surgical site infection

1. Surgical Site Infection
(Wound Infection)

2. “Constant attention to a surgical
wound is as much important as a
major operation by a surgeon”

3. Overview
• Introduction
• Definition
• Incidence
• Risk factors
• Classification
• Scoring
• Clinical features
• Diagnosis
• Differential diagnosis
• Management

4. Introduction
• Surgical site infection (SSI) is the most
common preventable complications after
surgery.
• Occurs in 2-4% of all patients undergoing
inpatient surgical procedures
• Significant cause of mortality and morbidity
• Leading cause of hospital readmissions

5. Incidence
• The global estimate of SSI have varied from
0.5% to 15%
• Studies in India have consistently shown
higher rates ranging from 23% to 38%
A review of prevention of surgical site infections in Indian hospitals based on global guidelines for the
prevention of surgical site infection, 2016

6. Definition: according to center for disease control and
prevention (CDC)
• Surgical site infections (SSI) related to a
surgical procedure that occurs near the
surgical site within 30 days following surgery.
• 90 days following surgery when an implant is
involved.
https://www.cdc.gov/infectioncontrol/guideline
s/ssi/index.html

7. CDC : specific criteria for the
diagnosis of SSIs
Wounds are generally categorized as follows:
1. Superficial
skin and subcutaneous tissue
2. Deep
fascia and muscle
3. Organ space
which includes the internal organs
if the operation includes that area.

9. Classification of sources of infection
• Endogenous:
– present in or on the host e.g. SSSI following
contamination of the wound from a perforated
appendix
• Exogenous:
– acquired from a source outside the body such as the
operating theatre (inadequate air filtration, poor
antisepsis) or the ward (e.g. poor hand-washing
compliance). The cause of hospital acquired infection
(HAI)

10. Southampton wound grading system
Grade- Appearance Grade-Appearance Grade- Appearance
0 Normal healing IIc Along wound Major complications
I Normal healing with mild
bruising or erythema
IId Around wound IV Pus
Ia Mild bruising III Clear or haemoserous
discharge
IVa At one point only
(<2cm)
Ib Considerable bruising IIIa At one point only (≤2
cm)
IVb Along wound (>2cm)
Ic Mild erythema IIIb Along wound (>2 cm) V Deep or severe wound
infection with or without
tissue breakdown;
haematoma requiring
aspiration
II Erythema plus other
signs of inflammation
IIIc Large volume
IIa At one point IIId Prolonged (>3 days)
IIb Along sutures Bailey and love short practice of surgery 27th edition

11. Asepsis wound score
Criterion Points
Additional treatment
Antibiotics for wound infection
Drainage of pus under local
anaesthesia
Debridement of wound under
general anaesthesia
0
10
5
10
Serous discharge Daily 0-5
Erythema Daily 0-5
Purulent exudate Daily 0-10
Separation of deep tissues Daily 0-10
Isolation of bacteria from wound 10
Stay as inpatient prolonged over
14 days as result of wound
infection
5
Bailey and love short practice of surgery

12. From Bacteria’s point of view..
• Gram-positive cocci account for half of the infections
– Staphylococcus aureus (most common), coagulase- negative
Staphylococcus, and Enterococcus spp
– S. aureus infections normally occur in the nasal passages, mucous
membranes, and skin of carriers.
– Methicillin-resistant S. aureus [MRSA]
• consists of two subtypes, hospital-acquired and community-
acquired MRSA.
• In approximately one third of SSI cases, gram-
negative bacilli
– Escherichia coli, Pseudomonas aeruginosa, and Enterobacter spp.) are
isolated.
– predominant bacterial species are the gram-negative bacilli at
locations at which high volumes of GI operations are performed.

13. Common Bacteria causing surgical
infection
• Streptococci
– Gram positive on staining
– Group A streptococcus, Strep. pyogenes
– Streptolysin, streptolinase, streptodornase
– Streptococcus faecalis
– Sensitive to penicillin, erythromycin &
cephalosporins

14. • Staphylococci
– Gram positive cocci
– Suppuration in wounds / implanted prostheses
– B-lactamase producers-resistant to penicillin
– Flucloxacillin, vancomycin, aminoglycosides,
cephalosporins
– Linezolid, teicoplanin, daptomycin
– Staph epidermidis: vascular cannulas/ catheters

15. • Clostridia
– Gram positive
– Clostridium perfringens – gas gangrene
– Clostridium tetani – tetanus
– Clostridium difficile –
pseudomembranous colitis
– Imidazoles and Cephalosporins

16. In the National Nosocomial
Infections Surveillance System, the
risk of patients is stratified according
to three important factors:
• Wound classification (contaminated or dirty);
• Longer duration operation,
– defined as duration that exceeds the 75th percentile
for a given procedure;
• Medical characteristics of patients
– determined by American Society of Anesthesiology
classification of III, IV, or V (presence of severe
systemic disease that results in functional limitations,
is life-threatening, or is expected to preclude survival
from the operation) at the time of operation.

