Stewardship in Action: An Evaluation of Antibiotic De-Escalation Prescribing After Positive Pneumococcal Urinary Antigen Testing in a Safety Net Health System

The Infectious Diseases Society of America (IDSA) guidelines for community-acquired pneumonia (CAP) recommend pneumococcal urinary antigen testing (UAT) for a subset of inpatients admitted with pneumonia. Despite this, UAT testing is frequently performed on inpatients who do not meet the official IDSA criteria, and current evidence regarding antibiotic de-escalation in UAT-positive cases remains inconclusive. To explore this further, we conducted a retrospective cohort study examining antibiotic de-escalation patterns among hospitalized CAP patients who underwent UAT over a 60-day period during peak respiratory illness season (November and December, 2023). Patients with positive UAT results were compared to those who had negative UAT; the primary outcome was whether a positive UAT impacted antibiotic de-escalation prescribing. A total of 268 patients were analyzed—235 UAT-negative and 33 UAT-positive. Both groups were comparable in terms of disease severity, underlying health conditions, and readmission rates. Empiric therapy targeting Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) was used in 40% of patients (36% in the UAT-positive group and 46% of the UAG-negative group). The use of atypical coverage, MRSA coverage, or anti-pseudomonal β-lactams was frequently de-escalated in both cohorts (p < 0.05); however, the UAT-positive group had significantly shorter durations of anti-pseudomonal therapy (p = 0.03) and anti-MRSA therapy (p = 0.02). Despite this, the UAT-positive group was more commonly given fluoroquinolones, such as levofloxacin or moxifloxacin, over narrow-spectrum β-lactams for final antibiotic coverage (p = 0.021). Overall, positive UAT appeared to support earlier discontinuation of anti-MRSA and anti-pseudomonal antibiotics; however, it did not impact fluoroquinolone use. Future antimicrobial stewardship efforts may benefit from promoting greater use of narrow-spectrum β-lactams in these patients.