Antibiotic Escalation Following Rapid Multiplex PCR Pneumonia Panel Testing in Intensive Care Patients with Severe Pneumonia: A Retrospective Cohort Study

Background/Objectives: Severe community-acquired pneumonia (CAP) can be fatal and requires the rapid and appropriate administration of antibiotics. Rapid multiplex PCR pneumonia panels are widely used tools for antimicrobial de-escalation and stewardship; however, their role in driving antibiotic escalation in severe pneumonia requiring intensive care is less well characterized. Methods: We retrospectively analyzed 288 adults with severe CAP who were admitted to the intensive care unit (ICU) of a tertiary hospital and underwent lower-respiratory BioFire FilmArray Pneumonia Panel (BFPP) testing between April 2023 and September 2024. The primary outcome was antibiotic escalation, defined as addition of an agent or a change to broader-spectrum therapy after the BFPP result, and its associated factors. Secondary outcomes were in-hospital mortality, hospital and ICU length of stay (LOS), and ventilator duration according to the antibiotic escalation. Results: Patients were elderly (median 72 years old; 60.8% male) and critically ill (median SOFA 8; median APACHE-II 19; shock 49.0%; mechanical ventilation 56.9%). The panel was positive in 66.3% of cases, and results were obtained with a median turnaround time of 2 h versus 67 h for sputum culture. After the panel, antibiotics were escalated in 34.0% of cases, de-escalated in 2.8%, discontinued in 0.7%, and unchanged in 62.5%. Escalation was independently associated with resistance gene detection (adjusted odds ratio [aOR] 3.15, 95% CI 1.71–5.82), panel positivity (aOR 1.97, 95% CI 1.02–3.80), and SOFA score (aOR 1.10 per point, 95% CI 1.01–1.19). Thirty-day mortality, in-hospital mortality, hospital LOS, ICU LOS, and ventilator duration did not differ between escalation and non-escalation groups. Conclusions: In severe CAP requiring intensive care and managed with a comparatively narrow initial empirical regimen, panel testing was predominantly followed by antibiotic escalation rather than de-escalation, particularly when resistance genes were detected. No statistically measurable difference in clinical outcomes was observed, but the study was not powered to exclude any clinically meaningful benefit or harm of escalation.