Swab Testing to Optimize Pneumonia Treatment With Empiric Vancomycin: A Randomized Controlled Trial

Area of Science:

• Infectious Diseases
• Critical Care Medicine
• Clinical Microbiology

Background:

• Fear of methicillin-resistant Staphylococcus aureus (MRSA) often leads to empiric vancomycin use for community-acquired pneumonia (CAP).
• Limited data exists on using MRSA PCR nasal swab testing to guide vancomycin de-escalation in intensive care unit (ICU) patients.

Purpose of the Study:

• To evaluate the effectiveness of MRSA PCR nasal swab testing in guiding vancomycin de-escalation for ICU patients with suspected CAP.
• To assess the impact of MRSA PCR testing on vancomycin-free hours alive and 30-day mortality.

Main Methods:

• A randomized trial (STOP-Vanc) involving 277 adult ICU patients with suspected CAP.
• Patients were randomized to usual care with or without MRSA nares PCR testing.
• The primary outcome was vancomycin-free hours alive within the first 7 days.

Main Results:

• MRSA PCR nasal swab testing demonstrated a high negative predictive value (98.9%) in the intervention arm.
• No significant difference was found in vancomycin-free hours alive between the control (105.7 hours) and intervention (109.7 hours) groups.
• The study did not show a decrease in vancomycin use duration or 30-day mortality.

Conclusions:

• MRSA PCR nasal swab testing, despite high NPV, did not reduce vancomycin duration or mortality in critically ill patients with suspected CAP.
• Additional interventions, such as clinician education and antimicrobial stewardship, may be necessary to optimize vancomycin use.