17. Risk factors for surgical site infections

18. Halsted’s principles of surgical technique
• Gentle handling of tissues
• Preservation of blood supply
• Strict aseptic technique
• Minimum tension
• Accurate tissue apposition
• Obliteration of dead space
• Maintain hemostasis

19. Types of surgical procedures

20. Clinical Features
• Superficial incisional SSI:
• Pain or tenderness
• Localised swelling
• Erythema
• Local rise of temperature
• Purulent drainage

21. Clinical Features
• Deep incisional SSI:
• Fever (>38 C)
• Localised pain or tenderness
• Purulent discharge
• Wound dehiscence

22. Clinical Features
• Organ / space SSI
• Fever(>38 C)
• Hypotension
• Nausea, vomiting
• Abdominal pain or tenderness
• Elevated transaminases
• Jaundice
• Purulent drainage
• Abscess

23. Diagnosis
• History and examination
• Imaging
• Ultrasound
• CT scan with oral contrast
• Cultures

24. Differential Diagnosis
• Reactions to suture material/ dressings
• Subcutaneous hematoma
• Seroma
• Stitch abscess

25. Prevention of SSI:
• Pre operative preparation
– Bath/scrub
– Part preparation
– Antibiotic prophylaxis
• Intra operative
– Strict antiseptic precautions during surgery
– Hand hygiene
• Post operative care

26. Precautions- intra operative
• Careful handling of tissues .
• Meticulous dissection, hemostasis, and debridement of devitalized tissue .
• Compulsive control of all intraluminal contents
• Preservation of blood supply of the operated organs
• Elimination of any foreign body from the wound
• Maintenance of strict asepsis by the operating team (e.g., no holes in
gloves; avoidance of the use of contaminated instruments; avoidance of
environmental contamination, such as debris falling from overhead)
• Thorough drainage and irrigation with warm saline of any pockets of
purulence in the wound
• Ensuring that the patient is kept in a euthermic state, is well monitored,
and is fluid-resuscitated
• Expressing a decision about closing the skin or packing the wound at the
end of the procedure

27. Antibiotics used in treatment and
prophylaxis of surgical infection
• Penicillin
• Flucloxacillin
• Ampicillin, amoxicillin and co-amoxiclav
• Piperacillin and ticarcillin
• Cephalosporins
• Aminoglycosides
• Vancomycin and teicoplanin
• Carbapenems
• Metronidazole
• Ciprofloxacin

28. Prophylaxis
To be most effective, the antibiotic is administered intravenously within
60 minutes before the incision so that therapeutic tissue levels have
developed when the wound is created and exposed to bacterial
contamination.

29. Type of surgery Infection rate with
prophylaxis (%)
Infection rate without
prophylaxis (%)
Clean 1-2 1-2
Clean-contaminated 3 6-9
Contaminated 6 13-20
Dirty 7 40
SSI rates relating to wound contamination
with and without using antibiotic prophylaxis
Bailey and love Short practices of surgery

30. Management
• Treatment of SSIs depends on
– Depth of the infection
– For superficial and deep SSIs
• skin staples are removed over the area of the infection, and a cotton-tipped
applicator may be easily passed into the wound, with efflux of purulent
material and pus.
• if the fascia has separated or purulent material appears to be coming from
deep to the fascia, there is concern about dehiscence or an intra-abdominal
abscess that may require drainage or possibly a reoperation.
– The presence of crepitus in any surgical wound or gram-positive rods
(or both) suggests
• possibility of infection with C. perfringens
• Rapid and expeditious surgical débridement is indicated
– Most postoperative infections are treated with
• healing by secondary intention.
• Delayed primary closure may be considered after close observation of the
wound for 5 days if the wound looks clean

31. Management
• Wound debridement
• Drainage
• Lavage: warm normal saline
• Chlorhexidine/hydrogen peroxide/sodium
hypochlorite ???
• Medications??

32. Thank you