Pharmacist-Driven Methicillin-Resistant S. aureus Polymerase Chain Reaction Testing for Pneumonia

Area of Science:

• Infectious Diseases
• Clinical Pharmacy
• Critical Care Medicine

Background:

• Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor for infection.
• Nasal swab PCR assays rapidly detect MRSA colonization with high negative predictive value for pneumonia.
• Data on MRSA PCR utility in critically ill patients are limited.

Purpose of the Study:

• To evaluate the impact of a pharmacist-driven algorithm using MRSA PCR nasal screening.
• To determine the effect on the duration of anti-MRSA therapy in intensive care unit (ICU) patients with suspected pneumonia.

Main Methods:

• A single-center pre/post study design in four ICUs.
• Inclusion of adult ICU patients initiated on vancomycin or linezolid for pneumonia.
• Matching of an algorithm cohort with a historical cohort based on age, pneumonia type, and APACHE II score.

Main Results:

• The algorithm cohort had significantly shorter anti-MRSA therapy duration (47 vs. 95 hours; P < 0.001).
• Fewer vancomycin levels were ordered in the algorithm group (2 vs. 3; P = 0.026).
• MRSA rates, AKI, LOS, and mortality were similar between groups.

Conclusions:

• A pharmacist-driven MRSA PCR algorithm effectively reduced anti-MRSA therapy duration in critically ill pneumonia patients.
• This strategy can optimize antibiotic use in the ICU setting.
• Further validation in diverse critically ill populations and high MRSA prevalence settings is warranted.