Group B Streptococcus (GBS) is a leading cause of serious illness and death in neonates. With approximately 10-35% of women being asymptomatic carriers of GBS in the genital and gastrointestinal tracts detection of GBS is crucial to the prevention of neonatal GBS disease.
The aim of the study was to evaluate a commercial isothermal molecular method (Bioscience Illumigene GBS Assay) and compare the detection rate to the departments current traditional culture method for the detection of GBS in antenatal women.
A total of 245 swabs were screened utilising the traditional laboratory method of Granada Agar Plate (Oxoid PP2279) direct inoculation and Group B Streptococcal Broth (Oxoid TM1421) enrichment versus the Hardy Strep B Carrot BrothTM/Illumigene Group B Streptococcus Assay combination.
The study showed 187 concordant negative and 47 concordant positive results. However, there were 11 discordant results. All 11 were positive utilising the Hardy Strep B Carrot BrothTM /Illumigene Group B Streptococcus Assay, and reported negative on traditional laboratory method. All 11 were determined to be true positives by subculturing the Strep B Carrot Broth onto both Horse Blood and Granada media and identifying isolated colonies with the Brüker Maldi-TOF.
From this study, the utilisation of Strep B Carrot BrothTM with the Illumigene GBS Assay was found to be superior to traditional culture methods and has been implemented within the department.