BMC Seminar Thursday 7th of February at 12:00 in room 201 Læknagarður
Speaker: Sandra Berglind Tómasdóttir master student under supervision of dr. Gunnsteinn Haraldsson, Department of Clinical Microbiology, Landspítali University Hospital
Title: The epidemiology of Haemophilus influenzae in healthy carriers and infected following the introduction of Protein D conjugated vaccine in Iceland
Abstract: Haemophilus influenzae is a Gram-negative coccabacillus that is part of the normal flora in the respiratory tract of humans but can cause a variety of clinical symptoms. H.influenzae can express a capsule and six serotypes (a-f) have been identified. Strains without a capsule are called non-typeable H.influenzae (NTHi) and often cause respiratory infection in children, including middle ear infection and pneumonia. In 2011 a 10-valent conjugated pneumococcal vaccine (Synflorix) was introduced into Iceland’s routine childhood vaccination. The vaccine uses protein D (PD) derived from NTHi as a conjugate. PD is encoded by the hpd gene and is found in most H.influenzae. Antibiotic resistance because of modification in penicillin-binding proteins in H.influenzae has increased for the last decade. The aim of this study was to assess the epidemiology of H.influenzae before and after Synflorix vaccination. Nasopharyngeal samples were obtained from healthy children in daycare centers (n=2.840) (2009, 2012-2019). Clinical samples from the middle ear, lower respiratory tract (2012-2018) and invasive infection (1996-2018) (n=3.202) were also included in this study. PCR was used for H.influenzae identification with hpd primers, and fucK primers for hpd-negative strains. bexA primers were used for detection of capsule. All capsulated strains were then further serotyped. Antibiotic susceptibility was found with disk diffusion and E-tests. Part of the sample groups went through whole genome sequencing (WGS) (n=1.738). The H.influenzae susceptibility patterns from different samples were compared. The effect of Synflorix vaccination and the presence of PD on susceptibility were assessed and compared with WGS results.