Penamecillin is a semi-synthetic beta-lactamase sensitive penicillin. The compound is the acetoxymethyl ester of benzylpenicillin, which is rapidly hydrolysed to the latter by the action of non-specific esterases.

Cefatrizine is a broad-spectrum, semisynthetic, first-generation cephalosporin with antibacterial activity. Cefatrizine binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. PBPs are enzymes involved in the terminal stages of assembling the bacterial cell wall and in reshaping the cell wall during growth and division. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This results in the weakening of the bacterial cell wall and causes cell lysis. Cefatrizine is used to treat a large variety of bacterial infections, such as respiratory tract, ear, skin and urinary tract infections. Cefatrizine is less effective against gram positive bacteria than first generation drugs. Antibiotics require constant drug level in body for therapeutic effect.

Sulfamoxole is a sulfonamide antibacterial compound. Sulfamoxole is a competitive inhibitor of the bacterial enzyme dihydropteroate synthetase. Sulfamoxole alone or in combination with trimethoprim is used for the treatment of susceptible infections.

Rosoxacin, a quinolone derivative, is an antibiotic, which is used for the treatment of uncomplicated acute gonococcal urethritis. Administration of rosoxacin is an effective regimen for the therapy of chancroid and is a reasonable alternative to other short-course regimens. The drug binds to and inhibits two enzymes topoisomerase II (DNA gyrase), which is required for bacterial DNA replication, transcription, repair, and recombination.

Nitroxoline (8-hydroxy-5-nitroquinoline) has been used since 1962 in the treatment of urinary tract infections especially those due to gram negative bacilli (E. coli). Nitroxoline is active against most Gram-negative and –positive uropathogenic bacteria, against mycoplasmas (M. hominis, Ureaplasma urealyticum) and human pathogenic Candida spp. The mode of antibacterial and antifungal action is based on the ability of nitroxoline to chelate with various metallic bivalent cations. Nitroxoline is a fluorquinolone that is active against bacterial gyrases. This drug may also have antitumor activity by inhibition of type 2 methionine aminopeptidase (MetAP2) protein which is involved in angiogenesis. Nitroxoline induces apoptosis and inhibits glioma growth in vivo and in vitro. Due to the excellent anticancer activity and its well-known safety profile and pharmacokinetic properties, nitroxoline has been approved to enter into a phase II clinical trial in China for non-muscle invasive bladder cancer treatment

Sulfalene (INN, USAN) or Sulfametopyrazine (BAN) is a long-acting sulfonamide antibiotic used for the treatment of chronic bronchitis, urinary tract infections, and malaria. Sulfametopyrazine, by virtue of a long half-life, achieves peak blood levels of 120 mkg/ml or more which fall to around 30-50 mkg/ml one week after a single oral dose of 2 g. Long-term administration of this drug in the treatment of leprosy for up to 3 years has been accomplished without serious unwanted effects

Dalbavancin is a second-generation lipoglycopeptide antibiotic that was designed to improve on the natural glycopeptides currently available, such as vancomycin and teicoplanin. Modifications from these older glycoprotein classes allowed a similar mechanism of action with increased activity and once weekly dosing. Its use is indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by the following gram-positive microorganisms: Staphylococcus aureus (including methicillin-susceptible and methicillin-resistant strains), S. pyogenes, S. agalactiae, and S. anginosus group (including S. anginosus, S. intermedius, and S. constellatus). Under the brand name DALVANCE Dalbavancin is indicated for acute bacterial skin and skin structure infections (ABSSSI) caused by designated susceptible strains of Gram-positive microorganisms. The bactericidal action of dalbavancin results primarily from inhibition of cell-wall biosynthesis. Specifically, dalbavancin prevents incorporation of N-acetylmuramic acid (NAM)- and N-acetylglucosamine (NAG)-peptide subunits from being incorporated into the peptidoglycan matrix; which forms the major structural component of Gram-positive cell walls. The large hydrophilic molecule is able to form hydrogen bond interactions with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides, which is normally a five-point interaction. Binding of dalbavancin to the D-Ala-D-Ala prevents the incorporation of the NAM/NAG-peptide subunits into the peptidoglycan matrix. In addition, dalbavancin alters bacterial-cell-membrane permeability and RNA synthesis.

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.

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.

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