Various families of antibiotics are used for various types of microorganisms to achieve control and assist body defenses during times of infection. Antibiotics are products of microorganisms that react with and inhibit the growth of other microorganisms. An antibiotic should be selectively toxic to pathogenic microorganisms, should not incite an allergic response in the body, should not upset the normal microbial population of various body sites, and should not foster the development of drug resistance.
Penicillin. Penicillin prevents Gram-positive bacteria from forming peptidoglycan, the major component of the cell wall. Without peptidoglycan, internal pressures cause the bacterium to swell and burst.
Penicillin is not one antibiotic, but a family of antibiotics. The family includes penicillin F, penicillin G, and penicillin X, as well as ampicillin, amoxicillin, nafcillin, and ticarcillin. The first penicillin was derived from the green mold Penicillium, but most penicillins are now produced by synthetic means. A few are used against Gram-negative bacteria.
People allergic to penicillin may suffer localized allergy reactions or whole body reactions known as anaphylaxis. Long-term use of penicillin encourages the emergence of penicillin-resistant bacteria because these bacteria produce penicillinase, an enzyme that converts penicillin to penicilloic acid.
Cephalosporin antibiotics. Cephalosporin antibiotics include cefazolin, cefoxitin, cefotaxime, cefuroxime, and moxalactam. The antibiotics were first produced by the mold Cephalosporium. They prevent synthesis of bacterial cell walls, and most are useful against Gram-positive bacteria; the newer cephalosporin antibiotics are also effective against Gram-negative bacteria. Cephalosporins are especially useful against penicillin-resistant bacteria and are often used as substitutes for penicillin.
Aminoglycoside antibiotics. The aminoglycoside antibiotics inhibit protein synthesis in...