Group B streptococcus
- Virulence factors that contribute to its pathogenicity:
–
Polysaccharide capsule inhibits phagocytosis.
–
Sialic acids in the capsule inhibit activation of the alternative complement pathway and
neutrophilic activities, thus facilitating host immune evasion.
- Colonization and Infection:
– Group B streptococcus commonly colonizes the
colon and genitourinary tracts of women.
– Group B streptococcus can be passed to the neonate, particularly if labor is prolonged; administration of antibiotics to infected mothers can help prevent bacterial transmission.
– Early-onset diseases occur within the first 7 days after birth, and include
bacteremia, pneumonia, and meningitis. This is typically the result of transmission during labor and birth.
– Late-onset diseases occur between 1 week and 3 months of age, and include
bacteremia with meningitis.
– In women, Group B streptococcus is associated with
post-partum endometritis, which is characterized by infiltration of plasma cells and inflammatory cells to the
endometrium; it also causes wound and urinary tract infections.
– In both men and women, Group B streptococcus is associated with bacteremia leading to
pneumonia and infections of the bones, joints, skin, and soft tissues; immunocompromised, diabetic, and alcoholic patients are at higher risk of Group B streptococcal infections.
–
Penicillin G is the preferred antibiotic to treat Group B streptococcal infections.
Endometritis (https://commons.wikimedia.org/wiki/File:Endometritis_-_2_-_cropped_-_very_high_mag.jpg).
Lung imaging, pneumonia (Adam Fisch, MD).
Blood smear (Braun, Mark. http://medsci.indiana.edu/c602web/602/c602web/virtual_nrml/nrml_lst_pad.htm).
