Antimicrobial agents in bacterial infection treatment and microbial control

Categories of Antimicrobial Agents
Antimicrobial agents refer to a broad classification of molecules that either kill or suppress the growth or multiplication of bacteria, fungi, viruses, protozoa, and helmiths (Greenwood & Irving, 2012; Musumeci & Puglisi, 2013). According to the World Health Organization (WHO, 2016), antimicrobials can be classified in various ways such as which microorganisms they target (such as antibacterial versus antiviral agents), their mechanisms or methods of intervention (such as penetration of cellular walls), or their utility in human medicine given some are considered “critically important,” due to their prevention of disease and death (p. 9). Because antimicrobial pharmacotherapy can lead to deleterious and unwanted side effects, it is important to properly identify the type of infection first and then administer the appropriate antimicrobial agent.
Antibacterial agents like antibiotics target bacterial infections, whereas antiviral agents target viruses. Generally, antibacterial agents inhibit cell wall synthesis or protein synthesis in the target bacteria, with Penicillin and other beta-lactams being the most notable antibiotic group (Greenwood & Irving, 2012). Other antibiotics that inhibit cell wall or protein synthesis include the cephalosporin and carbapenem groups (Maiyoh, 2015). Because viruses do not have cellular walls or conduct their own protein synthesis like bacteria, antiviral agents work totally differently and their mode of action depends on the infection.
Differences Between Viral and Bacterial Infections
Both viruses and bacteria are pathogens that can harm the human body. However, viruses and bacteria differ significantly on the molecular level, as well as how they are transmitted. Each pathogen has a different mode of transmission, with additional risk factors being patient vulnerability due to compromised immune system or genetic predisposition. Antiviral agents cannot kills bacteria and likewise, antibiotics cannot kill viral infections, making it important to differentiate between different types of infections. The goal of an antibacterial medication is to kill the bacteria or destroy its ability to synthesize proteins that enable it to reproduce itself. A virus acts more systemically when it infects the human body, effectively integrating itself with the host’s biology. Yet in all cases, antimicrobial agents can also harm healthy tissue while allowing both bacteria and viruses to adapt to the antimicrobials.
Proper Identification of the Infection
Improper administration of antimicrobials can lead to adverse patient outcomes, which is why proper diagnosis precedes pharmacological treatment. Infections also need to be differentiated between infectious versus non-infectious, although in many cases symptomology can be difficult to identify and properly diagnose (Sweeney, Wong & Khatri, 2016). The methods used to identify the pathogen include patient interview, full range of appropriate tests and diagnoses, and epidemiological research, a combination of which should reveal the “most likely organisms” causing the symptoms even when some guesswork is required (Gelone, Pacetti & O’Donnell, 2006, p. 78). Patient health history, demographics, and age may also be factors that will impact identification and selection of the appropriate antimicrobial agent, if one is necessary.
In situations where antimicrobials need to be administered immediately, prior to receiving laboratory reports or test results, the healthcare worker will be relying on a host of factors including the prevalence of similar symptoms within the population, whether or not the patient has travelled recently and where, and identifying additional patient risk factors such as autoimmune disease (Gelone, Pacetti & O’Donnell, 2006). Biological specimens like blood, urine, or feces tests can be used to properly identify the pathogen, allowing the healthcare worker to prescribe an appropriate antimicrobial agent at the correct dosage level.
References
Gelone, S.P., Pacetti, S. & O’Donnell, J.A. (2006). Principles of antimicrobial therapy. In Arcangelo & Peterson (Eds.). Pharmacotherapeutics for Advanced Practice. Lippincott & Williams.
Greenwood, D. & Irving, W.L. (2012). Antimicrobial agents. Medical Microbiology, 18th Ed., https://www.sciencedirect.com/science/article/pii/B9780702040894000202
Maiyoh, G.K.K. (2015). Classes of antimicrobial agents. https://www.slideshare.net/maiyoh07/lecture-022014
Musumeci, T. & Puglisi, G. (2013). Antimicrobial agents. Drug–Biomembrane Interaction Studies. https://www.sciencedirect.com/topics/medicine-and-dentistry/antimicrobial-agent
Sweeney, T.E., Wong, H.R. & Khatri, P. (2016). Robust classification of bacterial and viral infections via integrated host gene expression diagnostics. Science Translational Medicine 8(346): 346-91.
World Health Organization (2016). Critically important antimicrobials for human medicine. 5th Revision. http://apps.who.int/iris/bitstream/handle/10665/255027/978?sequence=1