What is the role of maternal GBS status in the etiology of neonatal sepsis?

Updated: Jun 13, 2019
  • Author: Nathan S Gollehon, MD, FAAP; Chief Editor: Muhammad Aslam, MD  more...
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Answer

The most common cause of neonatal bacterial sepsis remains GBS, despite a decreased overall incidence in the age of universal GBS prophylaxis. There are nine serotypes, each of which is related to the polysaccharide capsule of the organism. Types I, II, and III are commonly associated with neonatal GBS infection. The type III strain has been shown to be most highly associated with central nervous system (CNS) involvement in early-onset infection, whereas types I and V have been associated with early-onset disease without CNS involvement.

The GBS organism colonizes the maternal gastrointestinal (GI) tract and birth canal. Approximately 25% of women have asymptomatic GBS colonization during pregnancy. GBS is responsible for approximately 50,000 maternal infections per year in women, but only 0.36 neonates per 1000 live births are infected.

Women with heavy GBS colonization and chronically positive GBS culture results have the highest risk of perinatal transmission. Also, heavy colonization at 23-26 weeks’ gestation is associated with prematurity and low birth weight. Colonization at delivery is associated with neonatal infection.

Intrapartum chemoprophylaxis for women with positive GBS culture results has been shown to reduce transmission of the organism to the neonate during delivery. Mothers may have a negative prenatal culture for GBS but a positive one at the time of labor. [5]


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