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Detection of group D and viridans streptococci in blood by radiometric methods
Abstract:
A prospective study was conducted to evaluate the radiometric detection of group D and viridans streptococci in blood, using three media preparations, Bactec 6A and 6B isotonic media and 8B hypertonic medium. All enterococci tested were detected by the 6A and 6B media. However, the 6A medium failed to detect 76% of the Streptococcus bovis isolates and 57% of the viridans streptococci, whereas all S. bovis isolates and 95% of the viridans streptococci were detected with the 6B formulation. No improvement in detection was noted in comparing the 6B and the 8B hypertonic media. The importance of adequate detection of this group of organisms, especially in patients with endocarditis, is discussed.
Insights
The Bactec 6B blood culture medium effectively detects Streptococcus bovis and viridans streptococci, outperforming the 6A medium. This improved detection is crucial for diagnosing infections like endocarditis.
Area of Science:
- Clinical Microbiology
- Diagnostic Bacteriology
Background:
- Accurate detection of streptococci in blood is vital for patient management.
- Group D and viridans streptococci are significant pathogens, particularly in endocarditis.
Purpose of the Study:
- To compare the radiometric detection efficacy of three Bactec media for group D and viridans streptococci.
- To identify the optimal medium for detecting these streptococcal species in blood cultures.
Main Methods:
- A prospective study evaluated Bactec 6A (isotonic), 6B (isotonic), and 8B (hypertonic) media.
- Radiometric detection of group D streptococci (including Streptococcus bovis) and viridans streptococci was assessed.
Main Results:
- Bactec 6B detected all enterococci, Streptococcus bovis, and 95% of viridans streptococci.
- Bactec 6A failed to detect 76% of S. bovis and 57% of viridans streptococci.
- No significant difference in detection was observed between Bactec 6B and 8B media.
Conclusions:
- Bactec 6B is superior to 6A for detecting Streptococcus bovis and viridans streptococci in blood cultures.
- The findings highlight the importance of selecting appropriate media for optimal microbiological diagnosis.