This document outlines the use of antibiotics in surgery. It discusses the classification of antibiotics and their uses for prophylaxis and therapeutic purposes. For prophylaxis, a single preoperative dose is usually sufficient to prevent infection if administered within 1 hour before incision. Therapeutic antibiotics require culture and sensitivity testing to determine the appropriate treatment. Factors like infection severity, pathogen type, and patient status help determine the antibiotic regimen. Overuse and misuse of antibiotics can lead to increased resistance.

1. ANTIBIOTICS IN
SURGERY
Tuan Ahmad Zulkarnain
Nur-Liyana
Supervisor: Dr. Zalikha

2. OUTLINE
• Introduction
• Antibiotics Classification
• Uses of Antibiotics in Surgery
• Prophylaxis
• Therapeutic
• Take home messages

3. ANTIBIOTICS
• A substance which has the capacity to kill or inhibit the
growth/ spread of microorganism

4. NORMAL FLORA

5. ANTIBIOTICS CLASSIFICATION

7. Principles of Antibiotics in
Surgery
• Indication (prophylaxis vs. therapeutic)
• Susceptibility vs. empirical
• Pharmacokinetic
• Pharmacodynamics
• Combination ?
• Cost
• Availability
• Monitoring
• Compliance

8. Antibiotics Prophylaxis in Surgery
• Use of antibiotic where there is no evidence of infection
but expected to be exposed to pathogens that constitutes
a major risk of infection.
• Single dose regime, based on the most common organism,
which is given at the time of induction to ensure the minimum
inhibitory concentration during skin incision – reduces risk of
surgical site infection (SSI) and post op infection

9. • Usually a single dose is sufficient. A second dose
may be required in the following situations:
• a. in prolonged operations
• b. when there is contamination during operation
• Giving more than 1 or 2 doses postoperatively is
generally not advised. The practice of continuing
prophylactic antibiotics until surgical drains have
been removed is not recommended.
(NAG 2008)

10. General Principles of Surgical
Prophylaxis
• A single preoperative dose of antibiotic is as effective as
full five days course of therapy assuming uncomplicated
procedure.
• Prophylactic antibiotics should be administered within 1
hour prior to incision, preferably with induction of
anesthesia.
• Prophylactic antibiotics should target anticipated
organisms.

11. • Prophylaxis is generally recommended for clean-
contaminated (risk of infection is 6%) and
contaminated (risk of infection is 15%) operations
• In clean operation prophylaxis is also indicated under
certain conditions i.e. where there is prosthesis
implanted, high risk perforation where infection is
catastrophic e.g. neurosurgery or cardiac surgery.

12. Classification of SurgicalWound

13. Goals of Antibiotic Prophylaxis
• Reduce the incidence of surgical site infection (SSI)
• Minimize the effect on the patient’s normal bacterial
flora.
• Minimize adverse side effects of antibiotics.
• Minimize the emergence of antibiotics resistant strains of
bacteria.
• Cost effectiveness.

14. PROCEDURE SUGGESTED ANTIBIOTIC
1. GI surgery
2. HBS surgery
IV Cefoperazone 1g PLUS IV
Metronidazole 500mg
1. Hernia repair with mesh
(includes laparoscopic repair)
2. Breast
(not recommended for minor
excision
3.Burns
IV Cloxacillin 1G
Vascular Operation IV Ampicillin/Sulbactam 1.5g
Neurosurgery IV Ceftriaxone 1g AND
IV Metronidazole 500mg
Urology IV Amoxicillin / clavulanate 1.2g
GUIDELINES FOR SURGICAL
PROPHYLACTIC ANTIBIOTICS

15. THERAPEUTIC ANTIBIOTICS

16. Therapeutic
Antibiotics:
PRINCIPLES
C&S
Pharmaco-
dynamics &
TDM
Host status
Site of
infection
Combination
Prevent
resistance
Synergism/
Additive
therapy
Multiple
pathogens

17. THERAPEUTIC
ANTIBIOTICS
Empirical
Initiation of treatment prior
to determination of a firm
diagnosis
Definitive
Specific to organism isolated
in C&S

18. EMPIRICTHERAPY
• When to start ?
• Risk of surgical infection is high - based on the underlying disease
process (e.g. perforated appendicitis) [prophylaxis  empiric]
• Significant contamination during surgery has occurred (e.g.
considerable spillage of colon contents)
• In critically ill patients – potential site of infection has been identified
• Severe sepsis or septic shock
• Short course (3-5 days)
• Stop if the presence of a local site or systemic infection is not
revealed

19. MONOMICROBIALVS
POLYMICROBIAL
• Monomicrobial infections:
• Nosocomial which occurred in postoperative patients, e.g. UTI,
pneumonia, catheter-related infection
• Polymicrobial infections:
• culture results less helpful
• Thus, antibiotic regimen should not be modified solely on
culture information. Clinical course is more important.

