Antibiogram Surveillance to Determine Appropriate Initial Empiric Antibiotic Therapy for Ventilator-Associated Pneumonia

Abstract

Background:

Our protocolized empiric antibiotic therapy for early (≤7 d) ventilator-associated pneumonia (VAP) and late (>7 d) VAP based on our local antibiogram leads to inappropriate empiric antibiotic therapy (IEAT) approximately 15% of the time. We reviewed our trauma intensive care unit (TICU) antibiogram to determine if sensitivity patterns were changing and warranted protocol adjustments. We hypothesized there would be no change in IEAT over time.

Patients and Methods:

TICU patients with VAP (bronchoalveolar lavage culture ≥100,000 CFU/mL) between 2017 and 2022 were reviewed. We reviewed the pathogens and sensitivity patterns to identify the IEAT percentage, and we reviewed changes in the rate of antimicrobial days per 1,000 days present for 2018–2022.

Results:

We noted an increase in IEAT beginning in 2017. In early VAP, the increase in IEAT was because of an increase in identification of gram-negative bacteria isolates (7%–24%), specifically an increase in Pseudomonas (3%–10%) and a decrease in Streptococcus sp. (32%–23%) and Haemophilus influenzae (20%–17%). In late VAP, the increase in IEAT was largely because of an increase in identification of Stenotrophomonas (3%–5%) and Acinetobacter (4%–10%). Antimicrobial use changed as pathogens and sensitivity changed. There were increases in rates per 1,000 days for cefazolin (11.9%), vancomycin (22.8%), cefepime (33.1%), and meropenem (424.7%), whereas there were decreases in rates per 1,000 days for ampicillin/sulbactam (−4.5%) and piperacillin/tazobactam (−9.5%).

Conclusions:

The change in organisms identified and the increase in IEAT highlight the importance of continuous antibiogram monitoring.