Rapid diagnostic test and use of antibiotic against methicillin-resistant Staphylococcus aureus in adult intensive care unit.

Ventilator-associated pneumonia (VAP) due to methicillin-resistant Staphylococcus aureus (MRSA) is associated with excess mortality and costs. Molecular biology test allows rapid identification of MRSA in sputum with high negative predictive value. We hypothesized that use of a rapid diagnostic test in patients with suspected VAP was associated with reduced use of antibiotics directed against MRSA. This retrospective, observational study was conducted in a polyvalent intensive care unit (ICU) of a university hospital. We compared two periods: before (2007-2010) and after (2010-2015) the implementation of a rapid diagnostic test, which uses RT-PCR to detect pathogens in 60 minutes. The primary endpoint was the effect on the empirical use of anti-MRSA antibiotics. The second endpoint was the effect of this strategy on the cost regarding antibiotic treatment. The first group included 120 suspected VAP (88 patients) and the second group 121 suspected VAP (89 patients). Empirical use of vancomycin and linezolid decreased by 50 % between the two periods. Twenty-seven VAP (22 %) were treated with an anti-MRSA treatment between 2007 and 2010, and 13 (11 %) between 2010 and 2015 (p = 0.04). The mean cost of anti-MRSA treatment by patients in the first group was 63 ± 223 €, and 13 ± 52 € in the second group (p < 0.001). This study shows that a rapid diagnostic test was associated with reduced use and cost of anti-MRSA antibiotics in patients with suspected VAP. These results should be confirmed by further multicenter prospective studies.