Definition of Group B
: any of various strains of a streptococcus (Streptococcus agalactiae) that include the causative agents of certain infections (as pneumonia and meningitis) especially of newborn infants —usually used attributively <Group B streptococcal infections>
First Known Use of group b
Medical 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
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