Overview
This lecture covers the basics of antibiotics, including types, administration processes, testing procedures, possible complications, antibiotic resistance, and key nursing responsibilities.
Types of Antibiotics
- Two main categories: broad spectrum (act on many bacteria) and narrow spectrum (target specific bacteria).
- Broad spectrum antibiotics are given initially when the specific bacteria is unknown.
- Narrow spectrum antibiotics are used once the specific bacteria is identified.
Culture and Sensitivity Testing
- Culture and sensitivity tests identify the specific bacteria and which antibiotics it is sensitive to.
- Obtain cultures before starting antibiotics.
- Preliminary test results may be available in 2-4 hours; final results typically take about 48 hours.
- After results, switch from broad to narrow spectrum if possible.
Antibiotic Function and Effects
- Antibiotics only work against bacterial infections, not viruses or fungi.
- Bactericidal antibiotics kill bacteria; bacteriostatic antibiotics inhibit bacterial growth to aid the immune system.
- Administration to hard-to-reach areas (brain, abscesses, non-living tissue, poor blood supply, diabetic tissue) can be challenging.
Adverse Reactions & Complications
- Antibiotics are highly allergenic; allergic reactions and anaphylaxis are possible.
- Watch for toxic reactions like Stevens-Johnson Syndrome (SJS; severe rash and skin peeling) and acute tubular necrosis (ATN; kidney failure).
- Superinfections (e.g., oral thrush/candidiasis, C. diff) can develop after antibiotic use.
- Do not stop antibiotics for superinfections; notify the physician and treat the superinfection.
Antibiotic Administration and Monitoring
- Always check patient allergy history and monitor for allergic or toxic reactions during infusion.
- Draw trough levels 30 minutes before the next dose; draw peak levels 30 minutes after infusion finishes.
- Troughs check if dosage is enough (trough below MEC = underdosed); peaks check for toxicity.
Antibiotic Resistance
- Resistance occurs when bacteria survive antibiotics and adapt to evade them (e.g., MRSA).
- Overuse, misuse, or underdosing of antibiotics promotes resistance.
- Teach patients to take the full antibiotic course as prescribed and not to skip doses.
- Higher doses kill more bacteria and are preferable to avoid resistance (despite higher risk of side effects).
Key Terms & Definitions
- Broad spectrum antibiotic — acts against a wide range of bacteria.
- Narrow spectrum antibiotic — targets a specific type of bacteria.
- Culture and sensitivity — laboratory process to identify bacteria and effective antibiotics.
- Bactericidal — kills bacteria directly.
- Bacteriostatic — inhibits bacterial growth.
- Stevens-Johnson Syndrome (SJS) — life-threatening skin reaction to drugs.
- Acute Tubular Necrosis (ATN) — kidney injury due to toxic medications.
- Superinfection — new infection caused by antibiotic treatment (e.g., C. diff, thrush).
- MRSA — methicillin-resistant Staphylococcus aureus, a resistant bacteria.
- Peak level — highest drug concentration, drawn after infusion.
- Trough level — lowest drug concentration, drawn before next dose.
- Minimum Effective Concentration (MEC) — lowest blood level at which a drug is effective.
Action Items / Next Steps
- Know the process for culture and sensitivity and timing of sample collection.
- Memorize signs of adverse and superinfections to monitor during antibiotic therapy.
- Review patient teaching for correct antibiotic use: complete full course, do not skip doses.
- Study key definitions and be able to apply them to clinical scenarios.