Surgical Site Infections

Early detection of surgical site bacterial infections 

Despite precautions and protocols in place to prevent infection, millions of healthcare-associated infections (HAI) occur each year.1 Surgical site infections (SSI) are the most surveyed and frequent type of HAI in low- and middle-income countries and the second most frequent type of HAI in Europe and the United States.2 

Factors contributing to the risk of SSI including: 3

  • Type of surgery (e.g., emergent, elective, transplant, surgical site)
  • Microbial characteristics, such as the degree of contamination and virulence
  • Patient characteristics (e.g., immune status and the presence of comorbidities such as diabetes)
  • Incidents during surgery, such as the introduction of foreign material or tissue damage
  • Stringency of applied hygiene standards

Surgical site infections increase the mortality risk up to 11-fold and lead to longer hospital stays and increased costs.3

How to identify surgical site infections before the emergence of apparent clinical signs

The high specificity of the biomarker procalcitonin (PCT) allows for early identification of bacterial infections, helping clinicians make earlier diagnoses in surgical patients. In addition, the rapid increase of PCT in response to infection—in many cases before an infected patient presents symptoms—can further reduce time to diagnosis while minimizing infection severity.4

Independent of an infectious process, PCT levels can be elevated shortly after multiple trauma or major surgery. In these cases, the return to baseline is usually rapid, meaning that a second increase of PCT can be interpreted as the development of a sepsis episode.6

Immediate treatment of patients with elevated PCT levels—before clinical signs of infection become evident—results in:4

PCT presentation in patients after major aortic surgery5

Patient's levels after aortic surgery | Surgical site infections

PCT in patients after major aortic surgery with infection (n=67) and without infection (n=209) over the days before and after surgery.5



PCT reduces antibiotic therapy, costs, and length of stay

In one study, B·R·A·H·M·S PCT-aided antibiotic therapy in 205 patients after open-heart surgery reduced antibiotic prescription by 60% and lowered the cost of antibiotics per patient.12 And in another study, PCT-aided antibiotic therapy significantly reduced the number of days of antibiotic use as well as the duration of ICU stay.13

Antibiotic prescription after open heart surgery | Surgical site infections

Antibiotic prescription (%) in patients after open-heart surgery commonly treated or guided by PCT in addition to clinical symptoms.12 

ICU stay for patients after surgery | Surgical site infections

ICU stay for surgical patients was reduced by 12% and antibiotic therapy was reduced by 25%.13 

PCT is superior to C-reactive protein in identifying bacterial surgical site infections

When assessing a patient for surgical site infections, a PCT biomarker identifies postoperative infections more reliably than other biomarkers such as C-reactive protein. This is because a rise of PCT levels has a higher specificity for bacterial infection, and is less impacted by non-infectious surgery- or trauma-associated inflammation.7

Identify infectious complications in transplant patients with high specificity 

The major postoperative incidents endangering positive outcomes after transplantation are acute rejections and infections. Most mediators of inflammatory events indicate not only immunological reactions but also infections. However, it can be difficult to distinguish between infectious versus non-infectious inflammation.

After transplantation infectious complications significantly increase PCT values while in uncomplicated cases and rejections there is only a slight non-specific PCT increase, depending on the type and extension of intervention. Generally, these unspecific PCT increases reach their maximum one or two days after surgery and then return to normal.8

The use of anti-lymphocyte/thymocyte globuline preparations (or anti CD3) for the treatment of acute rejection after kidney-, heart- and liver-transplantation can induce PCT release for a brief period.14

An infection, but not rejection, causes an early and dramatic increase in PCT and allows the identification of infectious complications in contrast to CRP, which was not suitable to differentiate between both complications.8,15

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  1. European Centre for Disease Prevention and Control. Surveillance of surgical site infections in Europe, 2008-2009. Stockholm: ECDC; 2012 [cited 2021Mar17]. Available here.
  2. World Health Organization. Global guidelines for the prevention of surgical site infection. World Health Organization; 2016.
  3. Anderson DJ. Surgical site infections. Infectious Disease Clinics. 2011 Mar 1;25(1):135-53.
  4. Chromik AM, Endter F, Uhl W, Thiede A, Reith HB, Mittelkötter U. Pre-emptive antibiotic treatment vs ‘standard’treatment in patients with elevated serum procalcitonin levels after elective colorectal surgery: A prospective randomised pilot study. Langenbecks Arch Surg. 2006 Jun;391(3):187-94.
  5. Amour J, Birenbaum A, Langeron O, Le Manach Y, Bertrand M, Coriat P, et al. Influence of renal dysfunction on the accuracy of procalcitonin for the diagnosis of postoperative infection after vascular surgery. Crit Care Med. 2008 Apr 1;36(4):1147-54.
  6. Meisner M. Procalcitonin-biochemistry and clinical diagnosis. Dresden (Germany): UNI-MED-Verlag; 2010.
  7. Uzzan B, Cohen R, Nicolas P, Cucherat M, Perret GY. Procalcitonin as a diagnostic test for sepsis in critically ill adults and after surgery or trauma: a systematic review and meta-analysis. Crit Care Med 2006. 2006 Jul 1;34(7):1996-2003.
  8. Suberviola B, Castellanos‐Ortega A, Ballesteros MA, Zurbano F, Naranjo S, Miñambres E. Early identification of infectious complications in lung transplant recipients using procalcitonin. Transpl Infect Dis. 2012 Oct;14(5):461-7.
  9. Kuse ER, Langefeld I, Jaeger K, Külpmann WR. Procalcitonin–a new diagnostic tool in complications following liver transplantation. Int Care Med. 2000 Mar;26(2):S187-92.
  10. Zilahi G, McMahon MA, Povoa P, Martin-Loeches I. Duration of antibiotic therapy in the intensive care unit. J Thorac Dis. 2016 Dec;8(12):3774.
  11. Fagon JY, Chastre J, Novara A, Medioni P, Gibert C. Characterization of intensive care unit patients using a model based on the presence or absence of organ dysfunction and/or infection: the ODIN model. Intensive Care Med. 1993;19:137-144.
  12. Maravić-Stojković V, Laušević-Vuk L, Jović M, Ranković A, Borzanović M, Marinković J. Procalcitonin-based therapeutic strategy to reduce antibiotic use in patients after cardiac surgery: A randomized controlled trial. Srp Arh Celok Lek. 2011;139(11-12):736-42.
  13. Hochreiter M, Köhler T, Schweiger AM, Keck FS, Bein B, von Spiegel T, et al. Procalcitonin to guide duration of antibiotic therapy in intensive care patients: a randomized prospective controlled trial. Critical Care. 2009 Jun;13(3):1-7.
  14. Sabat R, Höflich C, Döcke WD, Kern F, Volk HD, Oppert M, et al. Massive elevation of procalcitonin plasma levels in the absence of infection in kidney transplant patients treated with pan-T-cell antibodies. Intensive Care Med. 2001 Jun;27(6):987-91.
  15. Kuse ER, Langefeld I, Jaeger K, Külpmann WR. Procalcitonin–a new diagnostic tool in complications following liver transplantation. Int Care Med. 2000 Mar;26(2):S187-92.
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