Marine Microbes: A Source of Novel Antibiotics against Antimicrobial-resistant (AMR) Pathogens: A Systematic Review

INTRODUCTION: The development of novel antibiotics is urgently needed due to the rise in multidrug-resistant (MDR) infections globally. Marine microorganisms have emerged as unexplored sources of bioactive compounds with unique mechanisms to combat antimicrobial resistance (AMR). METHODS: This review summarizes peer-reviewed and recent research from PubMed, Scopus, and Web of Science to evaluate the scope of marine-derived metabolites against AMR pathogens. The focus was on studies describing antimicrobial metabolites produced by marine actinomycetes, bacteria, and fungi. Studies involving non-resistant pathogens or non-marine sources were excluded. RESULTS: The review identifies various secondary metabolites, including peptides, polyketides, macrolides, fatty acid amines, equisetin, and aminolipids. These compounds target AMR pathogens such as MRSA, VRE, and VRSE. Marine actinomycetes-including Streptomyces spp., Micromonospora spp., and Verrucosispora spp.-are key producers of antimicrobial compounds. Likewise, marine bacterial species such as Bacillus spp., Aequorivita spp., and Zobellia galactanivorans, as well as fungal species like Penicillium spp. and Fusarium spp., produce bioactive compounds. DISCUSSION: These findings highlight the potential of marine microbes as sources of novel antibiotics. Despite this potential, several limitations persist, including scalability issues, the noncultivability of many microbes, toxicology concerns, source-dependent variability, and insufficient in vivo validation. These challenges can be addressed by integrating modern omics technologies to advance drug discovery for AMR. CONCLUSION: This review underscores marine microbes as promising sources in the fight against AMR. To unlock their full potential, greater interdisciplinary collaboration is needed to develop sustainable solutions, accelerate antibiotic discovery, and address the global AMR crisis.