Neosporin H

Polymyxin B is a cationic polypeptide antibiotic produced through the fermentation of the soil bacterium Paenibacillus polymyxa (formerly Bacillus polymyxa).[1] First discovered in 1947, it exhibits bactericidal activity against multidrug-resistant Gram-negative bacteria, including Pseudomonas aeruginosa, Acinetobacter baumannii, and certain Enterobacteriaceae, by disrupting the outer bacterial cell membrane through electrostatic interactions with lipopolysaccharides.[2][3] Primarily used as a last-resort treatment for severe systemic infections such as sepsis, meningitis, and urinary tract infections when other antibiotics fail, its administration is limited by a high risk of nephrotoxicity and neurotoxicity, necessitating close monitoring of renal function and neuromuscular status.[4][3]