1. Antibiotic Prophylaxis in SurgeryAntibiotic Prophylaxis in Surgery
Prevention of Surgical SitePrevention of Surgical Site
InfectionInfection
Dr sumer yadavDr sumer yadav

2. IntroductionIntroduction
Background: Infection of the surgical site is aBackground: Infection of the surgical site is a
common but avoidable complication of anycommon but avoidable complication of any
surgical procedure.surgical procedure.
Bacterial contamination of the surgical site isBacterial contamination of the surgical site is
inevitable, from the patient’s own flora or theinevitable, from the patient’s own flora or the
environment.environment.
A U.K. study (1993) showed the prevalence ofA U.K. study (1993) showed the prevalence of
wound infection to be 2.6% among 12947wound infection to be 2.6% among 12947
patients of different surgical specialties.patients of different surgical specialties.

3. It is based on the concept that bacterial contami-It is based on the concept that bacterial contami-
nation occurs during surgery, and that thenation occurs during surgery, and that the
administration ofadministration of
the antibiotic used for prevention must be timed forthe antibiotic used for prevention must be timed for
opti-opti-
mum blood levels during the operationmum blood levels during the operation..
..

4. Bacterial contamination of collections of blood or bodyBacterial contamination of collections of blood or body
fluid introduces organisms to an excellent culture medium,fluid introduces organisms to an excellent culture medium,
and abscess formation frequently follows. The administra-and abscess formation frequently follows. The administra-
tion of antibiotics once an abscess has formed is seldomtion of antibiotics once an abscess has formed is seldom
suf-suf-
ficient definitive treatment. However, the complication canficient definitive treatment. However, the complication can
be prevented if there are high concentrations of antibiotic inbe prevented if there are high concentrations of antibiotic in
these collections, making them an unfavourable culturethese collections, making them an unfavourable culture
medium. Antibiotic prophylaxis should therefore be admin-medium. Antibiotic prophylaxis should therefore be admin-
istered immediately before, or during, surgery. Furtheristered immediately before, or during, surgery. Further
prophylaxis for 48hours postoperatively is justified if oozingprophylaxis for 48hours postoperatively is justified if oozing
of blood or tissue fluid from internal raw surfaces isof blood or tissue fluid from internal raw surfaces is
expectedexpected
to continue during this period. The choice of antibiotic isto continue during this period. The choice of antibiotic is
dictated by the likely pathogenic contaminantsdictated by the likely pathogenic contaminants..

5. Goals of antibiotic prophylaxisGoals of antibiotic prophylaxis
Reduce the incidence of surgical siteReduce the incidence of surgical site
infection (SSI)infection (SSI)
Minimize the effect on the patient’s normalMinimize the effect on the patient’s normal
bacterial flora.bacterial flora.
Minimize adverse side effects ofMinimize adverse side effects of
antibiotics.antibiotics.
Minimize the emergence of antibioticsMinimize the emergence of antibiotics
resistant strains of bacteria.resistant strains of bacteria.
Cost effectiveness.Cost effectiveness.

6. Criteria for defining a surgical siteCriteria for defining a surgical site
infectioninfection
Superficial incisional SSI: involving the skin and the subcutaneousSuperficial incisional SSI: involving the skin and the subcutaneous
tissue. Occurs within 30 days after the operation and shows at leasttissue. Occurs within 30 days after the operation and shows at least
one of the followings: A(1/ pain 2/ swelling 3/ redness 4/heat 5/one of the followings: A(1/ pain 2/ swelling 3/ redness 4/heat 5/
tenderness)tenderness)
B Purulent drainageB Purulent drainage
C Isolation of organismsC Isolation of organisms
 Deep incisional SSI:1/ Purulent drainage from the deep incision butDeep incisional SSI:1/ Purulent drainage from the deep incision but
not from organ or space component of the surgical site.not from organ or space component of the surgical site.
2/ Deep incision dehiscence or deliberate opening2/ Deep incision dehiscence or deliberate opening
3/ Fever, localized pain or tenderness3/ Fever, localized pain or tenderness
4/ An abscess formation4/ An abscess formation
 Organ/space SSI: 1/ An abscess or infection found by radiological,Organ/space SSI: 1/ An abscess or infection found by radiological,
histopathological means or at reoperationhistopathological means or at reoperation
2/ Purulent discharge from the drain or culture isolation.2/ Purulent discharge from the drain or culture isolation.

