Surgical site infection (SSI) is defined as an infection occurring within 30 days of surgery or 1 year if implants are involved. The document outlines the history, epidemiology, risk factors, classification, pathogenesis, prevention and management of SSI. Prevention involves pre-operative, intra-operative and post-operative measures like skin preparation, proper attire, antibiotics and wound care. SSI increases morbidity, mortality and costs of surgery. Proper identification of causative organisms and source control along with appropriate antibiotics and surveillance are key to treatment. While advances have been made, SSI remains a challenge, especially in developing areas with limited resources and lack of protocol-based approaches.

1. SURGICAL SITE INFECTION
Dr. Itaman, Usifoh
Surgery Registrar
Presented 0n 7/11/2019 to the Department of Surgery,
ISTH, as part of the requirements for the Part 1 Post-
graduate Training Programme in Surgery

2. “Every operation is an experiment in bacteriology.”
- Moynihan (Br j 1920 8:27-35)

3. OUTLINE
• INTRODUCTION
• HISTORICAL PERSPECTIVES
• EPIDEMIOLOGY
• RISK FACTORS
• CLASSIFICATION OF WOUNDS
• PATHOGENESIS
• CLASSIFICATION OF SSI
• RISK ASSESSMENT
• PREVENTION
• MANAGEMENT
• COMPLICATIONS OF SSI
• LOCAL CHALLENGES
• CONCLUSION

4. INTRODUCTION
• After the conquest of pain, surgery became
commonplace. Surgical infection quickly became the
‘new evil’.
• The CDC coined the term surgical site infection in 1992.
• It is the defined as “infection of tissues, organs and
spaces manipulated during surgery occurring within
30days or 1yr in presence of an implant”.
• The common etiological organisms are endogenous
bacterial flora
• Preventive measures are targeted at various phases of
peri-op period.
• It is a cause of morbidity and mortality in surgical
patients and leads to prolonged stay and increased cost.

5. Definition of terms
• CONTAMINATION:
Transient presence of non-proliferating bacteria in wound.
• COLONISATION:
Presence of proliferating bacteria in wound with no signs of
inflammation. Bacterial count Usually less than 105 cfu/ml
• INFECTION
Bacteria proliferation with local and systemic signs of
inflammations. Bacterial count usually at least 105 cfu/ml
SURGICAL WOUND INFECTION IS SSI.

6. HISTORICAL PERSPECTIVES
• Its been a long journey.
• Over 300 -400yrs ago Egyptians through mummification
skills prevented putrefaction.
• Ignaz semmelweis, in 1846, first introduced hand washing.
• Louis Pasteur, late 19th century, first recognised microbial
growth as cause of infection(‘germ theory’)
• Robert Koch began culture of organisms.
• Joseph Lister, the father of antisepsis, used carbolic acid.
• Alexander Fleming discovered penicillin 1928
• Florey and Chain synthesized penicillin for clinical use 1940
• 19th century birth of aseptic surgery.
• Miles and Burke introduced Prophylactic antibiotic use in
the 1960s
• Several antimicrobials have been developed over the years.

9. EPIDEMIOLOGY
• 3rd Most common HAI 14 to 16%
• Most common HAI in surgical patients 38%
• Local data is lacking.
• Average overall incidence at 14 and 30 days post op 3.1 and 4.8
per 1000 procedure respectively.
• Studies show higher rates in aged patients and developing world.
• It remains a common cause of morbidity and mortality
• Doubles re-hospitalisation rates.
• A cause of prolong hospital stay (average 7days) and increased
cost (in Europe overall 1.5 to 19billion Euros)

10. Sources of infection
• Endogenous
• Exogenous

11. Etiological agents

13. Risk factors

14. PATHOGENESIS

16. CLASSIFICATION OF SSI
1. Based on depth (CDC)
Superficial incisional
Deep incisional
Organ/Space
2. Based on timing
Early : less than 30days
intermediate : 1 to 3 months
Late onset : more than3months
3. Based on severity
Minor
Major

17. CDC CLASSIFICATION OF SSI

18. Superficial incisional SSI
1. The infection occurs within 30 days after the operative
procedure
AND
2. Involves only skin or subcutaneous tissue of the incision.
AND
3. At least one of the following:
a. Purulent drainage from the superficial incision;
b. Organisms isolated from an aseptically obtained culture
of fluid or tissue from the superficial incision;
c. At least one of the following signs or symptoms of
infection-pain or tenderness, localized swelling, redness
or heat, and the superficial incision is deliberately opened
by surgeon unless the incision is culture-negative;
d. Diagnosis of superficial incisional SSI by the surgeon or
attending physician.

19. The following are not reported as superficial
incisional SSI:
• Stitch abscess
• Infection of an episiotomy or newborn
circumcision site
• Infected burn wound.
• Incisional SSI that extends into the fascial and
muscle layers

21. Deep incisional SSI
The infection occurs within 30 days after the operative procedure ( or within
one year if an implant is in place)
AND
The infection involves deep soft tissues (e.g., fascial and
muscle layers) of the incision.
AND
Patient has at least one of the following:
a. Purulent drainage from the deep incision but not from the organ/space
component of the surgical site.
b. Deep incision that spontaneously dehisces or is deliberately opened by
a surgeon when the patient has at least one of the following signs or
symptoms-fever (>38”C), localized pain, or tenderness, unless the
incision is culture negative.
c. An abscess or other evidence of infection involving the deep incision is
found on direct examination, during reoperation, or by histopathologic
or radiologic examination.
d. Diagnosis of a deep incisional SSI by a surgeon or attending physician.

