Unveiling the Antibacterial Activity Against Staphylococcus aureus of Slime Molds: The Role of Symbiotic Bacteria

The emergence of multidrug-resistant pathogens has significantly reduced the efficacy of current antimicrobial treatments against bacterial and fungal infections. To combat this challenge, the exploration of novel antimicrobial sources or the development of synthetic antibiotics is imperative. Microbes have emerged as promising natural reservoirs for antimicrobial compounds, with slime molds garnering attention due to their unique bioactive metabolites in recent years. Some of these metabolites demonstrate potent antibiotic properties. This study investigates the inhibitory effects of slime mold extracts on pathogenic bacteria, attributing this activity primarily to symbiotic bacteria associated with the slime molds rather than to the slime mold cells themselves. Furthermore, we demonstrate that this antibacterial effect can be horizontally transferred through bacterial ingestion, enabling recipient slime molds to exhibit antibacterial properties upon extraction. Importantly, slime molds selectively acquire bacteria from their environment to enhance their antibacterial characteristics, a process that appears non-random and persists through sexual cycles. These findings underscore slime molds as valuable reservoirs of antimicrobial agents. Nevertheless, it remains critical to ascertain whether these antimicrobial agents originate solely from symbiotic bacteria or result from complex interactions between these bacteria and their slime mold hosts. Understanding the mechanisms behind this antimicrobial activity not only expands our knowledge of host-microbe interactions but also provides new avenues for bioprospecting novel antibiotics. Investigating how slime molds selectively acquire and retain beneficial bacteria may offer insights into microbial symbiosis that could be leveraged for antimicrobial discovery, potentially addressing the urgent need for alternative treatments against resistant pathogens.