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Pneumococcal capsular antigen detection and pneumococcal serology in patients with community acquired pneumonia
W G Boersma1, A Löwenberg, Y Holloway
1Department of Pulmonary Diseases, University Hospital, Groningen, Netherlands.
Background:
Methods to determine the microbial cause of community acquired pneumonia include detection of pneumococcal antigen and measurement of pneumococcal capsular antibody response. Their usefulness compared with conventional microbiological techniques was investigated in patients with pneumonia, some of whom had been treated with antibiotics.
Methods:
Pneumococcal capsular antigen was detected by latex agglutination in sputum and the results compared prospectively with results of conventional microbiological techniques in 90 patients with community acquired pneumonia. Serum, urine, and pleural fluid samples were also tested for antigen. Serum pneumococcal capsular antibody titres were measured.
Results:
A diagnosis was established by conventional microbiological techniques in 53 patients, 30 of whom had pneumococcal pneumonia. The sensitivity of antigen detection in first day sputum specimens (n = 18) in those with pneumococcal pneumonia was 94%; antigen was present in 23 of the 27 patients who produced representative sputum on admission and during follow up. The specificity of antigen detection in sputum in patients with non-pneumococcal pneumonia and lung infarction was 87%. Antigen was present in 12 of 25 patients with pneumonia of unknown aetiology who produced representative sputum. Antigen was rarely detected in serum and urine, but was present in pleural fluid in three of four patients with pneumococcal pneumonia and in all four patients with pneumonia of unknown aetiology. Pneumococcal antigen remained detectable in patients treated with antibiotics. Pneumococcal capsular antibody detection was as specific (85%) as antigen detection, but had a lower sensitivity (50%).
Conclusion:
Pneumococcal antigen detection in sputum or pleural fluid is of value in making a rapid diagnosis and provides an additional diagnostic result in patients with pneumococcal pneumonia, especially those receiving antibiotic treatment.
Insights
Pneumococcal antigen detection in sputum or pleural fluid aids rapid diagnosis of community-acquired pneumonia, even with antibiotic treatment. This method offers valuable results, especially for pneumococcal pneumonia cases.
Area of Science:
- Microbiology
- Infectious Diseases
- Diagnostic Medicine
Background:
- Community-acquired pneumonia diagnosis relies on detecting pneumococcal antigen or antibody response.
- Conventional microbiological techniques are standard but can be time-consuming.
Purpose of the Study:
- To compare the utility of pneumococcal antigen and antibody detection with conventional methods for diagnosing pneumonia.
- To evaluate diagnostic performance in patients, including those treated with antibiotics.
Main Methods:
- Pneumococcal capsular antigen detection via latex agglutination in sputum, serum, urine, and pleural fluid.
- Prospective comparison with conventional microbiological techniques in 90 pneumonia patients.
- Measurement of serum pneumococcal capsular antibody titers.
Main Results:
- Conventional methods diagnosed 53 patients, with 30 having pneumococcal pneumonia.
- Sputum antigen detection showed 94% sensitivity and 87% specificity.
- Antigen was detectable in patients receiving antibiotics; antibody detection had lower sensitivity (50%) but comparable specificity (85%).
Conclusions:
- Pneumococcal antigen detection in sputum or pleural fluid is valuable for rapid pneumonia diagnosis.
- It provides additional diagnostic information, particularly in patients receiving antibiotics.
- This method enhances diagnostic capabilities for pneumococcal pneumonia.