Bafilomycin B1, a macrolide antibiotic isolated from Streptomyces sp, acts as an inhibitor of K+-dependent ATPase of E. coli. It also inhibits Gram-positive bacteria and fungi.
Polymyxin B1, a potent antimicrobial lipopeptide derived from Bacillus polymyxa, has potential for treating multidrug-resistant Gram-negative bacterial infections.