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Diagnosis of pneumococcal pneumonia by antigen detection in sputum
Abstract:
Pneumococcal polysaccharide was detected by counterimmunoelectrophoresis in the sputum of 20 of 26 (77%) adults with community-acquired pneumonia and a positive sputum culture for Streptococcus pneumoniae. The test was negative in 29 pneumonia patients with negative sputum culture for S. pneumoniae. Pneumococcal antigen was also detected in the sputum of six of nine adults with chronic bronchitis and a positive sputum culture, but was not detected in expectorated respiratory secretions of 22 pneumococcal carriers with colds. Pneumococcal antigen could also be detected in sputum by immunodiffusion; antigen titers varied from 1:2 to 1:256. These results strongly suggest that the detection of pneumococcal antigen in respiratory tract secretions indicates infection caused by S. pneumoniae.
Insights
Detecting pneumococcal antigen in respiratory secretions, like sputum, using counterimmunoelectrophoresis or immunodiffusion, can effectively diagnose Streptococcus pneumoniae infections in pneumonia patients.
Area of Science:
- Microbiology
- Immunology
- Clinical Diagnostics
Background:
- Streptococcus pneumoniae is a common cause of community-acquired pneumonia.
- Accurate and rapid diagnostic methods for pneumococcal infections are crucial for timely treatment.
Purpose of the Study:
- To evaluate the efficacy of detecting pneumococcal antigen in respiratory secretions as a diagnostic marker for Streptococcus pneumoniae infection.
- To compare counterimmunoelectrophoresis and immunodiffusion for pneumococcal antigen detection.
Main Methods:
- Sputum samples from patients with community-acquired pneumonia, chronic bronchitis, and healthy carriers were tested.
- Counterimmunoelectrophoresis and immunodiffusion assays were used to detect pneumococcal polysaccharide antigen.
Main Results:
- Pneumococcal antigen was detected in 77% of pneumonia patients with positive sputum cultures for S. pneumoniae.
- The tests were negative in pneumonia patients without S. pneumoniae and in healthy carriers.
- Antigen titers ranged from 1:2 to 1:256 by immunodiffusion.
Conclusions:
- Detection of pneumococcal antigen in respiratory secretions is a reliable indicator of Streptococcus pneumoniae infection.
- These immunologic methods offer a valuable tool for diagnosing pneumococcal pneumonia and other related conditions.