23. Organ/Space
The infection occurs within 30 days after the operative procedure ( or
within one year if an implant is in place)
AND
the infection involves any part of the anatomy (e.g., organs or spaces),
other than the incision, opened or manipulated during the operative
procedure.
AND
Patient has at least one of the following:
a. Purulent drainage from a drain that is placed through a stab wound
into the organ/space
b. Organisms isolated from an aseptically obtained culture of fluid or
tissue in the organ/space.
c. An abscess or other evidence of infection involving the
organ/space that is found on direct examination, during
reoperation, or by histopathologic or radiologic examination.
d. Diagnosis of an organ/space SSI by a surgeon or attending
physician.

25. RISK ASSESSMENT
• Traditional method
• NNIS – National nosocomial infection surveillance system
• SENIC – study of the efficacy of nosocomial infection
control

26. Traditional method
Clean wounds : 1 -2%
Clean contaminated: 6-9%
Contaminated: 15 to 20%
Dirty: 40%

27. SENIC – study of the efficacy of nosocomial infection control
1. Abdominal surgery.
2. Duration of surgery greater than 2hrs
3. class III or IV
4. Three or more diagnosis at time of discharge
Risk of infection:
Score:0 1%
1 3.6%
2 9%
3 17%
4 27%

28. NNIS – National nosocomial infection surveillance system
1. Duration of surgery greater than 75th percentile of T
2. class III or IV
3. ASA greater than 2
Risk of infection:
Score:0 1.5%
1 2.9%
2 6.8%
3 13%

29. PREVENTION
The preventive measures could be:
• Pre-operative
• Intra-operative
• Post-operative

30. Preoperative
• Control of patient factors: stop smoking, control
blood sugar, treat remote infection, lose weight.
• Short Pre-operative hospital stay.
• Pre-operative antiseptic showering
• Pre-operative hair removal only when necessary
• Pre-operative hand washing (scrubbing)
• Proper theatre attire
• Prophylactic antibiotics

31. Principles of prophylactic antibiotics
use

32. HANDWASHING

33. Intraoperative
Theatre environment
• Positive pressure relative to surrounding
• Laminar air flow (top to bottom)
• Filter all air
• Temperature 18 to 25degC
• Humidity 40 to 60%
• Keep doors closed as much as possible
• Optimal sterilization of instruments (flash sterilisation
only for immediate use)
• Proper surgical attire
• Minimize personnel traffic

34. LAMINAR FLOW

35. Intraoperative
• Patient skin preparation.
• Proper drapes (incise-drapes must be iodophor
impregnated)
• Strict adherence to asepsis technique
• Maintain homeostasis: temperature, oxygenation,
blood sugar, transfuse if necessary
• Effective use of diathermy
• Table tips: gentle tissue handling, precise dissection,
effective hemostasis, no dead space, minimize
devitalize tissues and foreign bodies
• Suture choice
• Judicious use of drains
• Skin closure

37. Anti septic agents
Properties:
• Able to significantly reduce microbes on skin
• Broad spectrum
• Fast acting, persistent, safe,non-irritating
Examples:
Alcohol- ethanol,isopropanol,N-propanol
Iodophors –povidone iodine
Biguanidine –chlorhexidine gluconate

38. Postoperative
1. Incision care
• Sterile dressing for 24 to 48hrs
• Aseptic technique in changing dressing
2. Optimal blood sugar control
3. Surveillance

39. MANAGEMENT
• Clinical evaluation
• Investigation
• Treatment
• surveillance

40. Clinical features
• Pain
• Erythema
• Differential warmth
• Swelling
• Discharge of sero-purulent or purulent effluent
• Dehiscence of wound
• Systemic: fever, malaise, anorexia, features of
sepsis
• Features of organ/space SSI depends on organ
affected.

41. Investigations
• Microscopy culture and sensitivity
• Full blood count
• ESR
• CRP
• Imaging: X-rays, Ultrasound, CT for
organ/space

42. Wound assessment
• Southampton
• ASEPSIS

43. SOUTHAMPTON SCORING SYSTEM

44. ASEPSIS SCORING SYSTEM

45. Treatment
1. EARLY IDENTIFICATION OF ORGANISM
2. SOURCE CONTROL
-Open wounds to drain
-Drainage of abscess (open/percutaneous)
-Debridement
-Removal of implants
3. APPROPRIATE USE OF ANTIBIOTICS
4. SURVEILLANCE

46. COMPLICATIONS OF SSI
• Wound dehiscence
• Poor healing
• ugly scars including keloids
• Prolonged hospital stay
• Sepsis
• Psychological trauma
• Cost
• Mortality

47. LOCAL CHALLENGES
• Lack of proper health facilities.
• Out-of-pocket health financing.
• Poor surveillance/data system.
• Lack of a protocol based approach.

48. CONCLUSION
• SSI is still a cause of morbidity and mortality,
more so in the developing world.
• Over the years, a lot as been achieved in the
prevention and treatment of SSI.
• Adherence to recommended guidelines in all
phases of surgery is paramount.
• There is trend toward protocol based approach
“SSI bundle”
• THE WORLD HAS LEFT US. TIME TO ACT IS NOW.

49. “ SURGICAL SITE INFECTION IS HARD TO DEFINE
BUT I KNOW IT WHEN I SEE ONE.”
-Anonymous

50. References
• Brunicard F.C., Dana K.A., David L.D et al, 2015. Schwartz
Principles Of Surgery .10th Edn. McGraw Hill, New York.
• Horan TC, Gaynes RI: Martone m Jarvis WI, Emori TG. CDC
definitions of nosocomial surgical site infections, 1992: a
modification of CDC definitions of surgical wound infections.
Infect Control Hosp Epidemiol. 1992;13:606-608
• .

51. THANK YOU for listening.