Serotype IV and invasive group B Streptococcus disease in neonates, Minnesota, USA, 2000-2010

Emerg Infect Dis. 2013 Apr;19(4):551-8. doi: 10.3201/eid1904.121572.


Group B Streptococcus (GBS) is a major cause of invasive disease in neonates in the United States. Surveillance of invasive GBS disease in Minnesota, USA, during 2000-2010 yielded 449 isolates from 449 infants; 257 had early-onset (EO) disease (by age 6 days) and 192 late-onset (LO) disease (180 at age 7-89 days, 12 at age 90-180 days). Isolates were characterized by capsular polysaccharide serotype and surface-protein profile; types III and Ia predominated. However, because previously uncommon serotype IV constitutes 5/31 EO isolates in 2010, twelve type IV isolates collected during 2000-2010 were studied further. By pulsed-field gel electrophoresis, they were classified into 3 profiles; by multilocus sequence typing, representative isolates included new sequence type 468. Resistance to clindamycin or erythromycin was detected in 4/5 serotype IV isolates. Emergence of serotype IV GBS in Minnesota highlights the need for serotype prevalence monitoring to detect trends that could affect prevention strategies.

Keywords: CPS; GBS; Minnesota; United States; antimicrobial resistance; bacteria; capsular polysaccharide; clindamycin resistance; early-onset GBS disease; group B Streptococcus; invasive GBS disease; late-onset GBS disease; neonatal GBS disease; neonates; prophylaxis; serotype; serotype IV; streptococci.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anti-Bacterial Agents / therapeutic use
  • Clindamycin / therapeutic use
  • DNA, Bacterial / blood
  • DNA, Bacterial / classification
  • DNA, Bacterial / genetics*
  • Drug Resistance, Bacterial
  • Electrophoresis, Gel, Pulsed-Field
  • Erythromycin / therapeutic use
  • Genotype
  • Humans
  • Infant
  • Infant, Newborn
  • Minnesota / epidemiology
  • Multilocus Sequence Typing
  • Retrospective Studies
  • Serotyping
  • Streptococcal Infections / blood
  • Streptococcal Infections / drug therapy
  • Streptococcal Infections / epidemiology
  • Streptococcal Infections / microbiology*
  • Streptococcus agalactiae / classification
  • Streptococcus agalactiae / drug effects
  • Streptococcus agalactiae / genetics*
  • Streptococcus agalactiae / isolation & purification


  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Clindamycin
  • Erythromycin