title: Interrelationship of Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus colonization within and between pneumococcal-vaccine naïve mother-child dyads.
abstract: BACKGROUND
  A high prevalence of bacterial nasopharyngeal co-infections has been reported in children, however, such data is limited in adults. We examined the interaction of Haemophilus influenzae, Staphylococcus aureus and Streptococcus pneumoniae pharyngeal colonization in mother-child dyads.
  
  
  METHODS
  Pneumococcal-vaccine naïve children and their mothers had pharyngeal swabs undertaken at 1.6, 2.5, 3.5, 4.5, 7.4, 9.5, 12.5, 16.2 and 24.2 months of child's age. Swabs were cultured for S. pneumoniae, H. influenzae and S. aureus using standard microbiologic methods. Multivariate generalized estimating equation-models were used to explore the associations of the three bacteria within and between children and their mothers.
  
  
  RESULTS
  In children, the observed probability of co-colonization was higher than expected. Well-defined associations in colonization between the bacteria were observed in children but not among mothers. In children, a synergistic association was observed between S. pneumoniae and H. influenzae (Adjusted odds ratio (AOR): 1.75, 95% CI: 1.32-2.32) and a negative association between S. pneumoniae and S. aureus (AOR: 0.51, 95% CI: 0.39-0.67) or H. influenzae and S. aureus (AOR: 0.24, 95% CI: 0.16-0.34) colonization. Additionally, all three bacteria had a higher likelihood of concurrent colonization. There was a strong association in colonization by the bacteria in children and their mothers, including increased likelihood of maternal colonization if the child was colonized by S. pneumoniae (AOR: 1.84, 95% CI: 1.28-2.63) and H. influenzae (AOR: 6.34, 95% CI: 2.24-18.0).
  
  
  CONCLUSIONS
  The effects of immunization of children with pneumococcal-conjugate-vaccine in settings such as ours needs monitoring with regard to potential changes of pharyngeal bacterial ecology which could occur in vaccinated and -unvaccinated age-groups.
authors.forename: Tinevimbo
authors.initials: T
authors.lastname: Shiri
authors.forename: Marta C
authors.initials: MC
authors.lastname: Nunes
authors.forename: Peter V
authors.initials: PV
authors.lastname: Adrian
authors.forename: Nadia
authors.initials: N
authors.lastname: Van Niekerk
authors.forename: Keith P
authors.initials: KP
authors.lastname: Klugman
authors.affiliation: Department of Science and Technology/National Research Foundation, Vaccine Preventable Diseases, University of the Witwatersrand, Johannesburg, South Africa. shabirm@nicd.ac.za.
authors.forename: Shabir A
authors.initials: SA
authors.lastname: Madhi
mesh_terms: D000328:Adult; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology*; D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006193:Haemophilus influenzae / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D008297:Male; D009035:Mothers / Q000706:statistics & numerical data; D009305:Nasopharynx / Q000382:microbiology*; D013019:South Africa / Q000453:epidemiology; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*