Polypeptides, Glycopeptides, and Streptogramins

The polypeptides include bacitracin A, colistin (polymyxin E), novobiocin, and polymyxin B. Bacitracin is a complex mixture of branched, cyclic decapeptides produced by Bacillus subtilise, which was first isolated in 1945. The polymyxins, discovered in 1947, are synthesized by various strains of Bacillus polymyxa. Colistin (polymyxin E) comprises a family of polymyxins and was known as colimycin when first isolated from a broth of Bacillus polymyxa var. colistinus in 1951. The polymyxins are cationic detergents. Novobiocin, first reported in 1955 as streptonivicin, is produced by the actinomycete Streptomyces niveus. 

The glycopeptide antibiotics include avoparcin, teicoplanin, and vancomycin. Avoparcin is produced by Amycolatopsis coloradensis, while teicoplanin is a mixture of six closely related compounds produced by Streptococcus teichomyetius. Vancomycin is produced by Streptococcus orientalis. 

Virginiamycin is used to improve daily liveweight gain and feed conversion efficiency in feedlot and grazing cattle, broilers, turkeys, and pigs in several countries. However, 

Polymyxins are notably nephrotoxic and neurotoxic and cause intense pain if injected. Polymyxin B is a potent histamine releaser however, hypersensitivity reactions to all polymyxins are seen occasionally. The incidence of adverse reactions to novobiocin sodium is also relatively frequent. 

The limited literature available suggests that presently none of the polypeptide antibiotics, glycopeptide antibiotics, or streptogramins pose a risk to the environment. 

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