Empiric Antibiotics and Imaging: A Focused Analysis of Recommendations 1 and 2 of the 2025 ATS CAP Guidelines
by Richard Schaefer, 2027 PharmD Canddiate, Jonathan Baranowski, 2027 PharmD Candidate
Abstract:Background: Community-acquired pneumonia (CAP) remains a major global cause of morbidity and mortality. Patients with severe CAP (sCAP) experience high rates of intensive care admission and life-threatening complications. Despite advances in supportive care and antimicrobial therapy, outcomes remain poor.
Problem: The 2025 American Thoracic Society (ATS) CAP guidelines addressed four priority clinical questions and generated multiple recommendations. Most recommendations are conditional and based on very low-quality evidence or expert opinion. These concerns led the Infectious Diseases Society of America to withdraw support, ending a long-standing joint guideline effort.
Methods: A structured literature search was conducted using PubMed/MEDLINE and other journal databases, with a targeted review of key guidelines and publications. Studies before 2006 were excluded except for foundational mechanistic literature. Search terms included macrolide mortality benefit in CAP, quinolone versus macrolide mortality, antibiotic use in viral CAP, and lung ultrasound (LUS) accuracy in CAP detection. Studies were included if they reported clear primary outcomes and evaluated relevant antimicrobials or imaging.
Aim: This paper evaluates the evidence and methodology underlying the 2025 ATS recommendations by analyzing physiologic mechanisms and clinical evidence informing key guideline positions, with emphasis on empiric antibiotic use in viral CAP and imaging strategies.
Main Arguments: Recommendation 2—supporting empiric antibiotics despite confirmed viral infection—was made without qualifying randomized or observational studies. Evidence suggests unnecessary antibiotic exposure may increase risk in non-severe CAP. Support for LUS is limited to diagnostic accuracy, not to improved clinical outcomes. Macrolides appear to confer mortality benefit primarily in severe CAP.
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2026 July/August Table of Contents
Abstract:Background: Community-acquired pneumonia (CAP) remains a major global cause of morbidity and mortality. Patients with severe CAP (sCAP) experience high rates of intensive care admission and life-threatening complications. Despite advances in supportive care and antimicrobial therapy, outcomes remain poor.
Problem: The 2025 American Thoracic Society (ATS) CAP guidelines addressed four priority clinical questions and generated multiple recommendations. Most recommendations are conditional and based on very low-quality evidence or expert opinion. These concerns led the Infectious Diseases Society of America to withdraw support, ending a long-standing joint guideline effort.
Methods: A structured literature search was conducted using PubMed/MEDLINE and other journal databases, with a targeted review of key guidelines and publications. Studies before 2006 were excluded except for foundational mechanistic literature. Search terms included macrolide mortality benefit in CAP, quinolone versus macrolide mortality, antibiotic use in viral CAP, and lung ultrasound (LUS) accuracy in CAP detection. Studies were included if they reported clear primary outcomes and evaluated relevant antimicrobials or imaging.
Aim: This paper evaluates the evidence and methodology underlying the 2025 ATS recommendations by analyzing physiologic mechanisms and clinical evidence informing key guideline positions, with emphasis on empiric antibiotic use in viral CAP and imaging strategies.
Main Arguments: Recommendation 2—supporting empiric antibiotics despite confirmed viral infection—was made without qualifying randomized or observational studies. Evidence suggests unnecessary antibiotic exposure may increase risk in non-severe CAP. Support for LUS is limited to diagnostic accuracy, not to improved clinical outcomes. Macrolides appear to confer mortality benefit primarily in severe CAP.
Download PDF
2026 July/August Table of Contents