By Santa J. Bartholomew M.D. FAAP, FCCM
Group B Strep (GBS) is a huge burden of disease in developed countries. It is divided into three categories: early GBS, Late GBS (7-89 days post birth) and very late GBS (> 90 days post birth). Early onset rates have fallen in the last 20 years due in great part to screening and treatment of mothers prior to delivery and as written about in another blog early onset GBS is caused by passage through the birth canal. This is an organism that lives in the vagina without causing disease in the mother.
Late onset GBS rate have remained steady for the last 25 years: 0.4/1000 live births despite changes in care of mother making it clear that acquisition of disease is not via delivery through the birth canal but acquired after birth of infant. Late onset GBS disease is as severe as that suffered by younger infants causing 27% of all meningitis in this age group as well as severe sepsis without meningitis. The mortality rate of meningitis in late onset GBS ca be as high as 10% with 35% of survivors having severe neurologic sequelae. In addition to sepsis and meningitis, however, GBS has been the cause of bone infections in infants (osteomyelitis) as well as joint infections, cellulitis, urine infections, brain infarction (stroke), and subdural collections in infants.
Late onset GBS is acquired by the infant from the mother or other colonized household members through routine care and touching but this is not typically a disease acquired passing through the birth canal. The infant can also become colonized going through the birth canal by swallowing vaginal secretions that result in bacterial adherence in the respiratory and GI tract mucous membranes that can later cause bacterial invasion causing pneumonias and sepsis much later in infancy. As many as 50% of infants of mothers colonized with GBS can become colonized with the same organism as the mother.
Late onset GBS is acquired by the infant from the mother or other colonized household members through routine care and touching.
Although it is not acquired through the birth canal it is most seen in in pre-term infants born <28 weeks of gestation. Other risk facts for late onset group B strep include young maternal age, HIV exposure, ethnicity (being more common in black children). There is also emerging data that breast milk may also expose infant to GBS in colonized mothers however it is believed that the benefits of breast feeding overall outweigh the risk of acquiring late GBS infection.
Clinical Presentation
- Temperature: fever, low or unstable temperature
- Eating habits: feeds poorly, refuses to eat, not waking to feed, vomiting
- Sleeping habits: sleeping too much, difficulty being aroused
- Breathing: fast, slow, or difficult breathing
- Sounds: high pitch cry, shrill moaning, whimpering, inconsolable, constant grunting
- Behavior: marked irritability, reacting as if skin is tender, listless, floppy, not moving an arm or leg, blank stare, body stiffening, uncontrollable jerking
- Skin Appearance: blue, gray or pale skin, blotchy or red skin, tense or bulging fontanelle, infection at the base of umbilical cord or head punctures from internal fetal monitor. Sometimes jaundice.
How to Diagnose
It is imperative that late onset GBS be considered in any infant that presents with signs of infection in the first three moths of life. High index of suspicion and empiric treatment are invaluable in prognosis.
- Blood culture
- Urine culture
- CBC with differential
- Lumbar puncture
- Chest x-ray
- If there is concern about joint swelling than radiographs of joints or MRI may be indicated.
- If there is a twin, that infant should be evaluated.
Treatment
ANTIBIOTICS
- Recognition and management of shock
- Careful management of body salts
- Management of breathing if child has oxygenation issues or is not awake and alert including placement of breathing tube and ventilator management.
- Treatment of seizures
- Treatment of anemia
All of these secondary treatments are aimed at preventing secondary brain injury while the antibiotics kill the organism.
Duration of Therapy Differs
- Bacteremia without a focus – 10 days
- Meningitis – 14 days is sufficient for uncomplicated meningitis; complicated central nervous system (CNS) infections require longer treatment
- Cellulitis-adenitis – 10 to 14 days
- Septic arthritis – 14 to 21 days
- Osteomyelitis – 21 to 28 days
- Urinary tract infection – 10 days
Prognosis
Fatality is 1-3% for late onset disease, considerably higher in preterm infants up to 8%.
Meningitis in particular has substantial morbidity including:
- Seizures
- Permanent neurologic disability
- Cerebral palsy
- Greatly impaired cognitive development.
