Multidrug-resistant bacterial infections are a growing global health concern. Hospital-acquired pneumonia is one of the most common infections occurring during hospitalization and can be associated with high mortality, reaching up to 50% in severe cases. One of the main reasons for poor outcomes is the delay in starting the most appropriate antibiotic treatment.

Standard laboratory methods used to identify the bacteria and determine which antibiotics are effective usually take between 48 and 96 hours to provide results. During this time, patients often receive broad-spectrum antibiotics, which may not be optimal and can contribute to antimicrobial resistance.

Rapid diagnostic tests, such as the BIOFIRE® FILMARRAY® Pneumonia Panel, can detect multiple bacteria and important resistance markers directly from respiratory samples in about one hour. These tests are already approved for use in Brazil and are easy to perform. Previous studies in patients with community-acquired pneumonia have shown that these rapid tests can help doctors choose more appropriate antibiotics earlier and may improve patient outcomes.

However, their benefit has not been well studied in patients with hospital-acquired pneumonia, especially in settings where multidrug-resistant bacteria are common. In these situations, early and appropriate adjustment of antibiotic therapy is particularly important for improving outcomes and ensuring the responsible use of advanced antibiotics.

This study aims to compare the use of rapid diagnostic panels with standard laboratory methods in hospitalized patients with suspected pneumonia. The main focus is to evaluate how quickly and how appropriately antibiotic treatment can be adjusted after sample collection, using a structured scoring system, the Desirability of Outcome Ranking for the Management of Antimicrobial Therapy(DOOR-MAT), as well as to assess clinical outcomes.

The results of this study may help determine whether rapid diagnostic testing improves patient care in real-world hospital settings. The findings could support decision-making within the Brazilian Unified Health System (SUS) regarding the adoption of this technology, and may also contribute to future analyses of its cost-effectiveness.

Inclusion Criteria:

• Age ≥18 years.
• Clinical diagnosis of hospital-acquired pneumonia or clinically relevant tracheobronchitis requiring antimicrobial treatment, with or without mechanical ventilation.
• No respiratory cultures collected in the last 72 hours (except for the culture that will potentially be evaluated in the study-trigger for inclusion).
• Agreement from the patient or legal representative to sign the Informed Consent Form (ICF).

Exclusion Criteria:

• Inadequate respiratory samples according to laboratory cutoffs for squamous epithelial cells and polymorphonuclear leukocytes (sputum or endotracheal aspirate).
• Incarcerated populations.
• Pregnant women.

De-identified individual participant data (IPD) will be shared upon reasonable request. Data will be available to qualified researchers with methodologically sound proposals, subject to approval by the study investigators and compliance with institutional, ethical, and data protection regulations.