A study on the approaches in selective isolation for recovery of actinomycetes from an extreme environment

Multi-drug resistance (MDR) is an increasing global health threat, defined by microorganisms' ability to resist multiple antimicrobial agents. This resistance makes treating infectious diseases more challenging and reduces the effectiveness of standard therapies. The overuse and improper use of antibiotics in both healthcare and agriculture are significant contributors to the spread of MDR pathogens. Combating MDR requires a comprehensive strategy, including the discovery of new bioactive compounds and alternative treatment methods. The Great Salt Plains, a unique hypersaline environment, presents challenges for isolating microorganisms, including actinomycetes. These bacteria produce a wide range of metabolites with various bioactivities, such as antituberculosis, anticancer, immunomodulatory, immuno-protective, and antidiabetic properties. This study explores effective isolation methods for recovering actinomycetes from the Great Salt Plains. Different selective isolation strategies were tested, these included the use of diverse NaCl concentrations and the inclusion of CaSO4·2H2O into differing selective media for a strategic approach to the selective isolation. This study found that incorporating CaSO4·2H2O at 1.5% enhanced the recovery of actinomycetes, with a higher frequency of isolation observed in the absence of NaCl, compared to its inclusion at 3%. This suggests the recovery of halotolerant and gypsum-loving actinomycetes. Sites 3 and 2a yielded the highest number of isolates when 0% NaCl and 3% CaSO4·2H2O were used. This was irrespective of the NaCl concentrations in each of the environmental samples tested within the Great Salt Plains. These findings highlight the importance of tailored selective isolation techniques for successfully recovering actinomycetes from extreme environments.