ABSTRACT
Neisseria lactamica is a nonpathogenic commensal bacterium that is potentially associated with the development of natural immunity against N. meningitidis. However, the genetic variation present in natural populations of N. lactamica has not been fully investigated. To better understand its epidemiology and genetic variation, we studied N. lactamica carriage in 1200 students aged 11-19 years old in Salvador, Brazil. The carriage prevalence was 4.5% (54/1200), with no statistical difference among sex and age, although we observed a trend towards higher carriage prevalence among 11-year-old individuals. Whole genome sequence analysis revealed a high genetic diversity among the isolates, with the presence of 32 different STs, 28 (87.5%) of which were new. A total of 21/50 (42%) isolates belonged to three different clonal complexes. While none of the isolates contained nadA or fHpb alleles, we detected 21 FetA variants, 20 NhbA variants and two variants of PorB. The data provide detailed information on circulating N. lactamica isolates in adolescents in Brazil and are complementary to studies in other countries.
Subject(s)
Carrier State/epidemiology , Carrier State/microbiology , Meningococcal Infections/epidemiology , Meningococcal Infections/microbiology , Neisseria lactamica/genetics , Adolescent , Alleles , Bacterial Outer Membrane Proteins/genetics , Brazil/epidemiology , El Salvador/epidemiology , Female , Genotype , Humans , Male , Molecular Epidemiology , Neisseria lactamica/isolation & purification , Neisseria meningitidis/genetics , Polymorphism, Single Nucleotide , Porins/genetics , Students , Whole Genome Sequencing , Young AdultABSTRACT
Characterization of meningococci isolated from the pharynx is essential towards understanding the dynamics of meningococcal carriage and disease. Meningococcal isolates, collected from adolescents resident in Salvador, Brazil during 2014, were characterized by multilocus sequence typing, genotyping or whole-genome sequencing. Most were nongroupable (61.0%), followed by genogroups B (11.9%) and Y (8.5%). We identified 34 different sequence types (STs), eight were new STs, distributed among 14 clonal complexes (cc), cc1136 represented 20.3% of the nongroupable isolates. The porA and fetA genotypes included P1.18,25-37 (11.9%), P1.18-1,3 (10.2%); F5-5 (23.7%), F4-66 (16.9%) and F1-7 (13.6%). The porB class 3 protein and the fHbp subfamily A (variants 2 and 3) genotypes were found in 93.0 and 71.0% of the isolates, respectively. NHBA was present in all isolates, and while most lacked NadA (94.9%), we detected the hyperinvasive lineages B:P1.19,15:F5-1:ST-639 (cc32); C:P1.22,14-6:F3-9:ST-3780 (cc103) and W:P1.5,2:F1-1:ST-11 (cc11). This is the first report on the genetic diversity and vaccine antigen prevalence among N. meningitidis carriage isolates in the Northeast of Brazil. This study highlights the need for ongoing characterization of meningococcal isolates following the introduction of vaccines and for determining public health intervention strategies.
