Related Experiment Videos
Immunodiagnoses of community-acquired pneumonia in childhood
H I Requejo1, M L Guerra, M Dos Santos
1Instituto Adolfo Lutz, Department of Immunology, São Paulo, Brazil.
Abstract:
A diagnosis of bacterial pneumonia requires isolation of the pathogen from blood, lung or tracheal aspirate; however, cultures of blood and pleural fluid samples are usually insensitive. Thus, in the majority of patients the etiology is rarely determined. A total of 840 pleural fluid effusion samples from children with clinical and laboratory diagnoses of acute bacterial pneumonia were evaluated by Dot-ELISA. This method was standardized in order to detect polysaccharide capsular bacterial antigen in pleural fluid samples previously treated with 0.1 M EDTA and dotted on nitrocellulose membrane strips. Pneumococcal omniserum and H. influenzae type b antiserum diluted 1:200 were employed for detection of S. pneumoniae and H. influenzae type b antigens, respectively. Dot-ELISA showed relative indices of 0.913 for sensitivity and 0.552 for specificity, and a total positivity of 75.6 per cent, being 53.21 per cent for S. pneumoniae and of 22.38 per cent for H. influenzae.
Insights
A novel Dot-ELISA method accurately detects bacterial antigens in pleural fluid, improving diagnosis for childhood bacterial pneumonia. This technique identifies key pathogens like Streptococcus pneumoniae and Haemophilus influenzae type b.
Area of Science:
- Pediatric infectious diseases
- Microbiology
- Immunological assays
Background:
- Bacterial pneumonia diagnosis often relies on pathogen isolation, but blood and pleural fluid cultures have low sensitivity.
- This limitation frequently prevents etiological determination in pediatric bacterial pneumonia cases.
- Accurate etiological diagnosis is crucial for effective treatment and understanding disease burden.
Purpose of the Study:
- To develop and evaluate a Dot-Enzyme-Linked Immunosorbent Assay (Dot-ELISA) for detecting bacterial antigens in pleural fluid from children with acute bacterial pneumonia.
- To assess the sensitivity, specificity, and positivity rates of the Dot-ELISA for identifying Streptococcus pneumoniae and Haemophilus influenzae type b.
Main Methods:
- A total of 840 pleural fluid effusion samples from children diagnosed with acute bacterial pneumonia were analyzed.
- The Dot-ELISA method involved treating samples with EDTA, dotting them onto nitrocellulose membrane strips, and using specific antisera for antigen detection.
- Pneumococcal omniserum and Haemophilus influenzae type b antiserum were used to detect corresponding bacterial antigens.
Main Results:
- The Dot-ELISA demonstrated a relative sensitivity index of 0.913 and a specificity index of 0.552.
- The overall positivity rate for bacterial antigens in the pleural fluid samples was 75.6%.
- Specific positivity rates were 53.21% for Streptococcus pneumoniae and 22.38% for Haemophilus influenzae type b.
Conclusions:
- Dot-ELISA is a valuable tool for detecting bacterial antigens in pleural fluid, offering improved diagnostic capabilities for bacterial pneumonia in children.
- The assay successfully identified Streptococcus pneumoniae and Haemophilus influenzae type b as common etiological agents.
- This method can help overcome the limitations of conventional culture techniques, leading to more accurate etiological diagnoses.