The characteristics, diagnosis, treatment, and epidemiology of group B streptococci.
Lancefield group B streptococci (GBS), also called Streptococcus agalactiae, form part of the normal bacterial flora of the gut. GBS is also commonly found in the male and female genital tract.
GBS is mainly associated with disease in newborns (neonates) causing meningitis, septicaemia and pneumonia. It also causes septic abortion (loss of pregnancy as a result of infection) and puerperal sepsis (systemic and uterine infection at or following childbirth as a result of bacterial infection).
Infection in newborns may be divided into 2 types:
- early onset disease (EOD) - occurs in the first week of life. In these cases the source of the infection is usually the mother’s genital flora
- late onset disease (LOD) - occurs between the seventh and 90th day of life. In these cases the infant is presumed to have been infected after birth, and infection may have been acquired while in hospital. The exact mode of transmission in late onset disease is unclear
GBS infection in older adults is often associated with urinary tract infection (cystitis), or infections of pre-existing wounds or lesions such as diabetic foot ulcers. Deep-seated infections such as endocarditis and arthritis are also reported.
The Respiratory and vaccine preventable bacteria reference unit (RVPBRU) provides reference and microbiology services related to GBS.
SMI B 58: processing swabs for group B streptococcal carriage describes the processing of specimens from pregnant women to determine GBS carriage.
Treatment and prevention
Antibiotic treatment usually, with a penicillin or erythromycin (if the organism is sensitive to erythromycin) is the standard treatment of choice. Other alternatives are clindamycin, vancomycin or teicoplanin. Antibiotics such as penicillin or clindamycin are also used for prevention of early onset infection in the neonate when prescribed appropriately to the mother in labour.
See the group B streptococcal disease, early-onset (Green-top guideline No. 36) guidelines by the Royal College of Obstetricians and Gynaecologists (RCOG). This guideline provides guidance for obstetricians, midwives and neonatologists on the prevention of early-onset neonatal group B streptococcal (EOGBS) disease.
PHE publishes reports on streptococcal infection rates in Health Protection Report (HPR).
For reports from 2012 and earlier, see the HPR archive.
PHE’s position statement on enriched culture medium test for group B streptococcus infection.