Learning Objectives
By the end of this section, you will be able to:
- Describe the physiological mechanisms that contribute to antibiotic resistance
- Discuss the two most common diseases of antibiotic resistance encountered in clinical practice
- Define antibiotic stewardship
- Apply nursing interventions and associated therapies in the care of the patient with an antibiotic resistant infection
Imagine that you wake up one morning with a swollen, painful toe. You go to the clinic, where they swab your toe, diagnose a bacterial infection, and start you on an antibiotic. You take the antibiotic for the prescribed week but do not see any improvement in the infection. You go back to the clinic; after more tests, the provider determines the infection is caused by a microorganism that is not responsive to most medications, so you will have to be admitted to the hospital for administration of more potent IV antibiotics. If the infection does not improve while in the hospital, it could become life-threatening or even require invasive treatment such as amputation of the toe. What started as a simple toe infection has become potentially life-threatening because of antibiotic resistance. More and more, we are seeing bacterial infections that resist antibiotic treatment, highlighting the need for more education about the importance of adhering to prescribed medication regimens and other measures to prevent resistance from developing.
Pathophysiology of Antibiotic Resistance
There are several mechanisms by which bacteria can become resistant to antibiotics (CDC, 2022d). Some bacteria have outer membranes that antibiotics cannot penetrate. Others use pumps within their cell wall to remove the antibiotics after they enter the cell. Many bacteria also have their own internal enzymes that can be used to neutralize or destroy antibiotics. But the most significant driver of antibiotic resistance may be evolution. Bacteria can “remodel,” meaning they can change their characteristics as they learn to evade antibiotic medications. Also, a typical dose of antibiotics does not kill every invading bacterium. Due to genetic variance, some bacteria are naturally able to withstand the drug; when these bacteria reproduce, they may pass this natural resistance to their offspring. As this process continues, subsequent generations become increasingly resistant; given enough time, a strain of the bacteria may develop that cannot be effectively treated by the antibiotic. This is why it is crucial that health-care providers maintain diligence in appropriate antibiotic prescribing. It is also important for individuals who are prescribed a course of antibiotics not to miss a dose or stop taking the medication before they complete all doses—doing so only ensures that more bacteria survive to pass on resistance to new generations.
Regardless of the specific cause or mechanism, more and more bacteria are developing resistance to the antibiotics our health-care system has come to rely on. Although new medications are becoming available, the process of researching and developing them takes years. During that time, countless generations of bacteria live, reproduce, and evolve better defenses.
Methicillin-Resistant Staphylococcus Aureus
A strain of bacteria that has become resistant to many antibiotics in recent years is called methicillin-resistant Staphylococcus aureus (MRSA). MRSA infections are most commonly seen in patients who have been living in long-term care centers or have been admitted to the hospital for an extended time. MRSA typically occurs in wounds on the skin. Clinical manifestations include:
- fever
- purulent drainage
- red bumps and/or boils on the skin (Figure 22.12)
- warm skin
Though MRSA is usually confined to the skin, in some cases, it can spread deeper into the underlying tissues, bones, or organs, leading to severe systemic infection and sepsis if left untreated. Risk factors for the development of MRSA infection include (Mayo Clinic, 2022):
- HIV infection
- long-term hospitalization
- participation in contact sports
- residence in crowded environments (e.g., jail, dorms)
- residence in nursing home or long-term care facility
- treatment with invasive medical devices
Fortunately, there are still some combinations of antibiotics that can effectively treat MRSA, but, over time, these medications will likely become less effective.
