Study towards a simple and rapid test for group B streptococcus

Abstract

Since its emergence in the early 1970's, group B streptococcus (GBS) has been the predominant infectious cause of life-threatening illness in neonates. In the absence of a vaccine, intrapartum antibiotic prophylaxis (lAP) has been used to interrupt vertical transmission of GBS, and thus prevent infant infection. Although TAP decreases the incidence of neonatal GBS disease, there are concerns that its widespread use may result in maternal and infant morbidity from other causes, such as anaphylaxis and disease from virulent antibiotic resistant bacteria, for example disease caused by ampicillin resistant E. coli. To minimise the risks of such adverse outcomes, it is important that lAP administration is limited to mothers with intraparturn GBS colonisation. Although several tests have been developed for rapid detection of GBS, most have lacked the sensitivity required to identify light levels of colonisation.

The aim of this study was to develop a simple test capable of detecting all levels of GBS colonisation within 1-2 hours. Two approaches were taken. The first involved development of a fluorescent test for the GBS surface enzyme C5a peptidase (C5a-ase). This was not successful in that the substrate molecules used in the test were susceptible to the agents used to release C5a-ase from the cell wall. The second approach was based on PCR detection of the newly discovered and highly conserved GBS bsp gene. This test is highly specific and further improvement in sensitivity will undoubtedly make this a suitable test for intrapartum detection of GBS.

Date of Award	Nov 2001
Original language	English