Group B streptococcal infection

Case history #1

A 4-hour-old baby boy, born by vaginal delivery at 36 weeks' gestation, is noticed by his mother to be making a grunting noise when he breathes. On examination the infant is irritable, pale, and floppy. He has an increased respiratory rate (65 breaths per minute), tachycardia (170 bpm), and low blood pressure (45/25 mmHg). His temperature is 36.2°C (97°F). Blood tests reveal leukopenia, neutropenia, thrombocytopenia, and a blood glucose level of 2.5 mmol/L (45 mg/dL). The pregnancy had been uneventful. However, the labour was complicated by a presumed premature rupture of membranes approximately 18 hours before the delivery, and a maternal temperature of 38°C (100.4°F) 3 hours before delivery. Group B streptococcal carriage had not been screened for, but antibiotic prophylaxis had been given 30 minutes before delivery.

Case history #2

A 72-year-old diabetic woman is admitted from a nursing home with a fever of 38.2°C (100.8°F), tachycardia (110 bpm), increased respiratory rate (24 breaths per minute), and mild confusion. Chest x-ray is unremarkable, and heart sounds are normal. The patient has had a recurrent urinary tract infection (UTI) over the last 12 months, but has had no recent urinary symptoms. The patient is started on antibiotics for a presumed chest infection. Twenty-four hours after admission, blood cultures are positive for group B streptococci, and microscopy reveals gram-positive cocci in chains.

Other presentations

Presentation depends on the patient group.

In neonates, the most common presentations are sepsis with unknown focus, meningitis, UTI, and pneumonia.

In infants and children, the most common presentations are sepsis with unknown focus, meningitis, pneumonia, septic arthritis, and peritonitis.[3]Phares CR, Lynfield R, Farley M, et al. Epidemiology of invasive group B streptococcal disease in the United States, 1999-2005. JAMA. 2008 May 7;299(17):2056-65. https://jama.ama-assn.org/cgi/content/full/299/17/2056 http://www.ncbi.nlm.nih.gov/pubmed/18460666?tool=bestpractice.com

In pregnant women, the most common presentations are UTI, chorioamnionitis, and postnatal sepsis. Endometritis and wound infection are postnatal manifestations. Spontaneous mid-gestation abortion and preterm labour may also occur.[4]McDonald HM, Chambers HM. Intrauterine infection and spontaneous midgestation abortion. Is the spectrum of microorganisms similar to that in preterm labour? Infect Dis Obstet Genecol. 2000;8(5-6):220-7. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1784699/pdf/11220481.pdf http://www.ncbi.nlm.nih.gov/pubmed/11220481?tool=bestpractice.com

In non-pregnant adults, sepsis with unknown focus, skin and soft-tissue infection, meningitis, and UTI are the most common manifestations. Less common presentations include septic arthritis, pneumonia, conjunctivitis, sinusitis, otitis media, and intra-abdominal infection.