for mbbs students

1. WOUND
INFECTIO
N

2. Dr. Nabarun Biswas
Registrar Surgery
MMCH

3. A wound is a break in the integrity of the
skin or tissues often, which may be
associated with disruption of the
structure and function
Wound
Infection
The invasion and growth of
germs in the body is called
Infection

4. Classification of wound
 Rank and Wakefield Classification
 Classification based on Type of Wound
 Classification based on Involvement of
Structures
 Classification based on the Time Elapsed
 Classification of Surgical Wounds

5. The infection of a wound can be defined as the
invasion of organisms into tissues following a break
down of local and systemic host defenses, leading to
either cellulitis, lymphangitis, abscess formation or
bacteremia.
Infection of wound

6. History of surgical
infection:
 Surgical infection, particularly surgical
site infection (SSI) has always been a major
complication of a surgery and trauma and
has been documented for 4000-5000 years.

7. Koch’s postulate proving whether a given organism
is a cause of given disease:
 It must be found in every case
 It should be possible to isolate it
from the host and growth in culture
 It should reproduce the disease
when injected into another healthy
host.
 It should be recovered form an
experimentally infected host.

8. Advances in the control of infection in Surgery:
Aseptic operation theatre techniques have enhanced
the use of antiseptics

9. Antibiotics have reduced post operative infection rates
after elective and emergency surgery.

10. Delayed primary, or secondary closure remains useful
in heavily contaminated wound.

11. 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
acquired infection (HAI))

12. Common bacteria causing surgical infection:
 Streptococci
 Staphylococci
 Clostridia
 Aerobic gram-negative bacilli
 Bacteroides

13. The human body harbors
approximately 1014 organism. They can
be released into tissues before, during
after surgery, contamination being most
severe when a hollow viscus perforates
e.g. (fecal peritonitis following a
diverticular perforation)

14. Host Defense
Intact epithelial surface
Chemical: low gastric pH
Humoral: compliment, antibodies, opsonin
Cellular: macrophage, N-K call, neutrophil,
phagocyte, lymphocyte

15. Factors that determined whether a wound will
become infected:
Host response
Virulence and inoculum of infective agent.
Vascularity and health of tissue being invaded (including local
ischemia as well as Systemic shook)
Presence of dead or foreign tissue.
Presence of antibiotic during the ‘decisive period’ period.

16. Factors influencing SSIs
Patient Factors
 Local:
 High bacterial
load
 Wound
hematoma
 Necrotic tissue
 Foreign body
 Obesity
 Systemic:
 Advanced age
 Shock
 Diabetes
 Malnutrition
 Alcoholism
 Steroids
 Chemotherapy
 Immuno-compromise

17. Factors influencing SSIs
Surgical Risk Factors
Type of procedure
Degree of contamination
Duration of operation
Urgency of operation
skin preparation
operating room environment
Antibiotic prophylaxis

18. The decisive period:
The time when the invading bacteria may become
established in the tissues.
 There is up to a 4-hour interval before bacterial growth becomes
established enough to cause an infection after a breach in the tissues,
whether caused by trauma or surgery.
………..27th edi; B&L
 There is a delay before host defenses can become mobilized after a
breach in an epithelial surface, whether caused by trauma or surgery;
inflammatory, humoral and cellular defenses take up to 4 hours to be
mobilized.
………….26th edi; B&L

22. Classification of SSI:

23. Presentation of surgical infection:
Major surgical site infection
- Significant quantity of pus
- Delayed return home
- Patient are systemically ill.

24. Minor surgical site infection
Discharge pus or infected serous
fluid but are not associated with
excessive discomfort, systemic
sign or delay in return home.

25. There are scoring systems to assess the severity of
wound infection which are particularly useful in
surveillance and research such as-
 Southampton wound grading system
 The ASEPSIS wound score

26. Southampton wound grading system:
Grade Appearance
O Normal healing
I Normal healing with mild bruising or erythema
Ia Some bruising
Ib Considerable bruising
Ic Mild erythema
II Erythema + other signs of inflammation
IIa At ome point
IIb at sutune
IIc Along wound
IId Around wound

27. Grade Appearance
III Clear or haemo-serous discharge
IIIa At one point only (≤ 2 cm)
IIIb Along wound (>2cm)
IIIc Large volume
IIId Prolonged (> 3 days)
Major Camplication:
IV Pus
IVa At one point only (≤ 2 cm)
IVb Along wound
V Deep or severe wound infection with or, without tissue
breakdown,

