Antimicrobial peptides(University of Zurich/ Spexis)

The rise of multidrug-resistant (MDR) bacteria is becoming a significant challenge, with colistin serving as the last-resort antibiotic for treating drug-resistant infections. The emergence of colistin-resistant (ColR) isolates has limited its clinical utility, highlighting the need for novel antimicrobial agents. Despite the recent approval of a few new antibiotics, there remains an urgent need for innovative strategies to address this critical issue. Developing and approving new antibiotics is a complex and time-consuming process, prompting researchers to investigate the use of colistin in combination with other compounds to treat ColR bacterial isolates. Non-antibiotic adjuvants, antimicrobial peptides, and nanotechnology-based strategies are among the most promising approaches used in combination with colistin. Natural compounds have shown promising results in numerous studies, aiding in the fight against antibiotic resistance. Furthermore, repurposing non-antibiotic medications in combination with colistin has demonstrated effectiveness and potential for enhancing colistin's efficacy. This review aimed to identify compounds effective against ColR isolates, with the hope that these approaches could offer solutions for combating these dangerous resistant strains in the near future.

Biofouling due to marine microorganism adhesion poses significant challenges for marine vessels, necessitating innovative antifouling solutions. This study aimed to investigate the antifouling performance of an antimicrobial peptides (AMPs) immobilized on dopamine-modified stainless steel (SS) surfaces, as a novel approach for antifouling applications. Herein, dopamine was utilized to form a modification layer on SS, subsequently immersed in AMPs solution to create SS-DA-A samples. The surface characteristics were characterized through X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), contact angle measurement instrument, fourier transform infrared spectroscopy (FTIR), and confocal laser scanning microscopy (CLSM). Antimicrobial properties were assessed using plate counting, measuring bacterial adhesion, and optical density value, while algal resistance was determined through SEM and CLSM methods, specifically assessing the coverage by algae. The results demonstrated the successful modification of the SS surface, characterized by FTIR peaks corresponding to AMPs, and a significant reduction in contact angle with the introduction of dopamine. Notably, the SS-DA-A surface exhibited enhanced antimicrobial efficacy against Vibrio natriegens (V. natriegens), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli), with a marked reduction in biofilm formation, and C. pyrenoidosa and P. tricornutum coverage decreased by approximately 96.46 % and 91.61 %, respectively. Molecular dynamics simulation results reveal that antimicrobial peptides interact with the bacterial phospholipid bilayer, disrupting bacterial integrity and thus achieving surface antimicrobial activity. This study effectively demonstrates that dopamine facilitates the successful immobilization of AMPs on SS surfaces, leading to significantly improved antibacterial, anti-algal, and biofilm resistance properties, and offers a promising new strategy for antifouling technology in marine settings.