Author(s): Gonzalez-Diaz, Aida ; Carrera-Salinas, Anna ; Pinto, Miguel ; Cubero, Meritxell ; van der Ende, Arie ; Langereis, Jeroen D. ; Domínguez, M. Ángeles ; Ardanuy, Carmen ; Bajanca-Lavado, Paula ; Marti, Sara
Date: 2022
Persistent ID: http://hdl.handle.net/10400.18/8373
Origin: Repositório Científico do Instituto Nacional de Saúde
Subject(s): Haemophilus influenzae; Genetic Diversity; Serotype f; Multi-locus Sequence Type; Serotyping; Whole Genome Sequencing; Infecções Respiratórias
Haemophilus influenzae is an opportunistic pathogen adapted to the human respiratory tract. Non-typeable H. influenzae are highly heterogeneous, but few studies have analysed the genomic variability of capsulated strains. This study aims to examine the genetic diversity of 37 serotype f isolates from the Netherlands, Portugal, and Spain, and to compare all capsulated genomes available on public databases. Serotype f isolates belonged to CC124 and shared few single nucleotide polymorphisms (SNPs) (n = 10,999), but a high core genome (> 80%). Three main clades were identified by the presence of 75, 60 and 41 exclusive genes for each clade, respectively. Multi-locus sequence type analysis of all capsulated genomes revealed a reduced number of clonal complexes associated with each serotype. Pangenome analysis showed a large pool of genes (n = 6360), many of which were accessory genome (n = 5323). Phylogenetic analysis revealed that serotypes a, b, and f had greater diversity. The total number of SNPs in serotype f was significantly lower than in serotypes a, b, and e (p < 0.0001), indicating low variability within the serotype f clonal complexes. Capsulated H. influenzae are genetically homogeneous, with few lineages in each serotype. Serotype f has high genetic stability regardless of time and country of isolation.
