Carriage of Neisseria lactamica in 1- to 29-Year-Old People in Burkina Faso: Epidemiology and Molecular Characterization

Neisseria lactamica is a true commensal bacterium occupying the same ecological niche as the pathogenicNeisseria meningitidis , which is responsible for outbreaks and large epidemics, especially in sub-Saharan Africa. To better understand the epidemiology ofN. lactamica in Africa and its relationship toN. meningitidis , we studiedN. lactamica carriage in 1- to 29-year-old people living in three districts of Burkina Faso from 2009 to 2011.N. lactamica was detected in 18.2% of 45,847 oropharyngeal samples. Carriage prevalence was highest among the 2-year-olds (40.1%) and decreased with age. Overall prevalence was higher for males (19.1%) than females (17.5%) (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.04 to 1.18), while among the 18- to 29-year-olds, carriage prevalence was significantly higher in women (9.1%) than in men (3.9%) (OR, 2.49; 95% CI, 1.94 to 3.19). Carriage prevalence ofN. lactamica was remarkably homogeneous in the three districts of Burkina Faso and stable over time, in comparison with carriage ofN. meningitidis (P. A. Kristiansen et al., Clin. Vaccine Immunol. 18:435–443, 2011). There was no significant seasonal variation ofN. lactamica carriage and no significant change in carriage prevalence after introduction of the serogroup A meningococcal conjugate vaccine, MenAfriVac. Multilocus sequence typing was performed on a selection of 142 isolates. The genetic diversity was high, as we identified 62 different genotypes, of which 56 were new. The epidemiology ofN. lactamica carriage and the molecular characteristics of carried isolates were similar to those reported from industrialized countries, in contrast to the particularities ofN. meningitidis carriage and disease epidemiology in Burkina Faso.