Changing patterns of group B streptococcal serotypes associated with human infections

Area of Science:

• Microbiology
• Clinical Bacteriology
• Immunology

Background:

• Group B Streptococcus (GBS) is a leading cause of neonatal infections.
• Accurate GBS serotyping is crucial for epidemiological surveillance and vaccine development.
• Previous GBS serotype distribution studies are limited in scope and time.

Purpose of the Study:

• To serotype 100 clinical isolates of GBS using an indigenously prepared coagglutination system.
• To compare current GBS serotype prevalence with historical data from 1975-78.
• To identify emerging or unidentified GBS serotypes within the local community.

Main Methods:

• Collection of 100 GBS strains from diverse clinical specimens.
• Serotyping performed using a newly developed indigenous coagglutination test system.
• Comparison of serotype distribution with historical data from 1975-78.

Main Results:

• Serotype NT/c was the most predominant (24%), followed by Ia (23%), II/c (12%), and Ib (11%).
• Type Ia predominated in most specimens, except genital samples where NT/c was most prevalent.
• Significant increases in NT/c, II/c, and Ia prevalence were observed compared to 1975-78, with declines in types III, Ia/c, and Ib.
• Two strains were nontypable, suggesting the existence of novel GBS serotypes.

Conclusions:

• The GBS serotype landscape has significantly shifted, with NT/c, Ia, and II/c becoming more prevalent.
• The indigenous coagglutination system effectively identified common GBS serotypes.
• The presence of nontypable strains highlights the need for ongoing surveillance and identification of new GBS serotypes.