Astromicin is an aminoglycoside antibiotic produced by Micromonospora spp. It is effective against major gram-negative bacterias such as Proteus, Serratia, Citrobacter, Enterobacter spp., Klebsiella, Escherichia coli and Staphylococcus aureus. Astromicin sulfate has been given by intramuscular injection or intravenous infusion. Side effects are: rash, urticaria, itch, erythema, fever, nausea, vomiting, and diarrhea. Combination with strong diuretics can cause nephrotoxicity and ototoxicity.

Cefprozil is a 2nd generation cephalosporin that is FDA approved for the treatment of mild to moderate infections of upper respiratory tract, lower respiratory tract, and uncomplicated skin and skin-structure infections. Cefprozil, like the penicillins, is a beta-lactam antibiotic. By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, it inhibits the third and last stage of bacterial cell wall synthesis. Common adverse reactions include diarrhea, nausea, vomiting, dizziness, abdominal pain and vaginitis. Nephrotoxicity has been reported following concomitant administration of aminoglycoside antibiotics and cephalosporin antibiotics. Concomitant administration of probenecid doubled the AUC for cefprozil.

Gentamicin is an antibiotic of the aminoglycoside group, is derived by the growth of Micromonospora purpurea, an actinomycete. Gentamicin is a complex of three different closely related aminoglycoside sulfates, Gentamicins C1, C2, and C1a. Gentamicin is a broad-spectrum antibiotic, but may cause ear and kidney damage. Gentamicin binds to the prokaryotic ribosome, inhibiting protein synthesis in susceptible bacteria. It is bactericidal in vitro against Gram-positive and Gram-negative bacteria. Adverse reactions include adverse renal effects, neurotoxicity (dizziness, vertigo, tinnitus, roaring in the ears, hearing loss, peripheral neuropathy or encephalopathy), respiratory depression, lethargy, confusion, depression, visual disturbances, etc.

Colistin sulfate is a polypeptide antibiotic which penetrates into and disrupts the bacterial cell membrane. It is a cyclic polypeptide antibiotic from Bacillus colistinus. It is composed of Polymyxins E1 and E2 (or Colistins A, B, and C). Colistin was first isolated in Japan in 1949 from a flask of fermenting Bacillus polymyxa var. colistinus and became available for clinical use in 1959. The following local adverse events have been reported with topical corticosteroids, especially under occlusive dressings: burning, itching, irritation, dryness, folliculitis, hypertrichosis, etc. Healthcare providers had largely stopped using colistin in the 1970s because of its toxicity. However, with antibacterial resistance on the rise, colistin is increasingly being used today to treat severe, multidrug-resistant Gram-negative bacterial infections, particularly among intensive care-based patients. The problem with re-introducing an older drug, such as colistin, though, is that techniques for evaluating new drugs have evolved since the 1950s, and therefore, little is known about the dose needed to effectively fight infection while limiting the potential emergence of antimicrobial resistance and reducing potentially toxic side effects. More data are needed to guide optimal use of these older medications. An international team of NIAID-funded researchers is making progress in obtaining better dosing information about colistin and how best to use the antibiotic to treat Gram-negative bacterial infections. Resistance to colistin is rare. The first colistin-resistance gene that is carried in a plasmid and can be transferred between bacterial strains was described in 2016. This plasmid-borne mcr-1 gene has since been isolated in China, Europeand the United States.

Colistimethate is a methanesulfonate of polymyxin antibacterial colistin. Colistimethate is a nonactive prodrug. In aqueous solutions, colistimethate is hydrolyzed and forms a complex mixture of partially sulfomethylated derivatives and colistin. The antimicrobial activity of colistin is similar to that of polymyxin B and is restricted to gram-negative bacteria, including P aeruginosa, Acinetobacter species, Enterobacter-Klebsiella tribe, Escherichia coli, Salmonella and Shigella species, Citrobacter species, Yersinia pseudotuberculosis, Morganella morganii and Haemophilus influenzae. Colistin has also been shown to possess considerable in vitro activity against Stenotrophomonas maltophilia. Colistin and polymyxin B, however, do not have activity against Proteus, Providencia, Serratia species, Pseudomonas mallei, Burkholderia cepacia, Brucella species, most gram-positive bacteria, gram-negative cocci, anaerobes, fungi and parasites. Parenteral or nebulized colistimethate is indicated for the treatment of acute or chronic infections due to sensitive strains of certain gram-negative bacilli. It is particularly indicated when the infection is caused by sensitive strains of Pseudomonas aeruginosa.

Crotamiton is a scabicidal and antipruritic agent available as a cream or lotion for topical use. The drug was approved by FDA for the treatment of scabies and pruritic skin. Crotamiton is a mixture of the cis and trans isomers of N-ethyl-N-(o-methylphenyl)-2butenamide. Although the activity of crotamiton was shown both in vitro and in vivo, the mechanism of its action is still unknown.

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

Polymyxin B is a lipopeptide antibiotic isolated from Bacillus polymyxa. Its basic structure consists of a polycationic peptide ring and a tripeptide side chain with a fatty acid tail. Polymyxin B is a mixture of at least four closely related components, polymyxin B1 to B4, with polymyxin B1 and B2 being the two major components. Polymyxin B acts on Gram-negative bacteria by interacting with lipopolysaccharide (LPS) of the outer membrane and destabilizing it. Polymyxin B is indicated for the treatment of many bacterial diseases such as meningeal infections, urinary tract infections and bacteremia.

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.