Related Experiment Video
Updated: Oct 1, 2026

Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
Published on: February 24, 2014
Application of serum opacity factor in subtyping of group A streptococci & identification of new M-types
Abstract:
Out of 742 isolates of group A streptococci (GAS), 34.0 per cent were positive for production of serum opacity factor (SOF). The T and M typability of these GAS strains was 93.3 and 10.8 per cent respectively. Clustering of the strains under the T patterns 5/12/27, 8/25/Imp. 19 and 3/13/B3264 and low M typability indicated the utility of SOF testing as an additional marker in epidemiological characterisation of GAS. SOF was further found to be useful in identification of new M type and simplified M typing by saving time, labour and sera.
Related Concept Videos
Blood Typing
Antigens are protein molecules that reside on the surface of red blood cells (RBCs). The ABO and Rh blood typing systems target antigens A,...
Special Staining Techniques
Methods of Classification and Identification

