Genomic characterization of novel Neisseria species
Diallo K., MacLennan J., Harrison OB., Msefula C., Sow SO., Daugla DM., Johnson E., Trotter C., MacLennan CA., Parkhill J., Borrow R., Greenwood BM., Maiden MCJ.
AbstractOf the ten human-restrictedNeisseriaspecies two,Neisseria meningitidis, andNeisseria gonorrhoeae, cause invasive disease: the other eight are carried asymptomatically in the pharynx, possibly modulating meningococcal and gonococcal infections. Consequently, characterizing their diversity is important for understanding the microbiome in health and disease. Whole genome sequences from 181Neisseriaisolates were examined, including those of three well-defined species (N. meningitidis; N. gonorrhoeae;andNeisseria polysaccharea) and genomes of isolates unassigned to any species (Nspp). Sequence analysis of ribosomal genes, and a set of core (cgMLST) genes were used to infer phylogenetic relationships. Average Nucleotide Identity (ANI) and phenotypic data were used to define species clusters, and morphological and metabolic differences among them. Phylogenetic analyses identified two polyphyletic clusters (N. polysacchareaandNspp.), while, cgMLST data groupedNsppisolates into nine clusters and identified at least threeN. polysacchareaclusters. ANI results classifiedNsppinto seven putative species, and also indicated at least three putativeN. polysacchareaspecies. Electron microscopy identified morphological differences among these species. This genomic approach provided a consistent methodology for species characterization using distinct phylogenetic clusters. Seven putative novelNeisseriaspecies were identified, confirming the importance of genomic studies in the characterization of the genusNeisseria.