Streptococcus agalactiae is a catalase-negative, beta-haemolytic, gram-positive coccus. Strep Agalactiae is a Lancefield Group B Streptococcus (GBS). It appears as gram-positive cocci in chains.
Another beta haemolytic gram-positive coccus is Streptococcus pyogenes, we differentiate the two by the fact that Strep agalactiae is bacitracin resistant whilst Strep pyogenes is bacitracin sensitive.
Strep Agalactiae’s virulence factors include:
Strep Agalactiae preferentially colonises the gastrointestinal (GI) tract and the genitourinary (GU) tract, particularly the vagina; with transmission to the baby either in utero or during the birthing process.
Obstetric complications provide added opportunities for Strep Agalactiae transmission to the neonate e.g. premature birth, or prolonged membrane rupture.
Strep Agalactiae can cause:
And can cause:
Blood culture and Cerebro-Spinal Fluid (CSF) analysis can aid in diagnosing Strep Agalactiae.
Treatment is with:
Screening of pregnant women in their 3rd trimester is recommended; as well as penicillin prophylaxis for those positive with Strep agalactiae.