Surgical Infections, Antibiotics & Asepsis

1. Surgical Infections,Antibiotics & Asepsis Dr.MohdAlAkeely Associate Professor & Consultant General Surgery

2. Objectives: • To be able to diagnosed, investigate and manage common community acquired infections. • To have a basic understanding of prevention and management of hospital acquired infection (noso-comial). • To have a basic understanding of the methods of Asepsis and its implications. • To have a guideline in the use of antibiotics for both therapy and prophylaxic and the awareness of main side effects of commonly used antibiotics.

3. References: . Sabiston Textbook of Surgery 18th Edition Pages 299- 327 . Schwartz Principles of Surgery 8th Edition Pages 109- 127 Baily & love 24th edition

4. Introduction Definition; it is the infection that requires surgical treatment 0R a complication of a surgical treatment. It accounts for one-third of surgical patients. Important complication of any invasive procedure.

5. For an infection to develop, four factors: 1- adequate dose of the micro-organism. 2- virulence of the organism. 3- susceptible host. 4- suitable environment.

6. The virulence Is the ability of bacteria to produce toxins or resist phagocytosis (encapsulated organisms). There are two types of toxins: - exotoxins. - endotoxins.

7. Endotoxins • Lipopolysaccharides • Part of gram –ve bacterial wall [ released after destruction of bacteria]. • Do not have specific effects for each type of bacteria • It causes gram –ve shock (septicemia)

8. Exotoxins * Soluble proteins * Released from intact bacteria (gram +ve & -ve) * Have specific effects for each type of bacteria * Their effects are local and remote from the site of release

9. Pathogenic potential is exalated by; . genetic mutation ( e.g. β-lactamase of staph.aureus). . Synergesty

10. Host resistance: • Intact skin & mucous membrane. • Good inflammatory response. • Intact acquired immunity.

11. Phagocytosis and intraleucyticmicrobicidalsystem is Affected by: • Poor blood perfusion • low oxygenatation • Hypothermia These are called “the lethal triad’

12. Diagnosis of infection Clinical features: * Local features of inflammation (redness,hotness,pain,odema and loss of function) which may not be all present. * Systemic symptoms. Investigations : * CBC, ESR, CRP. * Sample for gram stain & culture. * Others.eg; serology & radiology.

13. Principles of treatment • Debridement of wounds (necrotic tissue). • Drainage of pus. • Removal of the source and foreign bodies. eg: appendicectomy and cholecystectomy • Supportive measures.

14. Surgical infection • Cellulitis • Erysipelas • Lymphangitis • Boil (Furuncle) • Carbuncle • Hidradenitissuppurativa • Necrotizing fasciitis • Gas gangrene & tetanus • Pseudo memranous colitis

15. Common surgical infections 1- cellulitis: .Spreading infection of skin & subcutaneous tissue. • very common. • Caused by streptococcus (mainly ) & staph. • The area affected becomes red, hot, painfulindurated and tender.

19. Treatment: • Penicilline • (or erythromycin in sensitive patients). • Rest & elevation of the affected limb. • Hospital admission in severe cases.

20. Erysipelas. . Superficial spreading skin infection . Area of redness, sharply defined and irregular border . Follows minor skin injuries . Organism-Strep pyogenes . Sensitive to Penicillin & Erythromycin

23. 2- lymphangitis: Inflammation of lymphatic pathway caused by hemolytic streptococci (usually secondary to cellulitis). * Appears as red streaks on extremities. * Treatment: antibiotics, rest and elevation.

25. 3- Necrotizing fasciitis: • Necrosis of subcutaneous tissue underlying the skin. • usually Polymicrobial infection. • Common sites are: abdominal wall, perineum and limbs. • Usually follows abdominal surgery or trauma. • Immune compromised [e.g.Diabetics and IV drug addicts] are more susceptible .

26. Cont. • Starts as cellulitiswith early systemic toxicity. But; • Characterized by non-blanching erythema, with blisters and frank necrosis of the skin. • No definitive margins ( usually requires multiple debridements ). • Extensive surgical debridement of the affected area, in combination with high dose broad spectrum antibiotics is the appropriate Rx till C/S result is available.

34. 4- gas gangrene: Caused by cl. Perfringens (mainly) or cl. Septicum • Commonly enter the body through wounds contaminated with soil. • Produce exotoxins. • It is characterized by progressive rapidly spreading edema.

35. Cont. • Rapid myonecrosis it results in swelling, seropurulent discharge, crepitus in subcutaneous tissues, gas production and foul smelling wounds. • Other findings: ill looking patient, profound toxemia, tachycardia and in X-ray appearance of gas under skin and in muscles.

37. Non clostredial gas gangrene can be caused by gas forming anaerobic bacteria as in diabetic foot which is usually multi microbial infection.

40. Treatment: • Wound debridement, drainage and exposure. • Antibiotics (penicillins, clindamycin or metronidazole). *Antibiotics are not effective without aggressive debridement.

41. Cont Rx. • Putting the patient in a hyperbaric oxygen chamber may help (anerobic infection). • Amputation may be required.

42. 5- Tetanus: • Caused by cl. tetani as complication of wound contamination. • Usually the wound is healed when the symptoms start to appear. • Incubation period one to three weeks. * Cl. tetani produces a neurotoxin that stimulates the nerves in spinal cord that leads to muscle spasm.

43. Cont. • The first manifestations include trismus(lockjaw), neck and back stiffness. • Other manifestations include risussardonicus (an anxious look with mouth drawn up), progressive dysphasia and difficult respiration and reflex convulsions along with intense tonic contractions of body muscles.

44. Cont. • May result in death due to exhaustion, aspiration or asphyxia.

48. Treatment & prophylaxis • Rx include wound debridement, penicillin, muscle relaxants, ventilation and nutrition in Intensive care unit. Prophylaxis: • Wound care & antibiotics. • Vaccination by tetanus immunoglobulin in high risk pts ( passive immunization ). • Commence active immunization (T. toxoid).

49. Cont. In previously immunized pt, if the booster was: • > 5 years, the pt needs another booster. • < 5 years, no treatment.

50. PSEUDOMEMBRANOUS COLITIS • Cl. Difficile Overtakes normal flora in patients on antibiotics Watery diarrhea, lower abdominal pain, fever Sigmoidoscopy: membrane of exudates (pseudomembranes) Stool- culture and toxin assay Treatment : Stop offending antibiotic oral vancomycin/ metronidazole , rehydration, Isolate patient.