An antimicrobial agent, chloramphenicol, was isolated from Actinobacteria 10CM9. The strain was isolated from lake sediment collected from Ercek Lake, Van (38 degrees 29'57.76 '' N and 43 degrees 33'10.98 '' E) and AIA medium was used as a isolation medium. 16S rRNA gene sequence analysis that showed the strain belongs to the genus Streptomycetes. A fermentation study in AIA broth medium (3L) followed by extraction with EtOAc afforded 105mg of crude extract. A bioactivity-guided fractionation by Open Column chromatography on silica gel led to the isolation of one secondary metabolite (10CM19-01, 31 mg). Structures of the metabolites were established as chloramphenicol, by means of NMR (H-1, C-13 and COSY) data. Antimicrobial activity of 10CM9 was tested by microdilution method against enteropathogenic Escherichia coli 0157:H7 (RSKK 234), methicillin resistant Staphylococcus aureus ATCC 43300, vancomycin resistant Enterococcus faecium DSMZ 13590, Candida albicansDSMZ 5817 and Pseudomonas aeruginosa ATCC 27853. As a result, 0.5 mu g/ml, 0.5 mu g/ml and 1 mu g/ml MIC values were observed against Escherichia coli 0157:H7, Enterococcus faecium and Staphylococcus aureus, respectively. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.