Screening for nasal carriage of Staphylococcus (S.) aureus reduces the risk of S. aureus peritonitis in patients on peritoneal dialysis (PD)

Introduction Screening for nasal carriage of Staphylococcus (S.) aureus is associated with a reduction of peritoneal dialysis (PD)-related infections, but conflicting results have questioned the benefit of this practice. This study evaluated the clinical effectiveness of the screening program for nasal carriage of S. aureus in reducing the peritonitis rate in the PD population. Methods A single-center retrospective study was conducted on all patients on PD diagnosed with peritonitis from 1999 to 2023. From 2011, screening for S. aureus with nasal swabs was implemented in our program. It was performed before the start of PD and in any case of peritonitis. Consequently, the study period was divided into pre-screening (1999-2010) and screening (2011-2023) phases. Results The study included 195 patients who experienced 345 peritonitis episodes. Median age was 67 years. The overall peritonitis rate was 0.21 episodes/patient-year. Post-screening, the S. aureus peritonitis rate decreased significantly from 0.036 to 0.009 episodes/patient-year (P < 0.001). The screening did not reduce the total episodes of peritonitis (0.23 vs. 0.19 episodes/patient-year). Indeed, the cumulative peritonitis rate difference between the two phases was not significant (P = 0.31). The screening of previously decolonized patients with S. aureus peritonitis showed that 50% of them were colonized by S. aureus and that recolonization frequently occured in this population. Multivariate regression analysis showed that S. aureus screening was the only protective measure to reduce the risk of S. aureus peritonitis (OR, 0.36; CI95% 0.14-0.91; P = 0.03). Conclusions In our center, screening for nasal carriage of S. aureus significantly reduced the incidence of S. aureus peritonitis but did not impact the overall peritonitis rate. Recolonization is a real event that warrants a better preventive strategy.