Overview
Staphylococcus aureus (S. aureus)
- Food Poisoning: From meats, mayonnaise, custard; caused by preformed enterotoxin.
- Prosthetic Joint Infection:
- Early (<3 months): S. aureus.
- Delayed (3–12 months): Coagulase-negative staph.
- Late (>12 months): S. aureus.
- IV Drug Users: Right-sided infective endocarditis (tricuspid valve).
Neonatal Meningitis
- Common Causes (BEL): Group B Strep, E. coli, Listeria.
- Treatment: Add ampicillin for Listeria coverage.
Meningitis Empiric Therapy
- Age 2–50: Vancomycin + 3rd-gen cephalosporin.
- Neonates & Age >50: Add ampicillin.
Pelvic Inflammatory Disease (PID)
- Causes:
- Acute: N. gonorrhoeae.
- Subacute: C. trachomatis (D-K).
- Treatment: Ceftriaxone + doxycycline.
Nausea & Vomiting Management
- Drugs:
- Ondansetron (QT prolongation risk).
- Metoclopramide (risk: acute dystonia).
- Aprepitant (chemotherapy-induced nausea).
- Torsades Treatment: Magnesium sulfate or defibrillation (if unstable).
Clostridium difficile (C. diff)
- Symptoms: Watery diarrhea, pseudomembranes.
- Treatment: Fidaxomicin or oral vancomycin.
Enzyme Interactions
- Inhibitors: Cimetidine, omeprazole (increase drug levels).
- Inducers: Phenytoin (reduce drug levels).
Proton Pump Inhibitors (PPIs)
- Risks: C. diff, pneumonia, osteoporosis, B12 deficiency.
Hepatic Encephalopathy
- First-line: Lactulose (traps NH3 as NH4+).
- Alternative: Rifaximin (kills ammonia-producing bacteria).