National Genomic Surveillance of Haemophilus influenzae: Monitoring Antimicrobial Resistance and Molecular Epidemiology through Whole Genome Sequencing

The Swedish Public Health Agency (Folkhälsomyndigheten) conducts a national microbial surveillance program targeting invasive Haemophilus influenzae (Hi) infections, with a particular focus on Haemophilus influenzae type b (Hib). This program aims to monitor the effectiveness of the Hib vaccination within the national childhood immunization schedule, detect potential vaccine breakthroughs, and observe changes in antimicrobial resistance patterns and virulence factors.? The surveillance encompasses invasive isolates collected from children under five years of age. These isolates undergo whole genome sequencing (WGS) to facilitate molecular serotyping, multilocus sequence typing (MLST), and the identification of resistance genes and mutations. This genomic approach enables the detection of emerging strains with altered transmissibility or virulence and provides insights into the molecular epidemiology of invasive Hi infections.? By integrating WGS into routine surveillance, the program enhances the capacity for early detection of outbreaks, informs public health interventions, and contributes to the global understanding of Hi epidemiology and resistance trends. The findings support evidence-based updates to vaccination strategies and antimicrobial stewardship policies, ensuring continued protection against invasive Hi diseases.