Infection Prevention, Healthcare Epidemiology, and Antimicrobial Stewardship
Core concepts
Understand transmission-based precautions: contact (MRSA, VRE, C. difficile, scabies), droplet (influenza, pertussis, meningococcus, diphtheria), airborne (TB, measles, varicella, smallpox). Hand hygiene is the single most effective intervention. Know the chain of infection and the role of environmental cleaning, isolation, and cohorting.
Stewardship principles
Appropriate empiric therapy, de-escalation based on culture, duration optimization, and IV-to-PO conversion. Antibiotic time-outs. Avoid treating asymptomatic bacteriuria except in pregnancy and before urologic procedures. Prophylaxis: surgical (cefazolin for most; add metronidazole for colorectal), endocarditis (amoxicillin before dental procedures in high-risk cardiac lesions), and medical (TMP-SMX for PJP in immunosuppressed).
Traps
C. difficile requires contact precautions and soap-and-water handwashing (alcohol doesn't kill spores). MRSA nares screening has high negative predictive value-useful for de-escalation. Don't treat positive urine cultures without symptoms. Blood culture contamination-use aseptic technique and avoid culturing through existing lines unless necessary.
Worked rule of thumb
If a patient has asymptomatic bacteriuria and no urinary symptoms, do not treat. Exception: pregnancy or pre-urologic procedure. This is a classic stewardship question trap.