20. Systemic Inflammatory Response
Syndrome (SIRS)
• Empiric antibiotics are not indicated for all patients with
SIRS
• Indications for antibiotic therapy include the following:
• Suspected or diagnosed infectious etiology (e.g. UTI,
pneumonia, cellulitis)
• Neutropenia or other immunocompromised states
• Asplenia - Due to the potential for overwhelming
postsplenectomy infection

21. HBS:
1) Liver
• Enterobacteriaceae,
Enterococci,
Bacteroides
• Cefobid & Flagyl -
penetrate well into
abscess cavity
• Ampicillin &
Gentamicin & Flagyl
2) GB
• E. coli, Klebsiella,
Strep. faecalis
• Only certain
antibiotics can be
excreted in bile
• Unasyn, Cefobid &
Flagyl
• Cholangitis –
Imipenem,Tazocin
Stomach & Duodenum:
• H. pylori
• Clarithromycin &
Flagyl or Amoxycillin
Pancreas:
• Enterobacteriaceae,
B. fragilis
• Ciprofloxacin/Flagyl,
Carbapenems
Jejunum, Ileum, Large bowel:
• Enterobacteriaceae,
Enterococci, Bacteroides
• Ampicillin & Gentamicin &
Metronidazole
• Broad spectrum (3rd
generation Cephalosporins)
& Flagyl

22. • Abdominal trauma – 3rd generation Cephalosporins,
Cefuroxime,Augmentin, Unasyn
• Perforated viscus, Peritonitis - 3rd generation Cephalosporins
& Flagyl
• Breast abscess (S. aureus) – Cloxacillin
• Mycotic pseudoaneurysm – Cloxacillin
• Prostethic graft infection - 3rd generation Cephalosporins
• MRSA -Vancomycin

23. DURATION OFTHERAPY
• Duration should be long enough to prevent
relapse yet not excessive, as it can increase side
effects and resistance
• Factors such as decreasing trend ofWBCs and
lack of fever guide the length of therapy
• The search for extra abdominal source of
infection or a residual /ongoing source of intra
abdominal infection should be sought

24. DURATION OFTHERAPY
• Penetrating GI trauma without extensive
contamination
• 12-24hours
• Perforated/gangrenous appendicitis
• 3-5days
• Peritoneal soilage due to perforated viscus with
moderate degrees of contamination
• 5-7days
• Extensive peritoneal soilage/immunocompromised
host
• 7-14days

25. SIDE EFFECTS
Antibiotic Side Effects
Penicillins • Allergy (serious anaphylaxis)
Cephalosporins • Allergy
Aminoglycosides • Hearing loss
• Vertigo
• Renal dysfunction
Carbapenems • Seizures (Imipenem)
• Rashes
Macrolides • Prolonged QT interval
(Erythromycin)
• Hearing loss
• Jaundice

26. ANTIBIOTIC RESISTANCE
• Resistance of a microorganism to an
antimicrobial agent to which it was previously
sensitive
• Resistant organisms are able to withstand attack
by antimicrobial medicines so that standard
treatments become ineffective and infections
persist and may spread to others

27. ANTIBIOTIC RESISTANCE
Intrinsic
• Drug target is not present in the bacteria’s metabolic
pathways
Acquired
• Mutation
• Transfer of genetic material from resistant to susceptible
organisms (plasmids, transposons, bacteriophages)

28. Main factors contributing to resistance are:
• Excess antibiotic usage
• Incorrect use of broad spectrum agents
• Incorrect dosing
• Non compliance

29. TAKE HOME MESSAGES
• Prophylactic antibiotic should be given in clean surgery which involves
prosthetic implants, in clean-contaminated and contaminated surgeries
• Prophylactic antibiotics should be administered within 1 hour prior to incision
• Therapeutic antibiotic should be started for dirty wound
• Empirical therapy should be altered according to the sensitivity of the culture
• Escalation and de-escalation of antibiotics should be done based on clinical
response and aided by culture and sensitivity results
• Therapeutic drug monitoring is done in antibiotics with narrow therapeutic
range (Amikacin, Gentamycin,Vancomycin)
• Allergic reactions include anaphylaxis, fever, rashes, nephritis,
granulocytopenia & hemolytic anemia are possible side effects of Penicillins
and Cephalosporins
• Appropriate choice of antibiotics, dosage, compliance should be ensured to
avoid emergence of resistance

30. THANKYOU
References:
• National Antibiotic Guideline 2008
• Schwartz’s Principles of Surgery
• Niederman MS. Principles of appropriate antibiotic use
• Medscape
• Enterococcal Resistance – An Overview (YA Marothi, H
Agnihotri, D Dubey) Indian Journal of Medical Microbiology,
(2005) 23 (4):214-9
• Antibiotics in the treatment of biliary infection (J S Dooley, J M
Hamilton-Miller, W Brumfitt, and S Sherlock) Gut. 1984 Sep;
25(9): 988–998.