Streptococcus agalactiae (Group B Streptococcus – GBS) infection is the most common cause of early-onset sepsis in newborns and a significant cause of late-onset sepsis and meningitis cases [1,2]. GBS can also cause infections such as fetus death, bacteremia, endometritis, chorioamnionitis, pneumonia, and puerperal sepsis in pregnant women as a result of infection of the lower genital tract, placenta, or amniotic fluid [3]. The primary risk factor for invasive GBS infection in newborns is colonisation of the mother's genitourinary or gastrointestinal tract with GBS [4]. Screening of pregnant women is recommended in order to administer intrapartum antibiotic prophylaxis (IAP) to prevent infection in infants during the first week of life, defined as early-onset sepsis [1].

The accuracy, speed and applicability of screening methods are decisive in the prevention of neonatal infections. Although the traditional culture method is currently used in GBS screening, this method has certain limitations in terms of sensitivity rates, turnaround time, and sample processing [5]. In addition, low bacterial loads or failure to maintain bacterial viability can cause false negatives in cultures [6]. Molecular methods are noteworthy for their ability to provide faster results than culture and their high sensitivity, but their sensitivity varies [5].

In recent years, the ST-17 clone, characterised by its ‘hypervirulent’ properties, has been isolated at high rates from neonatal invasive GBS infections, particularly meningitis cases [7]. Due to its unique virulence characteristics, the ST-17 clone is also considered a serious public health threat that necessitates the development of targeted preventive strategies [8,9].

This study aims to determine the GBS colonisation rate in pregnant women and to evaluate the agreement between culture and a rapid novel qPCR test. The presence of the hypervirulent ST-17 clone and the potential risk factors associated with colonisation are also investigated.