2019A13 Outline the principles of antibiotic prophylaxis for surgical site infections using
cefazolin in knee joint replacement surgery as an example.



·      Aims x 6

·      Practical considerations x 7


Aims: (note prevention, not treatment)


Cefazolin for joint replacement surgery


(i.e. not in all surgery at clean sites)

·   Moderate risk

·   Severe morbidity

·   Use of implant

Bactericidal preferably

·   Yes

Penetrates the relevant tissues

·   Good for skin, bone, joint

Targets the relevant microbes

·   First generation cephalosporins effective against skin commensal gram positive cocci

·   (Note gram negative rods common in hospitalized patients)

Low risk of encountering antimicrobial resistance

·   Low risk if from community

·   But ineffective against MRSA, use vancomycin instead if in hospital several days

Low risk of promoting microbial resistance

·   Minimal necessary duration: 24 hours total

·   Minimal necessary spectrum: i.e. not piperacillin/tazobactam




Cefazolin for joint replacement surgery


·   25mg/kg pre-induction


·   IV ideal

Rapid onset

·   Ideally 30-60 mins pre-incision, to allow penetration of skin

·   MUST be well before tourniquet if knee replacement

Long duration: ensure cover during long procedure

·   Repeat at 4 hours if surgery ongoing

·   Repeat at 8 hours post-op

Adjustment in organ dysfunction

·   Cefazolin is renally cleared. ↓ frequency if CrCl reduced esp <30mL/min

Side effects

·   High therapeutic index

·   Risk of anaphylaxis


·   Cheap



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