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Streptococci with dual antigen specificity for Lancefield groups D and G
European Journal of Clinical Microbiology
|December 1, 1984
Summary
Some Streptococcus bacteria may be misidentified as Lancefield group G due to shared antigens, but are actually group D. This misidentification can lead to ineffective antibiotic treatments for patients.
Area of Science:
- Microbiology
- Clinical Diagnostics
- Immunoserology
Background:
- Streptococci are a diverse group of bacteria with various pathogenic potentials.
- Accurate bacterial identification is crucial for effective antimicrobial therapy.
- Serological grouping, like Lancefield grouping, is a common diagnostic tool for streptococci.
Purpose of the Study:
- To investigate streptococcal isolates misidentified as Lancefield group G but belonging to group D.
- To elucidate the serological basis for the cross-reactivity between group D and group G streptococci.
- To highlight the clinical implications of such misidentification.
Main Methods:
- Isolation and characterization of 22 streptococcal cultures from four countries.
- Serological testing to confirm Lancefield group.
- Cross-absorption procedures and epitope analysis to identify antigen similarities.
Main Results:
- Twenty-two isolates, including *Streptococcus bovis*, *Streptococcus durans*, and *Streptococcus faecalis*, showed cross-reactivity with Lancefield group G antisera.
- The group G reaction was attributed to an epitope with partial identity to the reference group G antigen.
- These findings confirm that certain group D streptococci can be erroneously identified as group G.
Conclusions:
- Misidentification of enterococci as group G streptococci can result in incorrect and ineffective chemotherapy.
- Routine antibiotic sensitivity testing for all group G streptococcus isolates is recommended.
- Implementing bile-aesculin and salt-tolerance tests for suspected group G isolates is a prudent diagnostic measure.