Group B

Group B

noun \-ˈbē\

Definition of GROUP B

: the Lancefield group of usually beta-hemolytic streptococci that comprises all strains of a species of the genus Streptococcus (S. agalactiae) and that includes the causative agents of certain infections (as septicemia, pneumonia, and meningitis) especially of newborn infants—usually used attributively <affected with Group B strep>; compare group a