Method for rapid detection of group B streptococci by coagglutination

Area of Science:

• Microbiology
• Clinical Diagnostics
• Bacteriology

Background:

• Group B Streptococcus (GBS) is a significant pathogen, particularly in neonates.
• Accurate and rapid identification of GBS is crucial for timely treatment and infection control.
• Existing diagnostic methods can be time-consuming or require specialized equipment.

Purpose of the Study:

• To develop a rapid, reliable, and cost-effective method for identifying group B streptococci.
• To evaluate the efficacy of this new technique in both laboratory and clinical settings.
• To assess the detection rates and time to results for group B streptococci identification.

Main Methods:

• A coagglutination assay utilizing specifically sensitized protein A-containing Staphylococcus aureus.
• Mixing Staphylococcus aureus particles with the supernatant of actively growing cultures or suspect colonies.
• Macroscopic observation of agglutination indicating the presence of group B streptococci.

Main Results:

• The method provides macroscopically readable agglutination upon reaction with group B streptococci.
• Positive reactions were observed within 6 hours for a single colony in Todd-Hewitt broth, with faster results for larger inoculums.
• In laboratory studies, 59.3% of positive cultures were detected within 8 hours and 71.7% within 24 hours.
• In clinical studies using vaginal swabs, 78.6% of positive cultures were detected within 8 hours and 92.9% within 24 hours.

Conclusions:

• The developed coagglutination technique is a quick, reliable, and accessible method for identifying group B streptococci.
• The assay is effective for detecting GBS in mixed broth cultures and from suspect colonies on agar plates.
• This method offers a valuable diagnostic tool for clinical laboratories, enabling faster patient management.