Lecture Notes: Carbapenems and Monobactams

Overview

• Lecturer: Dr. Rowe
• Main Focus: Carbapenems
• Additional Topic: Monobactams
• Both are classifications of beta-lactam antibiotics, similar to penicillins and cephalosporins.

Monobactams

• Primary Monobactam: Aztreonam
  • Narrow-spectrum antibiotic
  • Effective against Pseudomonas
  • Relevant for studying antibiotic resistance

Carbapenems

• Examples:
  • Imipenem
  • Meropenem
  • Doripenem
• Characteristics:
  • Broad-spectrum antibiotics
  • Resistant to beta-lactamase enzymes
  • Broadest spectrum among beta-lactams
  • Effective against many Gram-negative bacteria

Usage and Resistance

• Usage:

  • Broad-spectrum nature means they are widely used
  • Often used in a "shotgun approach" for unknown infections

• Resistance:

  • High usage leads to increased bacterial resistance
  • Carbapenem-resistant Enterobacteriaceae (CRE) are a significant concern
  • CRE includes organisms like Shigella, Klebsiella, E. coli, and Pseudomonas
  • CRE are often resistant to all but one antibiotic: colistin

Issues and Concerns

• Imipenem Example:

  • Often combined with cilastatin to prevent rapid breakdown in kidneys
  • Historically effective against over 90% of hospital pathogens
  • Effectiveness is slowly decreasing

• CRE Organisms:

  • Known as "superbugs"
  • Resistant to multiple drug types
  • If also resistant to colistin, treatment options become extremely limited
  • Current treatment success rate is low; 50% mortality for bloodstream infections

Future Challenges

• Antibiotic Development:

  • A need for new antibiotics or alternatives
  • Current antibiotics are losing effectiveness due to resistance

• Potential Doomsday Scenario:

  • CRE organisms resistant to all known treatments
  • The world without effective antibiotics poses significant health risks

Conclusion

• The importance of understanding carbapenems given their current effectiveness and the looming threat of antibiotic resistance.
• Optimism for future solutions in antibiotic development or alternatives.

Note: Stay informed and understand the significance of antibiotic resistance and the critical role of carbapenems in current medical treatments.