Penicillin V is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The name "penicillin" can either refer to several variants of penicillin available, or to the group of antibiotics derived from the penicillins. Penicillin V has in vitro activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of Penicillin V results from the inhibition of cell wall synthesis and is mediated through Penicillin V binding to penicillin binding proteins (PBPs). Penicillin V is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases. By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, Penicillin V inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that Penicillin V interferes with an autolysin inhibitor. Used for the treatment of mild to moderately severe infections (e.g. dental infection, infections in the heart, middle ear infections, rheumatic fever, scarlet fever, skin infections, upper and lower respiratory tract infections) due to microorganisms.

Penicillin G, also known as benzylpenicillin, is a penicillin derivative commonly used in the form of its sodium or potassium salts in the treatment of a variety of infections. It is effective against most gram-positive bacteria and against gram-negative cocci. It is administered intravenously or intramuscularly due to poor oral absorption. Penicillin G may also be used in some cases as prophylaxis against susceptible organisms. Microbiology Penicillin G is bactericidal against penicillin-susceptible microorganisms during the stage of active multiplication. It acts by inhibiting biosynthesis of cell-wall mucopeptide. It is not active against the penicillinase-producing bacteria, which include many strains of staphylococci. Penicillin G is highly active in vitro against staphylococci (except penicillinase-producing strains), streptococci (groups A, B, C, G, H, L and M), pneumococci and Neisseria meningitidis. Other organisms susceptible in vitro to penicillin G are Neisseria gonorrhoeae, Corynebacterium diphtheriae, Bacillus anthracis, clostridia, Actinomyces species, Spirillum minus, Streptobacillus monillformis, Listeria monocytogenes, and leptospira; Treponema pallidum is extremely susceptible. Adverse effects can include hypersensitivity reactions including urticaria, fever, joint pains, rashes, angioedema, anaphylaxis, serum sickness-like reaction.

Penicillin G, also known as benzylpenicillin, is a penicillin derivative commonly used in the form of its sodium or potassium salts in the treatment of a variety of infections. It is effective against most gram-positive bacteria and against gram-negative cocci. It is administered intravenously or intramuscularly due to poor oral absorption. Penicillin G may also be used in some cases as prophylaxis against susceptible organisms. Microbiology Penicillin G is bactericidal against penicillin-susceptible microorganisms during the stage of active multiplication. It acts by inhibiting biosynthesis of cell-wall mucopeptide. It is not active against the penicillinase-producing bacteria, which include many strains of staphylococci. Penicillin G is highly active in vitro against staphylococci (except penicillinase-producing strains), streptococci (groups A, B, C, G, H, L and M), pneumococci and Neisseria meningitidis. Other organisms susceptible in vitro to penicillin G are Neisseria gonorrhoeae, Corynebacterium diphtheriae, Bacillus anthracis, clostridia, Actinomyces species, Spirillum minus, Streptobacillus monillformis, Listeria monocytogenes, and leptospira; Treponema pallidum is extremely susceptible. Adverse effects can include hypersensitivity reactions including urticaria, fever, joint pains, rashes, angioedema, anaphylaxis, serum sickness-like reaction.

Discovered as natural products from actinomycetes soil bacteria, the tetracyclines were first reported in the scientific literature in 1948. They were noted for their broad spectrum antibacterial activity and were commercialized with clinical success beginning in the late 1940s to the early 1950s. By catalytic hydrogenation of Aureomycin, using palladium metal and hydrogen, the C7 deschloro derivative was synthesized, producing a compound of higher potency, a better solubility profile, and favorable pharmacological activity; it was subsequently named tetracycline. Tetracyclines are primarily bacteriostatic and exert their antimicrobial effect by the inhibition of protein synthesis by binding to the 30S ribosomal subunit. Tetracycline is active against a broad range of gram-negative and gram-positive organisms. Tetracycline is indicated in the treatment of infections caused by susceptible strains. To reduce the development of drug-resistant bacteria and maintain the effectiveness of tetracycline hydrochloride and other antibacterial drugs, tetracycline hydrochloride should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

Oxytetracycline, a tetracycline analog isolated from the actinomycete streptomyces rimosus, was the second of the broad-spectrum tetracycline group of antibiotics to be discovered The drug is used for the prophylaxis and local treatment of superficial ocular infections due to oxytetracycline- and polymyxin-sensitive organisms for animal use only. These infections include the following: Ocular infections due to streptococci, rickettsiae E. coli, and A. aerogenes (such as conjunctivitis, keratitis, pinkeye, corneal ulcer, and blepharitis in dogs); ocular infections due to secondary bacterial complications associated with distemper in dogs; and ocular infections due to bacterial inflammatory conditions which may occur secondary to other diseases in dogs. Allergic reactions may occasionally occur. Treatment should be discontinued if reactions are severe. If new infections due to nonsensitive bacteria or fungi appear during therapy, appropriate measures should be taken. Oxytetracycline inhibits cell growth by inhibiting translation. It binds to the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. The binding is reversible in nature. Oxytetracycline is lipophilic and can easily pass through the cell membrane or passively diffuses through porin channels in the bacterial membrane.

