An Audit Demonstrating a Reduction in MRSA Infection in a Specialised Vascular Unit Resulting from a Change in Infection Control Protocol

INTRODUCTION: In 2003, 18% of all admissions to our vascular ward were colonised by MRSA, with an MRSA infection rate of 10.6%. Standard practice was to segregate patients with proven MRSA from the rest of the patient pool. After a prospective audit, regression analysis was used to identify factors that could stratify patients into high and low risk for MRSA colonisation. A change in isolation policy was introduced that segregated patients according to their risk of MRSA acquisition, and isolated all patients undergoing prosthetic vascular reconstruction. Antibiotic policy was also altered. This audit reports the impact of these changes on MRSA colonisation and infection rates. METHODS: The MRSA status of patients during 777 in-patient episodes was prospectively recorded during three time spans; period 1 (November 2002-April 2003) before the change in isolation and antibiotic policy and, periods 2 (August-December 2003) and 3 (October 2004-January 2005) after the change in policy. RESULTS: Hospital acquired MRSA colonisation was reduced from 10.6% in period 1, to 1.1 and 1.4% in periods 2 and 3, respectively (p<0.001). Similarly, MRSA infection rates fell from 10.6 to 2.9 and 0.9% over the same time frame (p<0.001). The most dramatic changes in MRSA infection rates occurred in patients undergoing aneurysm repair (MRSA infection 30.1% in period 1 vs. 3.9 and 2.9% in periods 2 and 3) and lower limb revascularization (31 vs. 0 vs. 4.2%). Stepwise regression analysis revealed that the system of isolation was a significant factor reducing MRSA infection and colonisation rates (p<0.001). CONCLUSIONS: These data demonstrate that a change in infection control policy can significantly reduce MRSA infection in a vascular unit.