Surgical site infections following elective surgery

We read with great interest the Personal View by John Alverdy and colleagues1Alverdy JC Hyman N Gilbert J Re-examining causes of surgical site infections following elective surgery in the era of asepsis.Lancet Infect Dis. 2020; 20: 38-43Summary Full Text Full Text PDF PubMed Scopus (36) Google Scholar on surgical site infections (SSIs) following elective surgery in the current era of asepsis. We fully agree with the conclusion that further research, including microbiome research and the use of whole-genome sequencing, is required in the field of SSI prevention;2Zingg W Park BJ Storr J et al.Technology for the prevention of antimicrobial resistance and healthcare-associated infections: 2017 Geneva IPC-Think Tank (part 2).Antimicrob Resist Infect Control. 2019; 8: 83Crossref PubMed Scopus (5) Google Scholar however, we would like to highlight several flaws and inconsistencies that show a degree of cherry-picking of the data. Alverdy and colleagues' main tenet is that the current SSI framework is simplistic because there is insufficient data linking the causative infecting strain(s) in SSIs to microbial contamination of the wound at the end of a surgical procedure. Evidence from a small, yet well designed prospective study (n=100) in elective colon surgery, in which intraoperative swabs were taken and patients followed up, was dismissed by Alverdy and colleagues because more than 80% of the wounds that tested positive did not develop an SSI.3Fa-Si-Oen PR Kroeze F Verhoef LHM Verwaest C Roumen RMH Bacteriology of abdominal wounds in elective open colon surgery: a prospective study of 100 surgical wounds.Clin Microbiol Infect. 2005; 11: 155-157Summary Full Text Full Text PDF PubMed Scopus (17) Google Scholar Their statement that the "predictive rate for developing an SSI of 18%" is incorrect. We calculated the crude odds ratio using the Haldane–Anscombe correction and found it to be 28·6 (95% CI 1·6–503·8); it is rare to find associations of this magnitude. To substantiate their arguments, the authors comment on practices intended to prevent SSI as though they were evidence-based and recommended in guidelines without acknowledging that these practices belie current recommendations (appendix). Furthermore, many strong and peremptory arguments are based on very low-quality data without acknowledging limitations of the data sources. One such example is the study by Grabel and colleagues4Grabel ZJ Boden A Segal DN Boden S Millby AH Heller JG The impact of prophylactic intraoperative vancomycin powder on microbial profile, antibiotic regimen, length of stay, and reoperation rate in elective spine surgery.Spine J. 2019; 19: 261-266Summary Full Text Full Text PDF PubMed Scopus (25) Google Scholar on use of vancomycin powder, a retrospective study that has numerous sources of bias and confounders, the results of which should be interpreted with extreme caution. There is no discussion of the high-quality evidence showing strong associations between Staphylococcus aureus carriage and SSI5Kluytmans J van Belkum A Verbrugh H Nasal carriage of Staphylococcus aureus: epidemiology, underlying mechanisms, and associated risks.Clin Microbiol Rev. 1997; 10: 505-520Crossref PubMed Google Scholar or the highly protective effect of pre-surgical decolonisation.6WHOGlobal guidelines for the prevention of surgical site infection.https://www.who.int/gpsc/ssi-prevention-guidelines/enDate: 2018Date accessed: March 12, 2020Google Scholar Several statements are unsubstantiated—eg, "most prevention strategies (eg, barrier protectors, irrigants, high-efficiency particulate air-filters, space suits, and vacuum-assisted wound-closure systems) are aimed at reducing environmental wound contamination"—and there is a failure to mention high-quality evidence-based measures to prevent SSIs, such as decolonisation of S aureus for clean surgery, adequate preoperative skin preparation, or optimal antimicrobial prophylaxis. The claim that "approximately 50% of the microbes causing SSI today have been shown to be resistant to the antibiotics used for prophylaxis", referring to work by Teillant and colleagues,7Teillant A Gandra S Barter D Morgan DJ Laxminarayan R Potential burden of antibiotic resistance on surgery and cancer chemotherapy antibiotic prophylaxis in the USA: a literature review and modelling study.Lancet Infect Dis. 2015; 15: 1429-1437Summary Full Text Full Text PDF PubMed Scopus (195) Google Scholar is misleading in the context in which it is framed. Among its many methodological flaws, the cited study grossly overestimates the proportion of resistance by assuming that all SSIs are monomicrobial. Also, an adequate interpretation is lacking; antimicrobial prophylaxis will select for pathogens resistant to the chosen regimen and thus increase the probability these pathogens cause an infection—a fact that has been known for almost 40 years.8Hill C Mazas F Flamant R Evrard J Prophylactic cefazolin versus placebo in total hip replacement. Report of a multicentre double-blind randomised trial.Lancet. 1981; 1: 795-796Summary PubMed Scopus (282) Google Scholar The Personal View by Alverdy and colleagues is an example of a narrow and surgeon-centred perspective on SSI prevention, which is regrettable as it does not acknowledge the research or preventative activities by the diversity of health-care professionals. We declare no competing interests. Download .pdf (.24 MB) Help with pdf files Supplementary appendix Surgical site infections following elective surgery – Authors' replyWe thank Mohamed Abbas and colleagues for citing the many methods by which surgical site infection (SSI) prevention can be approached. Given space restrictions, a comprehensive review was not possible. Yet, despite decades of research, guidelines, and best practices, SSI rates remain unacceptably high following elective surgery. Therefore, we felt compelled to offer an alternative hypothesis to explain SSIs beyond direct intraoperative wound contamination. Full-Text PDF