Rapid Diagnostic Test for Detection of Group B Streptococcus in Pregnancy (GBS)

• Culture of Group B streptococcus [ Time Frame: 48 hours ] [ Designated as safety issue: No ]
  Rapid assay results will be compared to routine culture results.
  
  

Intrapartum infection with group B streptococci (GBS) may lead to untoward neonatal sequelae such as pneumonia, septicemia, and meningitis. Several clinical trials have demonstrated that the use of intrapartum intravenous antibiotic prophylaxis (with penicillin being the agent of choice due to a narrower spectrum of antimicrobial activity) is highly effective to prevent early-onset neonatal GBS infections. It has been estimated that 10% to 30% of all pregnant women are GBS carriers, and it is likely that GBS colonizes virtually every female at some point. Consensus guidelines from the Centers for Disease Control and Prevention (CDC), American College of Obstetricians and Gynecologists (ACOG), and the American Academy of Pediatrics, recommend prenatal screening at 35 to 37 weeks of gestation and chemoprophylaxis at delivery based upon this culture result. The CDC-recommended method for detecting GBS colonization involves collecting a combined vaginal and rectal specimen and culturing the organism in a selective broth medium, followed be subculturing onto blood agar plates.

However, this traditional method of culture takes up to 72 hours for results to be available. With 12.8% of patients experiencing a preterm delivery prior to when a GBS screening occurs, and up to 15% of term pregnancies not having routine GBS screening performed, a significant portion of women present with unknown GBS status at the time of potential delivery. These clinical situations require obstetricians to utilize a risk-based strategy that has been shown to be only half as effective as culture-based screening. Thus, a need exists for a rapid detection method for GBS.

Recent research has focused on polymerase chain reaction (PCR) based methods for detection of GBS. Sensitivity for detection of GBS by the PCR assay has ranged from 87% to 91%. These methods are limited by high cost, and inability to perform antibiotic sensitivities for GBS (in women with a penicillin allergy). New technologies, called bionanopore (BNP) and bionanofilter (BNF) are rapid, microbial detection systems that utilizes sandwiched-membrane petri technology. These have the advantage of detecting GBS in less than 6 hours, with less cost, and the potential of allowing antibiotic sensitivities to be performed.