28. ASEPSIS wound score:
Criteria point
A= Additional treatment 10
Antibiotic 10
Drainage of pus L/A 05
Debridement G/A 10
S= Serous discharge Daily 0-5
E= Erythema Daily 0-5
P= Purulent exudate Daily 0-10
S= Separation of deep tissue Daily Daily 0-10
I= Isolation of bacteria from wound  10
S= Stay as in patient prolonged over 14 days as result of infection  05
Within
2
months
For
Forst
7
days

29. ASEPSIS wound score:
Daily assessment
Wound character Proportion of wound affected
0% <20% 20-40% 40-60% 60-80% >80%
Serous discharge 0 1 2 3 4 5
Erythema 0 1 2 3 4 5
Purulent 0 2 4 6 8 10
Seperation of deep tissee 0 2 4 6 8 10

30. ASEPSIS wound score:
score Interpretation:
0-10 Satisfactory healing
11-20 Disturbance in healing
21-30 Minor wound infection
31-40 Moderate wound infection
>40 Severe wound infection

31. Localized infection:
FAbcess
Lymphangiti
s
Cellulitis

32. Specific Local wound infection:
Gas Gangrene:
Caused byt Cbotridium perfningens
Gas and small are chracterstics
Immunocmpromised patients are most at risk
Antibiotic prophylaxis are essential when performing
amputations to remove dead tissues.

33. Specific Local wound infection:
Clostridium Tetani:
This is another anaerobic, terminal opore-
bearing, gram pobitive bacterium, which can
cause tetenus following implantation in tissues or
a wound. The spores are wide spread in soil and
manure, and so the infection is more common in
traumatic civilion or military wound.

34. Prevention of surgical infection:
Preoperative Preparation:
1. A short preoperative hospital stay.
2. Medical and nursing staff always wash their hand often any patient
contact.
Alcoholic hand gels can act as a substitute for hand washing.
3. Clean Hospital
4. Staff with open, infected skin lesion should not entering the
operating theatre
5. preoperative skin shaving should be undertaken in the operating
theatre
immediately before surgery.

35. Scrabbing

36. Skin preparation:

37. Prophylactic
antibiotics:
The principles of antibiotic prophylaxis are:
 Identify patient at risk
 Select an appropriate antibiotic according to
the type of operation
 Take account of the patient allergies and cost
involved.
 Administer the antibiotic, either I/V at
induction or I/M with the premedication;
ensure adequate serum and tissue levels at the
time of surgery .
 Repeat the administration of antibiotic in
operations lasting longer then 4 hour.

38. Choice of
Prophylactic
antibiotic:
 Emperical cover against expected pathogens.
 Single- shot intravenous administration at
induction of anaesthesia.
 Repeat only in prosthetic surgery, long
operations or there is excessive blood loss.
 Continues as therapy if there is unexpected
contamination.
 Benzylpenicillin should be used if clostridium gas
gangrene infection is a possibility.
 Patient with heart valve disease or a prosthesis
should be protected from bacteremia caused by
dental or, urethral instrumentation or visceral
surgery.

39. Approach of a
patient with SSI
Clinical presentation
 Redness
 Pain
 Swelling
 Temperature
 Discharging pus
 Wound gapping/ popping

40. Naked Eye Examination
• Staphylococci - thick creamy pus
• Strep. Pyogenes -straw colored & watery
• Proteus -fishy smell
• Pseudomonas - sweet, musty odor & a blue
pigment
• Anaerobes – offensive, putrid smell
• Actinomycosis -Sulphur granules
• Mycetoma - black or brown granules
• Amoebic abscess -anchovy sauce

41. MICROSCOPY
• Presence of relative numbers of polymorphs and
bacteria
• Morphology and arrangement
• Wet film - fungi or motile bacteria
- fluid aspirated from inflamed joint
resembling septic arthritis may show uric
acid crystals
-Dark ground microscopy
• Ziehl Neelsen or Fluorescent staining: - AFB
• lmmunofluorescent staining- Clostridia species
• Hematoxylin & Eosin - viral inclusions

42. CULTURE
• Blood agar - aerobic
- anaerobic
• MacConkey agar or CLED Agar
• Cooked Meat Broth
• PNPG Blood Agar
• Firm agar
• Special media

43. Treatment of SSI
• Surveillance
• Drainage of pus
-Culture and sensitivity
• Debridement
• Antibiotics
• Removal of Implant