Antimicrobials and Infection Treatment

Principles of Antimicrobial Therapy

• Antimicrobials are used to treat infections caused by bacteria, viruses, fungi, and parasites.
• Mechanisms of action include:
  • Destroying bacterial cell walls.
  • Inhibiting unique bacterial enzymes essential for survival.
  • Impairing protein synthesis in ribosomes.
  • Disrupting RNA and DNA synthesis/functions.
  • Inhibiting viral replication.
• Classified into narrow-spectrum (target specific bacteria) and broad-spectrum (target a wide range of bacteria).

Selection of Antimicrobials

• Accurate identification of pathogens is essential for effective treatment.
• Lab tests (blood, urine, sputum, wound drainage) used to identify microorganisms.
• Gram stain allows direct identification of organisms under a microscope.
• Cultures grow colonies over time and are preferred if gram stains yield inconclusive results.
• Culture specimens must be collected before starting medication to avoid contamination.

Penicillins

• Serve to destroy bacteria by weakening their cell walls.
• Common uses include treating pneumonia, meningitis, endocarditis (prophylaxis), UTIs, and syphilis.
• Adverse effects involve anaphylaxis, nausea/vomiting/diarrhea (N/V/D), nephrotoxicity, thrombocytopenia, Steven-Johnson syndrome, and Clostridium difficile (C. diff).
• Prefix: -CILLIN, with examples including:
  • Natural penicillins: Bicillin CR (narrow spectrum).
  • Aminopenicillins: Amoxil (amoxicillin), Principin (ampicillin) (broad spectrum).
  • Combination therapies: Augmentin, Zosyn, Unasyn.
  • Extended spectrum: Geocillin, Ticar.
• Nursing interventions include administering via deep IM injection in large muscle, rotating sites, and ensuring medications are taken on an empty stomach.
• Client education emphasizes adherence to the full course and proper suspension storage.

Penicillins and Antibiotic Resistance

• Methicillin-resistant Staphylococcus aureus (MRSA) does not respond to standard penicillin therapies; requires higher potency antibiotics like Vancomycin.
• Vancomycin-resistant enterococci (VRE) represent a newer antibiotic resistance challenge.

Cephalosporins

• Prefix: CEF- and CEPH-, with examples:
  • First Generation: Duricef (cefadroxil), Ancef (cefazolin), Keflex (cephalexin).
  • Second Generation: Mefoxin (cefoxitin), Cefzil (cefprozil).
  • Third Generation: Omnicef (cefdinir), Cefobid (cefoperazone), Claforan (cefotaxime), Rocephin (ceftriaxone).
• Function similarly to penicillins by destroying bacterial cell walls.
• Most drugs administered IM or IV due to poor GI absorption.
• Uses include respiratory infections, otitis media, bone/joint infections, UTIs, and surgical site infections.
• Adverse effects are similar to penicillins, including cross-sensitivity with PCN.

Inhibitors of Cell Wall Synthesis

• Key examples include Azactam (aztreonam), Primaxin (imipenem/cilastatin), and Vancomycin.
• Purpose is to disrupt bacterial cell walls leading to microorganism death.
• Primarily used against MRSA and C. diff infections.

Explore the principles and methods of antimicrobial therapy for treating infections. This quiz covers various mechanisms of action, classifications of anti-infectives, and the process of selecting appropriate antimicrobials based on lab testing. Enhance your understanding of how these therapies work against bacteria and viruses.