An investigation on the suitability of tailored selective isolation techniques for the isolation of Actinomycetes

Multi-drug resistance (MDR) is a growing global health concern characterised by microorganisms' ability to resist the effects of multiple antimicrobial agents. This phenomenon complicates the treatment of infectious diseases and limits the efficacy of standard therapies. The overuse and misuse of antibiotics in healthcare and agriculture further accelerate the spread of MDR pathogens. Addressing MDR requires a multifaceted approach, including the search for novel bioactive compounds and alternative treatment strategies. The Great Salt Plains is a unique hypersaline environment that presents challenges for the isolation of microorganisms, including actinomycetes, a diverse group of filamentous, Gram-positive bacteria renowned for their prolific production of antimicrobial agents, stand as a cornerstone in this pursuit. Their diverse metabolites exhibit multifaceted bioactivities, including potent antituberculosis, anticancer, immunomodulatory, immuno-protective, antidiabetic, etc.  This study investigates the suitability of selective isolation techniques for recovering actinomycetes from the Great Salt Plains. Different selective isolation approaches including saline-tolerant media, addition of gypsum and chemical inhibitors (e.g., antifungals and antibiotics), were tested to suppress competing microbial growth while enhancing the recovery of actinomycetes. Additionally, physical treatments, such as heat pre-treatment, were employed to eliminate non-target microorganisms. Results indicate that using highsalinity media combined with gypsum, selective inhibitors, and pre-treatments significantly improved the yield and purity of actinomycetes colonies from hypersaline samples. These findings suggest that tailored selective isolation methodologies are essential for the successful recovery of Actinomycetes from extreme environments, which hold potential for the discovery of novel bioactive compounds and industrially relevant enzymes.