title: Group B streptococcal colonization and transmission dynamics in pregnant women and their newborns in Nigeria: implications for prevention strategies.
abstract: OBJECTIVE
  Because few studies have been conducted on group B Streptococcus (GBS) in Nigeria, we sought to estimate GBS colonization and transmission frequencies for 500 women and their newborns and identify risk factors for both outcomes.
  
  
  METHODS
  GBS strains were characterized for antibiotic susceptibilities, capsule (cps) genotype, pilus island profile and multilocus sequence type (ST).
  
  
  RESULTS
  In all, 171 (34.2%) mothers and 95 (19.0%) of their newborns were colonized with GBS; the vertical transmission rate was 48.5%. One newborn developed early-onset disease, yielding an incidence of 2.0 cases per 1000 live births (95% CI 0.50-7.30). Rectal maternal colonization (OR 26.6; 95% CI 13.69-51.58) and prolonged rupture of membranes (OR 4.2; 95% CI 1.03-17.17) were associated with neonatal colonization, whereas prolonged membrane rupture (OR 3.4; 95% CI 1.04-11.39) and young maternal age (OR 2.0; 95% CI 1.22-3.39) were associated with maternal colonization. Women reporting four or more intrapartum vaginal examinations (OR 6.1; 95% CI 3.41-10.93) and douching (OR 3.7; 95% CI 2.26-6.11) were also more likely to be colonized. Twelve STs were identified among 35 mother-baby pairs with evidence of transmission; strains of cpsV ST-19 (n = 9; 25.7%) and cpsIII ST-182 (n = 7; 20.0%) predominated.
  
  
  CONCLUSIONS
  These data demonstrate high rates of colonization and transmission in a population that does not use antibiotics to prevent neonatal infections, a strategy that should be considered in the future.
authors.affiliation: Department of Medical Microbiology and Parasitology, National Hospital Abuja, Abuja, Nigeria.
authors.forename: N
authors.initials: N
authors.lastname: Medugu
authors.affiliation: Department of Medical Microbiology and Parasitology, National Hospital Abuja, Abuja, Nigeria.
authors.forename: K C
authors.initials: KC
authors.lastname: Iregbu
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Parker
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
authors.forename: J
authors.initials: J
authors.lastname: Plemmons
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA.
authors.forename: P
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Paediatrics, National Hospital Abuja, Abuja, Nigeria.
authors.forename: L I
authors.initials: LI
authors.lastname: Audu
authors.affiliation: Department of Obstetrics and Gynaecology, National Hospital Abuja, Abuja, Nigeria.
authors.forename: E
authors.initials: E
authors.lastname: Efetie
authors.affiliation: Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: H D
authors.initials: HD
authors.lastname: Davies
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA. Electronic address: mannin71@msu.edu.
authors.forename: S D
authors.initials: SD
authors.lastname: Manning
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control / Q000706:statistics & numerical data*; D008137:Longitudinal Studies; D008875:Middle Aged; D017720:Molecular Epidemiology; D009549:Nigeria / Q000453:epidemiology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000517:prevention & control; D012307:Risk Factors; D018805:Sepsis; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D013292:Streptococcus agalactiae; D055815:Young Adult
keywords: Colonization; Molecular epidemiology; Neonatal disease; Risk factors; Sepsis; Streptococcus agalactiae