Prevalence of Staphylococcus aureus Colonization in Spinal Cord Stimulator Surgical Procedures

Abstract

Objectives: To determine the prevalence of Staphylococcus aureus (S aureus) colonization for spinal cord stimulation (SCS) surgical patients and to identify specific at-risk patient populations.

Materials and methods: Following Institutional Review Board approval, a retrospective review identified 232 SCS surgical patients. Preoperative Saureus nasal swab results were reviewed. Preoperative characteristics that included age at the time of procedure, body mass index, and medical comorbidities including, but not limited to, diabetes, smoking, obesity, and a history of surgical site infections were identified for each patient. The Clopper-Pearson method was used to calculate 95% CIs for proportions, and Fisher exact tests were used to estimate odds ratios (95% CI) for patient characteristics.

Results: The 232 SCS surgical patients who were identified underwent 396 unique neuromodulation procedures, with 100% screened for methicillin-resistant Saureus (MRSA) and 98.3% screened for methicillin-sensitive Saureus (MSSA). Overall, 23.3% (n = 54/232, 95% CI: 18.0%-29.3%) of patients were preoperatively colonized with Saureus, according to the following classification: 4.3% (n = 10/232, 95% CI: 2.1%-7.8%) were positive for MRSA and 20.2% (n = 46/228, 95% CI: 15.2%-26.0%) were positive for MSSA. Two patients were colonized with both MRSA and MSSA. Furthermore, 95.7% (n = 44/46, 95% CI: 85.2%-99.5%) of patients that were MSSA colonized were MRSA negative. Analysis of independent patient characteristics revealed anxiety and hypothyroidism as the only conditions associated with significantly increased odds of MRSA and MSSA colonization, respectively.

Conclusions: Staphylococcusaureus colonization was present in >20% of SCS patients, with MSSA carriage occurring at a rate nearly five times that of MRSA. MRSA screening alone would not have identified >90% of Saureus-colonized patients with only MSSA carrier status. Therefore, consideration should be given to preoperative screening for both MRSA and MSSA. Since limited patient characteristics were associated with greater risk for Saureus colonization, all patient populations should be screened.

Keywords: Methicillin-resistant Staphylococcus aureus; Staphylococcus aureus; methicillin-sensitive Staphylococcus aureus; spinal cord stimulation; surgical site infection.