Prospective, multicentre audit of complex vascular wound and graft infections: the impact of methicillin-resistant Staphylococcus aureus

Abstract

Abstract Background A number of studies have looked at the outcome of vascular graft infections, but these often include small numbers of patients collected over a prolonged period of changing practice. Many of these studies do not contain cases of methicillin-resistant Staphylococcus aureus (MRSA). Methods Between February 1998 and January 1999, a prospective, multicentre audit was performed in order to examine the outcome of complex wound and graft infections in vascular surgery, with particular reference to MRSA. Results Some 66 grade II or III Szilagyi wound infections occurred. Overall, 23 per cent of type II infections progressed to graft infection. Of those with type III infections, 83 per cent had an adverse outcome (death, major amputation or ongoing infection). No vein graft became infected, but 12 of 38 prosthetic grafts were affected. MRSA accounted for 42 per cent of infections and was present in 67 per cent of patients with an adverse outcome. Adverse events occurred in 32 per cent of MRSA cases and in 10 per cent of non-MRSA cases (P = 0·04). Wound infection proceeded to graft infection in 58 per cent of MRSA cases and in 32 per cent of non-MRSA cases (P = 0·08). Seven of eight patients with MRSA before operation developed postoperative MRSA infection. Median length of stay was 31 days for MRSA versus 18 days for non-MRSA infections (P = 0·001). Forty-three graft infections occurred; 12 were associated with a complex wound infection. Median time to presentation was 39 (range 2–2450) days. There were 16 deaths, nine major limb amputations and three ongoing infections among patients with a graft infection. The median length of stay was 36 days. MRSA was present in 36 per cent of all graft infections. Only one of these infections involved a vein graft (P = 0·001). MRSA infection occurred more frequently where the primary procedure had been urgent rather than elective (P = 0·03). MRSA graft infection accounted for seven of the nine major limb amputations. The median length of stay in patients with MRSA graft infection was 25 days longer (P = 0·001). Conclusion Complex wound and graft infections continue to be associated with postoperative deaths and amputations. MRSA infection is now the most common organism involved in complex infections following vascular procedures. It is associated with an increase in the number of adverse outcomes and a significant increase in length of stay.