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Minimum number of pneumococci required for capsular antigen to be detectable by latex agglutination
Y Holloway1, W G Boersma, H Kuttschrütter
1Regional Public Health Laboratory, University Hospital, Groningen, The Netherlands.
Abstract:
Forty-eight strains of Streptococcus pneumoniae were tested in vitro to determine the minimum number required for pneumococcal capsular antigen to be detectable by latex agglutination. It was found that 10(6) to 10(7) microorganisms per ml were needed and that antigen remained detectable even when viable pneumococci could no longer be demonstrated.
Insights
Detecting pneumococcal capsular antigen with latex agglutination requires 10^6 to 10^7 Streptococcus pneumoniae per ml. The antigen remains detectable even after viable bacteria are no longer present.
Area of Science:
- Microbiology
- Immunology
- Diagnostic Testing
Background:
- Streptococcus pneumoniae is a leading cause of bacterial pneumonia and meningitis.
- Accurate and sensitive detection methods are crucial for diagnosing pneumococcal infections.
- Latex agglutination is a common serological test for identifying bacterial antigens.
Purpose of the Study:
- To determine the minimum bacterial concentration of Streptococcus pneumoniae needed for capsular antigen detection.
- To assess the persistence of detectable antigen relative to viable bacterial counts.
Main Methods:
- In vitro testing of 48 Streptococcus pneumoniae strains.
- Quantitative analysis of bacterial concentration.
- Latex agglutination assay for pneumococcal capsular antigen detection.
Main Results:
- A concentration of 10^6 to 10^7 microorganisms per ml was required for antigen detectability.
- Pneumococcal capsular antigen remained detectable by latex agglutination even when viable bacteria were no longer demonstrable.
Conclusions:
- Latex agglutination is a sensitive method for detecting pneumococcal capsular antigen.
- The test can detect antigen even in the absence of viable Streptococcus pneumoniae, suggesting potential for detecting residual or non-viable bacteria.