A. Characteristics

1. Serology
   1. Encapsulated organism
   2. Five major serotypes
   3. Serotype III associated with neonatal infection
   4. Serotype Ia/c, Ia, or nontypable in non-pregnant adults
2. Disease Spectrum
   1. Major cause of sepsis and meningitis in newborn infants in USA
   2. Pregnancy-related morbidity and mortality including prematurity, death [1]
   3. Necrotizing Fasciitis [7]
   4. Streptococcal toxic shock-like syndrome [7]
   5. Incidence has been increasing in non-pregnant adults, up to 68% of cases
   6. Up to 20% of cases in adults appear to be nosocomial (including bacteremia)
   7. Increasing incidence mainly in older adults with comorbid conditions [5]
3. Risk Factors [5]
   1. Age >60 years - incidence increasing
   2. Diabetes mellitus
   3. Malignancy, especially breast cancer
   4. Major systems chronic disease: cirrhosis, heart failure
   5. Decubitus ulcer, stroke, neurogenic bladder
   6. HIV

B. Symptoms

1. Rash may be first manifestation
2. Skin, soft tissue, bone infections are common in non-pregnant adults
3. Bacteremia without obvious focus, is most common in several studies [4,5]
4. Urosepsis, pneumonia, endocarditis, and peritonitis may also occur
5. Most common cause of meningitis in neonates <1 month of age [6]
6. Recurrence is ~4% in one year [8]
7. May be asymptomatic carrier

C. Diagnosis

1. Critical to diagnose carrier state or early infection in pregnant women (at delivery)
2. Culture requires ~36 hours
3. New polymerase chain reaction (PCR) test provides results in 30-45 minutes [10]

D. Treatment [11]

1. All pregnant women should be tested [3]
   1. Patients testing positive tests should receive prophylaxis
   2. Antibiotic prophylaxis for group B strep infections in pregnancy reduced disease [3,9]
2. The incidence in pregnant women has declined 21% over 6 years with prophylaxis
3. Antibiotic Treatment
   1. Intravenous or intramuscular antibiotics prior to onset of labor or rupture of membranes
   2. Nearly all strains are sensitive to penicillin, but susceptibility testing should be done
   3. Ampicillin is often used
   4. In penicillin allergic patients, vancomycin, erythromycin, or cephalosporin is used
   5. Cephalosporins are generally active, but macrolide resistance is increasing [5]
4. Mortality may be as high as ~20%
5. Group B Streptococcal polysaccharide vaccine is in Phase II Clinical Trials

References

1. Gibbs RS and Roberts DJ. 2007. NEJM. 357(9):918 (Case Record)
2. Schuchat A. 1999. Lancet. 352(9146):51
3. Schrag SJ, Zell ER, Lynfield R, et al. 2002. NEJM. 347(4):233
4. Jackson LA, Hilsdon R, Farley MM, et al. 1995. Ann Intern Med. 123(6):415
5. Munoz P, Llancuaqueo A, Rodriguez-Creixems M, et al. 1997. Arch Intern Med. 157(2):213
6. Schuchat A, Robinson K, Wenger JD, et al. 1997. NEJM. 337(14):970
7. Gardam MA, Low DE, Saginur R, Miller MA. 1998. Arch Intern Med. 158(14):1704
8. Harrison LH, Ali A, Dwyer DM, et al. 1995. Ann Intern Med. 123(6):421
9. Schrag SJ, Zywicki S, Farley MM, et al. 2000. NEJM. 342(1):15
10. Bergeron MG, Ke D, Menard C, et al. 2000. NEJM. 343(3):175
11. Choice of Antibacterial Drugs. 2001. Med Let. 43(1111):69