Haemophilus influenzae is an important pathogenic bacterium that colonizes the human respiratory tract. This bacterium may be surrounded by a capsule of sugars, an important virulence factor that divides H. influenzae strains into two groups, capsulated and non-capsulated. Within this second group, six serotypes (a-f) have been distinguished based on the composition of their sugars.
Fortunately, the introduction of the vaccine against serotype b, associated with meningitis in children, changed the epidemiology of this bacterium. However, with the virtual disappearance of serotype b, non-encapsulated H. influenzae are currently the main disease-associated agent, followed by encapsulated serotype f bacteria.
Recently, a study published in the journal Scientific Reports, carried out by the Bacterial Epidemiology research group at IDIBELL, Bellvitge Hospital, and CIBERES, has studied the diversity of genes present in clinical strains of H. influenzae serotype f.
All the serotype f isolates analyzed in this study belonged to a single clone with a low number of genetic variations and a high rate of stability of its genome, even more than other encapsulated serotypes. All the bacteria used came from an international multicentre study that includes IDIBELL and the Bellvitge University Hospital, and the reference centers for this bacterium in Portugal and the Netherlands.
Drs. Aida González and Sara Martí, project leaders, comment that “the genetic homogeneity of serotype f could explain its high clonal expansion. Although the capsulated strains of H. influenzae indeed have high genomic homogeneity as opposed to the non-capsulated ones, this difference could be due to the capsule itself, which could act as a physical barrier reducing recombination levels, or its lower presence as colonizers hindered the interaction with other microorganisms”.
The Bellvitge Biomedical Research Institute (IDIBELL) is a biomedical research center created in 2004. It is participated by the Bellvitge University Hospital and the Viladecans Hospital of the Catalan Institute of Health, the Catalan Institute of Oncology, the University of Barcelona and the City Council of L’Hospitalet de Llobregat.
IDIBELL is a member of the Campus of International Excellence of the University of Barcelona HUBc and is part of the CERCA institution of the Generalitat de Catalunya. In 2009 it became one of the first five Spanish research centers accredited as a health research institute by the Carlos III Health Institute. In addition, it is part of the “HR Excellence in Research” program of the European Union and is a member of EATRIS and REGIC. Since 2018, IDIBELL has been an Accredited Center of the AECC Scientific Foundation (FCAECC).