Surgical Infections Antibiotics Asepsis Dr Mohd Al Akeely

Surgical Infections, Antibiotics & Asepsis Dr. Mohd Al. Akeely Associate Professor & Consultant General Surgery

Objectives: 1. To be able to diagnosed, investigate and manage common community acquired infections. 2. To have a basic understanding of prevention and management of hospital acquired infection (noso-comial). 3. To have a basic understanding of the methods of Asepsis and its implications. 4. 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.

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

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

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.

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

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)

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

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

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

Phagocytosis and intraleucytic microbicidal system is Affected by: § Poor blood perfusion § low oxygenatation § Hypothermia These are called “the lethal triad’

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.

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

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

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

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

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

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.

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.

Cont. • Starts as cellulitis with 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.

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.

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.

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

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

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

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.

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

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

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).

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

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.

Staphylococci • Normal flora of the skin. • The most common cause of surgical site infection in surgical practice. • Can cause endocarditis, Abscesses, furuncle (boil), carbuncles. * Antibiotics effective against staph: penicillin, cephalospoin and vancomycin (MRSA).

Abscess : • localized pus collection • Treated by drainage &? ? antibiotics. Furuncle : • Inflammation of hair follicles or sweat glands treated by drainage & antibiotics. Carbuncle : a large extension of furuncle. • Common in diabetics, usually on the back and the neck, treated by drainage & antibiotics.

Furunculoisis

paronychia

Pseudomonas • Aerobic opportunistic bacteria that cause skin infections, but also can cause lethal infections. • It enter the body through minor skin. abrasions, ventilator tubes, urinary catheter, I. V. lines etc… • Treatment : • aminoglycosides, piperacillin, ceftazidime.

Intra - abdominal abscess • Important complication of G. I. & biliary surgery. • Clinical feature : abdominal pain tenderness fever & leukocytosis. • Investigation : X-ray, ultrasound, CT (the most useful ). • Treatment : drainage (surgical versus radiological ) & broad spectrum antibiotics.

Hydradenitis suppurativa. Infection of apocrine sweat glands. axilla, groin, perineum, any skin fold : TREATMEANT. Single abscess treated by I&D. Doxycycline or cephalosporin. Excision with STSG (15%) in severe chronic cases

Classification of wounds 1 - Clean wound: surgery done through clean tissue planes, no need for prophylaxis except for high risk group. Ex: thyroid, breast, hernia surgeries. 2 -Clean/contaminated : surgery with suspesion of infection. Ex: cholecystectomy, urinary tract surgery, etc… prophylaxis is advisable.

Cont. 3 - Contaminated : surgery where micro-organism are definitely present. ex: bowel surgery. Therapeutic antibiotics is advisable. 4 - Dirty : surgery through well established infection ex: abscess surgery. the use of antibiotic is considered to be of therapeutic nature.

Pressure sore

Surgical site infections (SSI). Accounts for about 38% of all surgical infections. . Infection within 30 days of operation. . Infection within 1 year if prosthetic device used.

Surgical site infection (SSI) Classification: Superficial SSI: skin & subcutaneous plane (47%) Deep SSI: subfascial and muscle plane (23%) Organ/ space SSI: intra-abdominal, other spaces (30%) Staph. aureus- most common organism E coli, Entercoccus , B fragilis

Surgical site infection (SSI) Risk factors. age. malnutrition. obesity. Immune compromised. poor surgical technique. prolonged surgery. preoperative shaving. type of surgery

Surgical site infection (SSI) • Diagnosis: Sup. SSI- erythema, oedema, discharge and pain RX: antibiotics & remove clips and drainage of pus (Cl. S) and daily dressing. Deep infections- no local signs, fever, pain, hypotension ? Abd. Destention………. Needs investigations. Treatment: surgical / radiological intervention.

Management (ssi): 1. remove sutures or clips. 2. swab (c&c). 3. drainag of pus. 4. daily dressing.

Prevention of SSI Pre-op: Treat pre-existing infection. Improve general nutrition. Shorter hospital stay. Pre-op. shower. Hair removal -shaving vs clipping. Intra-operative: Antiseptic technique. Good surgical technique. Normothermia. Post-operative: Wound dressing in 48 -72 hours. Early drain removal. Blood sugar control.

ANTIBIOTICS Chemotherapeutic agents directed towards micro-organisms. They are either synthetic or semi-synthetic. Penicillin: has a wide safety margin, Inhibits cell-wall synthesis. Hyper sensitivity is the main side effect but luckely it is a rare event. Therefore skin sensitivity test is a must before intravenous therapy.

Gentamycine: q Is the main aminoglycoside. q It inhibits ribosome synthesis. q Effective in Gram-ve bacteria. eg: psudomonas and E. coli. side effects includes ; ototoxicity and nephrotoxicity. It has a narrow safety margin.

Tetracycline v Is a wide spectrum bacteriostatic antibiotic (gram+ve & gram-ve ). v It alters the ribosome synthesis in bacteria. v Main side effects includes: - teeth discolouration - risk of super infection

Amphotericin B is an anti fungal which acts by impairing DNA synthesis. Ø It is a hepatotoxic and nephrotoxic in high doses like gentamycine. (narrow safety margine ) Ø This antibiotic should always be given with frequent pre and post dose serum level assessment. Ø

Prophylactic antibiotic Antibiotic which is given to patients bfeore surgery or invasive procedure in order to prevent infection. A high serum level of the antibiotic is essential just before starting the procedure. It is usually given intravenously or one hour intramuscularely before the surgery. Antibiotic selection depends on common bacteria in the operative site. It is usually given in clean contaminated procedures.

Asepsis - sterilization • Wet heat in an autoclave at 121° c for 20 minutes, or at a higher temperature for a shorter time (HTST) to provide an equivalent exposure. • Dry heat in a hot-air oven at 160° c for one hour. • Irradiation under strictly controlled conditions (used predominantly in industry). • Special sterilizing chemicals, liquids or gases, such as formaldehyde, glutaradehyde (cidex) or ethylene oxide, under strictly controlled conditions. - disinfection - Antisepses

Thank you !! Now an example of exam questions:

Example of exam. MCQ A 30 years old house-maid has a puncture wound in her right hand 5 days ago, now she is presenting with painful , red , hot and swollen hand. PE revealed tenderness and the redness in the hand is flat with the skin. What is the most likely diagnosis? a. Carbuncle. b. Cellulitis. c. Lymphangitis. d. Erysipelas.

Example of exam. MCQ A 30 years old house-maid has a puncture wound in her right hand 5 days ago, now she is presenting with painful , red, hot and swollen hand. PE revealed tenderness and the redness in the hand is flat with the skin. What is the most likely diagnosis? a. Curbuncle. b. Cellulitis. c. Lymphangitis. d. Erysipelas.

MCQ Example : A 25 years old male patient admitted via emergency room complaining of fever, lower abdominal pain and loose motion. He had no vomiting. He had appendectomy for acute appendicitis 7 days ago. His s. site is clean. What is the likely diagnoses ? a. b. c. d. Gastro- enteritis. Urinary tract infection. Pelvic collection (abscess). Diverticulitis.

MCQ Example : A 25 years old male patient admitted via emergency room complaining of fever, lower abdominal pain and diarrhoea. He had appendectomy for acute appendicitis 7 days ago. His s. site is clean. What is the likely diagnoses ? a. b. c. d. Gastro- enteritis. Urinary tract infection. Pelvic collection (abscess). Diverticulitis.