Eradication of nasal carriage of Staphylococcus aureus--is it cost-effective?

In cardiothoracic surgery, the costs of surgical-site infection (SSI) arise from additional postoperative procedures (approximately US $5000 per patient) and prolonged hospital stay (approximately $11,500 per patient). Application of nasal mupirocin reduced SSIs by 63% compared with historical controls. This would have resulted in savings provided that the attributable cost of an SSI was more than $245. Mupirocin was estimated to reduce the risk of bacteraemia in haemodialysis patients by 84% compared with historical controls. A model using data on Medicare payments for haemodialysis admissions was used to estimate the impact on hospital costs. The conclusion was that mupirocin would have been cost-saving but the model did not provide sufficient detail about hospital costing to allow assessment of its relevance in other settings. In a prospective, randomized, placebo-controlled trial in continuous ambulatory peritoneal dialysis (CAPD) patients, mupirocin reduced the risk of staphylococcal exit-site infection (ESI) from 0.42 to 0.14 per patient-year. However, as in a previous comparison with historical controls, there was an increase in the rates of ESIs caused by Gram-negative bacteria in patients who received mupirocin, bringing the rate of total ESIs up to that observed in the placebo group. There was some evidence that infections caused by Gram-negative bacteria had less severe consequences than staphylococcal infections. It is concluded that application of nasal mupirocin to nasal carriers of Staphylococcus aureus may be cost-saving in patients undergoing cardiac surgery or haemodialysis but, if the analysis is restricted to the cost of management of ESIs, it may not be cost-saving in CAPD. However, reducing the risk of staphylococcal ESI may reduce the risk of catheter loss and subsequent transfer to haemodialysis and this merits further study.