050074: PCR-Based Capsular Typing Method for Serotyping Group B Streptococci

Group B streptococci (GBS), although generally carried asymptotically, can cause invasive disease in newborns, pregnant women, and immunocompromised adults. This bacteria is the most common cause of neonatal and obstetric sepsis and an increasing cause of septicemia in the elderly and immunocompromised patients. It affects approximately 20,000 people/year, nearly half of these cases in newborns. The incidence of neonatal GBS sepsis has been reduced in recent years by the use of antibiotic prophylaxis, but there are problems with this approach. The ability to determine the clonal composition and antigenic diversity would help to better target treatments. Although various serotyping methods have been used, they are generally not able to provide this level of information.


This invention employs a novel method to determine the clonal composition and antigenic diversity of Group B streptococci (GBS). The analysis is based on polymerase chain reaction (PCR) using restriction fragment length polymorphism (RFLP). Specific primers have been designed to amplify conserved regions of the GBS capsule gene.
The amplified products are then digested with restriction enzymes, and the pattern of fragments is used to identify the capsular strain.


  • Improved identification of GBS: This method offers the potential to allow for more specific identification of capsular strains of GBS in infection.


Potential applications include providing an alternative or adjunct to the current methods of GBS identification, use in a bacteriology reference lab, or in clinical research for development of improved treatments for GBS.

Better identification of specific isolates could help to determine which are most associated with disease and consequently provide important information for determining the need for prophylactic treatment. In addition, this invention could aid in targeted drug development.

IP Protection Status

US 11,294,830 (published US application)
Patent Information:

For Information, Contact:

Randy Ramharack
Technology Manager
Michigan State University - Test