7. Site specific classification of organSite specific classification of organ
space SSI infectionspace SSI infection
1/ Gastrointestinal tract 2/ Intraabdominal1/ Gastrointestinal tract 2/ Intraabdominal
1/ Male or female reproductive tract1/ Male or female reproductive tract
1/ Breast1/ Breast
1/ Upper respiratory tract 2/lower respiratory tract1/ Upper respiratory tract 2/lower respiratory tract
1/Sinusitis 2/ Ear,mastoiditis1/Sinusitis 2/ Ear,mastoiditis
1/Oral cavity1/Oral cavity
1/ Eye other than conjunctivitis1/ Eye other than conjunctivitis
1/ Mediastinitis 2/ Pericarditis 3/Myocarditis 4/ Endocarditis1/ Mediastinitis 2/ Pericarditis 3/Myocarditis 4/ Endocarditis
1/ Arterial or venous infection1/ Arterial or venous infection
1/ Osteomyelitis 2/ Joint or bursa 3/ Disc space1/ Osteomyelitis 2/ Joint or bursa 3/ Disc space
1/ Brain abscess 2/ Meningitis, ventriculitis 3/ Spinal abscess1/ Brain abscess 2/ Meningitis, ventriculitis 3/ Spinal abscess

8. Guidelines to antibiotic prophylaxisGuidelines to antibiotic prophylaxis
of SSIof SSI
Risk factors for SSIRisk factors for SSI
Common pathogensCommon pathogens
Benefits and risks of antibiotic prophylaxisBenefits and risks of antibiotic prophylaxis
Administration of intravenous prophylacticAdministration of intravenous prophylactic
antibioticantibiotic
Cost effectivenessCost effectiveness
Factors to be considered in auditing practiceFactors to be considered in auditing practice
Antibiotic prophylaxis other than for SSI controlAntibiotic prophylaxis other than for SSI control

9. Risk factors for surgical siteRisk factors for surgical site
infectioninfection
Classification of operationClassification of operation
Insertion of prosthetic implantsInsertion of prosthetic implants
Duration of surgeryDuration of surgery
Co morbiditiesCo morbidities

10. Classification of operationsClassification of operations
Clean: No inflammation.Clean: No inflammation.
Alimentary,genitourinary or respiratory notAlimentary,genitourinary or respiratory not
entered. No break in aseptic technique.entered. No break in aseptic technique.
Clean contaminated: Alimentary, genitourinaryClean contaminated: Alimentary, genitourinary
or respiratory tracts entered but withoutor respiratory tracts entered but without
significant spillage.significant spillage.
Contaminated: There is acute inflammationContaminated: There is acute inflammation
without pus, macroscopic spillage or openedwithout pus, macroscopic spillage or opened
wounds operated within four hours.wounds operated within four hours.
Dirty: The presence of pus, previous perforatedDirty: The presence of pus, previous perforated
hollow viscous or open injuries more than fourhollow viscous or open injuries more than four
hours.hours.

11. Insertion of prosthetic implantInsertion of prosthetic implant
Implants has a detrimental effect on theImplants has a detrimental effect on the
host defences. As a result a lowerhost defences. As a result a lower
inoculum of bacteria is needed to causeinoculum of bacteria is needed to cause
SSI of a prosthetic implant than a viableSSI of a prosthetic implant than a viable
tissue, this increases the incidence of SSItissue, this increases the incidence of SSI

12. Duration of surgeryDuration of surgery
The risk is additional to that ofThe risk is additional to that of
classification of the operation.classification of the operation.

13. Co morbiditiesCo morbidities
ASA score of >2 is associated with an increasedASA score of >2 is associated with an increased
risk of SSI, and this is additional to therisk of SSI, and this is additional to the
classification of the operation.classification of the operation.
ASA: 1: Normal healthy personASA: 1: Normal healthy person
2: Mild systemic disease2: Mild systemic disease
3:Severe systemic disease that limits3:Severe systemic disease that limits
activities of the patientactivities of the patient
4: Incapacitating disease with a constant4: Incapacitating disease with a constant
threat to life.threat to life.
5: Not expected to survive more than 245: Not expected to survive more than 24
hours with or without an operation.hours with or without an operation.

