LAUSR

Abstract The aim of this study is to identify potential antibacterial compounds of endophytic actinomycetes (EA) from marine algae Caulerpa racemosa for inhibit the multi drug resistant (MDR) Gram negative bacteria (GNB) including Eschericia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Proteus mirabilis (P. mirabilis), Klebsiella pnumonia (K. pnumoniae) and Enterobacter sp., which were confirmed by UTI panel antibiotic discs. Among the 100 EA, five strains were showed better antogonistic activity against all the selected uropathogens. In the ethyl acetate extract, the NMS 5 strains of EA showed excellent anti-bacterial activity against all the MDR uropathogen. Further, the NMS 5 extract was partially purified from thin layar chramatogaraphy (TLC) and spot 3 of TLC crude compound showed 14, 12 mm zone of inhibition against both the uropathogens. In addition, the minimum inhibition concentration (MIC) of crude exhibited the inhibition percentage was 87 and 84 at 120 µg/mL concentration. The MIC was confirmed by minimum bactericidal concentration (MBC) and it was indicated same as MIC. The treated NMS 5 crude compound of P. aeruginosa and K. pneumonia cells were showed more dead cells, intracellular damage and morphological damage with disaggregated cells by confocal laser scanning electron microscope (CLSM) and scanning electron microscope (SEM). Hence, the present study was revealed that the algae derived EA have the potential anti-bacterial metabolites for inhibition of MDR bacteria and it can be applied for various other infections after further purification.