This document outlines the principles of antibiotic prophylaxis for surgery. It defines antibiotics and their prophylactic use to prevent surgical site infections. The potential benefits are listed as preventing infections, related morbidity and mortality, and reducing healthcare costs. Potential harms include allergic reactions and contributing to antibiotic resistance. Guidelines on antibiotic choice, timing, redosing, and considerations for continuing post-operatively are provided for common surgical procedures.

1. Principle of Antibiotic
Prophylaxis
Short Note 2014

2. Outline
• Introduction
– What is antibiotic
– What is antibiotic prophylaxis
• Indication
• Potential benefit
• Potential harm
• Antibiotic
– Choice
– Timing
– Redosing
– Consideration to continue as therapeutic

3. Introduction
• Antibiotic is any substance of natural,
synthetic or semi-synthetic origin which kill
(bactericidal) or inhibit (bacteriostatic) the
growth of bacteria
• Prophylactic antibiotic is the use of antibiotic
to prevent infections at the surgical site
• The risk of surgical site infection reduce to 0.5-
1%

4. Indication of Prophylactic Antibiotic
• Clean contaminated surgery
– Risk of surgical site infection 10%
• Clean surgery with insertion of an artificial
device or prosthetic material
– E.g: hernioplasty, chemoport insertion
• Patient in whom the consequences of
infection may be catastrophic
– E.g: neurosurgery, open heart surgery, opthamic
surgery

5. • Impaired immune status
– Poor nutrition state
– Morbid Obesity
– Poor control diabetes mellitus
– Taking immunosuppression drug

6. Potential Benefit
• Prevent surgical site infection (SSI)
• Prevent SSI-related morbidity and mortality
• Reduce the duration and cost of health care

7. Potential Harm
• Risk of allergic reaction
• Risk of contributing to antimicrobial resistance
• Specific risk related to antibiotic
– E.g: aminoglycoside - renal toxicity, erythromycin –
GI upset

8. Choice of Antibiotic
• Avoid antibiotic that can cause allergy
• Active against pathogen most likely to
contaminate the surgical site
• Narrow spectrum antibiotic

9. Common Antibiotic Used
Condition Antibiotic
Upper GI IV Cefobid 1g
Distal GI and colorectal IV cefobid 1g and IV flagyl 500mg
Hernioplasty IV cloxacillin 1g or IV augmentin 1.2g
Cholecystectomy IV cefobid 1g or IV zinacef 1.5g
Vascular Surgery IV Augmentin / IV Unasyn
IV Vancomycin when prosthetic graft in
patients at risk

10. Route and Timing
• Been given bolus intravenously
• 30 minutes before skin incision or upon
induction (induction to skin incision take 20-
30 minutes)
• To provide serum and tissue concentration
exceeding the minimum inhibitory
concentration (MIC)

12. Redosing
• Redosing needed to keep antibiotic concentration
within therapeutic range for entire surgery
• Indication
– Excessive blood loss >1.5L
– Prolong surgery > 4 hours
• Single dose of antibiotic is adequate if the
condition above not present
• Continuation of prophylactic antibiotic post op
doesn’t show any benefit.

13. Consideration to Continue as
Therapeutic
• Breach of sterility during surgery
• Extensive contamination during surgery

14. Thank You

15. References
• Antibiotic for Surgical Prophylaxis, Australian
prescriber, 2005
• SIGN antibiotic prophylaxis in Surgery, 2014
• ASHP Therapeutic Guideline