Evaluation of actinomycetes isolated antimicrobial metabolites as potent inhibitor of multidrug resistant organisms

Abstract

With the increased metabolic diversity and adaptability, microorganisms are capable of living in diverse environmental conditions. Various microorganisms present in natural environment are resistant to some of the current antibiotics that has lead to discovery of new antibiotic compounds. Soil organisms have been paid a great attention and are recognized as a good source of antibiotic compounds. Actinomycetes are well known for their importance as bioactive metabolites in different sectors. Present study was carried out via isolation of actinomycetes from rhizospheric soil from four different locations of Rajasthan and the isolation was performed on Actinomycetes Isolation Agar (AIA) medium. In this study AIA10 isolate was screened for their antimicrobial potential against five selected microbial pathogens viz. Staphyloccocus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus vulgaris and Bacillus subtilis. After Solvent extraction, crude extracts of benzene and ethyl acetate were tested for antibacterial activity. GC-MS technique identified the presence of major components like Heptadecane at retention time (RT) - 18.131 (5.07 %), Heneicosane at RT - 20.935 (14.63 %), Hexadecanoic acid, Butyl ester at RT - 25.611 (4.92 %), Eicosanoic acid, 2,3-Bis(Acetyloxy)Propyl ester at RT - 32.509 (8.15 %), 9-Octadecenoic acid (Z)-, 2,3-Bis(Acetyloxy)Propyl ester at RT - 34.978 (34.32 %) in benzene crude extract.
In ethyl acetate extract major compounds identified were, Pentadecanoic acid at RT - 6.25 (21.251 %), N-Hexadecanoic acid at RT - 22.527 (12.79 %), Eicosanoic acid at RT - 23.788 (14.18 %), Hexadecanoic acid, 2-Hydroxy-1-(Hydroxymethyl) Ethyl ester at RT - 29.593 (5.59 %), Octadecanoic acid, 2,3-Dihydroxypropyl ester at RT - 33.182 (3.50 %) and 5,11,17,
23-Tetratert Butyl pentacyclo [19.3.1.1~3,7~.1~9,13~.1~15,19~]Octacosa1(25),3(28),4,6,9(27),10,12,15(26),16,18,21,
23-Dodecaene-25,26,27,28 Tetrol at RT - 54.152 (9.92 %). Primary screening was tested and the activity was observed against S. aureus and P. vulgaris. In secondary screening, benzene and ethyl acetate extract was found active against
S. aureus, at inhibition zone IZ = 10 and 20 mm, respectively. The study conducted proposes these actinomycetes as a potent source for antimicrobial metabolites.