Evaluation of commercial latex agglutination reagents for grouping streptococci

Rapid grouping of beta-hemolytic streptococci by latex agglutination.

Latex agglutination was compared with fluorescent-antibody staining with group A conjugate and Lancefield precipitation for grouping of beta-hemolytic streptococci. Latex agglutination correctly grouped 98.8% of 82 group A streptococci and more than 95% of 187 group B, C, or G streptococci. Occasional cross-reactions occurred between groups A and C and groups B and G.

Grouping of beta-haemolytic streptococci by agglutination.

Streptococcal grouping sera, diluted and absorbed to remove cross-reactions, were bound to staphylococci and used to group trypsinised beta-haemolytic streptococci by coagglutination. The results compared well with those obtained using the Phadebact streptococcal grouping kit. The same sera bound to staphylococci without prior dilution and absorption could be used to group enzyme extracts of ha...

Serological grouping of streptococci by slide agglutination.

Streptococcal grouping sera for groups A, B, C, and G prepared for conventional testing by precipitation were made specific by absorption and used to identify streptococci by slide agglutination with and without staphyloccocal coagglutination. Trypsinised suspensions of 1055 strains, identified by precipitation as belonging to group A, B, C, or G, were tested by slide agglutination. Of these, 9...

Evaluation of an improved Streptex kit for the grouping of beta-haemolytic streptococci by agglutination.

A modified Streptex kit in which the extraction procedure had been simplified was used to group 200 streptococcal strains. Positive reactions could be obtained with live colonies and over 90% of isolates were correctly grouped from primary isolation plates. Some minor cross-reactions were seen with Streptex, but these were not strong enough to cause any confusion and no isolates were incorrectl...

Calculation of numbers of streptococci in latex agglutination swabs.