Bayer developed MEZLOCILLIN (previously known as BAYPEN); it is a semisynthetic ampicillin-derived penicillin. Mezlocillin is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The bactericidal activity of mezlocillin results from the inhibition of cell wall synthesis and is mediated through mezlocillin binding to penicillin binding proteins (PBPs). Mezlocillin is stable against hydrolysis by a variety of beta-lactamases, including penicillinases and cephalosporinases and extended spectrum beta-lactamases. Mezlocillin was poorly absorbed orally and was given either intramuscularly or intravenously. This drug was discontinued in the U.S.

Bacampicillin is a penicillin antibiotic. It is a prodrug of ampicillin with improved oral bioavailability. It exerts bactericidal activity via inhibition of bacterial cell wall synthesis by binding one or more of the penicillin binding proteins (PBPs). Spectrobid is used to treat bacterial infections such as tonsillitis, pneumonia (lung infection), bronchitis (inflammation of airway), urinary tract infections, gonorrhea, and infections of the skin. Adverse effects are: anemia, thrombocytopenia, neutropenia, agranulocytosis, seizures, nephrotoxicity, Jarisch-Herxheimer Reaction (fever, chills, sweating, tachycardia, hyperventilation, flushing, and myalgia). Drug interactions: Contraceptives - decreased contraceptive effectiveness; Live Typhoid Vaccine - decreased immunological response to the typhoid vaccine; Probenecid - increased bacampicillin levels.

Sisomicin is a new broad-spectrum aminoglycoside most closely related structurally to gentamicin C1a. In vitro and in experimental infections, sisomicin has been found to be more potent than or nearly as potent as the most active of the other available aminoglycosides. Although susceptible to many (but not all) aminoglycoside-inactivating enzymes, sisomicin is active against many microorganisms that are resistant to other aminoglycosides by nonenzymatic mechanisms. Sisomicin has been shown to interact synergistically with various beta-lactam antibiotics against enterococci, staphylocicci, Enterobacteriaceae, and nonfermentative gram-negative bacilli. The pharmacokinetics and toxicity of sisomicin in humans appear to be similar to those of gentamicin, despite earlier reports of greater acute toxicity in animals. Sisomicin binds to 30s and 50s ribosomal subunits of susceptible bacteria disrupting protein synthesis, thus rendering the bacterial cell membrane defective.

Cinoxacin is a synthetic antibacterial agent for oral administration. Cinoxacin mode of action involves the inhibiting of DNA gyrase, a type II topoisomerase, and topoisomerase IV. Adverse effects are nausea, anorexia, vomiting, abdominal cramps/pain, perverse taste, diarrhea, headache, dizziness, rash, urticaria, pruritus, edema and other.

Cefamandole (also known as cephamandole) is a broad-spectrum cephalosporin antibiotic. The clinically used form of cefamandole is an ester form, cefamandole nafate, a prodrug. Cefamandole is no longer available in USA, but it has prescription in UK. Cefamandole under brand name mandol is indicated for the treatment of serious infections caused by susceptible strains of the designated microorganisms such as: lower respiratory infections, including pneumonia, caused by S. pneumoniae. So as urinary tract infections caused by E. coli, Proteus spp.; peritonitis caused by E. coli and Enterobacter spp. Septicemia caused by E. coli; skin and skin structure infections caused by S. aureus; bone and joint infections caused by S. aureus (penicillinase- and non-penicillinase-producing). Like all beta-lactam antibiotics, cefamandole binds to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, causing the inhibition of the third and last stage of bacterial cell wall synthesis. Bacterial cell wall autolytic enzymes such as autolysins then mediate cell lysis; it is possible that cefamandole interferes with an autolysin inhibitor.

Ticarcillin (also known as Ticar) is a semisynthetic antibiotic with a broad spectrum of bactericidal activity against many gram-positive and gram-negative aerobic and anaerobic bacteria. Ticarcillin is not absorbed orally; therefore, it must be given intravenously or intramuscularly. Ticarcillin's antibiotic properties arise from its ability to prevent cross-linking of peptidoglycan during cell wall synthesis when the bacteria tries to divide, causing death. Usage of ticar was discontinued.

Oxolinic acid is a synthetic quinolone antibiotic related to nalidixic acid. It is authorized in veterinary medicine for use in finfish, calves, pigs, and poultry. It acts by inhibiting bacterial type II topoisomerase activity. Oxolinic acid has been used in human medicine in several countries in the past. Its use in human medicine has largely been replaced by the fluoroquinolone antibiotics.

Cephapirin is a first-generation cephalosporin. Cephapirin has been indicated for the treatment of infections when caused by susceptible strains in respiratory, genitourinary, gastrointestinal, skin and soft tissue, bone and joint infections, septicemia; treatment of susceptible gram-positive bacilli and cocci (never enterococcus); some gram-negative bacilli including E. coli, Proteus, and Klebsiella may be susceptible. Cephapirin is used in veterinary as an intra-uterine antibiotic infusion for the treatment of subacute and chronic endometritis in cows and repeat breeders.

Cephradine is a semisynthetic cephalosporin antibiotic. Cephradine is active against the following organisms in vitro: Group A beta-hemolytic streptococci; Staphylococci, including coagulase-positive, coagulase-negative, and penicillinase-producing strains; Streptococcus pneumoniae (formerly Diplococcus pneumoniae); Escherichia coli; Proteus mirabilis; Klebsiella species; Hemophilus influenza. It works by stopping the growth of bacteria. It is used to treat a wide variety of bacterial infections (e.g., skin, ear, respiratory and urinary tract infections). Pseudomembranous colitis has been reported in patients receiving cephradine both orally and intravenously. Diarrhea generally starts 1 to 16 days after starting cephradine therapy. Gastrointestinal side effects have included nausea, vomiting. Hypersensitivity reactions have included rash, urticaria, pruritus, and joint pain. Bacteriostats may interfere with the bactericidal action of cephalosporins in acute infection; other agents, e.g., aminoglycosides, colistin, polymyxins, vancomycin, may increase the possibility of nephrotoxicity.

Cephacetrile, a parenteral cephalosporin, is a broad-spectrum first generation cephalosporin antibiotic effective in Gram-positive and Gram-negative bacterial infections. It works by inhibition of bacterial cell wall synthesis. It attains high serum levels and is excreted quickly via the urine. 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. Cephacetrile was used in the treatment of female pelvic inflammatory disease, meningitis and number of other systemic, respiratory and urinary infections.