Speaker's Highlight

• Don Sin University of British Columbia, St. Paul Hospital (Canada)
  Kenneth R. Chapman Toronto General Hospital Research Institute (Canada)
• Parameswaran Nair McMaster University (Canada)
  Carolyn Calfee UCSF (U.S.A.)
• Gregory P. Downey University of Colorado School of Medicine (U.S.A.)
  David A. Schwartz University of Colorado School of Medicine (U.S.A.)
• Neil Schluger Tuberculosis Control Branch, California Department of Public Health (U.S.A.)
  Nick Kim Critical Care & Sleep Medicine, University of California San Diego (U.S.A.)
• Nicola Hananiah Baylor College of Medicine (U.S.A.)
  Jae-Joon Yim Seoul National University College of Medicine (Republic of Korea)
• Koichiro Asano Tokai University School of Medicine (Japan)
  Diahn-Warng Perng Taipei Veterans General Hospital (Taiwan)
• Konstantinos Kostikas University of Ioannina (Greece)
  Karin Klooster University Medical Center Groningen (Kingdom of the Netherlands)

• Community-acquired pneumonia: updated guidelines and treatment

  Community-acquired pneumonia (CAP) remains a major cause of hospital admission, respiratory failure, and avoidable mortality. Although many cases can be managed safely outside the hospital, treatment decisions must account for disease severity, age, comorbidities, local resistance patterns, and the possibility of viral infection.

  Current guidance emphasizes early clinical assessment, targeted testing, appropriate empiric antibiotics, and frequent reassessment. The goal is not simply to prescribe broader therapy, but to match treatment intensity to the patient’s risk while reducing unnecessary antimicrobial exposure.

  Recommendations from professional societies may differ in detail, and local protocols should always be checked. The principles below reflect contemporary approaches used in respiratory and acute-care medicine.

  Recognizing pneumonia and estimating severity

  A diagnosis of CAP is based on compatible symptoms and signs, such as cough, fever, sputum production, pleuritic chest pain, tachypnea, or reduced oxygen saturation, together with a new infiltrate on chest imaging when imaging is available. Older adults may present atypically, with confusion, weakness, or functional decline rather than prominent fever.

  Severity assessment should begin at first contact and continue after initial treatment. Respiratory rate, blood pressure, mental status, oxygenation, temperature, renal function, and blood tests help identify patients at risk of deterioration. The CRB-65 score can support decisions in primary care, while the Pneumonia Severity Index is useful when more detailed risk stratification is needed.

  No score should replace clinical judgment. Hypoxemia, rapidly increasing oxygen needs, multilobar disease, septic shock, severe comorbid illness, or an inability to take oral medication may justify hospital care even when a formal score appears reassuring.

  Diagnostic testing and microbiology

  Chest radiography is commonly used to confirm an infiltrate and assess its extent. Lung ultrasound may provide rapid bedside information, particularly in emergency and critical-care settings, while computed tomography is generally reserved for uncertain diagnoses, complications, or alternative pathology.

  Routine microbiological testing is not necessary for every mild outpatient infection. In hospitalized patients with severe pneumonia, clinicians should consider blood cultures, respiratory cultures, urinary antigen testing, and viral molecular assays when results could alter therapy or infection-control measures. Testing is especially relevant when there is concern about methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, influenza, or other circulating respiratory viruses.

  A positive viral test does not automatically rule out bacterial coinfection, particularly in severe illness. Conversely, a negative bacterial test and rapid clinical improvement may support narrowing or stopping antibiotics when the overall picture makes bacterial pneumonia unlikely.

  Choosing the initial treatment setting

  Many otherwise stable adults with uncomplicated CAP can receive oral treatment at home, provided they can maintain hydration, take medication reliably, and access follow-up. Hospital admission is more appropriate when oxygenation is impaired, vital signs are unstable, oral intake is poor, or social circumstances make home monitoring unsafe.

  For patients requiring supplemental oxygen, the target saturation should reflect their underlying condition. Most acutely ill adults are treated toward normal oxygenation, whereas people at risk of hypercapnic respiratory failure may require a lower, individualized target. For these patients, non-invasive ventilation guidance can help frame escalation decisions when conventional oxygen therapy is insufficient.

  High-flow nasal oxygen or non-invasive ventilation may be appropriate in selected patients, but worsening work of breathing, hemodynamic instability, or persistent hypoxemia should prompt early critical-care review. Delayed escalation can be more harmful than timely transfer to an intensive-care environment.

