Surgical Site Infections (SSI)

Frequently Asked Questions

Surgical Site Infection (SSI)

What is a Surgical Site Infection (SSI)?

  • An infection is considered to be an SSI when it occurs at the site of surgery within 30 days of an operation or within 1 year of an operation if a foreign body (e.g., an artificial heart valve or joint) is implanted as part of the surgery.
  • Most SSIs (about 70%) are superficial infections involving the skin only. The remaining infections are more serious and can involve tissues under the skin, organs, or implanted material.
  • The majority of SSIs do not become life-threatening.


How many surgical procedures are performed each year?

About 27 million surgical procedures are performed each year in the United States.


How many people every year get an SSI? How many people die every year from SSI?

A CDC estimate from 2001 suggests that approximately 290,000 SSIs occur every year. Approximately 8,000 patient deaths are associated with these infections.


How many orthopedic surgical procedures are performed each year? How many SSIs occur after orthopedic surgery each year?

  • Over 4 million orthopedic procedures are performed in hospitals each year, and over 500,000 of these operations involve the knee.
  • Depending on the type of operation, typically less than 1% of most orthopedic surgeries result in an SSI.


How many orthopedic SSIs are caused by Staphylococcus aureus? By MRSA?

  • The most common cause of serious SSIs (those involving more than just the skin) after orthopedic procedures is S. aureus. About 50% of all serious SSIs after orthopedic surgery are caused by this organism.
  • About 50% of these S. aureus SSIs are caused by MRSA, a form of this bacteria that is resistant to many antibiotics.
  • For the most current statistics on antimicrobial-resistant pathogens associated with SSIs, go to the National Healthcare Safety Network’s annual update of antimicrobial-resistant pathogens, which can be found at PDF (128 KB / 16 pages (link opens in new browser window)) .


What can patients do to protect themselves?

  • Patients should maintain a healthy weight, stop smoking at least 30 days prior to surgery, work with their doctors to keep blood sugar levels under control if diabetic, and take a shower or bath the day before surgery.
  • Patients can also ask that doctors make sure to use antibiotics correctly during surgery and follow proper infection control practices before, during, and after surgery. This includes practicing good hand hygiene and using clippers at the incision site instead of a razor if hair removal is necessary.
  • Additional guidelines are available from CDC’s Healthcare Infection Control and Prevention Advisory Committee (HICPAC) at (*)
    and SHEA/IDSA at (* PDF (2.7 MB / 1 page (link opens in new browser window)) and at* (link opens in new browser window).


What are the signs and symptoms of an SSI?

  • Signs and symptoms of an SSI can include fever and redness, swelling, heat, or pain at the surgical wound site.
  • Drainage of cloudy fluid or sudden opening of the surgical wound can also suggest an SSI.
  • Patients should receive instructions from their doctor before surgery explaining what to look for and what to do if they think they might have an infection.


What is CDC doing to help educate patients and clinicians about preventing SSIs?

CDC is committed to preventing infections associated with surgical procedures and has developed the Campaign to Prevent Antimicrobial Resistance in Healthcare Settings. This campaign includes educational materials for patients and clinicians about surgical site infections and can be found at (


Are professional athletes at higher risk?

All patients undergoing surgery are at risk for complications, including SSIs. Athletes are at no greater risk than other patients having surgery. Clinicians should adhere to appropriate infection control practices for all patients to minimize the risk of infections associated with surgery.


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* Links to non-Federal organizations found at this site are provided solely as a service to our users. These links do not constitute an endorsement of these organizations or their programs by CDC or the Federal Government, and none should be inferred. CDC is not responsible for the content of the individual organization Web pages found at these links.

Last modified: December 17, 2008
Last reviewed: December 17, 2008
Content source:
Division of Healthcare Quality Promotion (DHQP)
National Center for Preparedness, Detection, and Control of Infectious Diseases