Staph Nasal Screening Does Not Cut Surgical Site Infection Risk

Despite the success of preop testing and decolonization for methicillin-resistant staphylococcus aureus (MRSA) in arthroplasty patients, the benefits of such interventions in preventing surgical site infections (SSIs) in spine surgery remains unclear.

In an effort to explore this issue as related to primary lumbar fusion, a team from the Harvard Combined Orthopedic Residency Program and the Massachusetts General Hospital (MGH) looked at adult patients undergoing primary instrumented lumbar fusions from January 2015 to December 2019. Their study, “Nasal screening for methicillin-resistant Staphylococcus aureus does not reduce surgical site infection after primary lumbar fusion,” appears in the July 16, 2021, edition of The Spine Journal.

It’s not the nasal screening, it’s the patient.

Co-author Daniel Tolbert, M.D. of MGH told OTW, “We performed this study because our institutional culture was moving towards indiscriminate screening of patients, and we questioned that move as overly inclusive.”

The researchers collected data about MRSA testing that took place <90 days before surgery, mupirocin prescription <30 days before surgery, perioperative antibiotics, and the Elixhauser comorbidity index.

The research team enrolled 1,884 patients in the study, performed MRSA testing on 755 patients (40.1%) and were more likely to be performed in patients with lower Elixhauser index scores on multivariable analysis. The research team noted that vancomycin use increased significantly over time despite no change in mupirocin or incision and drainage rates. They also found that MRSA testing, mupirocin prescriptions, perioperative parenteral vancomycin use, and intrawound vancomycin powder use had no impact on incision and drainage rates. In fact, incision and drainage risk was more associated with higher BMI (body mass index) and a higher number of blood product units transfused.

Dr. Tobert summarized the study conclusions for OTW saying: “The findings from this paper underscore two points about infection prevention in spine surgery. The first is that indiscriminate nasal screening of spine patients does not lead to a decrease in surgical site infections. The second is that patient factors are the predominant determinate of surgical site infection.”

“MRSA nasal screens may impact surgical site infections for certain patients and certain procedures. However, for relatively low risk procedures like the cohort we studied it does not change the SSI rate. The implications are that MRSA nasal screening should likely be reserved for surgeries that have high risk for SSI.”