Microbial interactions in marine ecosystems occur through a diverse set of mechanisms, engaging genetic and molecular information. These include adhesive features (e.g., pili, nanotubes, cell surface recognition), secretion systems, vesicles, small bioactive molecules (including secondary metabolites with antibiotic effects), phages or viruses. Most of these mechanisms appear to have great potential for the medical and pharmaceutical sectors.

Since the 1980s, analytical technologies and increasing funds have enabled a trend in isolating novel bioactive compounds from different marine organisms, most of which are from microbial origin. Two of the most promising compounds towards the development of new therapies are novel antibiotics and auto-inducers, which regulate contact-independent microbial exchange to allow the control of larger microbial communities. Some “virus signaling” compounds (e.g., sphingolipids and reactive oxygen species) regulating algal-virus interactions are also compounds of interest.

The aim of this Special Issue is to solicit original research articles, as well as review articles highlighting current research on the medical, therapeutic, and pharmacological potential of marine microorganisms. Submissions including novel molecular data depository centers, and more inclusive data analysis tools are particularly encouraged. We hope that this Special Issue benefits researchers and practitioners in the fields of human health, animal health, and food security.

Potential topics include but are not limited to the following:

• Metagenomics and meta-transcriptomic analysis
• Enzymes, processes, secondary metabolic compounds (e.g., antibiotics), and small bioactive molecules (e.g., auto-inducers and signalling molecules) with medical pharmacological and therapeutic potential
• Quorum sensing
• Host-virus interactions
• Adhesive processes at a molecular level
• Virulence factors
• Secretion systems
• Novel bioinformatics tools for computational molecular biology