Dr. Hatem ElGohary
Lecturer of General Surgery MD, MRCS
Micro-organisms are normally prevented from
causing infection in tissues by intact epithelial
surfaces. These are broken down in trauma and
Protective mechanisms against infection can be
• Chemical: low gastric pH;
• Humoral: antibodies, complement and
• Cellular: phagocytic cells, macrophages,
Risk factors for increased risk of
■ Malnutrition (obesity, weight loss)
■ Metabolic disease (diabetes, uraemia, jaundice)
■ Immunosuppression (cancer, AIDS, steroids,
chemotherapy and radiotherapy)
■ Colonisation and translocation in the gastrointestinal
■ Poor perfusion (systemic shock or local ischaemia)
■ Foreign body material
■ Poor surgical technique (dead space, haematoma)
Pus or watery discharge
excessive swelling in
tenderness in the
Class I (Clean)
Operative wound clean, no inflammation,
Respiratory, gastrointestinal and genitor-
urinary tracts not entered.
Examples: Thyroidectomy, mastectomy.
Infection rate: 1-2%
Class II (Clean Contaminated)
Operative wound clean-contaminated
Gastrointestinal, respiratory or genitor-urinary
tracts entered without significant spillage
Examples: Appendectomy, cholecystectomy.
Infection rate: 20-30 %
Class III (Contaminated)
Operative wound contaminated
Gross spillage from the gastrointestinal
tract, genito-urinary or biliary tracts.
Infection rate: up to 60%
Class IV (Dirty Infected)
Operative wound dirty
Traumatic wound from dirty source, Fecal
contamination, Foreign body.
Examples: Drainage of Abscess
Debridement of Diabetic foot.
Infection rate: more than 60%.
Types of localized infection
Abscess (Acute suppurative inflammation
+Localized Collection of pus).
Caused by Staphylococcus aureus
Pus (dead and dying white blood cells).
Surrounded by Pyogenic membrane.
C/P: Redness, Hotness, Tenderness
Treatment: Incision and drainage.
Cellulitis and Lymphangitis (non suppurative
Caused by β-haemolytic streptococci.
C/P: Redness, Hotness, Tenderness and
Specific wound infections
Caused by C. perfringens. Gram-positive,
anaerobic bacilli found in soil and faeces.
Common in wounds containing necrotic or
C/P: severe local wound pain and crepitus (gas
in the tissues).
X-ray: Gas in tissues.
Treatment: 1.Intravenous penicillin.
2.Aggressive debridement of
Caused by Clostridium tetani (anaerobic, Gram-
common in traumatic civilian or military wounds.
Mechanism: release of the exotoxin tetanospasmin,
which affects myo-neural junctions and the motor
neurones of the anterior horn of the spinal cord.
C/P: prodromal period, leads to spasms in the
distribution of the motor nerves of the face followed by
the development of severe generalised motor spasms
respiratory arrest and death.
1. Prophylaxis with tetanus toxoid is the
best preventative treatment
2. Debridement of the wound may need to
3. Antibiotic treatment with benzylpenicillin
4. Ventilation in respiratory spasm.
Maximal blood and tissue levels should be
present at the time incision is made
Givin at induction of anaesthesia.
The choice of an antibiotic depends on the
expected spectrum of organisms likely to
Patients with known valvular disease of the
heart, prophylactic antibiotics during dental,
urological or open viscus surgery.
Short preoperative hospital stay lowers the
risk of acquiring infection.
Medical staff should always wash their
hands between patients.
personal hygiene is vital.
Staff with open, infected skin lesions
should not enter the operating theatres.
Preoperative shaving immediate before
3.Scrubbing and skin preparation
Aqueous antiseptics should be used,
and the scrub should include the nails,
washing to the elbows e.g. Betadine or
Numbers of staff in the theatre and
movement in and out of theatre should
be kept to a minimum.
dead spaces and haematomas should
be avoided and the use of diathermy
kept to a minimum.
Postoperative care of wounds
Tissue or pus for culture should be taken
before antibiotic cover is started.
The choice of antibiotics is empirical
until sensitivities are available.
Wounds are best managed by delayed
primary or secondary closure.
The use of Anti-microbials
The use of antibiotics for the treatment
of established surgical infection ideally
requires recognition and determination
of the sensitivities of the causative
choice being empirical and later
modified depending on microbiological
Drainage of pus should not be delayed.
Types of antibiotics use
A narrow-spectrum antibiotic may be
used to treat a known sensitive infection.
Combinations of broad-spectrum
antibiotics can be used when the
organism is not known.
Precautions In HIV Patients
• Use of a full face mask ideally, or protective spectacles.
• use of fully waterproof, disposable gowns and drapes
• boots to be worn, not clogs, to avoid injury from dropped
• double gloving needed
• allow only essential personnel in theatre;
• avoid unnecessary movement in theatre;
• respect is required for sharps, with passage in a kidney dish;
• a slow meticulous operative technique is needed with minimised