Assessment of sputum cultures for the diagnosis of lower-respiratory tract infections in the outpatient setting

摘要

To the Editor: The clinical relevance of lower-respiratory tract (LRT) specimens remains debatable. While a positive blood or pleural fluid culture provides a definitive cause, an organism cultured from a respiratory specimen is not definitive proof of an aetiological agent. Many bacterial species are normal flora or colonisers of the respiratory tract; therefore, routine use of sputum cultures, except for suspected Mycobacterium tuberculosis (TB), is not endorsed. Notably, the South African (SA) guideline for the management of community-acquired pneumonia (CAP) in adults and the American Thoracic Society/Infectious Diseases Society of America do not recommend the submission of a sputum sample in outpatients.