This study will assess the performance of two novel breath collection devices and their subsequent detection of respiratory pathogens compared to sputum samples in patients with lower respiratory tract infections.

Inclusion Criteria:

• Able to understand the scope of the study and provide written informed consent

• Age >18 years

• Speaking German or English

• Health status (assessed by study personnel at local site) well enough to use the breath collection devices

• Willing to provide all three study samples (sputum and two breath samples) required for the study

• Clinical diagnosis of a lower respiratory tract infection (LRTI) defined as:

  (i) New infiltrate (chest X-ray, ultrasound, or CT scan), and (ii) at least one clinical symptom suggestive of LRTI (fever ≥38°C, chills, new or worsening cough, new or worsening sputum production, new or worsening dyspnea, tachypnoea, chest pain)

Exclusion Criteria:

• Patients for whom the collection of all three study specimens within 48 hours of initiating antibiotic treatment is not feasible
• Patients with known cystic fibrosis or bronchiectasis
• Critically ill patients at the discretion of the investigator
• Patients on oxygen supplementation with a face mask, high-flow-oxygen, non-invasive or mechanical ventilation; oxygen supplementation via nasal cannula will be permitted.
• Patients with proven acute pulmonary embolism
• Patients with best supportive care
• Patients with severe hypoxemia (SpO2 <88%) despite oxygen supplementation
• Hospitalization within the last 14 days prior to admission

Adults aged 18 and older admitted to the hospital with a clinical diagnosis of lower respiratory tract infection.