14. Common pathogens antibioticCommon pathogens antibiotic
susceptibilitysusceptibility
SSI for a skin wound at any site: 1/ Staph aureus . 90% remainsSSI for a skin wound at any site: 1/ Staph aureus . 90% remains
sensitive to flucloxacillin, macrolides and clindamycin. 2/ Betasensitive to flucloxacillin, macrolides and clindamycin. 2/ Beta
haemolytic streptococci. 90% remains sensitive to penicillinhaemolytic streptococci. 90% remains sensitive to penicillin
macrolides and clindamycinmacrolides and clindamycin
Additional pathogens: Head and neck surgery: 1/Oral anaerobes.Additional pathogens: Head and neck surgery: 1/Oral anaerobes.
95% remains sensitive to metronidazole and co-amoxyclav95% remains sensitive to metronidazole and co-amoxyclav
Additional pathogens: Operations below the waist: 1/ Anaerobes.Additional pathogens: Operations below the waist: 1/ Anaerobes.
95% remains sensitive to metronidazole and co-amoxyclav 2/ E. coli95% remains sensitive to metronidazole and co-amoxyclav 2/ E. coli
and other entrobacteriaceae. Complex resistance, but 90% remainsand other entrobacteriaceae. Complex resistance, but 90% remains
sensitive to second generation cephalosporins, gentamicin or betasensitive to second generation cephalosporins, gentamicin or beta
lactam beta lactamase inhibitors.lactam beta lactamase inhibitors.
Insertion of prosthesis, graft or shunt: 1/ Coagulase negativeInsertion of prosthesis, graft or shunt: 1/ Coagulase negative
Staph.90% remains sensitive to flucloxacillin, clindamycin orStaph.90% remains sensitive to flucloxacillin, clindamycin or
microlides. 2/Staph aureus. 2/3 are MRSA but beta lactammicrolides. 2/Staph aureus. 2/3 are MRSA but beta lactam
antibiotics are still appropriate.antibiotics are still appropriate.

18. MRSE/MRSA antibiotic prophylaxisMRSE/MRSA antibiotic prophylaxis
Beta lactam drugsBeta lactam drugs
GlycopeptidesGlycopeptides

19. Benefits and risks of antibioticBenefits and risks of antibiotic
prophylaxisprophylaxis
Benefits of prophylaxis:1/ related to the severity of consequences ofBenefits of prophylaxis:1/ related to the severity of consequences of
SSI e.g. in colonic anastomosis prophylaxis reduces the mortality. InSSI e.g. in colonic anastomosis prophylaxis reduces the mortality. In
total hip replacement reduces the long term morbidity, however intotal hip replacement reduces the long term morbidity, however in
most operation reduces the short term morbidity.most operation reduces the short term morbidity.
2/ surgical wound infection increases the length of hospital stay2/ surgical wound infection increases the length of hospital stay
depends on the type of the operation.depends on the type of the operation.
 Risks of prophylaxis:1/ Increased rates of antibiotic resistantRisks of prophylaxis:1/ Increased rates of antibiotic resistant
bacteria. 2/ increased incidence of C. defficile carriage in patientsbacteria. 2/ increased incidence of C. defficile carriage in patients
received > 24 hours prophylaxis.received > 24 hours prophylaxis.
 The final decision depends on: 1/ The patient’s risk of SSI. 2/TheThe final decision depends on: 1/ The patient’s risk of SSI. 2/The
potential severity of the consequences of SSI. 3/ The effectivenesspotential severity of the consequences of SSI. 3/ The effectiveness
of prophylaxis in that operation. 4/ The consequences of prophylaxisof prophylaxis in that operation. 4/ The consequences of prophylaxis
in that patient (e.g. risk of colitis)in that patient (e.g. risk of colitis)

