CDC definitions for surgical site infections

Definitions of surgical site infections in the Centers for Disease Control and Prevention's draft SSI guidelines are summarized as follows.1 The CDC definition for "implant" when referred to in the guidelines is: "a nonhuman-derived implantable foreign body (e.g., prosthetic heart valve, nonhuman vascular graft, mechanical heart, or hip prosthesis) that is permanently placed in a patient during surgery."

Superficial incisional SSI: Infection occurs within 30 days after the operation and involves only skin or subcutaneous tissue of the incision and at least one of the following:

1. Purulent drainage, with or without laboratory confirmation, from the superficial incision.

2. Organisms isolated from an aseptically obtained culture of fluid or tissue from the superficial incision.

3. At least one of the following signs or symptoms of infection: pain or tenderness, localized swelling, redness, or heat, and superficial incision is deliberately opened by surgeon, unless incision is culture-negative.

4. Diagnosis of superficial incisional SSI by the surgeon or attending physician.

Deep incisional SSI: Infection occurs within 30 days after the operation if no implant is left in place or within one year if implant is in place and the infection appears to be related to the operation and involves deep soft tissues (e.g., fascial and muscle layers) of the incision and at least one of the following:

1. Purulent drainage from the deep incision but not from the organ/space component of the surgical site.

2. A deep incision spontaneously dehisces or is deliberately opened by a surgeon when the patient has at least one of the following signs or symptoms: fever (>38 degrees C), localized pain, or tenderness, unless site is culture-negative.

3. An abscess or other evidence of infection involving the deep incision is found on direct examination, during reoperation, or by histopathologic or radiologic examination.

4. Diagnosis of a deep incisional SSI by a surgeon or attending physician.

Organ/Space SSI: Infection occurs within 30 days after the operation if no implant is left in place or within one year if implant is in place and the infection appears to be related to the operation; and the infection involves any part of the anatomy (e.g., organs or spaces), other than the incision, that was opened or manipulated during the operative procedure; and at least one of the following:

1. Purulent drainage from a drain that is placed through a stab wound into the organ/ space. (If the area around a stab wound becomes infected, it is not an SSI. It is considered a skin or soft-tissue infection, depending on its depth.)

2. Organisms isolated from an aseptically obtained culture of fluid or tissue in the organ/ space.

3. An abscess or other evidence of infection involving the organ/space that is found on direct examination, during reoperation, or by histopathologic or radiologic examination.

4. Diagnosis of an organ/space SSI by a surgeon or attending physician.

Reference

1. Centers for Disease Control and Prevention. Draft guideline for prevention of surgical site infections, 1998. 63 Fed Reg 167-133, 192 (June 17, 1998).