Group B streptococcal infection , also known as Group B streptococcal disease or just Group B strep infection, is the infectious disease caused by the bacterium Streptococcus agalactiae. Streptococcus agalactiae is the most common human pathogen belonging to group B of the Lancefield classification of streptococci βhence the name of group B stretococcal GBS. Infection with GBS can cause serious illness and sometimes death, especially in newborns, the elderly, and people with compromised immune systems.
The most severe form of group B streptococcal disease is neonatal meningitis in infants, which is frequently lethal and can cause permanent neuro-cognitive impairment. It can cause bovine mastitis inflammation of the udder in dairy cows. The species name "agalactiae" meaning "no milk", alludes to this.
Its significance as a human pathogen was first described in , [ 1 ] and in the early s, GBS came to be recognized as a major cause of infections in newborns. As mentioned, S. GBS is characterized by the presence in the cell wall of the group B antigen of the Lancefield classification Lancefield grouping that can be detected directly in intact bacteria using latex agglutination tests.
GBS is found in the gastrointestinal, genitourinary tract, and oropharynx of humans. GBS is also a normal component of the intestinal and vaginal microbiota in some women. Though GBS colonization is asymptomatic and, in general, does not cause problems, it can sometimes cause serious illness for the mother and the baby during gestation and after delivery.
GBS infections in the mother can cause chorioamnionitis intra-amniotic infection or severe infection of the placental tissues infrequently, postpartum infections after birth and it had been related to prematurity and fetal death. In the western world, GBS in the absence of effective prevention measures is the main cause of bacterial infections in newborns, such as sepsis , pneumonia , and meningitis , which can lead to death or long-term after effects.
