An antibacterial substance, a white crystal identified as 3 nitro propionic acid, was isolated from fermentation broth of an endophytic fungus, by silica gel chromatography, thin layer chromatography and recrystallization technology. Its structure was elucidated by spectroscopic methods, mainly 1H and 13C nuclear magnetic resonance (NMR), Infrared Radiation spectrometry, and high resolution mass spectra. 3 nitro propionic acid was displayed a broad inhibition effect on tested pathogenetic bacteria by broth microdilution method. The results showed minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 3 nitropropionic acid against Bacillus subtilis were 1.25 mg/mL and 2.5 mg/mL respectively, against Escherichia coli were 1.25 mg/mL and 5 mg/mL, and against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa, Salmonella pullorum CVCC 533, Salmonella enteritidis CVCC 3377 were 2.5 mg/mL and 5 mg/mL. Moreover it revealed a distinct antibacterial activity against multidrug resistant strains including 17 resistant Salmonella, 17 resistant Staphylococcus aureus and 14 resistant Escherichia coli.
