Serotyping of Streptococcus agalactiae isolates was carried out by ImmuLex® Strep-B Latex (Statens Serum Institut, Copenhagen, Denmark), classifying them in serotypes 1a,1b, II, III, IV, V, VII, VIII, or IX.
Steps
1.
Use one colony from a 5-10% blood agar plate.
2.
Add one drop (10l) of latex reagent on a glass slide.
Note
NOTE: Before using the latex reagent, the bottles should be at roomtemperature. Remember to shake it.
3.
Apply 10l phosphate buffer saline next to the drop of latex and suspend one
colony from the agar plate into the drop of saline.
Note
NOTE: Do not add too much colony material because that might give falsepositives.
4.
Mix the two drops
Note
NOTE: Use a different stick for each reaction.
5.
Spread to cover the area of the circle.
6.
Observe for agglutination within 5-10 seconds.
Note
NOTE: Any agglutination after 30 seconds is not a positive result.
