A review of laboratory methods for identification of group B streptococci (Streptococcus agalactiae)

A selected review is presented of the history of Group B streptococcal infections and the laboratory tests used to identify Group B streptococcus (Streptococcus agalactiae), an opportunistic pathogen which causes serious infections in newborn infants and compromised patients in other age groups. Its isolation may be increased by growth in a selective medium. The methods for Group B streptococci identification include the hydrolysis of sodium hippurate, the CAMP reaction, pigment production, and antibiotic disk susceptibility. Also, immunological tests, such as Lancefield's classical precipitin test, immunofluorescence staining, counterimmunoelectrophoresis, and coagglutination are available.