Antibiotics are the most active chemotherapeutics among drugs; they exert their therapeutic effect by antagonizing
the growth of bacteria. Since 1910 many antibiotics have been developed with different mechanisms of action
including: (1) Inhibition of bacteria’s cell wallsynthesis; this class of antibiotics includes vancomycin and
β-lactam antibiotics such aspenicillins, cephalosporins, and carbapenems, (2) inhibition of protein synthesis
including tetracyclines, aminoglycosides, macrolides, and chloramphenicol, and (3) DNA synthesis inhibitors
such as fluoroquinolones and sulfonamides that inhibit folic acid synthesis. In this chapter, we describe the three
antibiotic classes, their mechanism of action, clinical uses, side effects, and their resistance by different bacteria