[Impact on morbidity and costs of methicillin-resistant Staphylococcus aureus nosocomial pneumonia in intensive care patients].

Objectives: Prevention of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections in the intensive care units (ICU) has been recommended for several years. However, the workload and the costs of these programs are to be weighed against the benefit obtained in terms of reduction of morbidity and costs induced by the infection. The purpose of this study was to evaluate the cost and the current morbidity of the infection with MRSA in the ICU.

Methods: In a retrospective case-control study carried out in 2004, all patients of the 6 intensive care units of a teaching hospital having developed a MRSA nosocomial infection were included. They were paired with controls on the following criteria: department, Simplified Acute Physiology Score II (SAPSII), age (+/- 5 years), type of surgery (for the surgical intensive care units). The duration of hospitalization of the paired control had to be at least equal to the time from admission to infection of the infected patient. The costs were evaluated using the following parameters: scores omega 1, 2 and 3, duration of artificial ventilation, hemodialysis, length of ICU stay, radiological procedures, surgical procedures, total antibiotic cost and other expensive drugs.

Results: Twenty-one patients with MRSA infection were included. All had nosocomial pneumonia. The 21 paired patients were similar with regard to both initial criteria and sex. Hospital mortality was not different between the 2 groups (cases=8; controls=6; p=0.41), as well as median duration of hospital stay (cases=41 days; controls=43 days; p=0.9). The duration of mechanical ventilation, number of hemodialysis or hemofiltration sessions, number of radiological procedures were similar in both groups. The total omega score was not significantly different between cases (median 435; IQR: 218-579) and controls (median 281, IQR: 231-419; p=0.55). The median duration of isolation was 12 days for cases and 0 day for controls (p=0.0007). The pharmaceutical expenditure was significantly higher in cases (median: 1414euro; IQR: 795-4349), by comparison with the controls (median: 877euro, IQR: 687-2496) (p=0.049).

Conclusion: In the ICU having set up a policy intended to reduce the risk of MRSA nosocomial infections, MRSA pneumonia does not seem to involve major additional morbidity, as compared to a control population matched for similar severity of illness. It increases modestly the use of the medical resources.