Introduction: Staphylococcus aureus (SA) is the most common organism responsible for surgical-site infections (SSIs) in neurosurgical operations. SSIs impart substantial morbidity and mortality and have become a national focus of quality improvement. Patients colonized with SA preoperatively are at an increased risk of postoperative SA infections. However, the prevalence of SA colonization in the neurosurgical population is not well characterized.

Methods: Patients were enrolled from our ongoing randomized controlled trial, “Topical Vancomycin for Neurosurgery Wound Prophylaxis” (NCT02284126), which will determine whether topical vancomycin applied at wound closure reduces the incidence of SSIs at postoperative day (POD) 30. Swabs of the nares and surgical site were obtained preoperatively before draping and at POD 14-30. Samples were screened for SA using standard microbiological procedures. Instrumented spine procedures were excluded due to a lack of clinical equipoise in this patient population.

Results: Of the 128 patients enrolled in the trial as of 2/4/2015, 22 (17.2%) were colonized with SA in either the nares or at the surgical site. The vast majority (77.8%) remained colonized by POD 30. Two subjects, one treatment and one control, were newly colonized in the nares by POD 30. The control patient was also colonized at the incision site while the treatment patient was not. No SA isolates were methicillin-resistant. In univariate analysis, preoperative colonization was associated with postoperative colonization (P<0.001). Colonization was not significantly associated with application of topical vancomycin, ethnicity, BMI, inpatient status, or length of stay.

Conclusions: These preliminary data report the prevalence of SA colonization and antibiotic resistance in the neurosurgical population. Our results suggest that SA colonization among this subgroup of neurosurgical patients at academic centers is low, however patients are likely to remain colonized (and thus at risk of infection) postoperatively. As enrollment continues, we will better characterize risk factors for SA colonization, SSIs, and potentially improve perioperative antibiotic management.

Patient Care: We provide data on S. aureus prevalence in a neurosurgical population, showing that preoperatively colonized patients are likely to remain colonized after discharge. In addition, we found that several patients who were SA-negative preoperatively were colonized at follow-up, suggesting that new colonization, which would confer an increased risk of surgical-site infection, may be related to hospitalization or to the procedure performed. More generally, our ongoing trial will improve patient care by determining whether topical vancomycin reduces the incidence of surgical-site infections in neurosurgery.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of identifying patients at risk for surgical-site infections after neurosurgical procedures 2) Discuss, in small groups, the hospital and patient-specific factors that may influence the risk of S. aureus colonization, in particular “new” colonization 3) Identify an effective means of identifying S. aureus-colonized patients in order to better define prevalence at other centers

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