Antimicrobial Stewardship Principles

Responsible Use of Antimicrobials

• Antimicrobial stewardship focuses on optimizing antibiotic use to combat resistance and ensure effective treatment.
• Dosage optimization is crucial; consider patient-specific factors like age, weight, renal function when determining dosages.
• Avoid unnecessary antibiotic use to minimize the risk of resistance and protect microbiome diversity.
• Evidence-based treatment plans require current understanding of infection etiology and antibiotic susceptibility patterns.

Antibiotics Mechanisms of Action

• Antibiotics can be categorized as bactericidal (kill bacteria) or bacteriostatic (inhibit growth).
• Cell Wall Synthesis Inhibitors:
  • Beta-lactams (penicillins, cephalosporins) block peptidoglycan cross-linking.
  • Glycopeptides target peptidoglycan subunits.
  • Bacitracin inhibits peptidoglycan transport.
• Inhibition of Protein Synthesis:
  • 30S inhibitors (aminoglycosides, tetracyclines).
  • 50S inhibitors (macrolides, lincosamides, chloramphenicol, oxazolidinones).
• Membrane Disruption: Polymyxin B and colistin target lipopolysaccharide in Gram-negative bacteria.
• Inhibition of Nucleic Acid Synthesis:
  • Rifamycin targets RNA synthesis.
  • Fluoroquinolones inhibit DNA synthesis.
• Antimetabolites:
  • Sulfonamides and trimethoprim interfere with folic acid synthesis.
  • Isoniazid inhibits mycolic acid synthesis in bacteria.
• ATP Synthase Inhibition: Diarylquinoline blocks bacterial ATP synthase.

Beta-Lactams

• Essential for bactericidal activity against various pathogens; includes:
  • Penicillins: Amoxicillin/Ampicillin are prone to adverse effects like diarrhea and hypersensitivity.
  • Carbapenems: Broad-spectrum, last-resort options with risks of CNS toxicity and secondary infections.
  • Monobactams: Aztreonam effective solely against Gram-negative bacteria; less susceptible to beta-lactamases.
  • Cephalosporins: Multiple generations with differing sensitivity profiles.

Lincosamides and Oxazolidinones

• Lincosamides (Clindamycin): Bacteriostatic; effective against anaerobes and Group A Streptococcus but can cause severe GI upset and pseudomembranous colitis.
• Oxazolidinones (Linezolid): Targets multi-drug-resistant bacteria like VRE and MRSA; potential side effects include serotonin syndrome when used with SSRIs.

Amphenicols and Fluoroquinolones

• Amphenicols (Chloramphenicol): Bacteriostatic, effective in CNS infections; risks include gray baby syndrome and bone marrow suppression.
• Fluoroquinolones: Multiple generations, used for a variety of infections; side effects may include tendon damage.

Current Developments in Antimicrobial Therapy

• Emerging resistance patterns challenge treatment effectiveness, necessitating ongoing surveillance and adaptation of guidelines.
• New classes of drugs are being developed to overcome resistance mechanisms and provide alternative options.
• Guidelines are evolving to emphasize a combination of traditional and novel agents for more effective management of infections.

This quiz explores the key principles of responsible antimicrobial use, including the formulation of evidence-based treatment plans for infectious diseases. Participants will examine the importance of dosage optimization and the need to prevent unnecessary antibiotic use, along with current developments in antimicrobial therapy and resistance patterns.