Abstract
Introduction
MRSA colonisation increases the risk of acquiring a surgical site infection (SSI). Screening identifies such patients and provides them with suitable eradication treatment prior to surgery to decrease their risk of infection. Our aim was to determine whether receiving effective eradication therapy decreases the risk of infection in a patient previously screening positive for MRSA to that of someone screening negative.
Methods
1061 patients underwent elective total knee or hip replacement between March 2008 and July 2010. 1047 had pre-operative screening for MRSA and MSSA using nasal and perineum swabs. If positive for MRSA they underwent a course of eradication treatment and were required to provide a negative swab result prior to undertaking surgery. However during the time of this study those screening positive for MSSA did not receive eradication treatment. Surgical site infections were recorded and the rate of infection, relative risk and odds ration were calculated.
Results
Overall 24 (2.26%) SSIs were observed post-operatively. There were 15 infections (1.78%) in 851 patients screening negative. Twenty-five patients (2.4%) screened positive for MRSA with 2 (8%) suffering a post-operative infection (Relative Risk 4.49, Odds Ratio 4.79). 181 patients (17.3%) screened positive for MSSA with 7 (3.9%) suffering an SSI (Relative Risk 2.12, Odds Ratio 2.22). The group screening positive for MRSA was at a statistically significantly higher risk of suffering a post-operative infection (p=0.03).
Conclusion
An increased rate of post-operative infection is observed in patients screening positive for MRSA pre-operatively in spite of the administration of eradication therapy and the provision of a negative swab prior to surgery. A second group of patients screening positive for MSSA are also at a higher risk of post-operative infection than those that screen negative. Further work is required to establish if eradication therapy would decrease the SSI rate amongst this group.
