Antimicrobial agents

Antimicrobial agents

Infections are among the common diagnoses made among patients in healthcare today. This has prompted antimicrobial agents to be the most widely used medications. Antimicrobials include all the agents that are applied against any microorganism, including bacteria, virus, fungi, and protozoa that may cause illness in the body (Weston, Burgess, & Roberts, 2016). Once microorganisms enter the body, they start to reproduce and grow into tissues hindering the normal functioning of the tissues hence infection or illness.  Antimicrobial agents can either act through killing the microorganisms of hindering their growth. The objective of this article is to classify antimicrobials discuss the difference between viral and bacterial antimicrobial agents.

Describe the categories of antimicrobial agents.

Primarily antimicrobial agents are classified based on the microorganism they are meant to act against (World Health Organization 2017). Infections are caused by various organisms, including bacteria, fungi, virus, and protozoa. Therefore, based on the pathogens they act against, antimicrobial agents are classified into Antibiotics, antifungals, antiviral, anti-parasitic, antiseptics, and disinfectants. Antibacterial agents/ antibiotics are applied to inhibit or counteract the effects of bacteria in the body. Azithromycin is an example of an antibacterial agent.  Antifungal drugs are used to prevent the impacts of fungi in the body. Metronidazole is one of the drugs belonging to this class. Antiviral agents are applied to the effects of the virus in the body. Acyclovir is one of the examples. On the other side, anti-parasitic drugs are used to counteract the effects of parasites in the body. Albendazole is one of such agents.

Differences between viral and bacterial infections.

Viral and bacterial infections share several factors. The main common factor shared is that both are caused by microbes. Through activities such as contact with infected individuals, contact with contaminated surfaces, consumption and intake of contaminated food and water, respectively, viral or bacterial infections are spread out.

However, bacterial infections are caused by bacteria, while viral infections are caused by viruses.  Unlike in bacterial infection, a patient is less likely to experience fever in viral infection. Viral and bacterial infections are different. Starting from the organisms themselves, bacteria are usually single-celled and contain cell wall. Bacteria reproduce on their own. On the other side, viruses have no cell wall and only multiply inside the host tissues. In terms of presentation, bacterial and viral infections present differently depending on the affected body organ. According to Sterling (2016), the main difference between viral and bacterial infection is that bacterial infections increase neutrophil and eosinophil levels in the body, while viral infections increase lymphocyte levels. Unlike in bacterial infection, a patient is less likely to experience fever in viral infection.

In terms of pathophysiology, bacterial infection results in the production of inflammatory mediators. Extracellular bacteria trigger the flow of neutrophils to the site of infection, while intracellular bacteria triggers eosinophils and neutrophils. This makes full blood count of these cells extremely high. Red blood cells count relatively low in bacterial infection as compared to viral infection. Platelet count in bacterial infection usually remains normal. In a viral infection, lymphocyte largely dominate in the body reaction against the pathogens. Therefore, white blood cell count increases, platelet count, as well as red blood cells count may drop.


why proper identification of viral and bacterial infections is key to selecting the proper antimicrobial agent.

Viral and bacterial infections ought to be keenly identified and treated differently. This is to ensure the most effective treatment is given to a given infection. Proper identification of the infection also applies to the main differences identified between viral and bacterial infection. Just like the differences in the infections, antimicrobial drugs too manufactured to have a different mechanism of action. For example, some bacterial antimicrobials are meant to target the cell wall, which is absent in the viruses. Meaning the wrong administration of antimicrobials may end up not relieving one of the symptoms they are presenting or effects of microbial infection they are experiencing. Therefore, wrong identification of infection leads the administration of wrong antimicrobials, which are less effective upon being used.

Use of antibiotics to treat viral infection has contributed largely to the increased incidences of antibiotic resistance (Humphries, & Hindler, 2016). Use of antimicrobial agent to treat a different infection is termed as misuse of antimicrobials. Usually, the body gets used to the effects of the antimicrobial. Hence, the body fails to respond in case the antimicrobial is applied to treat an active infection. This makes it important for the physician and clinicians to confirm the cause of the infection before they administer treatment.


Diagnosis of infections, especially bacterial and viral, are common amongst patients. Despite the discovery of antimicrobial agents used to treat various infections, research shows antimicrobial agents are misused. Classification of antimicrobials majorly depends on the pathogens they are meant to act against.  Mostly, the misuse of antimicrobial agents is related to the wrong diagnosis of infections. Interchange of use of antimicrobials used in treating bacterial and viral infections has to lead to decreased effectiveness and increased resistance to these antimicrobials. Also, different antimicrobials act differently targeting various areas. This makes a proper identification of viral and bacterial infections vital in selecting the appropriate antimicrobial agent.


Humphries, R. M., & Hindler, J. A. (2016). Emerging resistance, new antimicrobial agents… but no tests! The challenge of antimicrobial susceptibility testing in the current US regulatory landscape. Clinical Infectious Diseases, 63(1), 83-88.

Sterling, J. C. (2016). Viral infections. Rook’s Textbook of Dermatology, Ninth Edition, 1-124.

Weston, D., Burgess, A., & Roberts, S. (2016). Infection Prevention and Control at a Glance. John Wiley & Sons.

World Health Organization. (2017). Critically important antimicrobials for human medicine: ranking of antimicrobial agents for risk management of antimicrobial resistance due to non-human use.

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