Rifampin-producing Streptomyces Isolated in Iraqi Desert Soil, Molecular Identification and HPLC Analysis
Background: The emergence of antimicrobial resistance is growing swiftly and this requires the discovery of new antibiotic-producing microorganisms. The species of Streptomyces are still a major source of clinically significant secondary metabolites, including rifampin, one of the bactericidal agents critical to the treatment of tuberculosis. Aim: The aim of the study was to investigate some desert-derived Streptomyces isolates to identify their potential in the production of rifampin-like compounds. Methods: Soil samples (n= 9) were taken at varying depths in the desert of Al-Anbar Governorate, Iraq. Molecular identification was done through 16S rRNA gene sequencing and phylogenetic analysis were done. HPLC was used to analyze crude secondary metabolites, and the retention time was used as an external standard through the use of rifampin. The antimicrobial activity was tested against six pathogenic microorganisms. Results: It was recorded that three phylogenetically divergent Streptomyces were identified. The results of bioassays showed differences between the antimicrobial activity of the extracts, with quantifiable zones of inhibition against the tested pathogens. HPLC profiling showed that isolates SS1, SS26, and SS81 had chromatographic peaks with retention times very similar to that of rifampin. Conclusion: Desert ecosystems are untapped sources of metabolically rich Streptomyces having immense biosynthetic capability. The mentioned isolates show a high potential in the synthesis of rifampin-like products, which highlights their importance in antibiotic discovery programs.