Abstract
I
The experimental studies by Ashley Miles et al. [2] and John Burke [3] demonstrated the importance of antibiotic presence in the tissue before surgical contamination occurred for the prevention of SSI. The clinical trial of systemic antibiotic agents versus placebo by Hiram Polk and Lopez-Mayor [4] ushered the antibiotic era into clinical practice. Antiseptic agents of the skin at the surgical site before incision, infection control practices in the operating room, and systemic antibiotic agents have reduced SSIs. There continues to be rates of these complications, however, that require better applications of current standards and the need for newer methods to extend the progress in prevention.
In the current issue of Surgical Infections, the theme of prevention of SSIs is presented. Guidelines from the American College of Surgeons/Surgical Infection Society are summarized [5]. The guidelines by the Centers for Disease Control and Prevention are highlighted in the editorial by Selwyn Rogers (this issue) as an introduction to the supplemental articles that support the main document that is being published in JAMA Surgery [6]. Publications of presentations by members of the Surgical Infection Society at the Annual Meeting in May 2016 at West Palm Beach, Florida, on different facets of causes and prevention of SSI are included, as are original research contributions that address the many different aspects for consideration in this complication of surgical care. Our understanding of the pathogenesis and prevention of SSI has progressed over recent decades, but much remains to be done.
The focus of the last decades of effort to reduce SSIs have been in the reduction of bacteria that make contact with the surgical site during the operative procedure. The larger the inoculum of bacterial contamination, the greater the probability of infection as the outcome. There are other factors, however, that amplify a given bacterial inoculum to result in infection in a patient while a similar inoculum of contamination in other patients has no impact on an uneventful recovery. The role of the local environment of the surgical site and the integrity of host defense of the patient become important considerations in the outcome.
Pasteur has been paraphrased at the time of his death in stating that the “microbe is nothing, the terrain is everything.” The role of surgical site hematoma, necrotic tissue from over-exuberant use of electrocautery, the presence of foreign bodies (e.g., sutures) in the surgical site, and dead space in the surgical terrain (i.e., the closed incision) are all contributors to SSI. These variables reduce the number of bacteria that are necessary to result in infection instead of an uneventful recovery. These are technical issues that are generally not covered in published guidelines but are of great significance in the prevention of infection.
The integrity of host defense for the surgical patient in the avoidance of SSI and other infection at locations remote from the surgical incision has been the source of considerable investigation over recent decades. There is a genetically programmed host defense that is very elusive to measure but does appear to give each patient a unique vulnerability or resistance to infection [7]. The recent studies of supplemental oxygenation, core body temperature control, and glucose control imply that acquired impairment of host responsiveness may be corrected with appropriate supportive care [8]. The search for supportive care measures that may enhance the innate and acquired immune response will continue as an important aspect of future efforts to augment the host.
The challenges for the prevention of SSI in the future are significant. The advance of surgical care will likely expand the role of interventions in patients who are vulnerable to infectious complications. Microbial resistance will test the adequacy of those antimicrobial agents used for prevention, but also requires the development of newer antibiotic agents to meet this evolving challenge. Methods for prevention that require additional investigation include:
• The utility of delayed primary closure of the contaminated surgical site. • Negative-pressure surgical site management. • Topical antimicrobial agents at the time of incision closure. • Applications of antibacterial sutures. • Applications of pressure irrigation.
As is emphasized in several publications within this theme issue, progress has been considerable over the last 70 years in the prevention of SSI, but there is still much to be learned and newer methods to be implemented in the prevention of these complications.