N333: Antimicrobial Therapy

3 Principles and Approaches of Antimicrobial Pharmacotherapy

Principles:

• Eradicate or inhibit pathogen growth

• Minimize harm to the host

• Reduce antibiotic resistance

Approaches:

• Use the narrowest effective spectrum

• Adjust therapy based on culture and sensitivity (C&S)

• Avoid unnecessary use

Empiric Therapy

• Initiated before pathogen identification

• Based on clinical presentation and resistance patterns

Targeted Therapy

• Adjusted after pathogen identification

• Uses narrow-spectrum agents

What should the Duration of Therapy be when using antimicrobials?

Limit to the shortest effective period

Antimicrobial Stewardship - Goals and Strategies

Goals:

• Optimize patient outcomes

• Minimize resistance and ADRs

• Ensure cost-effective use

Strategies:

• Regularly review and de-escalate antibiotic use

• Educate healthcare providers

What are the contributors to Antibiotic Resistance?

• Overprescribing of antibiotics

• Incomplete or improper patient use

Mutlidrug-Resistant Organisms (MDROs)

Pathogens resistant to multiple antibiotic classes, making infections difficult to treat; significant cause of nosocomial infections

What are some MDRO prevention strategies?

• Strict hand hygiene

• Antimicrobial Stewardship

• Environmental cleaning

• Infection control protocol

Example MDROs (7)

• Methicillin-Resistant Staphylococcus aureus (MRSA)

• Vancomycin-Resistant Enterococcus (VRE)

• Carbapenem-Resistant Enterobacteriaceae (CRE)

• Extended-Spectrum Beta-Lactamase-Producing Entereobacteriaceae (ESBL)

• Multidrug-Resistant Pseudomonas aeruginosa (MDR-PA)

• Clostridium difficile (C. diff)

• Multidrug-Resistant Tuberculosis (MDR-TB)

Superinfections

Secondary infection arising during treatment of a primary infection; caused by broad-spectrum antibiotics disrupting normal flora

• E.g., Candida infections and Clostridium difficile

Host Factors Affecting Antibiotic Selection (6)

• Immune status: Compromised immunity alters drug efficacy

• Infection site: Penetration varies

  • Bone infections are the most difficult to combat

• Allergy history: Hypersensitivity risks

• Pregnancy and lactation: Risks to fetus or infant

• Age: Infants and elderly are at higher risk of toxicity

  • Decreased kidney and liver function

• Genetics: Enzyme deficiencies impact drug metabolism

Goals of Anti-Infective Therapy (3)

• Eliminate the pathogen or inhibit its growth

• Support the host’s immune system in overcoming the infection

• Prevent or reduce antibiotic resistance