Outcomes Associated With De-escalating Therapy for Methicillin-Resistant Staphylococcus aureus in Culture-Negative Nosocomial Pneumonia.

Abstract

In culture-positive nosocomial pneumonia, de-escalation (DE) from broad-spectrum empirical antimicrobials to narrower-spectrum agents has shown to decrease broad-spectrum antibiotic use without compromising patient outcomes. However, uncertainty exists regarding the safety of anti-methicillin-resistant Staphylococcus aureus (MRSA) agent DE in culture-negative nosocomial pneumonia. This study aimed to determine if anti-MRSA agent DE in culture-negative nosocomial pneumonia affects 28-day and hospital mortality, ICU and hospital length of stay (LOS), treatment failure, and safety. This single-center retrospective cohort study included adult patients admitted from 2012 to 2017 with nosocomial pneumonia and a negative respiratory culture. DE was defined as anti-MRSA agent discontinuation within 4 days of initiation. Secondary outcomes included hospital mortality, hospital and ICU LOS, treatment failure, and occurrence of acute kidney injury (AKI). Of 279 patients included, 92 were in the DE group and 187 were in the no DE (NDE) group. Patients who were not de-escalated received 5 more days of MRSA coverage than patients who were de-escalated; however, there was no difference in 28-day mortality (NDE group, 28% vs DE group, 23%; difference, -5.5%; 95% CI, -16.1 to 6.5). Patients who were de-escalated had shorter hospital (DE group, 15 days vs NDE group, 20 days; difference, 3.2 days; 95% CI, 0.1-6.4) and ICU (DE group, 10 days vs NDE group, 13 days; difference, 2.2 days; 95% CI, -0.3 to 4.9) LOSs after the index date. The incidence of AKI was significantly higher in patients who were not de-escalated (DE group, 36% vs NDE group, 50%; difference, -13.8%; 95% CI, -26.9 to -0.4). Although anti-MRSA agent DE in culture-negative nosocomial pneumonia did not affect 28-day mortality, it was associated with a shorter hospital LOS and lower incidence of AKI.