Most common cause of neonatal meningitis is
**Core Concept**
Neonatal meningitis is a serious infection that affects the meninges, the protective membranes surrounding the brain and spinal cord, in newborns. It is a medical emergency that requires prompt diagnosis and treatment to prevent long-term neurological damage or death. The most common causative agents of neonatal meningitis are typically bacterial or viral pathogens that are acquired during birth or shortly after.
**Why the Correct Answer is Right**
The most common cause of neonatal meningitis is Group B Streptococcus (GBS), a gram-positive bacterium that is a leading cause of neonatal sepsis and meningitis. GBS can be transmitted to the newborn during vaginal delivery or through contact with contaminated maternal genital secretions. The bacteria then colonize the infant's respiratory tract, where they can cause pneumonia, sepsis, and meningitis. The high incidence of GBS neonatal meningitis is thought to be due to the bacterium's ability to evade the infant's immune system and produce toxins that damage the meninges.
**Why Each Wrong Option is Incorrect**
* **Option A:** Escherichia coli (E. coli) is a common cause of neonatal meningitis, but it is not the most common cause. E. coli is often associated with urinary tract infections and can cause neonatal meningitis, but GBS is still the leading cause.
* **Option B:** Listeria monocytogenes is a rare but serious cause of neonatal meningitis, particularly in premature infants. However, it is not the most common cause of neonatal meningitis.
* **Option C:** Viral meningitis is a common cause of meningitis in older children and adults, but it is not the most common cause of neonatal meningitis. Viral pathogens such as enteroviruses and herpes simplex virus can cause neonatal meningitis, but bacterial causes like GBS are more common.
**Clinical Pearl / High-Yield Fact**
GBS is a leading cause of neonatal meningitis, and prompt diagnosis and treatment are critical to prevent long-term neurological damage or death. Obstetric providers should perform GBS screening tests on pregnant women between 36 and 37 weeks of gestation to identify those who are colonized with the bacterium.
**Correct Answer: A. Group B Streptococcus**