20. Administration of intravenousAdministration of intravenous
prophylactic antibioticsprophylactic antibiotics
The choice of antibioticsThe choice of antibiotics
Usually a small number of pathogens need to beUsually a small number of pathogens need to be
covered. The antibiotic used must reflect thecovered. The antibiotic used must reflect the
local information about common pathogens.local information about common pathogens.
The choice should include economicThe choice should include economic
considerations.considerations.
Must be aware that if infection occurs, usually itMust be aware that if infection occurs, usually it
remains sensitive to the antibiotic used forremains sensitive to the antibiotic used for
prophylaxis.prophylaxis.
Penicillin allergy( anaphylaxis, articaria andPenicillin allergy( anaphylaxis, articaria and
rash): Do not use penicillin, challenge test forrash): Do not use penicillin, challenge test for
cephalosporins and admit another antibiotic incephalosporins and admit another antibiotic in
the regime.the regime.

21. Timing of administrationTiming of administration
The risk begins at the time of incision soThe risk begins at the time of incision so
effective tissue concentration must beeffective tissue concentration must be
reached at that time.reached at that time.
This depends on pharmacokinetic of theThis depends on pharmacokinetic of the
drug and the route of administration.drug and the route of administration.
Ideally 30 minutes within induction ofIdeally 30 minutes within induction of
anaesthesia.anaesthesia.
Considerations when use a tourniquet andConsiderations when use a tourniquet and
in caesarian sections.in caesarian sections.

23. Additional dose during theAdditional dose during the
operationoperation
Using antibiotics of short half life(1_2 hours) itUsing antibiotics of short half life(1_2 hours) it
seems logical to give an additional dose duringseems logical to give an additional dose during
operations that last more than 4 hours.operations that last more than 4 hours.
Controlled trials did not show any evidence toControlled trials did not show any evidence to
support thissupport this
All antibiotics should be administeredAll antibiotics should be administered
intravenouslyintravenously
Additional doses may be needed if there is bloodAdditional doses may be needed if there is blood
loss and dilution by fluid replacementloss and dilution by fluid replacement
Controlled trials did not show any benefit ofControlled trials did not show any benefit of
further postoperative dosesfurther postoperative doses

24. Cost effectivenessCost effectiveness
Rule 1: The number of patients needed to treatRule 1: The number of patients needed to treat
to prevent one wound infection increases into prevent one wound infection increases in
operations with low risk of wound infectionoperations with low risk of wound infection
Rule 2: Prophylactic antibiotics are given if theyRule 2: Prophylactic antibiotics are given if they
are likely to reduce the overall antibioticsare likely to reduce the overall antibiotics
consumption (use NNT to compare the likelyconsumption (use NNT to compare the likely
prophylactic and therapeutic consumption ofprophylactic and therapeutic consumption of
antibiotics)antibiotics)
Rule 3: Prophylactic antibiotics are given if theyRule 3: Prophylactic antibiotics are given if they
are likely to reduce the overall hospital costsare likely to reduce the overall hospital costs

25. Factors to be considered in auditingFactors to be considered in auditing
practicepractice
Date and time of administration and surgicalDate and time of administration and surgical
incisionincision
Operation performed (elective or emergency)Operation performed (elective or emergency)
Classification of operationClassification of operation
Justification for prophylaxisJustification for prophylaxis
Antibiotic name, dose and routeAntibiotic name, dose and route
Number of doses given and indicationsNumber of doses given and indications
Duration of operationDuration of operation
Previous adverse reactions to antibioticsPrevious adverse reactions to antibiotics

26. Antibiotics prophylaxis other thanAntibiotics prophylaxis other than
for SSI controlfor SSI control
Prevention of urinary tract or respiratory tractPrevention of urinary tract or respiratory tract
infections after surgeryinfections after surgery
Prevention of endocarditisPrevention of endocarditis
Topical antibioticsTopical antibiotics
Treatment of anticipated infection in dirtyTreatment of anticipated infection in dirty
emergency operationsemergency operations
Oral antibiotics to achieve selectiveOral antibiotics to achieve selective
decontamination of the gutdecontamination of the gut
Patients with prosthetic implants undergoingPatients with prosthetic implants undergoing
surgery that may cause bacteraemiasurgery that may cause bacteraemia
Transplant surgeryTransplant surgery

27. THE END