Wound infection

for mbbs students

1. WOUND INFECTION

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 10 14 organism. They can be released into tissues before, during or 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:

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: T he 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. ………..27 th 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. ………….26 th edi ; B&L

19. Classification of SSI:

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

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

22. 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

23. 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

24. 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,

25. 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

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

27. 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

28. Localized infection: F Abcess Lymphangitis Cellulitis

29. 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.

30. 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.

31. Prevention of surgical infection: Preoperative Preparation: A short preoperative hospital stay. 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.

32. Scrabbing

33. Skin preparation:

34. 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.

35. 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.

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

37. 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

38. 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

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

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