Group B streptococcus (GBS) is a bacterial infection found in the reproductive or gastrointestinal tracts of up to 35% of healthy women. It’s caused by the bacterium Streptococcus agalactiae. Mothers with this infection can pass it to their babies during birth. This can lead to neonatal sepsis and/or meningitis.
It’s important to check for GBS in pregnant women during the third trimester. They might get antibiotics to lower the risk of their babies getting sick right after birth. Unfortunately, this doesn’t always stop the disease if it shows up later, between 7 and 89 days after birth.
GBS can be especially dangerous for pregnant women and those with weakened immune systems. Testing for GBS helps doctors know who’s at risk and what can be done to protect them.
Key Takeaways
- Group B streptococcus (GBS) is a bacterial infection commonly found in women’s reproductive or gastrointestinal tracts.
- GBS can be transmitted from GBS-colonized mothers to their newborns during childbirth, leading to neonatal sepsis and/or meningitis.
- Screening pregnant women during the third trimester and providing antibiotic prophylaxis has reduced the incidence of early-onset GBS disease.
- Late-onset GBS disease, occurring between 7 and 89 days of life, is not effectively prevented through maternal antibiotic prophylaxis.
- GBS can cause invasive infections in individuals with weakened immune systems.
Group B Strep Infections: Etiology and Virulence Factors
Group B streptococcus, or GBS, is a type of gram-positive bacterium that is named after its features . It looks round and often grows in pairs or chains. When it grows on blood agar, it creates small, colorless colonies with a hint of color, known as beta-hemolysis.
GBS is known for making a capsule, pili, and beta-hemolysin. The capsule helps GBS avoid the immune system and stick to cells. Pili help it hold onto and grow in the body’s tissues.
Another thing GBS makes is beta-hemolysin. This can cause blood cells to break down. GBS also makes an enzyme called C5a-ase. This enzyme stops part of the immune system from working, which helps GBS stay and cause infection.
Many people, especially women, have GBS in their gut and urinary areas with no symptoms. But certain things, like being pregnant or having a weak immune system, can make GBS grow more. When pregnant women have GBS, they can pass it to their babies during birth, causing infection.
Virulence Factors of Group B Streptococcus
| Pathogen Characteristics | Description |
|---|---|
| Capsule | Aids in immune evasion and host cell attachment |
| Pili | Facilitates adhesion and colonization in host tissues |
| Beta-Hemolysin | Causes hemolysis and tissue damage |
| C5a-ase | Inactivates complement component C5a, allowing evasion of the host’s immune response |
Because of the way GBS works and how easily it can be in the body without showing signs, it’s vital to know how it infects people. Finding and understanding what makes GBS harmful can help scientists and doctors fight it better. This knowledge can lead to better ways to prevent and treat GBS.
Prevention and Management of Group B Strep Infections
Group B strep infections are often managed by many methods. One key step is screening pregnant women for GBS in the third trimester. This helps find those who might pass the bacteria to their babies. Antibiotics are given to these women in labor to lower the infection risk for the newborns.
Early-onset GBS disease in newborns shows up quickly with serious symptoms. These can include apnea, tiredness, low blood pressure, breathing problems, and a high risk of death. Late-onset GBS disease happens after the first week of life. It can lead to blood poisoning or brain inflammation.
The first step in treating GBS infections is testing to pick the right antibiotics. Looking into using stem cell therapy is also happening. But, we still need more research on this.