Instructions: Application: Antimicrobial Agents
Antimicrobial agents are essential components in the treatment of various bacterial infections as they help to kill or prevent the growth of microbes such as bacteria, fungi, and protozoans. Prior to the discovery of antimicrobial agents, treatment options for patients with bacterial infections were limited. For many patients, treatment often resulted in the amputation of limbs or even death. Today, treatment options for bacterial infections typically have a more positive prognosis. Due to the various types of infections presented in patients, it is essential to be able to identify the underlying cause of the infection—whether bacterial or viral—before recommending drug treatments. This will help you identify whether or not an antimicrobial agent would be appropriate and which specific agent would target the infection. In this Assignment, you consider the appropriate use of antimicrobial agents for infections.
Review this week’s media presentation on principles of antimicrobial therapy, as well as Chapter 8 of the Arcangelo and Peterson text.
Consider the categories of antimicrobial agents.
Think about differences between viral and bacterial infections.
Reflect on why proper identification of the infection is key to selecting the proper antimicrobial agent.
Write a 2- to 3- page paper that addresses the following:
Describe the categories of antimicrobial agents.
Describe differences between viral and bacterial infections.
Explain why proper identification of viral and bacterial infections is key to selecting the proper antimicrobial agent.
Categories of Antimicrobial Agents
Antimicrobial substances are those that kill microorganisms or inhibit their growth. Antimicrobial agents fall into different categories based on a variety of factors such as the type of microorganisms against which they work. There are four types of microorganisms, which are bacteria, viruses, fungi and parasites (Antimicrobials, 2011). Consequently, there are four corresponding categories of antimicrobial agents, which are antibacterial, antiviral, antifungal and antiparasitics. This is a generally broader classification of antimicrobials. Further classification is based on the effect of the agent and its mode of action. Based on the effect on microorganisms, antimicrobials can either be microbiocidal or microbiostatic. Microbiocidal agents are those that act by killing microorganisms whereas microbiostatic agents merely retard the growth of microorganisms.
Antimicrobial agents vary in the spectrum of their activities. Broad spectrum antimicrobials act on a wide range of microorganisms, including both gram-positive as well as gram-negative microorganisms (Antimicrobials, 2011). Contrawise, there are also narrow-spectrum antimicrobials, which are only active against certain species of microorganisms, say gram-positive microorganisms. Antimicrobial agents achieve their microbiocidal or microbiostatic effects through different biochemical and physiological pathways. In particular, antimicrobial agents inhibit cell walls – particularly in bacteria, cell membranes, protein synthesis, 30S and 50S subunits of intracellular ribosomes, synthesis of nucleic acids and folic acid (Antimicrobials, 2011). Some of these processes are selective, a factor which is embedded in the nature of the microorganism, while others are not.
Differences between Viral and Bacterial Infections
Bacterial infections originate from bacteria, which mostly do not occasion harm to people. Bacteria are single-celled microorganisms which thrive in a variety of varied environments. For instance, some do well in extremes of heat while others prosper in extremely cold conditions. Certain strains of bacteria reside within the human body, such as within intestines, where they assist in the process of digestion. Some of the common bacterial infections include tuberculosis and strep throat (Steckelberg, 2014). Viral infections, on the other hand, are brought about by viruses. Viruses differ from bacteria in a number of ways. They are much smaller and unlike bacteria which can thrive in varied environments, viruses require a living host in order to multiply and survive. Viruses operate by hijacking the cell machinery and instructing cells to reproduce the virus. Common viral infections include chicken pox and the common cold. Some infections such as meningitis and diarrhea can result from either of the microbes making them hard to diagnose (Steckelberg, 2014). Apart from the causative microorganism, another difference between bacterial and viral infections is the effectiveness of antibiotics which are able to kill bacteria but are ineffective against viruses.
Selecting the Proper Antimicrobial Agent
It has been noted that certain
infections can be brought about by either of the two types of microbes between
viruses and bacteria. Yet, antimicrobial agents are not usually effective in
killing viruses, as they are in annihilating bacteria. This is one of the reasons that make it essential to diagnose the infection properly, so as to
ensure accurate prescription. Arcangelo &
Peterson, 2011 note that the identification of the causative agent is essential
in optimizing the selection of antibiotics as well as patient outcomes. This is
further because successful application of microbial agents will further depend
on the biochemical/physiological pathway
since different antimicrobials act through different pathways. Finally, there
are other essential considerations, particularly because microorganisms will
usually develop resistance to antimicrobial agents. Such considerations include
host considerations, such as advanced age, immunosuppression or a diabetic
nature (Leekha, Terrell, & Edson,
The information obtained would be helpful in determining a predisposition
towards infection. Understanding the plethora of conditions pertaining to the
infection is, therefore, core to the
selection of the optimal antimicrobial agent.
Antimicrobials. (2011). Antimicrobials. Retrieved from Antimicrobials Resistance Learning Site: http://amrls.cvm.msu.edu/pharmacology/antimicrobials/mode-of-action
Arcangelo, V. P., & Peterson, A. M. (Eds.). (2011). Pharmacotherapeutics for advanced practice: a practical approach (3rd ed.). Philadelphia: Lippincott Williams & Wilkins.
Leekha, S., Terrell, C. L., & Edson, R. S. (2011). General principles of antimicrobial therapy. Mayo Clinic Proceedings. 86.2, pp. 156–167. Elsevier.
Steckelberg, J. M. (2014, October 24). Bacterial vs. viral infections: How do they differ? Retrieved from Mayo Clinic: http://www.mayoclinic.org/diseases-conditions/infectious-diseases/expert-answers/infectious-disease/faq-20058098