Antimicrobial Activity and Metabolic Fingerprinting of Rare Actinomycetes Isolated from Fresh Water Lakes and Seasonal Ponds in Northern Punjab, Pakistan

Abstract

Aims: To isolate and identify rare actinomycetes from fresh water lakes and seasonal ponds in northern Punjab, Pakistan, and to screen the isolated strains for antimicrobial activity and compounds against nosocomial pathogens Study Design: Collection of water and mud samples, sample enrichment and  selective isolation of rare actinomycetes, laboratory scale cultivations, solvent extractions, agar diffusion and disc diffusion assays, chemical profiling and metabolic fingerprinting by TLC and HPLC Place and Duration of Study: Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore, Pakistan, during September 2013 to August 2014.  Methodology: In this study about thirty rare actinomycetes strains were selectively isolated from the soil and mud samples collected from different fresh water lakes and seasonal ponds in district Narowal, Pakistan. The isolates were identified by cultural, morphological, biochemical and physiological characterization. The methanolic crude extracts obtained from the culture broth of the selected isolates were subjected to a comprehensive biological and chemical screening process using agar diffusion assay, cytotoxicity assay, thin layer chromatography, HPLC-UV/RI etc.    Results: The study revealed that the selected isolates exhibit close similarity with genera Nocardia and Micromonospora. The selected strains exhibited promising antimicrobial activity against a panel of nosocomial bacterial pathogens including Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, and Proteus. The methanolic crude extracts analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC-UV) exhibited an impressive diversity of the chemical constituents present in extracts. Conclusion: The study demonstrates that the isolation, identification and screening of the rare actinomycetes from untapped ecological niches like fresh water lakes and seasonal ponds in our area is highly useful for the discovery of novel bioactive compounds that are effective against wide range of pathogens.