An antibacterial compound Pyrimidomycin produced by Streptomyces sp. PSAA01 isolated from soil of Eastern Himalayan foot-hill

Abstract

Selective isolation of soil Actinobacteria was undertaken to isolate a new class of antibiotics and bioactive molecules. A Streptomyces sp. PSAA01 (MTCC 13157), isolated from soil of Eastern Himalaya foot-hill was cultivated on a large scale for the production of the antimicrobials SM02. It has been found that the maximum amount of SM02 produced while PSAA01 was grown in ISP-2 medium (pH 7.0) for 7 days at 30oC. A significant zone of inhibition against Staphylococcus aureus has been found with the crude cell-free culture media (50 µL) of 7 days grown PSAA01. After the purification and chemical structural characterization, we found that SM02 is a new class of antibiotic having 747 dalton molecular weight. The compound SM02 contains pyrimidine moiety in it and is produced by a species of Streptomyces and thus we have named this antibiotic pyrimidomycin. The antimicrobial spectrum of SM02 has been found to be restricted in Gram-positive organisms with a MIC of 12 µg/mL. SM02 was found active against Mycobacterium sp. and also multi-drug resistant Gram-positive bacteria with similar potency and found to disrupt the bacterial cell wall. SM02 also showed significant impairment in the biofilm formation by S. aureus. Furthermore, SM02 showed synergy with the most used antibiotic like ampicillin, vancomycin and chloramphenicol. SM02 did not have cytotoxicity towards human cell lines indicating its activity is limited within bacteria.