Antimicrobial peptides as promising antibiotic adjuvants to combat drug-resistant pathogens

Peptide-based self-assembled monolayers (SAMs): what peptides can do for SAMs and vice versa

Self-assembled monolayers (SAMs) represent highly ordered molecular materials with versatile biochemical features and multidisciplinary applications. Research on SAMs has made much progress since the early begginings of Au substrates and alkanethiols, and numerous examples of peptide-displaying SAMs can be found in the literature. Peptides, presenting increasing structural complexity, stimuli-responsiveness, and biological relevance, represent versatile functional components in SAMs-based platforms. This review examines the major findings and progress made on the use of peptide building blocks displayed as part of SAMs with specific functions, such as selective cell adhesion, migration and differentiation, biomolecular binding, advanced biosensing, molecular electronics, antimicrobial, osteointegrative and antifouling surfaces, among others. Peptide selection and design, functionalisation strategies, as well as structural and functional characteristics from selected examples are discussed. Additionally, advanced fabrication methods for dynamic peptide spatiotemporal presentation are presented, as well as a number of characterisation techniques. All together, these features and approaches enable the preparation and use of increasingly complex peptide-based SAMs to mimic and study biological processes, and provide convergent platforms for high throughput screening discovery and validation of promising therapeutics and technologies.

Xanthone Derivatives Enhance the Therapeutic Potential of Neomycin against Polymicrobial Gram-Negative Bacterial Infections

Gram-negative bacterial infections are difficult to manage as many antibiotics are ineffective owing to the presence of impermeable bacterial membranes. Polymicrobial infections pose a serious threat due to the inadequate efficacy of available antibiotics, thereby necessitating the administration of antibiotics at higher doses. Antibiotic adjuvants have emerged as a boon as they can augment the therapeutic potential of available antibiotics. However, the toxicity profile of antibiotic adjuvants is a major hurdle in clinical translation. Here, we report the design, synthesis, and biological activities of xanthone-derived molecules as potential antibiotic adjuvants. Our SAR studies witnessed that the p-dimethylamino pyridine-derivative of xanthone (X8) enhances the efficacy of neomycin (NEO) against Escherichia coli and Pseudomonas aeruginosa and causes a synergistic antimicrobial effect without any toxicity against mammalian cells. Biochemical studies suggest that the combination of X8 and NEO, apart from inhibiting protein synthesis, enhances the membrane permeability by binding to lipopolysaccharide. Notably, the combination of X8 and NEO can disrupt the monomicrobial and polymicrobial biofilms and show promising therapeutic potential against a murine wound infection model. Collectively, our results unveil the combination of X8 and NEO as a suitable adjuvant therapy for the inhibition of the Gram-negative bacterial infections.

The Combination of Antibiotic and Non-Antibiotic Compounds Improves Antibiotic Efficacy against Multidrug-Resistant Bacteria

Bacterial antibiotic resistance, especially the emergence of multidrug-resistant (MDR) strains, urgently requires the development of effective treatment strategies. It is always of interest to delve into the mechanisms of resistance to current antibiotics and target them to promote the efficacy of existing antibiotics. In recent years, non-antibiotic compounds have played an important auxiliary role in improving the efficacy of antibiotics and promoting the treatment of drug-resistant bacteria. The combination of non-antibiotic compounds with antibiotics is considered a promising strategy against MDR bacteria. In this review, we first briefly summarize the main resistance mechanisms of current antibiotics. In addition, we propose several strategies to enhance antibiotic action based on resistance mechanisms. Then, the research progress of non-antibiotic compounds that can promote antibiotic-resistant bacteria through different mechanisms in recent years is also summarized. Finally, the development prospects and challenges of these non-antibiotic compounds in combination with antibiotics are discussed.

Recent Advances of Biosensors for Detection of Multiple Antibiotics

The abuse of antibiotics has caused a serious threat to human life and health. It is urgent to develop sensors that can detect multiple antibiotics quickly and efficiently. Biosensors are widely used in the field of antibiotic detection because of their high specificity. Advanced artificial intelligence/machine learning algorithms have allowed for remarkable achievements in image analysis and face recognition, but have not yet been widely used in the field of biosensors. Herein, this paper reviews the biosensors that have been widely used in the simultaneous detection of multiple antibiotics based on different detection mechanisms and biorecognition elements in recent years, and compares and analyzes their characteristics and specific applications. In particular, this review summarizes some AI/ML algorithms with excellent performance in the field of antibiotic detection, and which provide a platform for the intelligence of sensors and terminal apps portability. Furthermore, this review gives a short review of biosensors for the detection of multiple antibiotics.