While the classic illness known as strep throat is rare in newborns, streptococcal infections remain a serious concern. Group A Streptococcus (GAS), the bacteria responsible for strep throat, typically requires close contact for transmission and is uncommon in babies under 28 days old. However, Group B Streptococcus (GBS) poses a significant threat, often leading to severe systemic infections. Understanding the difference between these two bacterial groups helps parents and caregivers recognize potential risks.
Understanding Strep A and Strep B in Newborns
Group A Streptococcus (Streptococcus pyogenes), the cause of strep throat in older children, is less likely to infect newborns due to limited exposure to droplet transmission. When GAS infections occur in infants, they may manifest as skin infections or a fever rather than the typical throat infection.
Group B Streptococcus (Streptococcus agalactiae) is the primary streptococcal concern in newborns. GBS often colonizes the tracts of many healthy women without causing illness. The bacteria can be transmitted vertically from the mother to the baby during labor and delivery, which is the cause of most early-onset infections.
GBS is the most common cause of serious infections in newborns, frequently leading to life-threatening conditions like sepsis, pneumonia, or meningitis. Early-onset GBS disease occurs within the first week of life, with most cases presenting within the first 24 hours after birth. Late-onset GBS infection occurs between one week and three months of age, and the source of the bacteria for these later cases is not always clear.
The newborn immune system is particularly vulnerable to GBS because it lacks the specific antibodies needed to fight off the bacteria effectively. This deficiency allows the bacteria to rapidly spread from the bloodstream (sepsis) to other organs, including the lungs (pneumonia) and the fluid surrounding the brain and spinal cord (meningitis). This rapid progression underscores why GBS is a high-risk pathogen for the neonatal period.
Urgent Symptoms of Streptococcal Infection in Infants
Unlike older children who complain of a sore throat, infants with a streptococcal infection present with non-specific, subtle, and rapidly worsening symptoms. Parents should watch for significant changes in their baby’s behavior and physical state, as these signs require immediate evaluation. A fever of 100.4°F (38°C) or higher is a red flag for infection, but temperature instability may also present as hypothermia, where the skin feels cold and clammy.
Lethargy is a key symptom, where the baby seems unusually sleepy, is difficult to wake up, or appears limp. Poor feeding is another common indicator; the infant may refuse to nurse or take a bottle, or may vomit forcefully.
Respiratory distress can manifest as rapid breathing, grunting noises, or periods where the baby temporarily stops breathing. The baby may also show extreme irritability, being overly fussy and inconsolable, or conversely, be unusually quiet and unresponsive. Jaundice, a yellowing of the skin and eyes, can also occur with GBS infection. These symptoms are not unique to streptococcal infections but indicate a serious medical emergency.
Diagnosis and Medical Intervention
When an infant displays signs of a serious infection, medical intervention must be swift due to the potential for rapid deterioration from sepsis or meningitis. Healthcare providers will perform a complete diagnostic workup to identify the cause of the illness. This process typically begins with a blood culture, which is used to identify any bacteria circulating in the infant’s bloodstream.
A lumbar puncture, commonly known as a spinal tap, is often performed to collect a sample of cerebrospinal fluid (CSF) if meningitis is suspected. Samples may also be taken from the urine or a swab from the ear or throat to identify the specific type of bacteria present.
Treatment for a suspected streptococcal infection, especially GBS, involves the immediate administration of broad-spectrum intravenous (IV) antibiotics. Treatment cannot wait for culture results, as the infection can progress too quickly. Penicillin G or ampicillin are the standard antibiotics used because they are highly effective against GBS and can be given to the mother during labor as a preventative measure. A positive diagnosis often requires a full course of IV antibiotics, typically lasting at least seven days, and may require the infant to be cared for in a neonatal intensive care unit (NICU).