Isolation, Purification And Identification Of The Biological Activities Of A Novel Antibiotic 19-1

The 19-1 complex was isolated from the fermentation broth of Streptomyces sp. AP19-1, whose major component 19-1, showed a strong activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus(MRSA) in vitro. The study of the activity comparing to the other antibiotics and the methods of purification was presented.The supernate of the fermentation broth was highly active against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Bacillus pumilus. The minimal inhibitory concentrations(MIC) of supernate against these bacteria were diluted 1000, 1600, 3600, 2400 fold, respectively. The MIC of 5 different MRSA, which were isolated from the clinical patients, B3892, B8208, B6172, B6189, B4524, were diluted 1280, 600, 1000, 1000, 400 fold, respectively. 5 supernate, 5g ampicillin, 5g penicillin, 5g ciprofloxacin, and 30p.g vancomycin commercial production were used to test whether there was an inhibitory effect against the MRSA. Ampicillin, penicillin, ciprofolxacin had no effect at all, while vancomycin produced 18.1mm inhibitory zone on average, the supernate produced 20.7mm inhibitory zone on average.The antibiotic substance was purified by silica gel column chromatography, thin layer chromatography(TLC), and high performance liquid chromatography(HPLC). The liquid chromatographic separation was performed using a Diamonsil C18, 5m(250 4.6mm,I.D.), reversed-phase column, and a mixture of 20mM ammonium acetate(pH 4.0)-acetonitrile(65:35, v/v) as mobile phase, delivered at 1ml/min, at 25. The compounds were detected by UV detector at 276nm. The separation yielded antibiotic principle with purity of 92.5%.