Surgical site infection incidence and surgical antibiotic prophylaxis in the ICU patient: a multicenter observational study

Surgical site infection (SSI) is a major cause of postoperative morbidity. Surgical antibiotic prophylaxis (SAP), defined as the pre-incision administration of an antimicrobial agent targeting likely organisms in clean or clean-contaminated procedures without active infection at the operative site, is a cornerstone of prevention in surgery. However, critically ill patients represent a distinct population with profound susceptibility to infection. Data on SSI incidence and SAP practices in patients undergoing surgery during an intensive care unit (ICU) stay remain scarce. Retrospective multicenter cohort study in five French ICUs (March 2022–March 2023). Adult patients (≥18 years) with an ICU stay ≥ 48 h who underwent surgery during their ICU stay were included. Primary outcome was SSI incidence after surgery. Generalized estimating equations (GEE) with a prespecified adjustment set were used to estimate the adjusted association between antimicrobial spectrum and SSI, accounting for clustering within centers. 338 patients were included (median age 56 years, IQR 35 – 67; 72% male). Overall SSI incidence was 21%. Procedures with suspected infection present at time of surgery (PATOS) (n = 52, 15%) had an SSI incidence of 37%, against 18% in PATOS-negative patients. In the primary adjusted GEE analysis, broad-spectrum vs. narrow-spectrum antimicrobials (OR 3.06; 95%CI 1.63–5.76; P < 0.001) and no antimicrobial vs. narrow-spectrum antimicrobials (OR 2.49; 95%CI 1.01–6.15; P = 0.048) were independently associated with SSI. Stratified analysis showed that antimicrobial spectrum also had significant effect on SSI risk on PATOS-positive and trauma patients. SSI was associated with prolonged ICU/hospital length of stay, increased organ support use, and worse outcomes at day 28 and day 90. SSI affects more than one in five critically ill patients. After adjustment for prespecified confounders, the association with broad-spectrum therapy likely reflected confounding by indication, whereas the absence of any antimicrobial coverage was independently associated with increased SSI risk. Conventional SAP guidelines derived from non-ICU populations may not apply to critically ill patients. ICU-specific prophylactic strategies, improved coordination between ICU and operating room teams, and prospective studies are needed to enhance SSI prevention in this high-risk population.