The resistance problem demands to discover new antibacterial agents effective against resistant pathogenic bacteria and fungi. It has been estimated that approximately one-third of the thousands of naturally occurring antibiotics have been obtained from actinomycetes. Actinomycetes are potential source of many bioactive compounds, which have diverse clinical effects and important applications in human medicine. Streptomyces are the dominant of all actinomycetes.Ī large number of actinomycetes have been isolated and screened from soil in the past several decades, accounting for 70%-80% of relevant secondary metabolites available commercially. Actinomycetes produce branching mycelium which may be of two types, viz., substrate mycelium and aerial mycelium. For this reason, they are also known as ray fungi. Actinomycetes have filamentous nature, branching pattern, and conidia formation, which are similar to those of fungi. The order actinomycetales is composed of approximately 80 genera, nearly all from terrestrial soils, where they live primarily as saprophytes, water and colonizing plants showing marked chemical and morphological diversity, but from a distinct evolutionary line.Īctinomycetes are gram-positive bacteria with high guanine+cytosine content of over 55% in their DNA, which have been recognized as sources of several secondary metabolites, antibiotics, and bioactive compounds that affect microbial growth. Among them, actinomycetales are an important group. Soil microorganisms provide an excellent resource for the isolation and identification of therapeutically important products. These isolates had antibacterial activity and could be used in the development of new antibiotics for pharmaceutical or agricultural purposes. aureus, while they showed less activity against S. All actinomycetes isolates showed antibacterial activity against S. MIC of actinomycete isolates was found to be 2.5 mg/ml against Shigella dysenteriae, Vancomycin-resistant enterococci, and Klebsiella pneumoniae, and was 1.25 mg/ml for Staphylococcus saprophyticus, Streptococcus pyogenes, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus, Bacillus cereus, Staphylococcus xylosus, Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, and Staphylococcus aureus. MIC was also determined for actinomycete isolates against all the tested microorganisms. Isolate AS7 exhibited the highest antagonistic activity against Bacillus cereus (24 mm) and AS16 showed the highest activity against Enterococcus faecalis (21 mm). Isolates AS14, AS27, and AS28 were highly active, while AS1 showed less activity against the pathogenic microorganisms. Totally 31 actinomycete isolates were tested for antagonistic activity against 12 pathogenic microorganisms. Antibacterial activity and Minimum Inhibitory Concentration (MIC) of the purified extract of isolates were evaluated. These isolates were subjected to extraction for production of the antibacterial compound. Isolates were morphologically and biochemically characterized. Potential colonies were screened, purified, and stored in glycerol stock. These samples were serially diluted and plated on actinomycete isolation agar media. Soils samples were taken from different niche habitats of Sheopur district, Madhya Pradesh, India. The main objective of the present study was isolation, purification, and characterization of actinomycetes from soil samples, having antimicrobial activity against 12 selected pathogenic strains.
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