Burden of invasive group B Streptococcus disease and early neurological sequelae in South African infants

PLoS One. 2015 Apr 7;10(4):e0123014. doi: 10.1371/journal.pone.0123014. eCollection 2015.

Abstract

Introduction: Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and meningitis. We aimed to evaluate the burden of invasive early-onset (0-6 days of life, EOD) and late-onset (7-89 days, LOD) GBS disease and subsequent neurological sequelae in infants from a setting with a high prevalence (29.5%) of HIV among pregnant women.

Methods: A case-control study was undertaken at three secondary-tertiary care public hospitals in Johannesburg. Invasive cases in infants <3 months age were identified by surveillance of laboratories from November 2012 to February 2014. Neurodevelopmental screening was done in surviving cases and controls at 3 and 6 months of age.

Results: We identified 122 cases of invasive GBS disease over a 12 month period. Although the incidence (per 1,000 live births) of EOD was similar between HIV-exposed and HIV-unexposed infants (1.13 vs. 1.46; p = 0.487), there was a 4.67-fold (95%CI: 2.24-9.74) greater risk for LOD in HIV-exposed infants (2.27 vs. 0.49; p<0.001). Overall, serotypes Ia, Ib and III constituted 75.8% and 92.5% of EOD and LOD, respectively. Risk factors for EOD included offensive draining liquor (adjusted Odds Ratio: 27.37; 95%CI: 1.94-386.50) and maternal GBS bacteriuria (aOR: 8.41; 95%CI: 1.44-49.15), which was also a risk-factor for LOD (aOR: 3.49; 95%CI: 1.17-10.40). The overall case fatality rate among cases was 18.0%. The adjusted odds for neurological sequelae at 6 months age was 13.18-fold (95%CI: 1.44-120.95) greater in cases (13.2%) than controls (0.4%).

Discussion: The high burden of invasive GBS disease in South Africa, which is also associated with high case fatality rates and significant neurological sequelae among survivors, is partly due to the heightened risk for LOD in infants born to HIV-infected women. An effective trivalent GBS conjugate vaccine targeted at pregnant women could prevent invasive GBS disease in this setting.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Black People
  • Case-Control Studies
  • Child, Preschool
  • Female
  • HIV / pathogenicity
  • HIV Infections / complications*
  • HIV Infections / epidemiology
  • HIV Infections / immunology
  • Humans
  • Incidence
  • Infant
  • Infant, Newborn
  • Infant, Newborn, Diseases / etiology*
  • Male
  • Nervous System Diseases / epidemiology
  • Nervous System Diseases / etiology*
  • Population Surveillance
  • Pregnancy
  • Prospective Studies
  • Risk Factors
  • South Africa / epidemiology
  • Streptococcal Infections / complications*
  • Streptococcal Infections / epidemiology
  • Streptococcal Infections / immunology
  • Streptococcus agalactiae / immunology
  • Streptococcus agalactiae / pathogenicity*

Grants and funding

ZD is funded in part by the Carnegie Corporation (Grant number B8749) of New York and the Discovery Foundation (Grant number 20289/1). SGL is funded in part by a career development award from the Medical Research Council of South Africa. SAM is funded in part by National Research Foundation/Department of Science and Technology: South African Research Chair Initiative in Vaccine Preventable Diseases and Medical Research Council of South Africa. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.