4 Defense and Immunity: Infection and Antimicrobials-Bacteria and Antibacterials
4 Defense and Immunity: Infection and Antimicrobials-Bacteria and Antibacterials
Understanding the fundamental concepts of defense and immunity, the pathophysiology of infection, and pharmacologic principles is essential for nurses to provide comprehensive patient care. The immune system, comprising innate and adaptive immunity, protects against pathogens through immediate, non-specific, targeted, long-term responses. Infections arise when pathogens invade, evade the immune system, and replicate, leading to tissue damage. Recognizing early signs of infection and understanding its progression are crucial for timely interventions. Pharmacologic management, involving antibiotics, antivirals, antifungals, and antiparasitics, requires knowledge of pharmacokinetics and pharmacodynamics for safe and effective administration.
Additionally, awareness of antimicrobial resistance and stewardship principles is vital. Integrating these concepts into nursing practice allows for accurate assessments, effective interventions, patient education, and collaboration with healthcare teams, ultimately enhancing patient care quality and outcomes. This chapter presents several units: a) normal mechanisms of defense and immunity, b) concepts of infection, c) considerations for antimicrobial therapy, and d) pharmacologic concepts of antimicrobial therapy. Clinical decision-making learning activities are integrated throughout this chapter.
The concepts of defense and immunity involving antimicrobials will be divided in two parts. This chapter focuses on the the foundational concepts of pathophysiology of infections to and foundations of pharmacology related to antimicrobial therapy. The following chapter goes into more details of pharmacologic therapy.
Learning Objectives
- Identify populations who have an increased risk of infection.
- Describe common pathogens and methods of infection control.
- Distinguish between antimicrobial agents in terms of mechanism of action, indication for use, adverse effects, and implications for the nursing process.
- Apply knowledge of ways to minimize the emergence of drug-resistant microorganisms.
The human immune system comprises a complex network of cells, tissues, and organs that work collaboratively to defend the body against pathogens such as bacteria, viruses, fungi, and parasites. The immune system’s defense mechanisms are categorized into two main types: innate (nonspecific) immunity and adaptive (specific) immunity.
A. Innate Immunity is the first line of defense and provides a rapid but nonspecific response to pathogens. It includes physical barriers, chemical barriers, and cellular defenses.
1. Physical Barriers: The skin and mucous membranes act as physical barriers to prevent the entry of pathogens. The skin provides a tough, impermeable barrier, while mucous membranes trap pathogens in mucus and are equipped with cilia to expel them (Delves et al., 2017).
2. Chemical Barriers: Secretions such as saliva, tears, and stomach ac