Should cardiac surgery be delayed among carriers of methicillin-resistant Staphylococcus aureus to reduce methicillin-resistant Staphylococcus aureus-related morbidity by preoperative decolonisation?

Abstract

Preoperative methicillin-resistant Staphylococcus aureus (MRSA) carriage is associated with higher rates of postoperative MRSA infection. Carriage can be eradicated but this requires delaying surgery, which presents a dilemma when the surgery is urgent. We analysed the incidence of preoperative MRSA carriage and the impact on postoperative outcomes in a cardiac surgery population.
Patient data were collected prospectively from 2000 to 2007 (n=3789). MRSA screening is performed at a preadmission clinic for elective patients and on admission to the hospital for all patients. Three groups of MRSA carriers were identified: patients who were identified as carriers at a preadmission clinic (n=22, group 1), patients whose admission screening was positive but where the result was received postoperatively (n=103, group 2) and patients who acquired an MRSA infection or colonisation more than 48 h after admission (n=60, group 3).
MRSA eradication measures prior to admission were successful in 21 of 22 in group 1 (95.4%). There were no MRSA infections in group 1. However, in group 2 there were 11 patients with an MRSA infection (10%) even though eradication measures were started on confirmation of carriage. In group 3, 19 of the 60 patients had an MRSA infection. The intensive care stay and mortality were significantly greater in groups 2 and 3 than in group 1 or compared with the overall patient population. However, groups 2 and 3 also had a significantly higher risk profile (European System for Cardiac Operative Risk Evaluation (EuroSCORE)). When matched with similar risk patients, patients in groups 2 and 3 had mortality outcomes that were consistent with matched risk patients.
Patients who were MRSA carriers were older, more likely to have been on haemodialysis and to have been admitted from another hospital and underwent more complex surgical procedures. Carriage of MRSA was associated with a very high rate of MRSA infection, particularly among patients with diabetes. This suggests that delaying surgery may be warranted in patients expected to require implantation of prosthetic material such as valves, especially with diabetes. However, the survival outcomes for MRSA carriers are determined by their EuroSCORE rather than their MRSA status. This suggests that urgent cardiac surgery should not be delayed in patients with MRSA carriage.