Introduction: Antimicrobial AgentsAlthough they are often over-prescribed, antimicrobial agents are a critical defense against microbial infections. The sources of microbial infections include bacteria, viruses, funguses, and parasites. Therefore, the key categories of antimicrobial pharmaceutical agents are antibiotics, antifungals, antiprotozoal, and antiviral drugs. Sometimes the terms antibiotic, antimicrobial, and anti-infective are used interchangeably, but it is crucial to differentiate between the type of infection in order to choose the appropriate antimicrobial agent (Leekha, Terrell, & Edson, 2011, p. 156). Incorrect treatment can lead to deleterious results including resistance. There are several different ways to classify antimicrobial agents, and likewise, different methods of determining whether the infection is related to a virus, bacteria, or otherwise.

Classifying Antimicrobial Agents

One method of classifying antimicrobial agents is via their chemical composition or molecular structure. Another method of classifying antimicrobial agents is via their mechanism of action, and a third method is their level of importance overall in human medicine, which pragmatic implications for public policy, public health policy, and healthcare procurement and logistics (“Categorization of Antimicrobial Drugs Based on Importance in Human Medicine,” 2009). Antimicrobials can also be classified based on their antibacterial activity, referring to features like mechanisms of resistance, sensitivity,...

In fact, antimicrobials can also be classified according to their source: as they are typically derived from at least three sources including molds or fungi, bacteria themselves, or from synthetic analysis (Purdue Research Foundation, 1996). The broadest means by which to classify antimicrobial agents would be to focus on what they target: such as a fungus, a virus, a parasite, or bacteria (“Antimicrobial Agents – An Overview,” 2015).
Chemical Classifications

Chemical classification systems divide antimicrobials into categories based on their chemical features. For example, penicillins differ from polypeptides, which differ from tetracyclines. Penicillins and cephalosporins together are sub-categories of the parent class of Beta-lactam antibiotics (Becker, 2013; Purdue Research Foundation, 1996). There are also macrolides, lincosamides, aminoglycosides, sulfanomides, fluoroquinolones, metronidazoles, clindamycin, and innumerable other sub-categories of antimicrobial agents based on their chemical composition (Becker, 2013; Purdue Research Foundation, 1996). Understanding the chemical composition of the antimicrobial helps the physician to treat the infection with the most efficacious, evidence-based intervention.

Mechanism of Action

Classifying antimicrobial agents according to their mechanism of action can also help narrow down which drugs to prescribe under which conditions. However, using a mechanism…