Group B Streptococcal Infections

Abstract

1. Laura Sass, MD* 1. *Division of Infectious Diseases, Children's Specialty Group, Children's Hospital of The King's Daughters, Norfolk, VA; Pediatrics, Eastern Virginia Medical School, Norfolk, VA. * Abbreviations: CDC: : Centers for Disease Control and Prevention CPS: : capsular polysaccharides CSF: : cerebrospinal fluid EOD: : early onset disease GBS: : group B Streptococcus IAP: : intrapartum antibiotic prophylaxis NAAT: : nucleic acid amplification test UTI: : urinary tract infection In 2010, revised guidelines were published with updated algorithms for group B Streptococcus screening, intrapartum prophylaxis, antibiotic doses, and revised management for newborns. After completing this article, readers should be able to: 1. Know the mode of transmission of group B Streptococcus (GBS) and the peripartum risk factors associated with a high risk of infection. 2. Know the major clinical manifestations of GBS and be able to differentiate the epidemiology and clinical presentation of early onset GBS disease from that of late-onset disease. 3. Know the laboratory testing for GBS: isolation, antigen detection, and susceptibility tests. 4. Know the treatment of GBS infections: drugs of choice, alternative drugs, and ineffective drugs. 5. Review the most recent guidelines for the prevention of perinatal GBS disease. 1. Understand the importance of maternal screening tests for GBS. 2. Know the criteria for the treatment of mothers known to be GBS carriers at the time of delivery. 3. Differentiate the prevention of early onset disease from that of late onset. Group B Streptococcus (GBS), or Streptococcus agalactiae , is an encapsulated gram-positive diplococcus that produces a narrow zone of β-hemolysis on blood agar and generally is resistant to bacitracin. GBS can be further differentiated by type-specific capsular polysaccharides (CPS) and protein antigens. Current circulating serotypes include Ia, Ib, Ia/c, II, III, IV, V, VI, VII, VIII, and IX. GBS initially was believed to be a bovine mastitis pathogen, but cases of puerperal sepsis in humans were described in the 1930s. The organism then became more prominent in the 1970s as a cause of maternal and neonatal disease. The most common maternal manifestations are asymptomatic bacteriuria, urinary tract infection (UTI), bacteremia, chorioamnionitis, and endometritis. In …