Maternal Group B Streptococcus colonisation

Streptococcus agalactiae, commonly known as Group B Streptococcus (GBS), is an important neonatal pathogen known to cause sepsis, meningitis and pneumonia. Australian pregnant women undergo screening during pregnancy in an effort to eradicate GBS before delivery where transmission to the neonate can occur. Preventative treatment includes intrapartum antibiotic prophylaxis and results in widespread treatment of the 10–40% of pregnant women colonised. GBS are separated into ten different capsular polysaccharide serotypes and previous studies have suggested associations between specific serotypes anddisease. At present, however, minimal data exist on serotype distribution within Western Australian-pregnant women, information that may play an important role in future prophylactic treatment regimens. Our preliminary data, obtained from GBS isolated from vaginal swabs from 191 pregnant women, suggests that GBS serotype distributions in Western Australia are different to other parts of Australasia. In particular, compared to the eastern Australian states and New Zealand, in our cohort, serotype Ib prevalence was 7–17 times lower, II was 2–6 times greater and VI was2–12timesgreater. Inaddition, serotypeIXrepresented 6.3% of all serotypes. Understanding which serotypes are present in our population will provide valuable data for future targeted treatment regimens such as vaccinationand bacteriophage therapy. Group B Streptococcus during pregnancy Neonates are among the most vulnerable forms of life, they enter this world withminimal immune defences and are facedwith a vast array of opportunistic pathogens ready to colonise. One such organism is Streptococcus agalactiae, commonly known as Group B Streptococcus (GBS), which is responsible for morbidity and mortality in the immunocompromised, elderly and in particular, neonatal populations. GBS infection is a leading cause of sepsis and can also lead to meningitis, pneumonia, shock and even death. It is understood that transmissionof this organismcanoccur froma commensally colonised mother to her baby during birth, in utero (vertical) or alternatively through nosocomial transmission once born (horizontal). In an effort toprevent infantGBS infection, riskbased and culture-based screening of pregnantwomen followedby intrapartum antibiotic prophylaxis has been introduced in a number of countries globally. In Australia, pregnant women are screened for presence of GBS several weeks before expected delivery to determine colonisation status. If a patient is found to carry GBS, antibiotics are administered prior to delivery in an effort to eradicate the organism before the neonate is exposed.