Bacitracin is a mixture of related cyclic polypeptides produced by organisms of the licheniformis group of Bacillus subtilis var Tracy. As a polypeptide, toxic, and difficult to use chemical, bacitracin doesn't work well orally, however is very effective topically. Bacitracin exerts pronounced antibacterial action in vitro against a variety of gram-positive and a few gram-negative organisms. However, among systemic diseases, only staphylococcal infections qualify for consideration of bacitracin therapy. Bacitracin is composed of a mixture of related compounds with varying degrees of antibacterial activity. Notable fractions include bacitracin A, A1, B, B1, B2, C, D, E, F, G, and X. Bacitracin A has been found to have the most antibacterial activity. Bacitracin intereferes with the dephosphorylation of the 55-carbon, biphosphate lipid transport molecule C55-isoprenyl pyrophosphate (undecaprenyl pyrophosphate), which carries the building blocks of the peptidoglycan bacterial cell wall outside the inner membrane for construction. Bacitracin binds divalent transition metal ions (Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)) which binds and oxidatively cleave DNA. Used for the treatment of infants with pneumonia and empyema caused by staphylococci shown to be susceptible to the drug. Also used in ointment form for topical treatment of a variety of localized skin and eye infections, as well as for the prevention of wound infections. Used against gram positive bacteria. Bacitracin is also used as an inhibitor of proteases and other enzymes. However, specific activity of bactracin's inhibition of protein disulfide isomerase has been called into question.

Neomycin is an aminoglycoside antibiotic found in many topical medications such as creams, ointments, and eye drops. In vitro tests have demonstrated that neomycin is bactericidal and acts by inhibiting the synthesis of protein in susceptible bacterial cells. It is effective primarily against gram-negative bacilli but does have some activity against gram-positive organisms. Neomycin is active in vitro against Escherichia coli and the Klebsiella-Entero. Topical uses include treatment for superficial eye infections caused by susceptible bacteria (used in combination with other anti-infective), treatment of otitis externa caused by susceptible bacteria, treatment or prevention of bacterial infections in skin lesions, and use as a continuous short-term irrigant or rinse to prevent bacteriuria and gram negative rod bacteremia in bacteriuria patients with indwelling catheters. May be used orally to treat hepatic encephalopathy, as a perioperative prophylactic agent, and as an adjunct to fluid and electrolyte replacement in the treatment of diarrhea caused to enter pathogenic E. coli (EPEC). Neomycin sulfate has been shown to be effective adjunctive therapy in hepatic coma by reduction of the ammonia forming bacteria in the intestinal tract. The subsequent reduction in blood ammonia has resulted in neurologic improvement. To reduce the development of drug-resistant bacteria and maintain the effectiveness of Neomycin Sulfate Oral Solution and other antibacterial drugs, susceptible bacteria should use Neomycin Sulfate Oral Solution only to treat or prevent infections that are proven or strongly suspected to be caused. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy. Neomycin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site near nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes

Bacitracin is a polypeptide antibiotic produced by Bacillus subtilis and Bacillus licheniformis. Bacitracin in combination with neomycin and polymyxin B is indicated for the treatment of many bacterial diseases. The antibacterial properties of bacitracin are mediated by its binding to C55-isoprenyl pyrophosphate, resulting in inhibition of cell wall biosynthesis.

Bacitracin is a polypeptide antibiotic produced by Bacillus subtilis and Bacillus licheniformis. Bacitracin in combination with neomycin and polymyxin B is indicated for the treatment of many bacterial diseases. The antibacterial properties of bacitracin are mediated by its binding to C55-isoprenyl pyrophosphate, resulting in inhibition of cell wall biosynthesis.

Bacitracin is a polypeptide antibiotic produced by Bacillus subtilis and Bacillus licheniformis. Bacitracin in combination with neomycin and polymyxin B is indicated for the treatment of many bacterial diseases. The antibacterial properties of bacitracin are mediated by its binding to C55-isoprenyl pyrophosphate, resulting in inhibition of cell wall biosynthesis.