Ceftobiprole is a fifth-generation cephalosporin antibiotic. It was discovered by Basilea Pharmaceutica and was developed by Johnson & Johnson Pharmaceutical Research and Development. The drug is demonstrates activity against clinically important gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, penicilliin-resistant Staphylococcus pneumoniae, and Enterococcus faecalis. The drug also has demonstrated activity against gram-negative bacteria including Citrobacter spp., Escherichia coli, Enterobacter spp., Klebsiella spp., Serratia marcescens, and Pseudomonas aeruginosa. The drug has gained regulatory authorization from European states for the treatment of hospital-acquired pneumonia (HAP, excluding ventilator-associated pneumonia, VAP) and community-acquired pneumonia (CAP).

Grepafloxacin is a monofluorinated quinolone with a cyclopropyl group at position 1, a 3-methyl-1piperazinyl group at position 7 and a methyl substitution at the 5 position, that was synthesized by Otsuka in Japan. It exhibited in vitro activity against a wide variety of both Gram-positive and Gram-negative bacteria including anaerobic species. The compound was reported to have a broad spectrum of activity, particularly against pathogens responsible for community-acquired respiratory infections including those caused by beta-lactam and macrolide-resistant strains of Streptococcus pneumoniae and Haemophilus influenzae. Japanese researchers also reported that unlike other quinolones, grepafloxacin reached high levels in the bile and might also be useful in the treatment of biliary tract infection. Grepafloxacin was administered once daily and did not require dosage adjustment for renal insufficiency, but grepafloxacin tablets were contraindicated in patients with hepatic failure. Otsuka Pharmaceutical signed a licensing agreement for grepafloxacin with GlaxoSmithKline. According to this agreement, GlaxoSmithKline had marketing rights to grepafloxacin in Europe, USA, and certain other markets. Otsuka retained rights for Japan and some Asian countries

Alatrofloxacin is a fluoroquinolone antibiotic developed as a mesylate salt and was sold under brand name Trovan, but was withdrawn from the U.S. market in 2001. Trovan was indicated for the treatment of patients initiating therapy in in-patient health care facilities (i.e., hospitals and long term nursing care facilities) with serious, life- or limb-threatening infections caused by susceptible strains of the designated microorganisms in the conditions listed below. Nosocomial pneumonia caused by Escherichia coli, Pseudomonas aeruginosa, Haemophilus influenzae, or Staphylococcus aureus. Community acquired pneumonia caused by Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Staphylococcus aureus. Complicated intra-abdominal infections, including post-surgical infections caused by Escherichia coli. Gynecologic and pelvic infections including endomyometritis, parametritis, septic abortion and post-partum infections caused by Escherichia coli, Bacteroides fragilis, viridans group streptococci, Enterococcus faecalis. Complicated skin and skin structure infections, including diabetic foot infections, caused by Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli, or Proteus mirabilis. After intravenous administration, alatrofloxacin is rapidly converted to trovafloxacin, which is responsible for therapeutic effect. Plasma concentrations of alatrofloxacin are below quantifiable levels within 5 to 10 minutes of completion of a 1 hour infusion.

Temafloxacin (marketed by Abbott Laboratories as Omniflox) is almost completely absorbed from the gastrointestinal tract, with an absolute bioavailability of approximately 93% and is not greatly affected by food. The time to reach peak concentrations ranges between 2 and 3 hours. In addition to the broad spectrum of activity all fluoroquinolones have against gram-negative pathogens, temafloxacin has improved antimicrobial activity against gram-positive aerobic cocci, intracellular microorganisms, and anaerobes. The bactericidal action of temafloxacin results from interference with the activity of the bacterial enzymes DNA gyrase. Omniflox was approved to treat lower respiratory tract infections, genital and urinary infections like prostatitis, and skin infections in the U.S. by the Food and Drug Administration in January 1992. Severe adverse reactions, including allergic reactions and hemolytic anemia, developed in about fifty patients during the first four months of its use, leading to three patient deaths. Abbott withdrew the drug from sale in June 1992.

Loracarbef (KT3777) is carbacephem antibiotic structurally identical to cefaclor, except that the sulfur atom of position 1 of the cephem nucleus has been replaced by carbon. It showed good affinity for penicillin-binding proteins. At low concentrations (< 2 mg/L) in vitro, it inhibits Streptococcus pneumoniae, S. pyogenes, beta-haemolytic streptococci groups B, C and G. Proteus mirabilis and Moraxella catarrhalis, including beta-lactamase-producing strains. At therapeutic plasma concentrations it is also active in vitro against most strains of Staphylococcus aureus, S. saprophyticus, Escherichia coli and beta-lactamase-positive and -negative strains of Haemophilus influenzae. Loracarbef has been indicated in the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms.