Control of endemic methicillin-resistant Staphylococcus aureus - A cost-benefit analysis in an intensive care unit

Context Despite the success of some countries in controlling endemic methic illin-resistant Staphylococcus aureus (MRSA), such programs have not been i mplemented for some hospitals with endemic infection because of concerns th at these programs would be costly and of limited benefit. Objective To compare the costs and benefits of an MRSA control program in a n endemic setting. Design and Setting Case-control study conducted at a medical intensive care unit (ICU) of a French university hospital with a 4% prevalence of MRSA ca rriage at ICU admission. Patients Twenty-seven randomly selected patients who had ICU-acquired MRSA infection between January 1993 and June 1997, matched to 27 controls hospit alized during the same period without MRSA infection. Main Outcome Measures Intensive care unit costs attributable to MRSA infect ion, computed from excess therapeutic intensity in cases using estimates fr om a cost model derived in the same ICU, were compared with costs of the co ntrol program, derived from time-motion study of nurses and physicians. The threshold for MRSA carriage that would make the control strategy dominant was determined; sensitivity analyses varied rates of MRSA transmission and ratio of infection to transmission, length of ICU stay, and costs of isolat ion precautions. Results The mean cost attributable to MRSA infection was US $9275 (median, $5885; interquartile range, $1400-$16720). Total costs of the control progr am ranged from $340 to $1480 per patient. A 14% reduction in MRSA infection rate resulted in the control program being beneficial. In sensitivity anal yses, the control strategy was dominant for a prevalence of MRSA carriage o n ICU admission ranging from 1% to 7%, depending on costs of control measur es and MRSA transmission, for infection rates greater than 50% following tr ansmission. Conclusions In this example of a hospital with endemic MRSA infection, sele ctive screening and isolation of carriers on ICU admission are beneficial c ompared with no isolation.