Abstract
Background
Several studies have shown that Staphylococcus aureus (S.aureus) nasal colonization is associated with postoperative surgical site infection and that preoperative decolonization can reduce infection rates. Up to 30% of joint replacement patients have positive S.aureus nasal swabs and patient risk factors for colonization remain largely unknown. Many joint replacement patients continue to undergo surgery without being screened.
Study Question
Is there a specific patient population at increased risk of S.aureus nasal colonization?
Methods
This study is a retrospective review of 716 consecutive patients undergoing hip or knee replacement surgery between 2011 and 2015. All patients were screened preoperatively for nasal colonization and patients who screened positive for S.aureus were treated with mupirocin. Bivariate and multivariate statistical analysis was used to assess risk factors for nasal colonization.
Results
716 patients undergoing joint replacement had preoperative nasal screening. 125 (17.50%) nasal swabs were positive for methicillin susceptible S.aureus(MSSA), 13 (1.80%) were positive methicillin resistant S.aureus (MRSA), 84 (11.70%) were positive for other organisms, and 494 (69.00%) were negative for colonization (Table 1). In bivariate analysis, diabetes (p = 0.04), renal insufficiency (p = 0.03), and immunosuppression (p = 0.02) were predictors of nasal colonization with MSSA/MRSA while smoking (p = 0.02) and immunosuppression (p = 0.001) were predictors of colonization with other bacteria. In multivariate analysis, immunosuppression (p = 0.04, OR: 1.95, 95%CI: 1.03–3.71) and renal insufficiency (p = 0.04, OR: 2.49, 95%CI: 1.01–6.18) were independent predictors of nasal colonization with MSSA/MRSA while smoking (p = 0.02, OR: 1.77, 95% CI: 1.10–2.88) and immunosuppression (p = 0.01, OR: 2.95, 95% CI: 1.45–5.86) were independent predictors of nasal colonization with other bacteria.
Conclusion
Our study shows that one third of patients screened positive for nasal colonization. Patients with diabetes, renal insufficiency, and immunosuppression are at increased risk of being colonized with S.aureus. Given that these comorbidities are already known independent risk factors for periprosthetic joint infection, these patients in particular should be screened and when necessary, decolonized.
