Nasal Methicillin-Resistant Staphylococcus Aureus Screening in Orthopaedic Patients: We Should Not Ignore Methicillin-Sensitive Staphylococcus Aureus.

Abstract

Background: Staphylococcus aureus (S. aureus) is a common cause of surgical site infections (SSIs) in orthopaedic patients. It is routine practice to screen patients for methicillin-resistant S. aureus (MRSA). However, little to no attention is usually paid to the presence of methicillin-sensitive S. aureus (MSSA) in screened patients. The purpose of this study was to document the prevalence of MSSA and MRSA in orthopaedic patients undergoing nasal screening and identify risk factors for colonization by both types of bacteria and associated SSI.

Methods: Prospectively collected data on 3,606 patients undergoing elective orthopaedic procedures in a single institution between 2017 and 2023 were analyzed. The results of nasal screening and detailed demographics of the patients were reviewed to identify the prevalence of MRSA and MSSA colonization as well as associated factors. The decolonization protocol was utilized before surgery. Following descriptive statistics, a set of logistic regressions was assessed, looking at using S. aureus, MRSA, and infection as dependent outcomes, respectively. All models were built using a stepwise approach, looking at demographic and comorbidity variables.

Results: The prevalence of MSSA and MRSA colonization was 26.3% (949 patients) and 7.7% (276 patients), respectively. A higher Charlson Comorbidity Index (CCI) (P < 0.001), underlying cardiac disease (P < 0.001), poorly controlled hypertension (P < 0.001), and history of coagulopathy (P < 0.001) were significant factors for S. aureus colonization. Decolonization appeared effective, as the incidence of 90-day postoperative infections was not different between those who had and did not have S. aureus colonization (P = 0.69).

Conclusion: Given the relatively high prevalence of MRSA and MSSA colonization, universal decolonization of patients undergoing orthopaedic procedures may be warranted. If such measures are not implemented, at least patients who have a high risk of colonization should be targeted.