Antibiotics: Infection Prevention in Surgery

Infection prevention in surgery is based first and foremost on incision and surgical site management and, in certain circumstances, through the judicious and sensible use of antibiotics.

Proper Incision Management

Important Tenets

  1. Asepsis
  2. Careful handling of tissues
  3. Hemostasis
  4. Two layer closure of body walls
  5. Suture selection
  6. Careful wound approximation

Silk should be avoided for skin closure as it is irritating and will wick fluids into wounds. If knots are tied improperly, dehissence is the consequence often with life-threatening consequences. If sutures are too tight, animals will over-zealously self-mutilate to remove them. Elizabethan collars may be helpful in certain species for breaking the irritation-mutilation cycle, but also may be stressful for unconditioned animals. Cyanoacrylate glues may be used for skin closure instead of sutures, but if applied to wet or unclean wound margins will crystallize into glass-like compounds in the incision. White paper beddings, such as Alpha-Dri®, can be used for housing of immediate post-operative animals. Contrast with the white bedding may be helpful in identifying animals where there may be problems with hemorrhage or other discharge from the incision. An ounce of prevention is clearly worth a pound of cure with regard to incisions.

Infection Prevention

Antibiotics are a poor substitute for good surgical technique. Proper hand washing and gloving by the surgeon, preparation of the operative site (clipping hair, disinfection), clean wound closure and minimal operating time are key considerations in preventing infection. In certain animals, antibiotic usage can predispose to enterotoxemia and other agents may be nephrotoxic. If antibiotics are indicated, a single dose should be given intravenously 0-2 hours prior to the first incision or preoperatively allowing sufficient time to obtain efficacious blood levels. Giving the first dose by any route in the middle or at the conclusion of a surgical procedure is worthless. Antibiotics are indicated with the following risk factors:

  1. procedures less than 2 hours in length
  2. abdominal (bowel) surgery
  3. severe blood loss
  4. diabetes mellitus
  5. foreign body implantation
  6. cardiac valvular disease or valve surgery
  7. debilitation
  8. trauma/infection cases

Use of Antibiotics

Federal law and standards dictate that the medical care of research animals should conform with current and established veterinary medical and nursing standards (9CFR§2.33(b)(5); Guide for the Care and Use of Laboratory Animals, NRC, 1996, p. 60). Accordingly, it is the opinion of the veterinary staff that antibiotics should only be given to research animals by and on the orders of a DAR veterinarian or after review and specific approval by the IACUC.

In addition, we live in a day and age when one can acquire infection caused by bacteria that are resistant to all antibiotics. This has been caused by a failure of those using antibiotics to adhere to sound principles of use. Certain antibiotics offer advantages over others in specific circumstances. Thus, a veterinarian should always be consulted for recommendations for antibiotic use.

Guidelines for Use:

  • Give single injection 0-2 hours pre-op.
  • Over 2 hours beforehand is too early; giving the first dose after the first surgical incision or after the procedure is too late (New Engl J Med 326: 281, 1992).
  • Re-dosing:
    1. cases > 1.5 hours
    2. significant blood loss
    3. gross contamination
  • Treatment beyond the perioperative period is rarely effective.