolites resources of endolichenic microorganisms. The chemical synthesis of the active compound was also performed in four steps, providing an alternative pathway to explore antimicrobial agents.

Enzymatic Synthesis of Vancomycin-Modified DNA

Many potent antibiotics fail to treat bacterial infections due to emergence of drug-resistant strains. This surge of antimicrobial resistance (AMR) calls in for the development of alternative strategies and methods for the development of drugs with restored bactericidal activities. In this context, we surmised that identifying aptamers using nucleotides connected to antibiotics will lead to chemically modified aptameric species capable of restoring the original binding activity of the drugs and hence produce active antibiotic species that could be used to combat AMR. Here, we report the synthesis of a modified nucleoside triphosphate equipped with a vancomycin moiety on the nucleobase. We demonstrate that this nucleotide analogue is suitable for polymerase-mediated synthesis of modified DNA and, importantly, highlight its compatibility with the SELEX methodology. These results pave the way for bacterial-SELEX for the identification of vancomycin-modified aptamers.

Lead/Drug Discovery from Natural Resources

Natural products and their derivatives have been shown to be effective drug candidates against various diseases for many years. Over a long period of time, nature has produced an abundant and prosperous source pool for novel therapeutic agents with distinctive structures. Major natural-product-based drugs approved for clinical use include anti-infectives and anticancer agents. This paper will review some natural-product-related potent anticancer, anti-HIV, antibacterial and antimalarial drugs or lead compounds mainly discovered from 2016 to 2022. Structurally typical marine bioactive products are also included. Molecular modeling, machine learning, bioinformatics and other computer-assisted techniques that are very important in narrowing down bioactive core structural scaffolds and helping to design new structures to fight against key disease-associated molecular targets based on available natural products are considered and briefly reviewed.

Carbazole Derivatives as Potential Antimicrobial Agents

Microbial infection is a leading cause of death worldwide, resulting in around 1.2 million deaths annually. Due to this, medicinal chemists are continuously searching for new or improved alternatives to combat microbial infections. Among many nitrogen-containing heterocycles, carbazole derivatives have shown significant biological activities, of which its antimicrobial and antifungal activities are the most studied. In this review, miscellaneous carbazole derivatives and their antimicrobial activity are discussed (articles published from 1999 to 2022).

Nanobiotics against antimicrobial resistance: harnessing the power of nanoscale materials and technologies

Given the spasmodic increment in antimicrobial resistance (AMR), world is on the verge of “post-antibiotic era”. It is anticipated that current SARS-CoV2 pandemic would worsen the situation in future, mainly due to the lack of new/next generation of antimicrobials. In this context, nanoscale materials with antimicrobial potential have a great promise to treat deadly pathogens. These functional materials are uniquely positioned to effectively interfere with the bacterial systems and augment biofilm penetration. Most importantly, the core substance, surface chemistry, shape, and size of nanomaterials define their efficacy while avoiding the development of AMR. Here, we review the mechanisms of AMR and emerging applications of nanoscale functional materials as an excellent substitute for conventional antibiotics. We discuss the potential, promises, challenges and prospects of nanobiotics to combat AMR.

Construction of multifunctional wound dressings with their application in chronic wound treatment

As the prevalence of diabetes increases year by year and the aging population continues to intensify in the world, chronic wounds such as diabetic foot ulcers and pressure ulcers have become serious problems that threaten people's health, and have brought an enormous burden to the world healthcare system. Conventional clinical treatment of chronic wounds relies on non-specific topical care (including debridement, infection/inflammation control, and frequent wound dressing changes), which can alleviate disease progression and reduce patient suffering to a certain extent, but the overall cure rate is less than 50% and the recurrence rate is high. Traditional wound dressings such as gauze, hydrocolloids, films and foams are single-function, acting as a physical barrier or absorbing exudates, and cannot meet all the needs of the entire chronic wound healing process. Recently, a large number of novel functional dressings have been reported for chronic wound repair. Based on the progress on wound dressings in recent years and the relevant research experience of our group, the review summarizes and discusses the progress on multifunctional wound dressings (such as microneedles, sponges and hydrogels) with anti-inflammatory, antioxidant, antibacterial, pro-angiogenic and tissue adhesive functions in detail. At the same time, the various responsive mechanisms (in vivo microenvironment or in vitro stimulation) of the smart multifunctional wound dressing are also analyzed in detail. It is expected that the review could provide some inspiration and suggestions for research on dressings for chronic wound treatment.