  Clinical situation	Typical initial approach	Key review point
  Stable outpatient without major comorbidity	Oral narrow-spectrum antibiotic according to local guidance	Reassess symptoms, hydration, and breathing within a few days
  Outpatient with significant comorbidity	Broader oral coverage or combination therapy when indicated	Check drug interactions, renal function, and adverse effects
  Inpatient, non-severe CAP	Intravenous or oral beta-lactam-based regimen, with atypical coverage when appropriate	Switch to oral therapy once clinically stable
  Severe CAP or intensive-care admission	Prompt intravenous combination therapy guided by local resistance data	Obtain relevant cultures and review for resistant pathogens
  Suspected influenza or another treatable virus	Appropriate antiviral therapy when indicated, with antibiotics based on bacterial risk	Reassess for coinfection and clinical deterioration

  Selecting antibiotics responsibly

  Empiric antibiotic selection should reflect disease severity, allergy history, recent antibiotic exposure, renal and hepatic function, and local antibiograms. Common approaches use a beta-lactam for typical bacterial pathogens, with additional atypical coverage in hospitalized or severe cases when clinically indicated. Respiratory fluoroquinolones may have a role in selected adults, but their potentially serious adverse effects require careful risk-benefit assessment.

  Broad anti-pseudomonal or anti-MRSA therapy should not be routine. It is generally reserved for patients with validated risk factors, such as previous isolation of these organisms, recent hospitalization with intravenous antibiotics, or a compatible clinical history. Unnecessary broad-spectrum treatment increases toxicity, Clostridioides difficile risk, and antimicrobial resistance.

  When microbiology identifies a pathogen, therapy should be narrowed whenever possible. Medication reconciliation is important because macrolides, fluoroquinolones, and other agents can interact with cardiovascular, psychiatric, and anticoagulant medicines.

  Duration, response, and treatment failure

  Shorter antibiotic courses are often sufficient when the patient reaches clinical stability, including improving temperature, heart rate, respiratory rate, blood pressure, oxygenation, and mental status. Many adults can complete treatment in about five days, although longer therapy may be needed for severe disease, slow response, abscess, empyema, bacteremia, or infection caused by less susceptible organisms.

  Clinical improvement should be assessed within 48 to 72 hours. Persistent fever, increasing oxygen requirements, hypotension, confusion, or worsening imaging should trigger a search for complications and alternative diagnoses. Possible explanations include resistant bacteria, viral infection, pulmonary embolism, heart failure, aspiration, obstructing malignancy, or an undrained pleural infection.

  Follow-up imaging is not automatically required for every patient. It is more useful when symptoms persist, the initial radiograph showed concerning features, or the patient has risk factors for underlying lung cancer. Older adults and people with chronic lung disease may recover slowly, so functional status is often as important as radiographic resolution.

  Groups requiring individualized care

  Older adults, pregnant patients, people with chronic obstructive pulmonary disease, bronchiectasis, asthma, diabetes, kidney disease, or immunosuppression may need modified diagnostic and treatment plans. Aspiration risk should be assessed, but routine anaerobic coverage is not required unless there is an abscess, empyema, or another strong indication.

  Immunocompromised patients may have atypical organisms, subtle imaging findings, or more rapid deterioration. Early involvement of respiratory, infectious-disease, or critical-care specialists is appropriate when the diagnosis is uncertain or the response is poor.

  Prevention remains part of CAP management. Influenza, pneumococcal, COVID-19, and other recommended vaccines reduce the risk of severe respiratory infection. Smoking cessation, oral hygiene, management of swallowing disorders, and optimization of chronic cardiopulmonary disease also reduce future episodes.

  Practical prescribing priorities

  A safe, guideline-informed workflow can be summarized as follows:

  • Confirm that pneumonia is clinically plausible and consider important alternatives.
  • Estimate severity using vital signs, oxygenation, comorbidities, and a validated risk tool.
  • Obtain microbiology and viral testing when results are likely to change management.
  • Start empiric therapy promptly in patients who need antibiotics, then narrow treatment when evidence allows.
  • Reassess within 48 to 72 hours and document criteria for oral switch, discharge, or escalation.

  Clear discharge instructions should cover antibiotic adherence, expected recovery, warning signs, oxygen use, hydration, and follow-up. Patients should seek urgent care for worsening breathlessness, blue lips, new confusion, fainting, inability to drink, or persistent low oxygen saturation.

  Applying updated CAP guidance requires more than following a fixed drug list. Use local protocols, resistance data, and clinical judgment together, while reviewing every patient for response, complications, and opportunities to reduce unnecessary treatment.

  Richard Russell Nuffield Department of Clinical Medicine, University of Oxford (United Kingdom)
• Mona Bafadhel King’s College London (United Kingdom)
  David Jackson Guy’s and St Thomas’ Hospital, King’s College London (United Kingdom)
• James Chalmers University of Dundee (United Kingdom)
  David Price University of Aberdeen (United Kingdom)