Vancomycin-Resistant Enterococcus
A strain of enterococci bacteria that has become resistant to treatment with vancomycin, a common antibiotic, is called vancomycin-resistant Enterococcus (VRE). Risk factors for infection with VRE include (Doganci et al., 2023):
- history of invasive surgical procedures or medical device placement
- long-term hospitalization
- previous use of vancomycin to treat an infection
- weak immune system (e.g., HIV, critically ill patients)
VRE can occur in many places in the body, but it is most commonly seen in the urinary tract, bloodstream, and wounds. It can be spread through contact with contaminated surfaces or from person to person, usually through contaminated hands. The best way to prevent the spread of VRE is through hand hygiene and frequent cleaning of surfaces; it is crucial to wear gloves if coming into contact with bodily fluids that may be contaminated with VRE. VRE can be treated with antibiotics other than vancomycin, but there are limited options available and, over time, the bacteria may become resistant to other antibiotics as well.
Antibiotic Stewardship
The term antibiotic stewardship refers to efforts to improve antibiotic prescribing strategies so infections are treated effectively without contributing to the development of antibiotic resistance. The CDC (2024) has developed a set of core elements that serve as guidelines for improving antibiotic use in practice. Some of the main takeaways from these guidelines include:
- ensuring patients take antibiotics as prescribed and finish the entire dose as ordered by the treating clinician
- not prescribing antibiotics for asymptomatic urinary tract infections
- prescribing the correct route, dose, and duration of antibiotic treatment regiments
- tailoring antibiotic therapy to specific organisms as opposed to immediately implementing broad-spectrum antibiotics
Link to Learning
For more detailed information about the CDC’s guidelines, visit the Core Elements of Antibiotic Stewardship web page.
Medical Therapies for Antibiotic Resistance
Increases in antibiotic-resistant bacteria have highlighted an urgent need for research and development of new antibiotics. In recent years, several new antibiotics have become available, but pharmaceutical research is relatively slow to ensure safety of the medications in humans. For that reason, the development of new medications is not keeping pace with the development of antibiotic-resistant strains of bacteria. This highlights the need for strategies to improve the effectiveness of existing antibiotics. In many cases, this has involved changing the route of the antibiotic from oral to IV for quicker, more potent treatment. In other cases, this means altering the duration of therapy to eradicate the resistant bacteria more effectively. More examples to reduce antibiotic resistance include:
- Alternative antibiotics and combinations:
- Broader-spectrum antibiotics: Use antibiotics with a broader spectrum of activity when appropriate, based on susceptibility testing.
- Combination therapy: Use combination antibiotic therapy to enhance efficacy and prevent resistance development in cases where one antibiotic may help the other be more effective.
- Infection control measures:
- Strict hygiene practices: Enhance infection control practices, including hand hygiene and environmental cleaning, to prevent the spread of resistant bacteria.
- Isolation protocols: Use isolation techniques for patients with resistant infections to prevent transmission to others.
- Monitoring and surveillance:
- Track resistance patterns: Monitor and track antibiotic resistance patterns in health-care settings to inform treatment decisions and policy adjustments.
Nursing Care to Avoid Antibiotic Resistance
One of the most important roles of the nurse in preventing antibiotic resistance is educating patients about taking their antibiotics as prescribed (National Institute of Allergy and Infectious Diseases, 2020). When patients stop a course of medication early, the bacteria are often not sufficiently treated. This allows any remaining bacteria to mutate and grow, contributing to their future resistance to antibiotic therapy. For this reason, nurses must emphasize the importance of finishing the entire course of antibiotics, even if the patient reports improved symptoms, and not sharing medications with others. Additionally, nurses can actively participate in antibiotic stewardship initiatives within their facility. This may simply mean adhering to best practices for using antibiotics and providing patient education, or it may involve active participation on a committee that is attempting to implement the initiatives on a specific unit or within the institution.
Life-Stage Context
Older Adults and Antibiotics
Older adults are at a higher risk of infection because they have a less effective immune system, and they often benefit from antibiotic treatment (Soraci et al., 2023). However, older adults are also more likely to develop adverse drug events from using antibiotics because of polypharmacy (taking many other medications that may interact with the antibiotic), renal and liver dysfunction, and reduced adherence due to cognitive or functional issues. For this reason, antibiotics should be used with caution in this population, and patients prescribed antibiotics should be monitored closely for the duration of therapy.